osh/cmd_parse.py

OILS / osh / cmd_parse.py View on Github | oilshell.org

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1	# Copyright 2016 Andy Chu. All rights reserved.
2	# Licensed under the Apache License, Version 2.0 (the "License");
3	# you may not use this file except in compliance with the License.
4	# You may obtain a copy of the License at
5	#
6	# http://www.apache.org/licenses/LICENSE-2.0
7	"""
8	cmd_parse.py - Parse high level shell commands.
9	"""
10	from __future__ import print_function
11
12	from _devbuild.gen import grammar_nt
13	from _devbuild.gen.id_kind_asdl import Id, Id_t, Id_str, Kind, Kind_str
14	from _devbuild.gen.types_asdl import lex_mode_e, cmd_mode_e, cmd_mode_t
15	from _devbuild.gen.syntax_asdl import (
16	loc,
17	SourceLine,
18	source,
19	parse_result,
20	parse_result_t,
21	command,
22	command_t,
23	condition,
24	condition_t,
25	for_iter,
26	ArgList,
27	BraceGroup,
28	LiteralBlock,
29	CaseArm,
30	case_arg,
31	IfArm,
32	pat,
33	pat_t,
34	Redir,
35	redir_param,
36	redir_loc,
37	redir_loc_t,
38	word_e,
39	word_t,
40	CompoundWord,
41	Token,
42	word_part_e,
43	word_part_t,
44	rhs_word,
45	rhs_word_t,
46	sh_lhs,
47	sh_lhs_t,
48	AssignPair,
49	EnvPair,
50	ParsedAssignment,
51	assign_op_e,
52	NameType,
53	proc_sig,
54	proc_sig_e,
55	Proc,
56	Func,
57	)
58	from core import alloc
59	from core import error
60	from core.error import p_die
61	from display import ui
62	from frontend import consts
63	from frontend import lexer
64	from frontend import location
65	from frontend import match
66	from frontend import reader
67	from mycpp.mylib import log
68	from osh import braces
69	from osh import bool_parse
70	from osh import word_
71
72	from typing import Optional, List, Dict, Any, Tuple, cast, TYPE_CHECKING
73	if TYPE_CHECKING:
74	from core.alloc import Arena
75	from core import optview
76	from frontend.lexer import Lexer
77	from frontend.parse_lib import ParseContext, AliasesInFlight
78	from frontend.reader import _Reader
79	from osh.word_parse import WordParser
80
81	_ = Kind_str # for debug prints
82
83	TAB_CH = 9 # ord('\t')
84	SPACE_CH = 32 # ord(' ')
85
86
87	def _ReadHereLines(
88	line_reader, # type: _Reader
89	h, # type: Redir
90	delimiter, # type: str
91	):
92	# type: (...) -> Tuple[List[Tuple[SourceLine, int]], Tuple[SourceLine, int]]
93	# NOTE: We read all lines at once, instead of parsing line-by-line,
94	# because of cases like this:
95	# cat <<EOF
96	# 1 $(echo 2
97	# echo 3) 4
98	# EOF
99	here_lines = [] # type: List[Tuple[SourceLine, int]]
100	last_line = None # type: Tuple[SourceLine, int]
101	strip_leading_tabs = (h.op.id == Id.Redir_DLessDash)
102
103	while True:
104	src_line, unused_offset = line_reader.GetLine()
105
106	if src_line is None: # EOF
107	# An unterminated here doc is just a warning in bash. We make it
108	# fatal because we want to be strict, and because it causes problems
109	# reporting other errors.
110	# Attribute it to the << in <<EOF for now.
111	p_die("Couldn't find terminator for here doc that starts here",
112	h.op)
113
114	assert len(src_line.content) != 0 # None should be the empty line
115
116	line = src_line.content
117
118	# If op is <<-, strip off ALL leading tabs -- not spaces, and not just
119	# the first tab.
120	start_offset = 0
121	if strip_leading_tabs:
122	n = len(line)
123	i = 0 # used after loop exit
124	while i < n:
125	if line[i] != '\t':
126	break
127	i += 1
128	start_offset = i
129
130	if line[start_offset:].rstrip() == delimiter:
131	last_line = (src_line, start_offset)
132	break
133
134	here_lines.append((src_line, start_offset))
135
136	return here_lines, last_line
137
138
139	def _MakeLiteralHereLines(
140	here_lines, # type: List[Tuple[SourceLine, int]]
141	arena, # type: Arena
142	do_lossless, # type: bool
143	):
144	# type: (...) -> List[word_part_t]
145	"""Create a Token for each line.
146
147	For <<'EOF' and <<-'EOF' - single quoted rule
148
149	<<- has non-zero start_offset
150	"""
151	# less precise type, because List[T] is an invariant type
152	tokens = [] # type: List[word_part_t]
153	for src_line, start_offset in here_lines:
154
155	# Maintain lossless invariant for STRIPPED tabs: add a Token to the
156	# arena invariant, but don't refer to it.
157	#
158	# Note: We could use Lit_CharsWithoutPrefix for 'single quoted' EOF
159	# here docs, but it's more complex with double quoted EOF docs.
160
161	if do_lossless: # avoid garbage, doesn't affect correctness
162	arena.NewToken(Id.Lit_CharsWithoutPrefix, start_offset, 0,
163	src_line)
164
165	t = arena.NewToken(Id.Lit_Chars, start_offset, len(src_line.content),
166	src_line)
167	tokens.append(t)
168	return tokens
169
170
171	def _ParseHereDocBody(parse_ctx, r, line_reader, arena):
172	# type: (ParseContext, Redir, _Reader, Arena) -> None
173	"""Fill in attributes of a pending here doc node."""
174	h = cast(redir_param.HereDoc, r.arg)
175	# "If any character in word is quoted, the delimiter shall be formed by
176	# performing quote removal on word, and the here-document lines shall not
177	# be expanded. Otherwise, the delimiter shall be the word itself."
178	# NOTE: \EOF counts, or even E\OF
179	ok, delimiter, delim_quoted = word_.StaticEval(h.here_begin)
180	if not ok:
181	p_die('Invalid here doc delimiter', loc.Word(h.here_begin))
182
183	here_lines, last_line = _ReadHereLines(line_reader, r, delimiter)
184
185	if delim_quoted:
186	# <<'EOF' and <<-'EOF' - Literal for each line.
187	h.stdin_parts = _MakeLiteralHereLines(here_lines, arena,
188	parse_ctx.do_lossless)
189	else:
190	# <<EOF and <<-EOF - Parse as word
191	line_reader = reader.VirtualLineReader(arena, here_lines,
192	parse_ctx.do_lossless)
193	w_parser = parse_ctx.MakeWordParserForHereDoc(line_reader)
194	w_parser.ReadHereDocBody(h.stdin_parts) # fills this in
195
196	end_line, start_offset = last_line
197
198	# Maintain lossless invariant for STRIPPED tabs: add a Token to the
199	# arena invariant, but don't refer to it.
200	if parse_ctx.do_lossless: # avoid garbage, doesn't affect correctness
201	arena.NewToken(Id.Lit_CharsWithoutPrefix, start_offset, 0, end_line)
202
203	# Create a Token with the end terminator. Maintains the invariant that the
204	# tokens "add up".
205	h.here_end_tok = arena.NewToken(Id.Undefined_Tok, start_offset,
206	len(end_line.content), end_line)
207
208
209	def _MakeAssignPair(parse_ctx, preparsed, arena):
210	# type: (ParseContext, ParsedAssignment, Arena) -> AssignPair
211	"""Create an AssignPair from a 4-tuples from DetectShAssignment."""
212
213	left_token = preparsed.left
214	close_token = preparsed.close
215
216	lhs = None # type: sh_lhs_t
217
218	if left_token.id == Id.Lit_VarLike: # s=1
219	if lexer.IsPlusEquals(left_token):
220	var_name = lexer.TokenSliceRight(left_token, -2)
221	op = assign_op_e.PlusEqual
222	else:
223	var_name = lexer.TokenSliceRight(left_token, -1)
224	op = assign_op_e.Equal
225
226	lhs = sh_lhs.Name(left_token, var_name)
227
228	elif left_token.id == Id.Lit_ArrayLhsOpen and parse_ctx.do_lossless:
229	var_name = lexer.TokenSliceRight(left_token, -1)
230	if lexer.IsPlusEquals(close_token):
231	op = assign_op_e.PlusEqual
232	else:
233	op = assign_op_e.Equal
234
235	assert left_token.line == close_token.line, \
236	'%s and %s not on same line' % (left_token, close_token)
237
238	left_pos = left_token.col + left_token.length
239	index_str = left_token.line.content[left_pos:close_token.col]
240	lhs = sh_lhs.UnparsedIndex(left_token, var_name, index_str)
241
242	elif left_token.id == Id.Lit_ArrayLhsOpen: # a[x++]=1
243	var_name = lexer.TokenSliceRight(left_token, -1)
244	if lexer.IsPlusEquals(close_token):
245	op = assign_op_e.PlusEqual
246	else:
247	op = assign_op_e.Equal
248
249	# Similar to SnipCodeString / SnipCodeBlock
250	if left_token.line == close_token.line:
251	# extract what's between brackets
252	s = left_token.col + left_token.length
253	code_str = left_token.line.content[s:close_token.col]
254	else:
255	raise NotImplementedError('%s != %s' %
256	(left_token.line, close_token.line))
257	a_parser = parse_ctx.MakeArithParser(code_str)
258
259	# a[i+1]= is a LHS
260	src = source.Reparsed('array LHS', left_token, close_token)
261	with alloc.ctx_SourceCode(arena, src):
262	index_node = a_parser.Parse() # may raise error.Parse
263
264	lhs = sh_lhs.IndexedName(left_token, var_name, index_node)
265
266	else:
267	raise AssertionError()
268
269	# TODO: Should we also create a rhs_expr.ArrayLiteral here?
270	parts = preparsed.w.parts
271	offset = preparsed.part_offset
272
273	n = len(parts)
274	if offset == n:
275	rhs = rhs_word.Empty # type: rhs_word_t
276	else:
277	w = CompoundWord(parts[offset:])
278	word_.TildeDetectAssign(w)
279	rhs = w
280
281	return AssignPair(left_token, lhs, op, rhs)
282
283
284	def _AppendMoreEnv(preparsed_list, more_env):
285	# type: (List[ParsedAssignment], List[EnvPair]) -> None
286	"""Helper to modify a SimpleCommand node.
287
288	Args:
289	preparsed: a list of 4-tuples from DetectShAssignment
290	more_env: a list to append env_pairs to
291	"""
292	for preparsed in preparsed_list:
293	left_token = preparsed.left
294
295	if left_token.id != Id.Lit_VarLike: # can't be a[x]=1
296	p_die(
297	"Environment binding shouldn't look like an array assignment",
298	left_token)
299
300	if lexer.IsPlusEquals(left_token):
301	p_die('Expected = in environment binding, got +=', left_token)
302
303	var_name = lexer.TokenSliceRight(left_token, -1)
304
305	parts = preparsed.w.parts
306	n = len(parts)
307	offset = preparsed.part_offset
308	if offset == n:
309	rhs = rhs_word.Empty # type: rhs_word_t
310	else:
311	w = CompoundWord(parts[offset:])
312	word_.TildeDetectAssign(w)
313	rhs = w
314
315	more_env.append(EnvPair(left_token, var_name, rhs))
316
317
318	def _SplitSimpleCommandPrefix(words):
319	# type: (List[CompoundWord]) -> Tuple[List[ParsedAssignment], List[CompoundWord]]
320	"""Second pass of SimpleCommand parsing: look for assignment words."""
321	preparsed_list = [] # type: List[ParsedAssignment]
322	suffix_words = [] # type: List[CompoundWord]
323
324	done_prefix = False
325	for w in words:
326	if done_prefix:
327	suffix_words.append(w)
328	continue
329
330	left_token, close_token, part_offset = word_.DetectShAssignment(w)
331	if left_token:
332	preparsed_list.append(
333	ParsedAssignment(left_token, close_token, part_offset, w))
334	else:
335	done_prefix = True
336	suffix_words.append(w)
337
338	return preparsed_list, suffix_words
339
340
341	def _MakeSimpleCommand(
342	preparsed_list, # type: List[ParsedAssignment]
343	suffix_words, # type: List[CompoundWord]
344	typed_args, # type: Optional[ArgList]
345	block, # type: Optional[LiteralBlock]
346	):
347	# type: (...) -> command.Simple
348	"""Create a command.Simple"""
349
350	# FOO=(1 2 3) ls is not allowed.
351	for preparsed in preparsed_list:
352	if word_.HasArrayPart(preparsed.w):
353	p_die("Environment bindings can't contain array literals",
354	loc.Word(preparsed.w))
355
356	# NOTE: It would be possible to add this check back. But it already happens
357	# at runtime in EvalWordSequence2.
358	# echo FOO=(1 2 3) is not allowed (but we should NOT fail on echo FOO[x]=1).
359	if 0:
360	for w in suffix_words:
361	if word_.HasArrayPart(w):
362	p_die("Commands can't contain array literals", loc.Word(w))
363
364	assert len(suffix_words) != 0
365	# {a,b,c} # Use { before brace detection
366	# ~/bin/ls # Use ~ before tilde detection
367	part0 = suffix_words[0].parts[0]
368	blame_tok = location.LeftTokenForWordPart(part0)
369
370	# NOTE: We only do brace DETECTION here, not brace EXPANSION. Therefore we
371	# can't implement bash's behavior of having say {~bob,~jane}/src work,
372	# because we only have a BracedTree.
373	# This is documented in spec/brace-expansion.
374	# NOTE: Technically we could do expansion outside of 'oshc translate', but it
375	# doesn't seem worth it.
376	words2 = braces.BraceDetectAll(suffix_words)
377	words3 = word_.TildeDetectAll(words2)
378
379	more_env = [] # type: List[EnvPair]
380	_AppendMoreEnv(preparsed_list, more_env)
381
382	# do_fork by default
383	return command.Simple(blame_tok, more_env, words3, typed_args, block, True)
384
385
386	class VarChecker(object):
387	"""Statically check for proc and variable usage errors."""
388
389	def __init__(self):
390	# type: () -> None
391	"""
392	Args:
393	oil_proc: Whether to disallow nested proc/function declarations
394	"""
395	# self.tokens for location info: 'proc' or another token
396	self.tokens = [] # type: List[Token]
397	self.names = [] # type: List[Dict[str, Id_t]]
398
399	def Push(self, blame_tok):
400	# type: (Token) -> None
401	"""Called when we enter a shell function, proc, or func.
402
403	Bash allows this, but it's confusing because it's the same as two
404	functions at the top level.
405
406	f() {
407	g() {
408	echo 'top level function defined in another one'
409	}
410	}
411
412	YSH disallows nested procs and funcs.
413	"""
414	if len(self.tokens) != 0:
415	if blame_tok.id == Id.KW_Proc:
416	p_die("procs must be defined at the top level", blame_tok)
417	if blame_tok.id == Id.KW_Func:
418	p_die("funcs must be defined at the top level", blame_tok)
419	if self.tokens[0].id in (Id.KW_Proc, Id.KW_Func):
420	p_die("shell functions can't be defined inside proc or func",
421	blame_tok)
422
423	self.tokens.append(blame_tok)
424	entry = {} # type: Dict[str, Id_t]
425	self.names.append(entry)
426
427	def Pop(self):
428	# type: () -> None
429	self.names.pop()
430	self.tokens.pop()
431
432	def Check(self, keyword_id, var_name, blame_tok):
433	# type: (Id_t, str, Token) -> None
434	"""Check for declaration / mutation errors in proc and func.
435
436	var x
437	x already declared
438	setvar x:
439	x is not declared
440	setglobal x:
441	No errors are possible; we would need all these many conditions to
442	statically know the names:
443	- no 'source'
444	- shopt -u copy_env.
445	- AND use lib has to be static
446
447	What about bare assignment in Hay? I think these are dynamic checks --
448	there is no static check. Hay is for building up data imperatively,
449	and then LATER, right before main(), it can be type checked.
450
451	Package {
452	version = '3.11'
453	version = '3.12'
454	}
455	"""
456	# No static checks are the global level! Because of 'source', var and
457	# setvar are essentially the same.
458	if len(self.names) == 0:
459	return
460
461	top = self.names[-1]
462	if keyword_id == Id.KW_Var:
463	if var_name in top:
464	p_die('%r was already declared' % var_name, blame_tok)
465	else:
466	top[var_name] = keyword_id
467
468	if keyword_id == Id.KW_SetVar:
469	if var_name not in top:
470	# Note: the solution could be setglobal, etc.
471	p_die(
472	"setvar couldn't find matching 'var %s' (OILS-ERR-10)" %
473	var_name, blame_tok)
474
475
476	class ctx_VarChecker(object):
477
478	def __init__(self, var_checker, blame_tok):
479	# type: (VarChecker, Token) -> None
480	var_checker.Push(blame_tok)
481	self.var_checker = var_checker
482
483	def __enter__(self):
484	# type: () -> None
485	pass
486
487	def __exit__(self, type, value, traceback):
488	# type: (Any, Any, Any) -> None
489	self.var_checker.Pop()
490
491
492	class ctx_CmdMode(object):
493
494	def __init__(self, cmd_parse, new_cmd_mode):
495	# type: (CommandParser, cmd_mode_t) -> None
496	self.cmd_parse = cmd_parse
497	self.prev_cmd_mode = cmd_parse.cmd_mode
498	cmd_parse.cmd_mode = new_cmd_mode
499
500	def __enter__(self):
501	# type: () -> None
502	pass
503
504	def __exit__(self, type, value, traceback):
505	# type: (Any, Any, Any) -> None
506	self.cmd_parse.cmd_mode = self.prev_cmd_mode
507
508
509	SECONDARY_KEYWORDS = [
510	Id.KW_Do, Id.KW_Done, Id.KW_Then, Id.KW_Fi, Id.KW_Elif, Id.KW_Else,
511	Id.KW_Esac
512	]
513
514
515	class CommandParser(object):
516	"""Recursive descent parser derived from POSIX shell grammar.
517
518	This is a BNF grammar:
519	https://pubs.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html#tag_18_10
520
521	- Augmented with both bash/OSH and YSH constructs.
522
523	- We use regex-like iteration rather than recursive references
524	? means optional (0 or 1)
525	* means 0 or more
526	+ means 1 or more
527
528	- Keywords are spelled in Caps:
529	If Elif Case
530
531	- Operator tokens are quoted:
532	'(' '\|'
533
534	or can be spelled directly if it matters:
535
536	Op_LParen Op_Pipe
537
538	- Non-terminals are snake_case:
539	brace_group subshell
540
541	Methods in this class should ROUGHLY CORRESPOND to grammar productions, and
542	the production should be in the method docstrings, e.g.
543
544	def ParseSubshell():
545	"
546	subshell : '(' compound_list ')'
547
548	Looking at Op_LParen # Comment to say how this method is called
549	"
550
551	The grammar may be factored to make parsing easier.
552	"""
553
554	def __init__(self,
555	parse_ctx,
556	parse_opts,
557	w_parser,
558	lexer,
559	line_reader,
560	eof_id=Id.Eof_Real):
561	# type: (ParseContext, optview.Parse, WordParser, Lexer, _Reader, Id_t) -> None
562	self.parse_ctx = parse_ctx
563	self.aliases = parse_ctx.aliases # aliases to expand at parse time
564
565	self.parse_opts = parse_opts
566	self.w_parser = w_parser # type: WordParser # for normal parsing
567	self.lexer = lexer # for pushing hints, lookahead to (
568	self.line_reader = line_reader # for here docs
569	self.eof_id = eof_id
570
571	self.arena = line_reader.arena # for adding here doc and alias spans
572	self.aliases_in_flight = [] # type: AliasesInFlight
573
574	# A hacky boolean to remove 'if cd / {' ambiguity.
575	self.allow_block = True
576
577	# Stack of booleans for nested Attr and SHELL nodes.
578	# Attr nodes allow bare assignment x = 42, but not shell x=42.
579	# SHELL nodes are the inverse. 'var x = 42' is preferred in shell
580	# nodes, but x42 is still allowed.
581	#
582	# Note: this stack could be optimized by turning it into an integer and
583	# binary encoding.
584	self.hay_attrs_stack = [] # type: List[bool]
585
586	# Note: VarChecker is instantiated with each CommandParser, which means
587	# that two 'proc foo' -- inside a command sub and outside -- don't
588	# conflict, because they use different CommandParser instances. I think
589	# this OK but you can imagine different behaviors.
590	self.var_checker = VarChecker()
591
592	self.cmd_mode = cmd_mode_e.Shell # type: cmd_mode_t
593
594	self.Reset()
595
596	# Init_() function for "keyword arg"
597	def Init_AliasesInFlight(self, aliases_in_flight):
598	# type: (AliasesInFlight) -> None
599	self.aliases_in_flight = aliases_in_flight
600
601	def Reset(self):
602	# type: () -> None
603	"""Reset our own internal state.
604
605	Called by the interactive loop.
606	"""
607	# Cursor state set by _GetWord()
608	self.next_lex_mode = lex_mode_e.ShCommand
609	self.cur_word = None # type: word_t # current word
610	self.c_kind = Kind.Undefined
611	self.c_id = Id.Undefined_Tok
612
613	self.pending_here_docs = [] # type: List[Redir]
614
615	def ResetInputObjects(self):
616	# type: () -> None
617	"""Reset the internal state of our inputs.
618
619	Called by the interactive loop.
620	"""
621	self.w_parser.Reset()
622	self.lexer.ResetInputObjects()
623	self.line_reader.Reset()
624
625	def _SetNext(self):
626	# type: () -> None
627	"""Call this when you no longer need the current token.
628
629	This method is lazy. A subsequent call to _GetWord() will
630	actually read the next Token.
631	"""
632	self.next_lex_mode = lex_mode_e.ShCommand
633
634	def _SetNextBrack(self):
635	# type: () -> None
636	self.next_lex_mode = lex_mode_e.ShCommandFakeBrack
637
638	def _GetWord(self):
639	# type: () -> None
640	"""Call this when you need to make a decision based on Id or Kind.
641
642	If there was an "unfulfilled" call to _SetNext(), it reads a word and sets
643	self.c_id and self.c_kind.
644
645	Otherwise it does nothing.
646	"""
647	if self.next_lex_mode != lex_mode_e.Undefined:
648	w = self.w_parser.ReadWord(self.next_lex_mode)
649	#log("w %s", w)
650
651	# Here docs only happen in command mode, so other kinds of newlines don't
652	# count.
653	if w.tag() == word_e.Operator:
654	tok = cast(Token, w)
655	if tok.id == Id.Op_Newline:
656	for h in self.pending_here_docs:
657	_ParseHereDocBody(self.parse_ctx, h, self.line_reader,
658	self.arena)
659	del self.pending_here_docs[:] # No .clear() until Python 3.3.
660
661	self.cur_word = w
662
663	self.c_kind = word_.CommandKind(self.cur_word)
664	# Has special case for Id.Lit_{LBrace,RBrace,Equals}
665	self.c_id = word_.CommandId(self.cur_word)
666	self.next_lex_mode = lex_mode_e.Undefined
667
668	def _Eat(self, c_id, msg=None):
669	# type: (Id_t, Optional[str]) -> word_t
670	"""Consume a word of a type, maybe showing a custom error message.
671
672	Args:
673	c_id: the Id we expected
674	msg: improved error message
675	"""
676	self._GetWord()
677	if self.c_id != c_id:
678	if msg is None:
679	msg = 'Expected word type %s, got %s' % (
680	ui.PrettyId(c_id), ui.PrettyId(self.c_id))
681	p_die(msg, loc.Word(self.cur_word))
682
683	skipped = self.cur_word
684	self._SetNext()
685	return skipped
686
687	def _NewlineOk(self):
688	# type: () -> None
689	"""Check for optional newline and consume it."""
690	self._GetWord()
691	if self.c_id == Id.Op_Newline:
692	self._SetNext()
693
694	def _AtSecondaryKeyword(self):
695	# type: () -> bool
696	self._GetWord()
697	if self.c_id in SECONDARY_KEYWORDS:
698	return True
699	return False
700
701	def ParseRedirect(self):
702	# type: () -> Redir
703	self._GetWord()
704	assert self.c_kind == Kind.Redir, self.cur_word
705	op_tok = cast(Token, self.cur_word) # for MyPy
706
707	# Note: the lexer could take distinguish between
708	# >out
709	# 3>out
710	# {fd}>out
711	#
712	# which would make the code below faster. But small string optimization
713	# would also speed it up, since redirects are small.
714
715	# One way to do this is with Kind.Redir and Kind.RedirNamed, and then
716	# possibly "unify" the IDs by subtracting a constant like 8 or 16?
717
718	op_val = lexer.TokenVal(op_tok)
719	if op_val[0] == '{':
720	pos = op_val.find('}')
721	assert pos != -1 # lexer ensures this
722	where = redir_loc.VarName(op_val[1:pos]) # type: redir_loc_t
723
724	elif op_val[0].isdigit():
725	pos = 1
726	if op_val[1].isdigit():
727	pos = 2
728	where = redir_loc.Fd(int(op_val[:pos]))
729
730	else:
731	where = redir_loc.Fd(consts.RedirDefaultFd(op_tok.id))
732
733	self._SetNext()
734
735	self._GetWord()
736	# Other redirect
737	if self.c_kind != Kind.Word:
738	p_die('Invalid token after redirect operator',
739	loc.Word(self.cur_word))
740
741	# Here doc
742	if op_tok.id in (Id.Redir_DLess, Id.Redir_DLessDash):
743	arg = redir_param.HereDoc.CreateNull()
744	arg.here_begin = self.cur_word
745	arg.stdin_parts = []
746
747	r = Redir(op_tok, where, arg)
748
749	self.pending_here_docs.append(r) # will be filled on next newline.
750
751	self._SetNext()
752	return r
753
754	arg_word = self.cur_word
755	tilde = word_.TildeDetect(arg_word)
756	if tilde:
757	arg_word = tilde
758	self._SetNext()
759
760	# We should never get Empty, Token, etc.
761	assert arg_word.tag() == word_e.Compound, arg_word
762	return Redir(op_tok, where, cast(CompoundWord, arg_word))
763
764	def _ParseRedirectList(self):
765	# type: () -> List[Redir]
766	"""Try parsing any redirects at the cursor.
767
768	This is used for blocks only, not commands.
769	"""
770	redirects = [] # type: List[Redir]
771	while True:
772	# This prediction needs to ONLY accept redirect operators. Should we
773	# make them a separate Kind?
774	self._GetWord()
775	if self.c_kind != Kind.Redir:
776	break
777
778	node = self.ParseRedirect()
779	redirects.append(node)
780	self._SetNext()
781
782	return redirects
783
784	def _MaybeParseRedirectList(self, node):
785	# type: (command_t) -> command_t
786	"""Try parsing redirects at the current position.
787
788	If there are any, then wrap the command_t argument with a
789	command.Redirect node. Otherwise, return argument unchanged.
790	"""
791	self._GetWord()
792	if self.c_kind != Kind.Redir:
793	return node
794
795	redirects = [self.ParseRedirect()]
796
797	while True:
798	# This prediction needs to ONLY accept redirect operators. Should we
799	# make them a separate Kind?
800	self._GetWord()
801	if self.c_kind != Kind.Redir:
802	break
803
804	redirects.append(self.ParseRedirect())
805	self._SetNext()
806
807	return command.Redirect(node, redirects)
808
809	def _ScanSimpleCommand(self):
810	# type: () -> Tuple[List[Redir], List[CompoundWord], Optional[ArgList], Optional[LiteralBlock]]
811	"""YSH extends simple commands with typed args and blocks.
812
813	Shell has a recursive grammar, which awkwardly expresses
814	non-grammatical rules:
815
816	simple_command : cmd_prefix cmd_word cmd_suffix
817	\| cmd_prefix cmd_word
818	\| cmd_prefix
819	\| cmd_name cmd_suffix
820	\| cmd_name
821	;
822	cmd_name : WORD /* Apply rule 7a */
823	;
824	cmd_word : WORD /* Apply rule 7b */
825	;
826	cmd_prefix : io_redirect
827	\| cmd_prefix io_redirect
828	\| ASSIGNMENT_WORD
829	\| cmd_prefix ASSIGNMENT_WORD
830	;
831	cmd_suffix : io_redirect
832	\| cmd_suffix io_redirect
833	\| WORD
834	\| cmd_suffix WORD
835
836	YSH grammar:
837
838	redirect = redir_op WORD
839	item = WORD \| redirect
840
841	typed_args =
842	'(' arglist ')'
843	\| '[' arglist ']'
844
845	simple_command =
846	cmd_prefix* item+ typed_args? BraceGroup? cmd_suffix*
847
848	Notably, redirects shouldn't appear after typed args, or after
849	BraceGroup.
850
851	Examples:
852
853	This is an assignment:
854	foo=1 >out
855
856	This is a command.Simple
857	>out
858
859	What about
860	>out (42)
861	"""
862	redirects = [] # type: List[Redir]
863	words = [] # type: List[CompoundWord]
864	typed_args = None # type: Optional[ArgList]
865	block = None # type: Optional[LiteralBlock]
866
867	first_word_caps = False # does first word look like Caps, but not CAPS
868
869	i = 0
870	while True:
871	self._GetWord()
872
873	# If we got { }, change it to something that's not Kind.Word
874	kind2 = self.c_kind
875	if (kind2 == Kind.Word and self.parse_opts.parse_brace() and
876	self.c_id in (Id.Lit_LBrace, Id.Lit_RBrace)):
877	kind2 = Kind.Op
878
879	if kind2 == Kind.Redir:
880	node = self.ParseRedirect()
881	redirects.append(node)
882
883	elif kind2 == Kind.Word:
884	w = cast(CompoundWord, self.cur_word) # Kind.Word ensures this
885
886	if i == 0:
887	# Disallow leading =a because it's confusing
888	part0 = w.parts[0]
889	if part0.tag() == word_part_e.Literal:
890	tok = cast(Token, part0)
891	if tok.id == Id.Lit_Equals:
892	p_die(
893	"=word isn't allowed. Hint: add a space after =, or quote it",
894	tok)
895
896	# Is the first word a Hay Attr word?
897	#
898	# Can we remove this StaticEval() call, and just look
899	# inside Token? I think once we get rid of SHELL nodes,
900	# this will be simpler.
901
902	ok, word_str, quoted = word_.StaticEval(w)
903	# Foo { a = 1 } is OK, but not foo { a = 1 } or FOO { a = 1 }
904	if (ok and len(word_str) and word_str[0].isupper() and
905	not word_str.isupper()):
906	first_word_caps = True
907	#log('W %s', word_str)
908
909	words.append(w)
910
911	else:
912	break
913
914	self._SetNextBrack() # Allow bracket for SECOND word on
915	i += 1
916
917	# my-cmd (x) or my-cmd [x]
918	self._GetWord()
919	if self.c_id == Id.Op_LParen:
920	# 1. Check that there's a preceding space
921	prev_byte = self.lexer.ByteLookBack()
922	if prev_byte not in (SPACE_CH, TAB_CH):
923	if self.parse_opts.parse_at():
924	p_die('Space required before (', loc.Word(self.cur_word))
925	else:
926	# inline func call like @sorted(x) is invalid in OSH, but the
927	# solution isn't a space
928	p_die(
929	'Unexpected left paren (might need a space before it)',
930	loc.Word(self.cur_word))
931
932	# 2. Check that it's not (). We disallow this because it's a no-op and
933	# there could be confusion with shell func defs.
934	# For some reason we need to call lexer.LookPastSpace, not
935	# w_parser.LookPastSpace. I think this is because we're at (, which is
936	# an operator token. All the other cases are like 'x=', which is PART
937	# of a word, and we don't know if it will end.
938	next_id = self.lexer.LookPastSpace(lex_mode_e.ShCommand)
939	if next_id == Id.Op_RParen:
940	p_die('Empty arg list not allowed', loc.Word(self.cur_word))
941
942	typed_args = self.w_parser.ParseProcCallArgs(
943	grammar_nt.ysh_eager_arglist)
944
945	self._SetNext()
946
947	elif self.c_id == Id.Op_LBracket: # only when parse_bracket set
948	typed_args = self.w_parser.ParseProcCallArgs(
949	grammar_nt.ysh_lazy_arglist)
950
951	self._SetNext()
952
953	self._GetWord()
954
955	# Allow redirects after typed args, e.g.
956	# json write (x) > out.txt
957	if self.c_kind == Kind.Redir:
958	redirects.extend(self._ParseRedirectList())
959
960	# my-cmd { echo hi } my-cmd (x) { echo hi } ...
961	if (self.parse_opts.parse_brace() and self.c_id == Id.Lit_LBrace and
962	# Disabled for if/while condition, etc.
963	self.allow_block):
964
965	# allow x = 42
966	self.hay_attrs_stack.append(first_word_caps)
967	brace_group = self.ParseBraceGroup()
968
969	# So we can get the source code back later
970	lines = self.arena.SaveLinesAndDiscard(brace_group.left,
971	brace_group.right)
972	block = LiteralBlock(brace_group, lines)
973
974	self.hay_attrs_stack.pop()
975
976	self._GetWord()
977
978	# Allow redirects after block, e.g.
979	# cd /tmp { echo $PWD } > out.txt
980	if self.c_kind == Kind.Redir:
981	redirects.extend(self._ParseRedirectList())
982
983	return redirects, words, typed_args, block
984
985	def _MaybeExpandAliases(self, words):
986	# type: (List[CompoundWord]) -> Optional[command_t]
987	"""Try to expand aliases.
988
989	Args:
990	words: A list of Compound
991
992	Returns:
993	A new LST node, or None.
994
995	Our implementation of alias has two design choices:
996	- Where to insert it in parsing. We do it at the end of ParseSimpleCommand.
997	- What grammar rule to parse the expanded alias buffer with. In our case
998	it's ParseCommand().
999
1000	This doesn't quite match what other shells do, but I can't figure out a
1001	better places.
1002
1003	Most test cases pass, except for ones like:
1004
1005	alias LBRACE='{'
1006	LBRACE echo one; echo two; }
1007
1008	alias MULTILINE='echo 1
1009	echo 2
1010	echo 3'
1011	MULTILINE
1012
1013	NOTE: dash handles aliases in a totally different way. It has a global
1014	variable checkkwd in parser.c. It assigns it all over the grammar, like
1015	this:
1016
1017	checkkwd = CHKNL \| CHKKWD \| CHKALIAS;
1018
1019	The readtoken() function checks (checkkwd & CHKALIAS) and then calls
1020	lookupalias(). This seems to provide a consistent behavior among shells,
1021	but it's less modular and testable.
1022
1023	Bash also uses a global 'parser_state & PST_ALEXPNEXT'.
1024
1025	Returns:
1026	A command node if any aliases were expanded, or None otherwise.
1027	"""
1028	# Start a new list if there aren't any. This will be passed recursively
1029	# through CommandParser instances.
1030	aliases_in_flight = (self.aliases_in_flight
1031	if len(self.aliases_in_flight) else [])
1032
1033	# for error message
1034	first_word_str = None # type: Optional[str]
1035	argv0_loc = loc.Word(words[0])
1036
1037	expanded = [] # type: List[str]
1038	i = 0
1039	n = len(words)
1040
1041	while i < n:
1042	w = words[i]
1043
1044	ok, word_str, quoted = word_.StaticEval(w)
1045	if not ok or quoted:
1046	break
1047
1048	alias_exp = self.aliases.get(word_str)
1049	if alias_exp is None:
1050	break
1051
1052	# Prevent infinite loops. This is subtle: we want to prevent infinite
1053	# expansion of alias echo='echo x'. But we don't want to prevent
1054	# expansion of the second word in 'echo echo', so we add 'i' to
1055	# "aliases_in_flight".
1056	if (word_str, i) in aliases_in_flight:
1057	break
1058
1059	if i == 0:
1060	first_word_str = word_str # for error message
1061
1062	#log('%r -> %r', word_str, alias_exp)
1063	aliases_in_flight.append((word_str, i))
1064	expanded.append(alias_exp)
1065	i += 1
1066
1067	if not alias_exp.endswith(' '):
1068	# alias e='echo [ ' is the same expansion as
1069	# alias e='echo ['
1070	# The trailing space indicates whether we should continue to expand
1071	# aliases; it's not part of it.
1072	expanded.append(' ')
1073	break # No more expansions
1074
1075	if len(expanded) == 0: # No expansions; caller does parsing.
1076	return None
1077
1078	# We are expanding an alias, so copy the rest of the words and re-parse.
1079	if i < n:
1080	left_tok = location.LeftTokenForWord(words[i])
1081	right_tok = location.RightTokenForWord(words[-1])
1082
1083	# OLD CONSTRAINT
1084	#assert left_tok.line_id == right_tok.line_id
1085
1086	words_str = self.arena.SnipCodeString(left_tok, right_tok)
1087	expanded.append(words_str)
1088
1089	code_str = ''.join(expanded)
1090
1091	# TODO:
1092	# Aliases break static parsing (like backticks), so use our own Arena.
1093	# This matters for Hay, which calls SaveLinesAndDiscard().
1094	# arena = alloc.Arena()
1095	arena = self.arena
1096
1097	line_reader = reader.StringLineReader(code_str, arena)
1098	cp = self.parse_ctx.MakeOshParser(line_reader)
1099	cp.Init_AliasesInFlight(aliases_in_flight)
1100
1101	# break circular dep
1102	from frontend import parse_lib
1103
1104	# The interaction between COMPLETION and ALIASES requires special care.
1105	# See docstring of BeginAliasExpansion() in parse_lib.py.
1106	src = source.Alias(first_word_str, argv0_loc)
1107	with alloc.ctx_SourceCode(arena, src):
1108	with parse_lib.ctx_Alias(self.parse_ctx.trail):
1109	try:
1110	# _ParseCommandTerm() handles multiline commands, compound
1111	# commands, etc. as opposed to ParseLogicalLine()
1112	node = cp._ParseCommandTerm()
1113	except error.Parse as e:
1114	# Failure to parse alias expansion is a fatal error
1115	# We don't need more handling here/
1116	raise
1117
1118	if 0:
1119	log('AFTER expansion:')
1120	node.PrettyPrint()
1121
1122	return node
1123
1124	def ParseSimpleCommand(self):
1125	# type: () -> command_t
1126	"""Fixed transcription of the POSIX grammar
1127
1128	io_file : '<' filename
1129	\| LESSAND filename
1130	...
1131
1132	io_here : DLESS here_end
1133	\| DLESSDASH here_end
1134
1135	redirect : IO_NUMBER (io_redirect \| io_here)
1136
1137	prefix_part : ASSIGNMENT_WORD \| redirect
1138	cmd_part : WORD \| redirect
1139
1140	assign_kw : Declare \| Export \| Local \| Readonly
1141
1142	# Without any words it is parsed as a command, not an assignment
1143	assign_listing : assign_kw
1144
1145	# Now we have something to do (might be changing assignment flags too)
1146	# NOTE: any prefixes should be a warning, but they are allowed in shell.
1147	assignment : prefix_part* assign_kw (WORD \| ASSIGNMENT_WORD)+
1148
1149	# an external command, a function call, or a builtin -- a "word_command"
1150	word_command : prefix_part* cmd_part+
1151
1152	simple_command : assign_listing
1153	\| assignment
1154	\| proc_command
1155
1156	Simple imperative algorithm:
1157
1158	1) Read a list of words and redirects. Append them to separate lists.
1159	2) Look for the first non-assignment word. If it's declare, etc., then
1160	keep parsing words AND assign words. Otherwise, just parse words.
1161	3) If there are no non-assignment words, then it's a global assignment.
1162
1163	{ redirects, global assignments } OR
1164	{ redirects, prefix_bindings, words } OR
1165	{ redirects, ERROR_prefix_bindings, keyword, assignments, words }
1166
1167	THEN CHECK that prefix bindings don't have any array literal parts!
1168	global assignment and keyword assignments can have the of course.
1169	well actually EXPORT shouldn't have them either -- WARNING
1170
1171	3 cases we want to warn: prefix_bindings for assignment, and array literal
1172	in prefix bindings, or export
1173
1174	A command can be an assignment word, word, or redirect on its own.
1175
1176	ls
1177	>out.txt
1178
1179	>out.txt FOO=bar # this touches the file
1180
1181	Or any sequence:
1182	ls foo bar
1183	<in.txt ls foo bar >out.txt
1184	<in.txt ls >out.txt foo bar
1185
1186	Or add one or more environment bindings:
1187	VAR=val env
1188	>out.txt VAR=val env
1189
1190	here_end vs filename is a matter of whether we test that it's quoted. e.g.
1191	<<EOF vs <<'EOF'.
1192	"""
1193	redirects, words, typed_args, block = self._ScanSimpleCommand()
1194
1195	typed_loc = None # type: Optional[Token]
1196	if block:
1197	typed_loc = block.brace_group.left
1198	if typed_args:
1199	typed_loc = typed_args.left # preferred over block location
1200
1201	if len(words) == 0: # e.g. >out.txt # redirect without words
1202	assert len(redirects) != 0
1203	if typed_loc is not None:
1204	p_die("Unexpected typed args", typed_loc)
1205	return command.Redirect(command.NoOp, redirects)
1206
1207	preparsed_list, suffix_words = _SplitSimpleCommandPrefix(words)
1208	if len(preparsed_list):
1209	# Disallow X=Y inside proc and func
1210	# and inside Hay Attr blocks
1211	# But allow X=Y at the top level
1212	# for interactive use foo=bar
1213	# for global constants GLOBAL=~/src
1214	# because YSH assignment doesn't have tilde sub
1215	if len(suffix_words) == 0:
1216	if (self.cmd_mode != cmd_mode_e.Shell or
1217	(len(self.hay_attrs_stack) and self.hay_attrs_stack[-1])):
1218	p_die('Use var/setvar to assign in YSH',
1219	preparsed_list[0].left)
1220
1221	# Set a reference to words and redirects for completion. We want to
1222	# inspect this state after a failed parse.
1223	self.parse_ctx.trail.SetLatestWords(suffix_words, redirects)
1224
1225	if len(suffix_words) == 0:
1226	if typed_loc is not None:
1227	p_die("Unexpected typed args", typed_loc)
1228
1229	# ShAssignment: No suffix words like ONE=1 a[x]=1 TWO=2
1230	pairs = [] # type: List[AssignPair]
1231	for preparsed in preparsed_list:
1232	pairs.append(
1233	_MakeAssignPair(self.parse_ctx, preparsed, self.arena))
1234
1235	left_tok = location.LeftTokenForCompoundWord(words[0])
1236	assign_node = command.ShAssignment(left_tok, pairs)
1237	if len(redirects):
1238	return command.Redirect(assign_node, redirects)
1239	else:
1240	return assign_node
1241
1242	kind, kw_token = word_.IsControlFlow(suffix_words[0])
1243
1244	if kind == Kind.ControlFlow:
1245	if not self.parse_opts.parse_ignored() and len(redirects):
1246	p_die("Control flow shouldn't have redirects", kw_token)
1247	if len(preparsed_list): # FOO=bar local spam=eggs not allowed
1248	p_die("Control flow shouldn't have environment bindings",
1249	preparsed_list[0].left)
1250
1251	if kw_token.id == Id.ControlFlow_Return:
1252	# return x - inside procs and shell functions
1253	# return (x) - inside funcs
1254	if typed_args is None:
1255	if self.cmd_mode not in (cmd_mode_e.Shell,
1256	cmd_mode_e.Proc):
1257	p_die('Shell-style returns not allowed here', kw_token)
1258	else:
1259	if self.cmd_mode != cmd_mode_e.Func:
1260	p_die('Typed return is only allowed inside func',
1261	typed_loc)
1262	if len(typed_args.pos_args) != 1:
1263	p_die("Typed return expects one argument", typed_loc)
1264	if len(typed_args.named_args) != 0:
1265	p_die("Typed return doesn't take named arguments",
1266	typed_loc)
1267	return command.Retval(kw_token, typed_args.pos_args[0])
1268
1269	# Except for return (x), we shouldn't have typed args
1270	if typed_loc is not None:
1271	p_die("Unexpected typed args", typed_loc)
1272
1273	# Attach the token for errors. (ShAssignment may not need it.)
1274	if len(suffix_words) == 1:
1275	arg_word = None # type: Optional[word_t]
1276	elif len(suffix_words) == 2:
1277	arg_word = suffix_words[1]
1278	else:
1279	p_die('Unexpected argument to %r' % lexer.TokenVal(kw_token),
1280	loc.Word(suffix_words[2]))
1281
1282	return command.ControlFlow(kw_token, arg_word)
1283
1284	# Alias expansion only understands words, not typed args ( ) or block { }
1285	if not typed_args and not block and self.parse_opts.expand_aliases():
1286	# If any expansions were detected, then parse again.
1287	expanded_node = self._MaybeExpandAliases(suffix_words)
1288	if expanded_node:
1289	# Attach env bindings and redirects to the expanded node.
1290	more_env = [] # type: List[EnvPair]
1291	_AppendMoreEnv(preparsed_list, more_env)
1292	exp = command.ExpandedAlias(expanded_node, more_env)
1293	if len(redirects):
1294	return command.Redirect(exp, redirects)
1295	else:
1296	return exp
1297
1298	# TODO: check that we don't have env1=x x[1]=y env2=z here.
1299
1300	# FOO=bar printenv.py FOO
1301	node = _MakeSimpleCommand(preparsed_list, suffix_words, typed_args,
1302	block)
1303	if len(redirects):
1304	return command.Redirect(node, redirects)
1305	else:
1306	return node
1307
1308	def ParseBraceGroup(self):
1309	# type: () -> BraceGroup
1310	"""
1311	Original:
1312	brace_group : LBrace command_list RBrace ;
1313
1314	YSH:
1315	brace_group : LBrace (Op_Newline IgnoredComment?)? command_list RBrace ;
1316
1317	The doc comment can only occur if there's a newline.
1318	"""
1319	ate = self._Eat(Id.Lit_LBrace)
1320	left = word_.BraceToken(ate)
1321
1322	doc_word = None # type: word_t
1323	self._GetWord()
1324	if self.c_id == Id.Op_Newline:
1325	self._SetNext()
1326	# Set a flag so we don't skip over ###
1327	with word_.ctx_EmitDocToken(self.w_parser):
1328	self._GetWord()
1329
1330	if self.c_id == Id.Ignored_Comment:
1331	doc_word = self.cur_word
1332	self._SetNext()
1333
1334	# Id.Ignored_Comment means it's a Token, or None
1335	doc_token = cast(Token, doc_word)
1336
1337	c_list = self._ParseCommandList()
1338
1339	ate = self._Eat(Id.Lit_RBrace)
1340	right = word_.BraceToken(ate)
1341
1342	# Note(andychu): Related ASDL bug #1216. Choosing the Python [] behavior
1343	# would allow us to revert this back to None, which was changed in
1344	# https://github.com/oilshell/oil/pull/1211. Choosing the C++ nullptr
1345	# behavior saves allocations, but is less type safe.
1346	return BraceGroup(left, doc_token, c_list.children, right)
1347
1348	def ParseDoGroup(self):
1349	# type: () -> command.DoGroup
1350	"""Used by ForEach, ForExpr, While, Until. Should this be a Do node?
1351
1352	do_group : Do command_list Done ; /* Apply rule 6 */
1353	"""
1354	ate = self._Eat(Id.KW_Do)
1355	do_kw = word_.AsKeywordToken(ate)
1356
1357	c_list = self._ParseCommandList() # could be anything
1358
1359	ate = self._Eat(Id.KW_Done)
1360	done_kw = word_.AsKeywordToken(ate)
1361
1362	return command.DoGroup(do_kw, c_list.children, done_kw)
1363
1364	def ParseForWords(self):
1365	# type: () -> Tuple[List[CompoundWord], Optional[Token]]
1366	"""
1367	for_words : WORD* for_sep
1368	;
1369	for_sep : ';' newline_ok
1370	\| NEWLINES
1371	;
1372	"""
1373	words = [] # type: List[CompoundWord]
1374	# The token of any semi-colon, so we can remove it.
1375	semi_tok = None # type: Optional[Token]
1376
1377	while True:
1378	self._GetWord()
1379	if self.c_id == Id.Op_Semi:
1380	tok = cast(Token, self.cur_word)
1381	semi_tok = tok
1382	self._SetNext()
1383	self._NewlineOk()
1384	break
1385	elif self.c_id == Id.Op_Newline:
1386	self._SetNext()
1387	break
1388	elif self.parse_opts.parse_brace() and self.c_id == Id.Lit_LBrace:
1389	break
1390
1391	if self.cur_word.tag() != word_e.Compound:
1392	# TODO: Can we also show a pointer to the 'for' keyword?
1393	p_die('Invalid word in for loop', loc.Word(self.cur_word))
1394
1395	w2 = cast(CompoundWord, self.cur_word)
1396	words.append(w2)
1397	self._SetNext()
1398	return words, semi_tok
1399
1400	def _ParseForExprLoop(self, for_kw):
1401	# type: (Token) -> command.ForExpr
1402	"""
1403	Shell:
1404	for '((' init ';' cond ';' update '))' for_sep? do_group
1405
1406	YSH:
1407	for '((' init ';' cond ';' update '))' for_sep? brace_group
1408	"""
1409	node = self.w_parser.ReadForExpression()
1410	node.keyword = for_kw
1411
1412	self._SetNext()
1413
1414	self._GetWord()
1415	if self.c_id == Id.Op_Semi:
1416	self._SetNext()
1417	self._NewlineOk()
1418	elif self.c_id == Id.Op_Newline:
1419	self._SetNext()
1420	elif self.c_id == Id.KW_Do: # missing semicolon/newline allowed
1421	pass
1422	elif self.c_id == Id.Lit_LBrace: # does NOT require parse_brace
1423	pass
1424	else:
1425	p_die('Invalid word after for expression', loc.Word(self.cur_word))
1426
1427	if self.c_id == Id.Lit_LBrace:
1428	node.body = self.ParseBraceGroup()
1429	else:
1430	node.body = self.ParseDoGroup()
1431	return node
1432
1433	def _ParseForEachLoop(self, for_kw):
1434	# type: (Token) -> command.ForEach
1435	node = command.ForEach.CreateNull(alloc_lists=True)
1436	node.keyword = for_kw
1437
1438	num_iter_names = 0
1439	while True:
1440	w = self.cur_word
1441
1442	# Hack that makes the language more familiar:
1443	# - 'x, y' is accepted, but not 'x,y' or 'x ,y'
1444	# - 'x y' is also accepted but not idiomatic.
1445	UP_w = w
1446	if w.tag() == word_e.Compound:
1447	w = cast(CompoundWord, UP_w)
1448	if word_.LiteralId(w.parts[-1]) == Id.Lit_Comma:
1449	w.parts.pop()
1450
1451	ok, iter_name, quoted = word_.StaticEval(w)
1452	if not ok or quoted: # error: for $x
1453	p_die('Expected loop variable (a constant word)', loc.Word(w))
1454
1455	if not match.IsValidVarName(iter_name): # error: for -
1456	# TODO: consider commas?
1457	if ',' in iter_name:
1458	p_die('Loop variables look like x, y (fix spaces)',
1459	loc.Word(w))
1460	p_die('Invalid loop variable name %r' % iter_name, loc.Word(w))
1461
1462	node.iter_names.append(iter_name)
1463	num_iter_names += 1
1464	self._SetNext()
1465
1466	self._GetWord()
1467	# 'in' or 'do' or ';' or Op_Newline marks the end of variable names
1468	# Subtlety: 'var' is KW_Var and is a valid loop name
1469	if self.c_id in (Id.KW_In, Id.KW_Do) or self.c_kind == Kind.Op:
1470	break
1471
1472	if num_iter_names == 3:
1473	p_die('Unexpected word after 3 loop variables',
1474	loc.Word(self.cur_word))
1475
1476	self._NewlineOk()
1477
1478	self._GetWord()
1479	if self.c_id == Id.KW_In:
1480	expr_blame = word_.AsKeywordToken(self.cur_word)
1481
1482	self._SetNext() # skip in
1483
1484	next_id = self.w_parser.LookPastSpace()
1485	#log('%s', Id_str(next_id))
1486
1487	if next_id == Id.Op_LParen: # for x in (expr) {
1488	enode = self.w_parser.ParseYshExprForCommand()
1489	node.iterable = for_iter.YshExpr(enode, expr_blame)
1490
1491	# We don't accept for x in (obj); do ...
1492	self._GetWord()
1493	if self.c_id != Id.Lit_LBrace:
1494	p_die('Expected { after iterable expression',
1495	loc.Word(self.cur_word))
1496
1497	elif next_id == Id.Redir_LessGreat: # for x in <> {
1498	# <> is Id.Redir_Great - reuse this for simplicity
1499	w = self._Eat(Id.Redir_LessGreat)
1500	p_die('Reserved syntax', loc.Word(self.cur_word))
1501
1502	#left = word_.AsOperatorToken(w)
1503
1504	#node.iterable = for_iter.Files(left, [])
1505
1506	## Must be { not 'do'
1507	#self._GetWord()
1508	#if self.c_id != Id.Lit_LBrace:
1509	# p_die('Expected { after files', loc.Word(self.cur_word))
1510
1511	elif next_id == Id.Redir_Less: # for x in < > {
1512	w = self._Eat(Id.Redir_Less)
1513	p_die('Reserved syntax', loc.Word(self.cur_word))
1514
1515	#left = word_.AsOperatorToken(w)
1516
1517	# TODO: we could accept
1518	#
1519	# for x in < README.md *.py > {
1520	# for x in < @myfiles > {
1521	#
1522	# And set _filename _line_num, similar to awk
1523
1524	#self._Eat(Id.Redir_Great)
1525
1526	#node.iterable = for_iter.Files(left, [])
1527
1528	## Must be { not 'do'
1529	#self._GetWord()
1530	#if self.c_id != Id.Lit_LBrace:
1531	# p_die('Expected { after files', loc.Word(self.cur_word))
1532
1533	else:
1534	semi_tok = None # type: Optional[Token]
1535	iter_words, semi_tok = self.ParseForWords()
1536	node.semi_tok = semi_tok
1537
1538	if not self.parse_opts.parse_bare_word() and len(
1539	iter_words) == 1:
1540	ok, s, quoted = word_.StaticEval(iter_words[0])
1541	if ok and match.IsValidVarName(s) and not quoted:
1542	p_die(
1543	'Surround this word with either parens or quotes (parse_bare_word)',
1544	loc.Word(iter_words[0]))
1545
1546	words2 = braces.BraceDetectAll(iter_words)
1547	words3 = word_.TildeDetectAll(words2)
1548	node.iterable = for_iter.Words(words3)
1549
1550	# Now that we know there are words, do an extra check
1551	if num_iter_names > 2:
1552	p_die('Expected at most 2 loop variables', for_kw)
1553
1554	elif self.c_id == Id.KW_Do:
1555	node.iterable = for_iter.Args # implicitly loop over "$@"
1556	# do not advance
1557
1558	elif self.c_id == Id.Op_Semi: # for x; do
1559	node.iterable = for_iter.Args # implicitly loop over "$@"
1560	self._SetNext()
1561
1562	else: # for foo BAD
1563	p_die('Unexpected word after for loop variable',
1564	loc.Word(self.cur_word))
1565
1566	self._GetWord()
1567	if self.c_id == Id.Lit_LBrace: # parse_opts.parse_brace() must be on
1568	node.body = self.ParseBraceGroup()
1569	else:
1570	node.body = self.ParseDoGroup()
1571
1572	return node
1573
1574	def ParseFor(self):
1575	# type: () -> command_t
1576	"""
1577	TODO: Update the grammar
1578
1579	for_clause : For for_name newline_ok (in for_words? for_sep)? do_group ;
1580	\| For '((' ... TODO
1581	"""
1582	ate = self._Eat(Id.KW_For)
1583	for_kw = word_.AsKeywordToken(ate)
1584
1585	self._GetWord()
1586	if self.c_id == Id.Op_DLeftParen:
1587	if not self.parse_opts.parse_dparen():
1588	p_die("Bash for loops aren't allowed (parse_dparen)",
1589	loc.Word(self.cur_word))
1590
1591	# for (( i = 0; i < 10; i++)
1592	n1 = self._ParseForExprLoop(for_kw)
1593	return self._MaybeParseRedirectList(n1)
1594	else:
1595	# for x in a b; do echo hi; done
1596	n2 = self._ParseForEachLoop(for_kw)
1597	return self._MaybeParseRedirectList(n2)
1598
1599	def _ParseConditionList(self):
1600	# type: () -> condition_t
1601	"""
1602	condition_list: command_list
1603
1604	This is a helper to parse a condition list for if commands and while/until
1605	loops. It will throw a parse error if there are no conditions in the list.
1606	"""
1607	self.allow_block = False
1608	commands = self._ParseCommandList()
1609	self.allow_block = True
1610
1611	if len(commands.children) == 0:
1612	p_die("Expected a condition", loc.Word(self.cur_word))
1613
1614	return condition.Shell(commands.children)
1615
1616	def ParseWhileUntil(self, keyword):
1617	# type: (Token) -> command.WhileUntil
1618	"""
1619	while_clause : While command_list do_group ;
1620	until_clause : Until command_list do_group ;
1621	"""
1622	self._SetNext() # skip keyword
1623
1624	if (self.parse_opts.parse_paren() and
1625	self.w_parser.LookPastSpace() == Id.Op_LParen):
1626	enode = self.w_parser.ParseYshExprForCommand()
1627	cond = condition.YshExpr(enode) # type: condition_t
1628	else:
1629	cond = self._ParseConditionList()
1630
1631	# NOTE: The LSTs will be different for OSH and YSH, but the execution
1632	# should be unchanged. To be sure we should desugar.
1633	self._GetWord()
1634	if self.parse_opts.parse_brace() and self.c_id == Id.Lit_LBrace:
1635	# while test -f foo {
1636	body_node = self.ParseBraceGroup() # type: command_t
1637	else:
1638	body_node = self.ParseDoGroup()
1639
1640	return command.WhileUntil(keyword, cond, body_node)
1641
1642	def ParseCaseArm(self):
1643	# type: () -> CaseArm
1644	"""
1645	case_item: '('? pattern ('\|' pattern)* ')'
1646	newline_ok command_term? trailer? ;
1647
1648	Looking at '(' or pattern
1649	"""
1650	self.lexer.PushHint(Id.Op_RParen, Id.Right_CasePat)
1651
1652	left_tok = location.LeftTokenForWord(self.cur_word) # ( or pat
1653
1654	if self.c_id == Id.Op_LParen: # Optional (
1655	self._SetNext()
1656
1657	pat_words = [] # type: List[word_t]
1658	while True:
1659	self._GetWord()
1660	if self.c_kind != Kind.Word:
1661	p_die('Expected case pattern', loc.Word(self.cur_word))
1662	pat_words.append(self.cur_word)
1663	self._SetNext()
1664
1665	self._GetWord()
1666	if self.c_id == Id.Op_Pipe:
1667	self._SetNext()
1668	else:
1669	break
1670
1671	ate = self._Eat(Id.Right_CasePat)
1672	middle_tok = word_.AsOperatorToken(ate)
1673
1674	self._NewlineOk()
1675
1676	self._GetWord()
1677	if self.c_id not in (Id.Op_DSemi, Id.Op_SemiAmp, Id.Op_DSemiAmp,
1678	Id.KW_Esac):
1679	c_list = self._ParseCommandTerm()
1680	action_children = c_list.children
1681	else:
1682	action_children = []
1683
1684	dsemi_tok = None # type: Token
1685	self._GetWord()
1686	if self.c_id == Id.KW_Esac: # missing last ;;
1687	pass
1688	elif self.c_id in (Id.Op_DSemi, Id.Op_SemiAmp, Id.Op_DSemiAmp):
1689	dsemi_tok = word_.AsOperatorToken(self.cur_word)
1690	self._SetNext()
1691	else:
1692	# Happens on EOF
1693	p_die('Expected ;; or esac', loc.Word(self.cur_word))
1694
1695	self._NewlineOk()
1696
1697	return CaseArm(left_tok, pat.Words(pat_words), middle_tok,
1698	action_children, dsemi_tok)
1699
1700	def ParseYshCaseArm(self, discriminant):
1701	# type: (Id_t) -> CaseArm
1702	"""
1703	case_item : pattern newline_ok brace_group newline_ok
1704	pattern : pat_words
1705	\| pat_exprs
1706	\| pat_eggex
1707	\| pat_else
1708	pat_words : pat_word (newline_ok '\|' newline_ok pat_word)*
1709	pat_exprs : pat_expr (newline_ok '\|' newline_ok pat_expr)*
1710	pat_word : WORD
1711	pat_eggex : '/' oil_eggex '/'
1712	pat_expr : '(' oil_expr ')'
1713	pat_else : '(' Id.KW_Else ')'
1714
1715	Looking at: 'pattern'
1716
1717	Note that the trailing `newline_ok` in `case_item` is handled by
1718	`ParseYshCase`. We do this because parsing that `newline_ok` returns
1719	the next "discriminant" for the next token, so it makes more sense to
1720	handle it there.
1721	"""
1722	left_tok = None # type: Token
1723	pattern = None # type: pat_t
1724
1725	if discriminant in (Id.Op_LParen, Id.Arith_Slash):
1726	# pat_exprs, pat_else or pat_eggex
1727	pattern, left_tok = self.w_parser.ParseYshCasePattern()
1728	else:
1729	# pat_words
1730	pat_words = [] # type: List[word_t]
1731	while True:
1732	self._GetWord()
1733	if self.c_kind != Kind.Word:
1734	p_die('Expected case pattern', loc.Word(self.cur_word))
1735	pat_words.append(self.cur_word)
1736	self._SetNext()
1737
1738	if not left_tok:
1739	left_tok = location.LeftTokenForWord(self.cur_word)
1740
1741	self._NewlineOk()
1742
1743	self._GetWord()
1744	if self.c_id == Id.Op_Pipe:
1745	self._SetNext()
1746	self._NewlineOk()
1747	else:
1748	break
1749	pattern = pat.Words(pat_words)
1750
1751	self._NewlineOk()
1752	action = self.ParseBraceGroup()
1753
1754	# The left token of the action is our "middle" token
1755	return CaseArm(left_tok, pattern, action.left, action.children,
1756	action.right)
1757
1758	def ParseYshCase(self, case_kw):
1759	# type: (Token) -> command.Case
1760	"""
1761	ysh_case : Case '(' expr ')' LBrace newline_ok ysh_case_arm* RBrace ;
1762
1763	Looking at: token after 'case'
1764	"""
1765	enode = self.w_parser.ParseYshExprForCommand()
1766	to_match = case_arg.YshExpr(enode)
1767
1768	ate = self._Eat(Id.Lit_LBrace)
1769	arms_start = word_.BraceToken(ate)
1770
1771	discriminant = self.w_parser.NewlineOkForYshCase()
1772
1773	# Note: for now, zero arms are accepted, just like POSIX case $x in esac
1774	arms = [] # type: List[CaseArm]
1775	while discriminant != Id.Op_RBrace:
1776	arm = self.ParseYshCaseArm(discriminant)
1777	arms.append(arm)
1778
1779	discriminant = self.w_parser.NewlineOkForYshCase()
1780
1781	# NewlineOkForYshCase leaves the lexer in lex_mode_e.Expr. So the '}'
1782	# token is read as an Id.Op_RBrace, but we need to store this as a
1783	# Id.Lit_RBrace.
1784	ate = self._Eat(Id.Op_RBrace)
1785	arms_end = word_.AsOperatorToken(ate)
1786	arms_end.id = Id.Lit_RBrace
1787
1788	return command.Case(case_kw, to_match, arms_start, arms, arms_end)
1789
1790	def ParseOldCase(self, case_kw):
1791	# type: (Token) -> command.Case
1792	"""
1793	case_clause : Case WORD newline_ok In newline_ok case_arm* Esac ;
1794
1795	-> Looking at WORD
1796
1797	FYI original POSIX case list, which takes pains for DSEMI
1798
1799	case_list: case_item (DSEMI newline_ok case_item)* DSEMI? newline_ok;
1800	"""
1801	self._GetWord()
1802	w = self.cur_word
1803	if not self.parse_opts.parse_bare_word():
1804	ok, s, quoted = word_.StaticEval(w)
1805	if ok and not quoted:
1806	p_die(
1807	"This is a constant string. You may want a variable like $x (parse_bare_word)",
1808	loc.Word(w))
1809
1810	if w.tag() != word_e.Compound:
1811	p_die("Expected a word to match against", loc.Word(w))
1812
1813	to_match = case_arg.Word(w)
1814	self._SetNext() # past WORD
1815
1816	self._NewlineOk()
1817
1818	ate = self._Eat(Id.KW_In)
1819	arms_start = word_.AsKeywordToken(ate)
1820
1821	self._NewlineOk()
1822
1823	arms = [] # type: List[CaseArm]
1824	while True:
1825	self._GetWord()
1826	if self.c_id == Id.KW_Esac:
1827	break
1828	# case arm should begin with a pattern word or (
1829	if self.c_kind != Kind.Word and self.c_id != Id.Op_LParen:
1830	break
1831
1832	arm = self.ParseCaseArm()
1833	arms.append(arm)
1834
1835	ate = self._Eat(Id.KW_Esac)
1836	arms_end = word_.AsKeywordToken(ate)
1837
1838	# no redirects yet
1839	return command.Case(case_kw, to_match, arms_start, arms, arms_end)
1840
1841	def ParseCase(self):
1842	# type: () -> command.Case
1843	"""
1844	case_clause : old_case # from POSIX
1845	\| ysh_case
1846	;
1847
1848	Looking at 'Case'
1849	"""
1850	case_kw = word_.AsKeywordToken(self.cur_word)
1851	self._SetNext() # past 'case'
1852
1853	if self.w_parser.LookPastSpace() == Id.Op_LParen:
1854	return self.ParseYshCase(case_kw)
1855	else:
1856	return self.ParseOldCase(case_kw)
1857
1858	def _ParseYshElifElse(self, if_node):
1859	# type: (command.If) -> None
1860	"""If test -f foo { echo foo.
1861
1862	} elif test -f bar; test -f spam { ^ we parsed up to here echo
1863	bar } else { echo none }
1864	"""
1865	arms = if_node.arms
1866
1867	while self.c_id == Id.KW_Elif:
1868	elif_kw = word_.AsKeywordToken(self.cur_word)
1869	self._SetNext() # skip elif
1870	if (self.parse_opts.parse_paren() and
1871	self.w_parser.LookPastSpace() == Id.Op_LParen):
1872	enode = self.w_parser.ParseYshExprForCommand()
1873	cond = condition.YshExpr(enode) # type: condition_t
1874	else:
1875	self.allow_block = False
1876	commands = self._ParseCommandList()
1877	self.allow_block = True
1878	cond = condition.Shell(commands.children)
1879
1880	body = self.ParseBraceGroup()
1881	self._GetWord()
1882
1883	arm = IfArm(elif_kw, cond, None, body.children, None)
1884	arms.append(arm)
1885
1886	self._GetWord()
1887	if self.c_id == Id.KW_Else:
1888	self._SetNext()
1889	body = self.ParseBraceGroup()
1890	if_node.else_action = body.children
1891
1892	def _ParseYshIf(self, if_kw, cond):
1893	# type: (Token, condition_t) -> command.If
1894	"""
1895	if test -f foo {
1896	# ^ we parsed up to here
1897	echo foo
1898	} elif test -f bar; test -f spam {
1899	echo bar
1900	} else {
1901	echo none
1902	}
1903	NOTE: If you do something like if test -n foo{, the parser keeps going, and
1904	the error is confusing because it doesn't point to the right place.
1905
1906	I think we might need strict_brace so that foo{ is disallowed. It has to
1907	be foo\{ or foo{a,b}. Or just turn that on with parse_brace? After you
1908	form ANY CompoundWord, make sure it's balanced for Lit_LBrace and
1909	Lit_RBrace? Maybe this is pre-parsing step in the WordParser?
1910	"""
1911	if_node = command.If.CreateNull(alloc_lists=True)
1912	if_node.if_kw = if_kw
1913
1914	body1 = self.ParseBraceGroup()
1915	# Every arm has 1 spid, unlike shell-style
1916	# TODO: We could get the spids from the brace group.
1917	arm = IfArm(if_kw, cond, None, body1.children, None)
1918
1919	if_node.arms.append(arm)
1920
1921	self._GetWord()
1922	if self.c_id in (Id.KW_Elif, Id.KW_Else):
1923	self._ParseYshElifElse(if_node)
1924	# the whole if node has the 'else' spid, unlike shell-style there's no 'fi'
1925	# spid because that's in the BraceGroup.
1926	return if_node
1927
1928	def _ParseElifElse(self, if_node):
1929	# type: (command.If) -> None
1930	"""
1931	else_part: (Elif command_list Then command_list)* Else command_list ;
1932	"""
1933	arms = if_node.arms
1934
1935	self._GetWord()
1936	while self.c_id == Id.KW_Elif:
1937	elif_kw = word_.AsKeywordToken(self.cur_word)
1938	self._SetNext() # past 'elif'
1939
1940	cond = self._ParseConditionList()
1941
1942	ate = self._Eat(Id.KW_Then)
1943	then_kw = word_.AsKeywordToken(ate)
1944
1945	body = self._ParseCommandList()
1946	arm = IfArm(elif_kw, cond, then_kw, body.children, then_kw)
1947
1948	arms.append(arm)
1949
1950	self._GetWord()
1951	if self.c_id == Id.KW_Else:
1952	else_kw = word_.AsKeywordToken(self.cur_word)
1953	self._SetNext() # past 'else'
1954	body = self._ParseCommandList()
1955	if_node.else_action = body.children
1956	else:
1957	else_kw = None
1958
1959	if_node.else_kw = else_kw
1960
1961	def ParseIf(self):
1962	# type: () -> command.If
1963	"""
1964	if_clause : If command_list Then command_list else_part? Fi ;
1965
1966	open : '{' \| Then
1967	close : '}' \| Fi
1968
1969	ysh_if : If ( command_list \| '(' expr ')' )
1970	open command_list else_part? close;
1971
1972	There are 2 conditionals here: parse_paren, then parse_brace
1973	"""
1974	if_node = command.If.CreateNull(alloc_lists=True)
1975	if_kw = word_.AsKeywordToken(self.cur_word)
1976	if_node.if_kw = if_kw
1977	self._SetNext() # past 'if'
1978
1979	if (self.parse_opts.parse_paren() and
1980	self.w_parser.LookPastSpace() == Id.Op_LParen):
1981	# if (x + 1)
1982	enode = self.w_parser.ParseYshExprForCommand()
1983	cond = condition.YshExpr(enode) # type: condition_t
1984	else:
1985	# if echo 1; echo 2; then
1986	# Remove ambiguity with if cd / {
1987	cond = self._ParseConditionList()
1988
1989	self._GetWord()
1990	if self.parse_opts.parse_brace() and self.c_id == Id.Lit_LBrace:
1991	return self._ParseYshIf(if_kw, cond)
1992
1993	ate = self._Eat(Id.KW_Then)
1994	then_kw = word_.AsKeywordToken(ate)
1995
1996	body = self._ParseCommandList()
1997
1998	# First arm
1999	arm = IfArm(if_kw, cond, then_kw, body.children, then_kw)
2000	if_node.arms.append(arm)
2001
2002	# 2nd to Nth arm
2003	if self.c_id in (Id.KW_Elif, Id.KW_Else):
2004	self._ParseElifElse(if_node)
2005
2006	ate = self._Eat(Id.KW_Fi)
2007	if_node.fi_kw = word_.AsKeywordToken(ate)
2008
2009	return if_node
2010
2011	def ParseTime(self):
2012	# type: () -> command_t
2013	"""Time [-p] pipeline.
2014
2015	According to bash help.
2016	"""
2017	time_kw = word_.AsKeywordToken(self.cur_word)
2018	self._SetNext() # skip time
2019	pipeline = self.ParsePipeline()
2020	return command.TimeBlock(time_kw, pipeline)
2021
2022	def ParseCompoundCommand(self):
2023	# type: () -> command_t
2024	"""
2025	Refactoring: we put io_redirect* here instead of in function_body and
2026	command.
2027
2028	compound_command : brace_group io_redirect*
2029	\| subshell io_redirect*
2030	\| for_clause io_redirect*
2031	\| while_clause io_redirect*
2032	\| until_clause io_redirect*
2033	\| if_clause io_redirect*
2034	\| case_clause io_redirect*
2035
2036	# bash extensions
2037	\| time_clause
2038	\| [[ BoolExpr ]]
2039	\| (( ArithExpr ))
2040	"""
2041	self._GetWord()
2042	if self.c_id == Id.Lit_LBrace:
2043	n1 = self.ParseBraceGroup()
2044	return self._MaybeParseRedirectList(n1)
2045	if self.c_id == Id.Op_LParen:
2046	n2 = self.ParseSubshell()
2047	return self._MaybeParseRedirectList(n2)
2048
2049	if self.c_id == Id.KW_For:
2050	# Note: Redirects parsed in this call. POSIX for and bash for ((
2051	# have different nodetypes.
2052	return self.ParseFor()
2053	if self.c_id in (Id.KW_While, Id.KW_Until):
2054	keyword = word_.AsKeywordToken(self.cur_word)
2055	n3 = self.ParseWhileUntil(keyword)
2056	return self._MaybeParseRedirectList(n3)
2057
2058	if self.c_id == Id.KW_If:
2059	n4 = self.ParseIf()
2060	return self._MaybeParseRedirectList(n4)
2061
2062	if self.c_id == Id.KW_Case:
2063	n5 = self.ParseCase()
2064	return self._MaybeParseRedirectList(n5)
2065
2066	if self.c_id == Id.KW_DLeftBracket:
2067	if not self.parse_opts.parse_dbracket():
2068	p_die('Bash [[ not allowed in YSH (parse_dbracket)',
2069	loc.Word(self.cur_word))
2070	n6 = self.ParseDBracket()
2071	return self._MaybeParseRedirectList(n6)
2072	if self.c_id == Id.Op_DLeftParen:
2073	if not self.parse_opts.parse_dparen():
2074	p_die(
2075	'Bash (( not allowed in YSH (parse_dparen, see OILS-ERR-14 for wart)',
2076	loc.Word(self.cur_word))
2077	n7 = self.ParseDParen()
2078	return self._MaybeParseRedirectList(n7)
2079
2080	# bash extensions: no redirects
2081	if self.c_id == Id.KW_Time:
2082	return self.ParseTime()
2083
2084	# Happens in function body, e.g. myfunc() oops
2085	p_die(
2086	'Unexpected word while parsing compound command (%s)' %
2087	Id_str(self.c_id), loc.Word(self.cur_word))
2088	assert False # for MyPy
2089
2090	def ParseFunctionDef(self):
2091	# type: () -> command.ShFunction
2092	"""
2093	function_header : fname '(' ')'
2094	function_def : function_header newline_ok function_body ;
2095
2096	Precondition: Looking at the function name.
2097
2098	NOTE: There is an ambiguity with:
2099
2100	function foo ( echo hi ) and
2101	function foo () ( echo hi )
2102
2103	Bash only accepts the latter, though it doesn't really follow a grammar.
2104	"""
2105	word0 = cast(CompoundWord, self.cur_word) # caller ensures validity
2106	name = word_.ShFunctionName(word0)
2107	if len(name) == 0: # example: foo$x is invalid
2108	p_die('Invalid function name', loc.Word(word0))
2109
2110	part0 = word0.parts[0]
2111	# If we got a non-empty string from ShFunctionName, this should be true.
2112	assert part0.tag() == word_part_e.Literal
2113	blame_tok = cast(Token, part0) # for ctx_VarChecker
2114
2115	self._SetNext() # move past function name
2116
2117	# Must be true because of lookahead
2118	self._GetWord()
2119	assert self.c_id == Id.Op_LParen, self.cur_word
2120
2121	self.lexer.PushHint(Id.Op_RParen, Id.Right_ShFunction)
2122	self._SetNext()
2123
2124	self._GetWord()
2125	if self.c_id == Id.Right_ShFunction:
2126	# 'f ()' implies a function definition, since invoking it with no args
2127	# would just be 'f'
2128	self._SetNext()
2129
2130	self._NewlineOk()
2131
2132	func = command.ShFunction.CreateNull()
2133	func.name = name
2134	with ctx_VarChecker(self.var_checker, blame_tok):
2135	func.body = self.ParseCompoundCommand()
2136
2137	func.name_tok = location.LeftTokenForCompoundWord(word0)
2138	return func
2139	else:
2140	p_die('Expected ) in function definition', loc.Word(self.cur_word))
2141	return None
2142
2143	def ParseKshFunctionDef(self):
2144	# type: () -> command.ShFunction
2145	"""
2146	ksh_function_def : 'function' fname ( '(' ')' )? newline_ok function_body
2147	"""
2148	keyword_tok = word_.AsKeywordToken(self.cur_word)
2149
2150	self._SetNext() # skip past 'function'
2151	self._GetWord()
2152
2153	cur_word = cast(CompoundWord, self.cur_word) # caller ensures validity
2154	name = word_.ShFunctionName(cur_word)
2155	if len(name) == 0: # example: foo$x is invalid
2156	p_die('Invalid KSH-style function name', loc.Word(cur_word))
2157
2158	name_word = self.cur_word
2159	self._SetNext() # skip past 'function name
2160
2161	self._GetWord()
2162	if self.c_id == Id.Op_LParen:
2163	self.lexer.PushHint(Id.Op_RParen, Id.Right_ShFunction)
2164	self._SetNext()
2165	self._Eat(Id.Right_ShFunction)
2166
2167	self._NewlineOk()
2168
2169	func = command.ShFunction.CreateNull()
2170	func.name = name
2171	with ctx_VarChecker(self.var_checker, keyword_tok):
2172	func.body = self.ParseCompoundCommand()
2173
2174	func.keyword = keyword_tok
2175	func.name_tok = location.LeftTokenForWord(name_word)
2176	return func
2177
2178	def ParseYshProc(self):
2179	# type: () -> Proc
2180	node = Proc.CreateNull(alloc_lists=True)
2181
2182	keyword_tok = word_.AsKeywordToken(self.cur_word)
2183	node.keyword = keyword_tok
2184
2185	with ctx_VarChecker(self.var_checker, keyword_tok):
2186	with ctx_CmdMode(self, cmd_mode_e.Proc):
2187	self.w_parser.ParseProc(node)
2188	if node.sig.tag() == proc_sig_e.Closed: # Register params
2189	sig = cast(proc_sig.Closed, node.sig)
2190
2191	# Treat 3 kinds of params as variables.
2192	wp = sig.word
2193	if wp:
2194	for param in wp.params:
2195	self.var_checker.Check(Id.KW_Var, param.name,
2196	param.blame_tok)
2197	if wp.rest_of:
2198	r = wp.rest_of
2199	self.var_checker.Check(Id.KW_Var, r.name,
2200	r.blame_tok)
2201	# We COULD register __out here but it would require a different API.
2202	#if param.prefix and param.prefix.id == Id.Arith_Colon:
2203	# self.var_checker.Check(Id.KW_Var, '__' + param.name)
2204
2205	posit = sig.positional
2206	if posit:
2207	for param in posit.params:
2208	self.var_checker.Check(Id.KW_Var, param.name,
2209	param.blame_tok)
2210	if posit.rest_of:
2211	r = posit.rest_of
2212	self.var_checker.Check(Id.KW_Var, r.name,
2213	r.blame_tok)
2214
2215	named = sig.named
2216	if named:
2217	for param in named.params:
2218	self.var_checker.Check(Id.KW_Var, param.name,
2219	param.blame_tok)
2220	if named.rest_of:
2221	r = named.rest_of
2222	self.var_checker.Check(Id.KW_Var, r.name,
2223	r.blame_tok)
2224
2225	if sig.block_param:
2226	b = sig.block_param
2227	self.var_checker.Check(Id.KW_Var, b.name, b.blame_tok)
2228
2229	self._SetNext()
2230	node.body = self.ParseBraceGroup()
2231	# No redirects for YSH procs (only at call site)
2232
2233	return node
2234
2235	def ParseYshFunc(self):
2236	# type: () -> Func
2237	"""
2238	ysh_func: (
2239	Expr_Name '(' [func_params] [';' func_params] ')' ['=>' type_expr] '{'
2240	)
2241	Looking at KW_Func
2242	"""
2243	node = Func.CreateNull(alloc_lists=True)
2244
2245	keyword_tok = word_.AsKeywordToken(self.cur_word)
2246	node.keyword = keyword_tok
2247
2248	with ctx_VarChecker(self.var_checker, keyword_tok):
2249	self.w_parser.ParseFunc(node)
2250
2251	posit = node.positional
2252	if posit:
2253	for param in posit.params:
2254	self.var_checker.Check(Id.KW_Var, param.name,
2255	param.blame_tok)
2256	if posit.rest_of:
2257	r = posit.rest_of
2258	self.var_checker.Check(Id.KW_Var, r.name, r.blame_tok)
2259
2260	named = node.named
2261	if named:
2262	for param in named.params:
2263	self.var_checker.Check(Id.KW_Var, param.name,
2264	param.blame_tok)
2265	if named.rest_of:
2266	r = named.rest_of
2267	self.var_checker.Check(Id.KW_Var, r.name, r.blame_tok)
2268
2269	self._SetNext()
2270	with ctx_CmdMode(self, cmd_mode_e.Func):
2271	node.body = self.ParseBraceGroup()
2272
2273	return node
2274
2275	def ParseCoproc(self):
2276	# type: () -> command_t
2277	"""
2278	TODO: command.Coproc?
2279	"""
2280	raise NotImplementedError()
2281
2282	def ParseSubshell(self):
2283	# type: () -> command.Subshell
2284	"""
2285	subshell : '(' compound_list ')'
2286
2287	Looking at Op_LParen
2288	"""
2289	left = word_.AsOperatorToken(self.cur_word)
2290	self._SetNext() # skip past (
2291
2292	# Ensure that something $( (cd / && pwd) ) works. If ) is already on the
2293	# translation stack, we want to delay it.
2294
2295	self.lexer.PushHint(Id.Op_RParen, Id.Right_Subshell)
2296
2297	c_list = self._ParseCommandList()
2298	if len(c_list.children) == 1:
2299	child = c_list.children[0]
2300	else:
2301	child = c_list
2302
2303	ate = self._Eat(Id.Right_Subshell)
2304	right = word_.AsOperatorToken(ate)
2305
2306	return command.Subshell(left, child, right)
2307
2308	def ParseDBracket(self):
2309	# type: () -> command.DBracket
2310	"""Pass the underlying word parser off to the boolean expression
2311	parser."""
2312	left = word_.AsKeywordToken(self.cur_word)
2313	# TODO: Test interactive. Without closing ]], you should get > prompt
2314	# (PS2)
2315
2316	self._SetNext() # skip [[
2317	b_parser = bool_parse.BoolParser(self.w_parser)
2318	bnode, right = b_parser.Parse() # May raise
2319	return command.DBracket(left, bnode, right)
2320
2321	def ParseDParen(self):
2322	# type: () -> command.DParen
2323	left = word_.AsOperatorToken(self.cur_word)
2324
2325	self._SetNext() # skip ((
2326	anode, right = self.w_parser.ReadDParen()
2327	assert anode is not None
2328
2329	return command.DParen(left, anode, right)
2330
2331	def ParseCommand(self):
2332	# type: () -> command_t
2333	"""
2334	command : simple_command
2335	\| compound_command # OSH edit: io_redirect* folded in
2336	\| function_def
2337	\| ksh_function_def
2338
2339	# YSH extensions
2340	\| proc NAME ...
2341	\| typed proc NAME ...
2342	\| func NAME ...
2343	\| const ...
2344	\| var ...
2345	\| setglobal ...
2346	\| setref ...
2347	\| setvar ...
2348	\| call EXPR
2349	\| = EXPR
2350	;
2351
2352	Note: the reason const / var are not part of compound_command is because
2353	they can't be alone in a shell function body.
2354
2355	Example:
2356	This is valid shell f() if true; then echo hi; fi
2357	This is invalid f() var x = 1
2358	"""
2359	if self._AtSecondaryKeyword():
2360	p_die('Unexpected word when parsing command',
2361	loc.Word(self.cur_word))
2362
2363	# YSH Extensions
2364
2365	if self.c_id == Id.KW_Proc: # proc p { ... }
2366	# proc is hidden because of the 'local reasoning' principle. Code
2367	# inside procs should be YSH, full stop. That means ysh:upgrade is
2368	# on.
2369	if self.parse_opts.parse_proc():
2370	return self.ParseYshProc()
2371	else:
2372	# 2024-02: This avoids bad syntax errors if you type YSH code
2373	# into OSH
2374	# proc p (x) { echo hi } would actually be parsed as a
2375	# command.Simple! Shell compatibility: quote 'proc'
2376	p_die("proc is a YSH keyword, but this is OSH.",
2377	loc.Word(self.cur_word))
2378
2379	if self.c_id == Id.KW_Typed: # typed proc p () { ... }
2380	self._SetNext()
2381	self._GetWord()
2382	if self.c_id != Id.KW_Proc:
2383	p_die("Expected 'proc' after 'typed'", loc.Word(self.cur_word))
2384
2385	if self.parse_opts.parse_proc():
2386	return self.ParseYshProc()
2387	else:
2388	p_die("typed is a YSH keyword, but this is OSH.",
2389	loc.Word(self.cur_word))
2390
2391	if self.c_id == Id.KW_Func: # func f(x) { ... }
2392	if self.parse_opts.parse_func():
2393	return self.ParseYshFunc()
2394	else:
2395	# Same reasoning as above, for 'proc'
2396	p_die("func is a YSH keyword, but this is OSH.",
2397	loc.Word(self.cur_word))
2398
2399	if self.c_id == Id.KW_Const and self.cmd_mode != cmd_mode_e.Shell:
2400	p_die("const can't be inside proc or func. Use var instead.",
2401	loc.Word(self.cur_word))
2402
2403	if self.c_id in (Id.KW_Var, Id.KW_Const): # var x = 1
2404	keyword_id = self.c_id
2405	kw_token = word_.LiteralToken(self.cur_word)
2406	self._SetNext()
2407	n8 = self.w_parser.ParseVarDecl(kw_token)
2408	for lhs in n8.lhs:
2409	self.var_checker.Check(keyword_id, lhs.name, lhs.left)
2410	return n8
2411
2412	if self.c_id in (Id.KW_SetVar, Id.KW_SetGlobal):
2413	kw_token = word_.LiteralToken(self.cur_word)
2414	self._SetNext()
2415	n9 = self.w_parser.ParseMutation(kw_token, self.var_checker)
2416	return n9
2417
2418	if self.c_id in (Id.KW_Call, Id.Lit_Equals):
2419	# = 42 + a[i]
2420	# call mylist->append('x')
2421
2422	keyword = word_.LiteralToken(self.cur_word)
2423	assert keyword is not None
2424	self._SetNext()
2425	enode = self.w_parser.ParseCommandExpr()
2426	return command.Expr(keyword, enode)
2427
2428	if self.c_id == Id.KW_Function:
2429	return self.ParseKshFunctionDef()
2430
2431	if self.c_id in (Id.KW_DLeftBracket, Id.Op_DLeftParen, Id.Op_LParen,
2432	Id.Lit_LBrace, Id.KW_For, Id.KW_While, Id.KW_Until,
2433	Id.KW_If, Id.KW_Case, Id.KW_Time):
2434	return self.ParseCompoundCommand()
2435
2436	# Syntax error for '}' starting a line, which all shells disallow.
2437	if self.c_id == Id.Lit_RBrace:
2438	p_die('Unexpected right brace', loc.Word(self.cur_word))
2439
2440	if self.c_kind == Kind.Redir: # Leading redirect
2441	return self.ParseSimpleCommand()
2442
2443	if self.c_kind == Kind.Word:
2444	# ensured by Kind.Word
2445	cur_word = cast(CompoundWord, self.cur_word)
2446
2447	# NOTE: At the top level, only Token and Compound are possible.
2448	# Can this be modelled better in the type system, removing asserts?
2449	#
2450	# TODO: This can be a proc INVOCATION! (Doesn't even need parse_paren)
2451	# Problem: We have to distinguish f( ) { echo ; } and myproc (x, y)
2452	# That requires 2 tokens of lookahead, which we don't have
2453	#
2454	# Or maybe we don't just have ParseSimpleCommand -- we will have
2455	# ParseYshCommand or something
2456
2457	if (self.w_parser.LookAheadFuncParens() and
2458	not word_.IsVarLike(cur_word)):
2459	return self.ParseFunctionDef() # f() { echo; } # function
2460
2461	# Parse x = 1+2*3 when inside HayNode { } blocks
2462	parts = cur_word.parts
2463	if self.parse_opts.parse_equals() and len(parts) == 1:
2464	part0 = parts[0]
2465	if part0.tag() == word_part_e.Literal:
2466	tok = cast(Token, part0)
2467	if (tok.id == Id.Lit_Chars and
2468	self.w_parser.LookPastSpace() == Id.Lit_Equals and
2469	match.IsValidVarName(lexer.LazyStr(tok))):
2470
2471	if (len(self.hay_attrs_stack) and
2472	self.hay_attrs_stack[-1]):
2473	# Note: no static var_checker.Check() for bare assignment
2474	enode = self.w_parser.ParseBareDecl()
2475	self._SetNext() # Somehow this is necessary
2476	# TODO: Use BareDecl here. Well, do that when we
2477	# treat it as const or lazy.
2478	return command.VarDecl(
2479	None,
2480	[NameType(tok, lexer.TokenVal(tok), None)],
2481	enode)
2482	else:
2483	self._SetNext()
2484	self._GetWord()
2485	p_die(
2486	'Unexpected = (Hint: use var/setvar, or quote it)',
2487	loc.Word(self.cur_word))
2488
2489	# echo foo
2490	# f=(a b c) # array
2491	# array[1+2]+=1
2492	return self.ParseSimpleCommand()
2493
2494	if self.c_kind == Kind.Eof:
2495	p_die("Unexpected EOF while parsing command",
2496	loc.Word(self.cur_word))
2497
2498	# NOTE: This only happens in batch mode in the second turn of the loop!
2499	# e.g. )
2500	p_die("Invalid word while parsing command", loc.Word(self.cur_word))
2501
2502	assert False # for MyPy
2503
2504	def ParsePipeline(self):
2505	# type: () -> command_t
2506	"""
2507	pipeline : Bang? command ( '\|' newline_ok command )* ;
2508	"""
2509	negated = None # type: Optional[Token]
2510
2511	self._GetWord()
2512	if self.c_id == Id.KW_Bang:
2513	negated = word_.AsKeywordToken(self.cur_word)
2514	self._SetNext()
2515
2516	child = self.ParseCommand()
2517	assert child is not None
2518
2519	children = [child]
2520
2521	self._GetWord()
2522	if self.c_id not in (Id.Op_Pipe, Id.Op_PipeAmp):
2523	if negated is not None:
2524	node = command.Pipeline(negated, children, [])
2525	return node
2526	else:
2527	return child # no pipeline
2528
2529	# \| or \|&
2530	ops = [] # type: List[Token]
2531	while True:
2532	op = word_.AsOperatorToken(self.cur_word)
2533	ops.append(op)
2534
2535	self._SetNext() # skip past Id.Op_Pipe or Id.Op_PipeAmp
2536	self._NewlineOk()
2537
2538	child = self.ParseCommand()
2539	children.append(child)
2540
2541	self._GetWord()
2542	if self.c_id not in (Id.Op_Pipe, Id.Op_PipeAmp):
2543	break
2544
2545	return command.Pipeline(negated, children, ops)
2546
2547	def ParseAndOr(self):
2548	# type: () -> command_t
2549	self._GetWord()
2550	if self.c_id == Id.Lit_TDot:
2551	# We got '...', so parse in multiline mode
2552	self._SetNext()
2553	with word_.ctx_Multiline(self.w_parser):
2554	return self._ParseAndOr()
2555
2556	# Parse in normal mode, not multiline
2557	return self._ParseAndOr()
2558
2559	def _ParseAndOr(self):
2560	# type: () -> command_t
2561	"""
2562	and_or : and_or ( AND_IF \| OR_IF ) newline_ok pipeline
2563	\| pipeline
2564
2565	Note that it is left recursive and left associative. We parse it
2566	iteratively with a token of lookahead.
2567	"""
2568	child = self.ParsePipeline()
2569	assert child is not None
2570
2571	self._GetWord()
2572	if self.c_id not in (Id.Op_DPipe, Id.Op_DAmp):
2573	return child
2574
2575	ops = [] # type: List[Token]
2576	children = [child]
2577
2578	while True:
2579	ops.append(word_.AsOperatorToken(self.cur_word))
2580
2581	self._SetNext() # skip past \|\| &&
2582	self._NewlineOk()
2583
2584	child = self.ParsePipeline()
2585	children.append(child)
2586
2587	self._GetWord()
2588	if self.c_id not in (Id.Op_DPipe, Id.Op_DAmp):
2589	break
2590
2591	return command.AndOr(children, ops)
2592
2593	# NOTE: _ParseCommandLine and _ParseCommandTerm are similar, but different.
2594
2595	# At the top level, we execute after every line, e.g. to
2596	# - process alias (a form of dynamic parsing)
2597	# - process 'exit', because invalid syntax might appear after it
2598
2599	# On the other hand, for a while loop body, we parse the whole thing at once,
2600	# and then execute it. We don't want to parse it over and over again!
2601
2602	# COMPARE
2603	# command_line : and_or (sync_op and_or)* trailer? ; # TOP LEVEL
2604	# command_term : and_or (trailer and_or)* ; # CHILDREN
2605
2606	def _ParseCommandLine(self):
2607	# type: () -> command_t
2608	"""
2609	command_line : and_or (sync_op and_or)* trailer? ;
2610	trailer : sync_op newline_ok
2611	\| NEWLINES;
2612	sync_op : '&' \| ';';
2613
2614	NOTE: This rule causes LL(k > 1) behavior. We would have to peek to see if
2615	there is another command word after the sync op.
2616
2617	But it's easier to express imperatively. Do the following in a loop:
2618	1. ParseAndOr
2619	2. Peek.
2620	a. If there's a newline, then return. (We're only parsing a single
2621	line.)
2622	b. If there's a sync_op, process it. Then look for a newline and
2623	return. Otherwise, parse another AndOr.
2624	"""
2625	# This END_LIST is slightly different than END_LIST in _ParseCommandTerm.
2626	# I don't think we should add anything else here; otherwise it will be
2627	# ignored at the end of ParseInteractiveLine(), e.g. leading to bug #301.
2628	END_LIST = [Id.Op_Newline, Id.Eof_Real]
2629
2630	children = [] # type: List[command_t]
2631	done = False
2632	while not done:
2633	child = self.ParseAndOr()
2634
2635	self._GetWord()
2636	if self.c_id in (Id.Op_Semi, Id.Op_Amp):
2637	tok = cast(Token, self.cur_word) # for MyPy
2638	child = command.Sentence(child, tok)
2639	self._SetNext()
2640
2641	self._GetWord()
2642	if self.c_id in END_LIST:
2643	done = True
2644
2645	elif self.c_id in END_LIST:
2646	done = True
2647
2648	else:
2649	# e.g. echo a(b)
2650	p_die(
2651	'Invalid word while parsing command line (%s)' %
2652	Id_str(self.c_id), loc.Word(self.cur_word))
2653
2654	children.append(child)
2655
2656	# Simplify the AST.
2657	if len(children) > 1:
2658	return command.CommandList(children)
2659	else:
2660	return children[0]
2661
2662	def _ParseCommandTerm(self):
2663	# type: () -> command.CommandList
2664	""""
2665	command_term : and_or (trailer and_or)* ;
2666	trailer : sync_op newline_ok
2667	\| NEWLINES;
2668	sync_op : '&' \| ';';
2669
2670	This is handled in imperative style, like _ParseCommandLine.
2671	Called by _ParseCommandList for all blocks, and also for ParseCaseArm,
2672	which is slightly different. (HOW? Is it the DSEMI?)
2673
2674	Returns:
2675	syntax_asdl.command
2676	"""
2677	# Token types that will end the command term.
2678	END_LIST = [
2679	self.eof_id, Id.Right_Subshell, Id.Lit_RBrace, Id.Op_DSemi,
2680	Id.Op_SemiAmp, Id.Op_DSemiAmp
2681	]
2682
2683	# NOTE: This is similar to _ParseCommandLine.
2684	#
2685	# - Why aren't we doing END_LIST in _ParseCommandLine?
2686	# - Because you will never be inside $() at the top level.
2687	# - We also know it will end in a newline. It can't end in "fi"!
2688	# - example: if true; then { echo hi; } fi
2689
2690	children = [] # type: List[command_t]
2691	done = False
2692	while not done:
2693	# Most keywords are valid "first words". But do/done/then do not BEGIN
2694	# commands, so they are not valid.
2695	if self._AtSecondaryKeyword():
2696	break
2697
2698	child = self.ParseAndOr()
2699
2700	self._GetWord()
2701	if self.c_id == Id.Op_Newline:
2702	self._SetNext()
2703
2704	self._GetWord()
2705	if self.c_id in END_LIST:
2706	done = True
2707
2708	elif self.c_id in (Id.Op_Semi, Id.Op_Amp):
2709	tok = cast(Token, self.cur_word) # for MyPy
2710	child = command.Sentence(child, tok)
2711	self._SetNext()
2712
2713	self._GetWord()
2714	if self.c_id == Id.Op_Newline:
2715	self._SetNext() # skip over newline
2716
2717	# Test if we should keep going. There might be another command after
2718	# the semi and newline.
2719	self._GetWord()
2720	if self.c_id in END_LIST: # \n EOF
2721	done = True
2722
2723	elif self.c_id in END_LIST: # ; EOF
2724	done = True
2725
2726	elif self.c_id in END_LIST: # EOF
2727	done = True
2728
2729	# For if test -f foo; test -f bar {
2730	elif self.parse_opts.parse_brace() and self.c_id == Id.Lit_LBrace:
2731	done = True
2732
2733	elif self.c_kind != Kind.Word:
2734	# e.g. f() { echo (( x )) ; }
2735	# but can't fail on 'fi fi', see osh/cmd_parse_test.py
2736
2737	#log("Invalid %s", self.cur_word)
2738	p_die("Invalid word while parsing command list",
2739	loc.Word(self.cur_word))
2740
2741	children.append(child)
2742
2743	return command.CommandList(children)
2744
2745	def _ParseCommandList(self):
2746	# type: () -> command.CommandList
2747	"""
2748	command_list : newline_ok command_term trailer? ;
2749
2750	This one is called by all the compound commands. It's basically a command
2751	block.
2752
2753	NOTE: Rather than translating the CFG directly, the code follows a style
2754	more like this: more like this: (and_or trailer)+. It makes capture
2755	easier.
2756	"""
2757	self._NewlineOk()
2758	return self._ParseCommandTerm()
2759
2760	def ParseLogicalLine(self):
2761	# type: () -> command_t
2762	"""Parse a single line for main_loop.
2763
2764	A wrapper around _ParseCommandLine(). Similar but not identical to
2765	_ParseCommandList() and ParseCommandSub().
2766
2767	Raises:
2768	ParseError
2769	"""
2770	self._NewlineOk()
2771	self._GetWord()
2772	if self.c_id == Id.Eof_Real:
2773	return None # main loop checks for here docs
2774	node = self._ParseCommandLine()
2775	return node
2776
2777	def ParseInteractiveLine(self):
2778	# type: () -> parse_result_t
2779	"""Parse a single line for Interactive main_loop.
2780
2781	Different from ParseLogicalLine because newlines are handled differently.
2782
2783	Raises:
2784	ParseError
2785	"""
2786	self._GetWord()
2787	if self.c_id == Id.Op_Newline:
2788	return parse_result.EmptyLine
2789	if self.c_id == Id.Eof_Real:
2790	return parse_result.Eof
2791
2792	node = self._ParseCommandLine()
2793	return parse_result.Node(node)
2794
2795	def ParseCommandSub(self):
2796	# type: () -> command_t
2797	"""Parse $(echo hi) and `echo hi` for word_parse.py.
2798
2799	They can have multiple lines, like this: echo $( echo one echo
2800	two )
2801	"""
2802	self._NewlineOk()
2803
2804	self._GetWord()
2805	if self.c_kind == Kind.Eof: # e.g. $()
2806	return command.NoOp
2807
2808	c_list = self._ParseCommandTerm()
2809	if len(c_list.children) == 1:
2810	return c_list.children[0]
2811	else:
2812	return c_list
2813
2814	def CheckForPendingHereDocs(self):
2815	# type: () -> None
2816	# NOTE: This happens when there is no newline at the end of a file, like
2817	# osh -c 'cat <<EOF'
2818	if len(self.pending_here_docs):
2819	node = self.pending_here_docs[0] # Just show the first one?
2820	h = cast(redir_param.HereDoc, node.arg)
2821	p_die('Unterminated here doc began here', loc.Word(h.here_begin))
2822
2823
2824	# vim: sw=4