OILS / core / value.asdl View on Github | oilshell.org

178 lines, 73 significant
1# Runtime value
2
3module value
4{
5 # import from frontend/syntax.asdl
6 use frontend syntax {
7 loc Token
8 expr command
9 DoubleQuoted
10 re proc_sig
11 LiteralBlock Func
12 NameType
13 EggexFlag
14 }
15
16 use core runtime {
17 Cell
18 }
19
20 IntBox = (int i)
21
22 ProcDefaults = (
23 List[value]? for_word, # all of them are value.Str
24 List[value]? for_typed,
25 Dict[str, value]? for_named,
26 value? for_block,
27 )
28
29 LeftName = (str name, loc blame_loc)
30
31 # for setvar, and value.Place
32 y_lvalue =
33 # e.g. read (&x)
34 Local %LeftName
35 # e.g. &a[0][1].key -- we evaluate a[0][1] first
36 | Container(value obj, value index)
37
38 # An sh_lvalue is for things mutation that happen with dynamic scope
39 #
40 # - sh_expr_eval uses this for unset / printf -v
41 # - word_eval uses this for ${a[0]=}
42 # - expr_eval / cmd_eval use this for setvar a[i] = 42
43 sh_lvalue =
44 Var %LeftName
45 | Indexed(str name, int index, loc blame_loc)
46 | Keyed(str name, str key, loc blame_loc)
47
48 eggex_ops =
49 # for BASH_REMATCH or ~ with a string
50 No
51 # These lists are indexed by group number, and will have None entries
52 | Yes(List[value?] convert_funcs, List[Token?] convert_toks,
53 List[str?] capture_names)
54
55 RegexMatch = (str s, List[int] indices, eggex_ops ops)
56
57 regex_match =
58 No
59 | Yes %RegexMatch
60
61 # prototype is for the attribute lookup chain
62 Dict_ = (Dict[str, value] d, Dict_? prototype)
63
64 # Commands, words, and expressions from syntax.asdl are evaluated to a VALUE.
65 # value_t instances are stored in state.Mem().
66 value =
67 # Only used for val_ops.StdinIterator. (It would be nice if we could
68 # express iter_value.{Eof,Interrupted,Str,Int,...} in ASDL)
69 Interrupted
70 | Stdin
71
72 # Methods on state.Mem return value.Undef, but it's not visible in YSH.
73 #
74 # A var bound to Undef is different than no binding because of dynamic
75 # scope. Undef can shadow values lower on the stack.
76 | Undef
77
78 | Str(str s)
79
80 # "holes" in the array are represented by None
81 | BashArray(List[str] strs)
82 # TODO: Switch to this more efficient representation?
83 # max_index makes append-sparse workload faster, and normal append loops too
84 | SparseArray(Dict[BigInt, str] d, BigInt max_index)
85
86 | BashAssoc(Dict[str, str] d)
87
88 # DATA model for YSH follows JSON. Note: YSH doesn't have 'undefined' and
89 # 'null' like JavaScript, just 'null'.
90 | Null
91 | Bool(bool b)
92 | Int(BigInt i)
93 #| Int(int i)
94 | Float(float f)
95 | List(List[value] items)
96 | Dict %Dict_
97
98 # CODE types
99 # unevaluated: Eggex, Expr, Template, Command/Block
100 # callable, in separate namespaces: Func, BoundFunc, Proc
101
102 # expr is spliced
103 # / d+; ignorecase / -> '[[:digit:]]+' REG_ICASE
104 | Eggex(re spliced, str canonical_flags,
105 List[value?] convert_funcs, List[Token?] convert_toks,
106 # str? is because some groups are not named
107 str? as_ere, List[str?] capture_names)
108
109 # The indices list has 2 * (num_group + 1) entries. Group 0 is the whole
110 # match, and each group has both a start and end index.
111 # It's flat to reduce allocations. The group() start() end() funcs/methods
112 # provide a nice interface.
113 | Match %RegexMatch
114
115 # ^[42 + a[i]]
116 | Expr(expr e)
117
118 # ^(echo 1; echo 2) and cd { echo 1; echo 2 }
119 | Command(command c)
120
121 # for Hay to get the backing lines
122 # TODO: Consolidate value.Command and value.LiteralBlock. All Command
123 # instance should have backing lines.
124
125 # TODO: ASDL doesn't support shared variant across module
126 # This would be more efficient
127 # | LiteralBlock %LiteralBlock
128 | Block(LiteralBlock block)
129
130 # A place has an additional stack frame where the value is evaluated.
131 # The frame MUST be lower on the stack at the time of use.
132 | Place(y_lvalue lval, Dict[str, Cell] frame)
133
134 # for Flags/flag and Flags/arg?
135 # for json read/write ?
136 # Possibly unify Hay and modules/namespaces
137 | Module(Dict[str, value] defs)
138
139 # The ability to use operating system functions. Right now some functions
140 # leak, like glob().
141 | IO(any cmd_ev, any prompt_ev)
142
143 # Do we need this?
144 # _guts->heapId() can be used to detect object cycles.
145 # It's considered impure; it depends on VM implementation details. The =
146 # operator and 'pp value' also print the heap ID.
147 | Guts(any vm)
148
149 # callable is vm._Callable.
150 # TODO: ASDL needs some kind of "extern" to declare vm._Callable and
151 # cmd_eval.CommandEvaluator. I think it would just generate a forward
152 # declaration.
153 | BuiltinFunc(any callable)
154 | BoundFunc(value me, value func)
155
156 # command.ShFunction and command.Proc evaluate to value.Proc
157 # They each have name, name_tok, and body.
158 #
159 # YSH procs disable dynamic scope, have default args to evaluate, and
160 # different @ARGV.
161
162 | Proc(str name, Token name_tok, proc_sig sig, command body,
163 ProcDefaults? defaults, bool sh_compat)
164
165 # module may be a frame where defined
166 | Func(str name, Func parsed,
167 List[value] pos_defaults, Dict[str, value] named_defaults,
168 Dict[str, Cell]? module_)
169
170 # a[3:5] a[:10] a[3:] a[:] # both ends are optional
171 | Slice(IntBox? lower, IntBox? upper)
172
173 # for i in (1:n) { echo $i } # both ends are required
174 | Range(int lower, int upper)
175}
176
177# vim: sw=2
178