| 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: 6
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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 $this
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| 94 | }
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| 95 |
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| 96 | ## status: 1
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| 97 | ## STDOUT:
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| 98 | TODO
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| 99 | ## END
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| 100 |
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| 101 | #### eval with argv bindings
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| 102 | eval ^[echo "$@"] (argv=:| foo bar baz |)
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| 103 | eval ^[pp line (:| $1 $2 $3 |)] (argv=:| foo bar baz |)
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| 104 |
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| 105 | ## status: 0
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| 106 | ## STDOUT:
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| 107 | foo bar baz
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| 108 | (List) ["foo","bar","baz"]
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| 109 | ## END
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| 110 |
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| 111 | #### eval with vars bindings
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| 112 | var myVar = "abc"
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| 113 | eval (^(pp line (myVar)))
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| 114 | eval (^(pp line (myVar)), vars={ 'myVar': '123' })
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| 115 |
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| 116 | # eval doesn't modify it's environment
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| 117 | eval (^(pp line (myVar)))
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| 118 |
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| 119 | ## status: 0
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| 120 | ## STDOUT:
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| 121 | abc
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| 122 | 123
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| 123 | ## END
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| 124 |
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| 125 | #### dynamic binding names and mutation
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| 126 | proc foreach (binding, in_; list ;; block) {
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| 127 | if (in_ !== "in") {
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| 128 | error 'Must use the "syntax" `foreach <binding> in (<expr>) { ... }`'
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| 129 | }
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| 130 |
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| 131 | for _ in (list) {
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| 132 | eval (block, vars={ binding: _ })
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| 133 | }
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| 134 | }
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| 135 |
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| 136 | var mydicts = [{'a': 1}, {'b': 2}, {'c': 3}]
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| 137 | foreach mydict in (mydicts) {
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| 138 | pp line (mydict)
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| 139 | setvar mydict.d = 0
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| 140 | }
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| 141 |
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| 142 | pp line (mydicts)
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| 143 |
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| 144 | ## status: 0
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| 145 | ## STDOUT:
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| 146 | (Dict) {"a":1}
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| 147 | (Dict) {"b":2}
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| 148 | (Dict) {"c":3}
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| 149 | (List) [{"a":1,"d":0},{"b":2,"d":0},{"c":3,"d":0}]
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| 150 | ## END
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| 151 |
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| 152 | #### binding procs in the eval-ed namespace
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| 153 | proc __flag (short, long) {
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| 154 | echo "flag $short $long"
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| 155 | }
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| 156 |
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| 157 | proc __arg (name) {
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| 158 | echo "arg $name"
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| 159 | }
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| 160 |
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| 161 | proc parser (; spec ;; block) {
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| 162 | eval (block, vars={ 'flag': __flag, 'arg': __arg })
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| 163 | }
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| 164 |
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| 165 | parser (&spec) {
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| 166 | flag -h --help
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| 167 | arg file
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| 168 | }
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| 169 |
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| 170 | ## status: 0
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| 171 | ## STDOUT:
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| 172 | flag -h --help
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| 173 | arg file
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| 174 | ## END
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| 175 |
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| 176 | #### vars initializes the variable frame, but does not remember it
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| 177 | var vars = { 'foo': 123 }
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| 178 | eval (^(var bar = 321), vars=vars)
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| 179 | pp line vars
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| 180 |
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| 181 | ## status: 0
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| 182 | ## STDOUT:
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| 183 | (Dict) {"foo":123}
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| 184 | ## END
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