| 1 | # YSH specific features of eval
|
| 2 |
|
| 3 | ## our_shell: ysh
|
| 4 | ## oils_failures_allowed: 6
|
| 5 |
|
| 6 | #### Eval does not take a literal block - can restore this later
|
| 7 |
|
| 8 | var b = ^(echo obj)
|
| 9 | eval (b)
|
| 10 |
|
| 11 | eval (^(echo command literal))
|
| 12 |
|
| 13 | # Doesn't work because it's a positional arg
|
| 14 | eval { echo block }
|
| 15 |
|
| 16 | ## status: 3
|
| 17 | ## STDOUT:
|
| 18 | obj
|
| 19 | command literal
|
| 20 | ## END
|
| 21 |
|
| 22 |
|
| 23 | #### Eval a block within a proc
|
| 24 | proc run (;;; block) {
|
| 25 | eval (block)
|
| 26 | }
|
| 27 |
|
| 28 | run {
|
| 29 | echo 'In a block!'
|
| 30 | }
|
| 31 | ## STDOUT:
|
| 32 | In a block!
|
| 33 | ## END
|
| 34 |
|
| 35 | #### Eval block created by calling a proc
|
| 36 | proc lazy-block ( ; out; ; block) {
|
| 37 | call out->setValue(block)
|
| 38 | }
|
| 39 |
|
| 40 | var myglobal = 0
|
| 41 |
|
| 42 | lazy-block (&my_block) {
|
| 43 | json write (myglobal)
|
| 44 | }
|
| 45 |
|
| 46 | eval (my_block)
|
| 47 | setvar myglobal = 1
|
| 48 | eval (my_block)
|
| 49 | ## STDOUT:
|
| 50 | 0
|
| 51 | 1
|
| 52 | ## END
|
| 53 |
|
| 54 | #### eval (block) can read variables like eval ''
|
| 55 |
|
| 56 | proc p2(code_str) {
|
| 57 | var mylocal = 42
|
| 58 | eval $code_str
|
| 59 | }
|
| 60 |
|
| 61 | p2 'echo mylocal=$mylocal'
|
| 62 |
|
| 63 | proc p (;;; block) {
|
| 64 | var mylocal = 99
|
| 65 | eval (block)
|
| 66 | }
|
| 67 |
|
| 68 | p {
|
| 69 | echo mylocal=$mylocal
|
| 70 | }
|
| 71 |
|
| 72 |
|
| 73 | ## STDOUT:
|
| 74 | mylocal=42
|
| 75 | mylocal=99
|
| 76 | ## END
|
| 77 |
|
| 78 | #### eval should have a sandboxed mode
|
| 79 |
|
| 80 | proc p (;;; block) {
|
| 81 | var this = 42
|
| 82 |
|
| 83 | # like push-registers? Not sure
|
| 84 | # We could use state.ctx_Temp ? There's also ctx_FuncCall etc.
|
| 85 | #
|
| 86 | # I think we want to provide full control over the stack.
|
| 87 | push-frame {
|
| 88 | eval (block)
|
| 89 | }
|
| 90 | }
|
| 91 |
|
| 92 | p {
|
| 93 | echo $this
|
| 94 | }
|
| 95 |
|
| 96 | ## status: 1
|
| 97 | ## STDOUT:
|
| 98 | TODO
|
| 99 | ## END
|
| 100 |
|
| 101 | #### eval with argv bindings
|
| 102 | eval ^[echo "$@"] (argv=:| foo bar baz |)
|
| 103 | eval ^[pp line (:| $1 $2 $3 |)] (argv=:| foo bar baz |)
|
| 104 |
|
| 105 | ## status: 0
|
| 106 | ## STDOUT:
|
| 107 | foo bar baz
|
| 108 | (List) ["foo","bar","baz"]
|
| 109 | ## END
|
| 110 |
|
| 111 | #### eval with vars bindings
|
| 112 | var myVar = "abc"
|
| 113 | eval (^(pp line (myVar)))
|
| 114 | eval (^(pp line (myVar)), vars={ 'myVar': '123' })
|
| 115 |
|
| 116 | # eval doesn't modify it's environment
|
| 117 | eval (^(pp line (myVar)))
|
| 118 |
|
| 119 | ## status: 0
|
| 120 | ## STDOUT:
|
| 121 | abc
|
| 122 | 123
|
| 123 | ## END
|
| 124 |
|
| 125 | #### dynamic binding names and mutation
|
| 126 | proc foreach (binding, in_; list ;; block) {
|
| 127 | if (in_ !== "in") {
|
| 128 | error 'Must use the "syntax" `foreach <binding> in (<expr>) { ... }`'
|
| 129 | }
|
| 130 |
|
| 131 | for _ in (list) {
|
| 132 | eval (block, vars={ binding: _ })
|
| 133 | }
|
| 134 | }
|
| 135 |
|
| 136 | var mydicts = [{'a': 1}, {'b': 2}, {'c': 3}]
|
| 137 | foreach mydict in (mydicts) {
|
| 138 | pp line (mydict)
|
| 139 | setvar mydict.d = 0
|
| 140 | }
|
| 141 |
|
| 142 | pp line (mydicts)
|
| 143 |
|
| 144 | ## status: 0
|
| 145 | ## STDOUT:
|
| 146 | (Dict) {"a":1}
|
| 147 | (Dict) {"b":2}
|
| 148 | (Dict) {"c":3}
|
| 149 | (List) [{"a":1,"d":0},{"b":2,"d":0},{"c":3,"d":0}]
|
| 150 | ## END
|
| 151 |
|
| 152 | #### binding procs in the eval-ed namespace
|
| 153 | proc __flag (short, long) {
|
| 154 | echo "flag $short $long"
|
| 155 | }
|
| 156 |
|
| 157 | proc __arg (name) {
|
| 158 | echo "arg $name"
|
| 159 | }
|
| 160 |
|
| 161 | proc parser (; spec ;; block) {
|
| 162 | eval (block, vars={ 'flag': __flag, 'arg': __arg })
|
| 163 | }
|
| 164 |
|
| 165 | parser (&spec) {
|
| 166 | flag -h --help
|
| 167 | arg file
|
| 168 | }
|
| 169 |
|
| 170 | ## status: 0
|
| 171 | ## STDOUT:
|
| 172 | flag -h --help
|
| 173 | arg file
|
| 174 | ## END
|
| 175 |
|
| 176 | #### vars initializes the variable frame, but does not remember it
|
| 177 | var vars = { 'foo': 123 }
|
| 178 | eval (^(var bar = 321), vars=vars)
|
| 179 | pp line (vars)
|
| 180 |
|
| 181 | ## status: 0
|
| 182 | ## STDOUT:
|
| 183 | (Dict) {"foo":123}
|
| 184 | ## END
|