| 1 | # YSH specific features of eval
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| 2 |
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| 3 | ## our_shell: ysh
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| 4 | ## oils_failures_allowed: 8
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| 5 |
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| 6 | #### Eval does not take a literal block - can restore this later
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| 7 |
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| 8 | var b = ^(echo obj)
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| 9 | eval (b)
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| 10 |
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| 11 | eval (^(echo command literal))
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| 12 |
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| 13 | # Doesn't work because it's a positional arg
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| 14 | eval { echo block }
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| 15 |
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| 16 | ## status: 3
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| 17 | ## STDOUT:
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| 18 | obj
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| 19 | command literal
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| 20 | ## END
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| 21 |
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| 22 |
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| 23 | #### Eval a block within a proc
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| 24 | proc run (;;; block) {
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| 25 | eval (block)
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| 26 | }
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| 27 |
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| 28 | run {
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| 29 | echo 'In a block!'
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| 30 | }
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| 31 | ## STDOUT:
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| 32 | In a block!
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| 33 | ## END
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| 34 |
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| 35 | #### Eval block created by calling a proc
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| 36 | proc lazy-block ( ; out; ; block) {
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| 37 | call out->setValue(block)
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| 38 | }
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| 39 |
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| 40 | var myglobal = 0
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| 41 |
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| 42 | lazy-block (&my_block) {
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| 43 | json write (myglobal)
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| 44 | }
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| 45 |
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| 46 | eval (my_block)
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| 47 | setvar myglobal = 1
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| 48 | eval (my_block)
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| 49 | ## STDOUT:
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| 50 | 0
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| 51 | 1
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| 52 | ## END
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| 53 |
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| 54 | #### eval (block) can read variables like eval ''
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| 55 |
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| 56 | proc p2(code_str) {
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| 57 | var mylocal = 42
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| 58 | eval $code_str
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| 59 | }
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| 60 |
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| 61 | p2 'echo mylocal=$mylocal'
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| 62 |
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| 63 | proc p (;;; block) {
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| 64 | var mylocal = 99
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| 65 | eval (block)
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| 66 | }
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| 67 |
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| 68 | p {
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| 69 | echo mylocal=$mylocal
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| 70 | }
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| 71 |
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| 72 |
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| 73 | ## STDOUT:
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| 74 | mylocal=42
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| 75 | mylocal=99
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| 76 | ## END
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| 77 |
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| 78 | #### eval should have a sandboxed mode
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| 79 |
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| 80 | proc p (;;; block) {
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| 81 | var this = 42
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| 82 |
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| 83 | # like push-registers? Not sure
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| 84 | # We could use state.ctx_Temp ? There's also ctx_FuncCall etc.
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| 85 | #
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| 86 | # I think we want to provide full control over the stack.
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| 87 | push-frame {
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| 88 | eval (block)
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| 89 | }
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| 90 | }
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| 91 |
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| 92 | p {
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| 93 | echo $this
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| 94 | }
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| 95 |
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| 96 | ## status: 1
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| 97 | ## STDOUT:
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| 98 | TODO
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| 99 | ## END
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| 100 |
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| 101 | #### eval with argv bindings
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| 102 | eval (^(echo "$@")) (pos_args=:| foo bar baz |)
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| 103 | eval (^(pp test_ (:| $1 $2 $3 |))) (pos_args=:| foo bar baz |)
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| 104 | ## STDOUT:
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| 105 | foo bar baz
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| 106 | (List) ["foo","bar","baz"]
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| 107 | ## END
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| 108 |
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| 109 | #### eval lines with argv bindings
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| 110 | proc lines (;;; block) {
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| 111 | while read --line {
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| 112 | var cols = _reply => split()
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| 113 | eval (block, pos_args=cols)
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| 114 | }
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| 115 | }
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| 116 |
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| 117 | printf 'a b\nc d' | lines { echo $1 }
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| 118 |
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| 119 | ## STDOUT:
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| 120 | a
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| 121 | c
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| 122 | ## END
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| 123 |
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| 124 | #### eval with custom arg0
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| 125 | eval (^(write $0)) (arg0="my arg0")
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| 126 | ## STDOUT:
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| 127 | my arg0
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| 128 | ## END
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| 129 |
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| 130 | #### eval with vars bindings
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| 131 | var myVar = "abc"
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| 132 | eval (^(pp test_ (myVar)))
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| 133 | eval (^(pp test_ (myVar)), vars={ 'myVar': '123' })
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| 134 |
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| 135 | # eval doesn't modify it's environment
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| 136 | eval (^(pp test_ (myVar)))
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| 137 |
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| 138 | ## STDOUT:
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| 139 | abc
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| 140 | 123
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| 141 | ## END
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| 142 |
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| 143 | #### dynamic binding names and mutation
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| 144 | proc foreach (binding, in_; list ;; block) {
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| 145 | if (in_ !== "in") {
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| 146 | error 'Must use the "syntax" `foreach <binding> in (<expr>) { ... }`'
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| 147 | }
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| 148 |
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| 149 | for _ in (list) {
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| 150 | eval (block, vars={ binding: _ })
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| 151 | }
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| 152 | }
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| 153 |
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| 154 | var mydicts = [{'a': 1}, {'b': 2}, {'c': 3}]
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| 155 | foreach mydict in (mydicts) {
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| 156 | pp test_ (mydict)
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| 157 | setvar mydict.d = 0
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| 158 | }
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| 159 |
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| 160 | pp test_ (mydicts)
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| 161 |
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| 162 | ## STDOUT:
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| 163 | (Dict) {"a":1}
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| 164 | (Dict) {"b":2}
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| 165 | (Dict) {"c":3}
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| 166 | (List) [{"a":1,"d":0},{"b":2,"d":0},{"c":3,"d":0}]
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| 167 | ## END
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| 168 |
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| 169 | #### binding procs in the eval-ed namespace
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| 170 | proc __flag (short, long) {
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| 171 | echo "flag $short $long"
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| 172 | }
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| 173 |
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| 174 | proc __arg (name) {
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| 175 | echo "arg $name"
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| 176 | }
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| 177 |
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| 178 | proc parser (; spec ;; block) {
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| 179 | eval (block, vars={ 'flag': __flag, 'arg': __arg })
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| 180 | }
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| 181 |
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| 182 | parser (&spec) {
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| 183 | flag -h --help
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| 184 | arg file
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| 185 | }
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| 186 |
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| 187 | # but flag/arg are unavailable outside of `parser`
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| 188 | # _error.code = 127 is set on "command not found" errors
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| 189 |
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| 190 | try { flag }
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| 191 | if (_error.code !== 127) { error 'expected failure' }
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| 192 |
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| 193 | try { arg }
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| 194 | if (_error.code !== 127) { error 'expected failure' }
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| 195 |
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| 196 | ## STDOUT:
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| 197 | flag -h --help
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| 198 | arg file
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| 199 | ## END
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| 200 |
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| 201 | #### vars initializes the variable frame, but does not remember it
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| 202 | var vars = { 'foo': 123 }
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| 203 | eval (^(var bar = 321), vars=vars)
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| 204 | pp test_ (vars)
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| 205 |
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| 206 | ## STDOUT:
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| 207 | (Dict) {"foo":123}
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| 208 | ## END
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| 209 |
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| 210 | #### eval 'mystring' vs. eval (myblock)
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| 211 |
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| 212 | eval 'echo plain'
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| 213 | echo plain=$?
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| 214 | var b = ^(echo plain)
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| 215 | eval (b)
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| 216 | echo plain=$?
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| 217 |
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| 218 | echo
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| 219 |
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| 220 | # This calls main_loop.Batch(), which catches
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| 221 | # - error.Parse
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| 222 | # - error.ErrExit
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| 223 | # - error.FatalRuntime - glob errors, etc.?
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| 224 |
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| 225 | try {
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| 226 | eval 'echo one; false; echo two'
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| 227 | }
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| 228 | pp test_ (_error)
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| 229 |
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| 230 | # This calls CommandEvaluator.EvalCommand(), as blocks do
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| 231 |
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| 232 | var b = ^(echo one; false; echo two)
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| 233 | try {
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| 234 | eval (b)
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| 235 | }
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| 236 | pp test_ (_error)
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| 237 |
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| 238 | ## STDOUT:
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| 239 | plain
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| 240 | plain=0
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| 241 | plain
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| 242 | plain=0
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| 243 |
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| 244 | one
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| 245 | (Dict) {"code":1}
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| 246 | one
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| 247 | (Dict) {"code":1}
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| 248 | ## END
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