mirror of
https://github.com/go-sylixos/elvish.git
synced 2024-12-05 03:17:50 +08:00
122 lines
2.9 KiB
Go
122 lines
2.9 KiB
Go
package eval
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import (
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"strconv"
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"syscall"
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"src.elv.sh/pkg/buildinfo"
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"src.elv.sh/pkg/eval/vars"
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)
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//elvdoc:var _
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//
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// A blackhole variable.
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//
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// Values assigned to it will be discarded. Referencing it always results in $nil.
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//elvdoc:var args
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//
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// A list containing command-line arguments. Analogous to `argv` in some other
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// languages. Examples:
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//
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// ```elvish-transcript
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// ~> echo 'put $args' > args.elv
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// ~> elvish args.elv foo -bar
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// ▶ [foo -bar]
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// ~> elvish -c 'put $args' foo -bar
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// ▶ [foo -bar]
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// ```
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//
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// As demonstrated above, this variable does not contain the name of the script
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// used to invoke it. For that information, use the `src` command.
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//
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// @cf src
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//elvdoc:var false
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//
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// The boolean false value.
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//elvdoc:var ok
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//
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// The special value used by `?()` to signal absence of exceptions.
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//elvdoc:var nil
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//
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// A special value useful for representing the lack of values.
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//elvdoc:var paths
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//
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// A list of search paths, kept in sync with `$E:PATH`. It is easier to use than
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// `$E:PATH`.
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//elvdoc:var pid
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//
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// The process ID of the current Elvish process.
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//elvdoc:var pwd
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//
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// The present working directory. Setting this variable has the same effect as
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// `cd`. This variable is most useful in a temporary assignment.
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//
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// Example:
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//
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// ```elvish
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// ## Updates all git repositories
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// for x [*/] {
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// pwd=$x {
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// if ?(test -d .git) {
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// git pull
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// }
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// }
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// }
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// ```
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//
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// Etymology: the `pwd` command.
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//
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// @cf cd
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//elvdoc:var true
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//
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// The boolean true value.
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//elvdoc:var buildinfo
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//
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// A [psuedo-map](./language.html#pseudo-map) that exposes information about the Elvish binary.
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// Running `put $buildinfo | to-json` will produce the same output as `elvish -buildinfo -json`.
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//
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// @cf version
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//elvdoc:var version
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//
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// The full version of the Elvish binary as a string. This is the same information reported by
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// `elvish -version` and the value of `$buildinfo[version]`.
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//
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// **Note:** In general it is better to perform functionality tests rather than testing `$version`.
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// For example, do something like
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//
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// ```
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// has-key $builtin: new-var
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// ````
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//
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// to test if variable `new-var` is available rather than comparing against `$version` to see if the
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// elvish version is equal to or newer than the version that introduced `new-var`.
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//
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// @cf buildinfo
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var builtinNs = BuildNsNamed("").AddVars(map[string]vars.Var{
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"_": vars.NewBlackhole(),
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"pid": vars.NewReadOnly(strconv.Itoa(syscall.Getpid())),
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"ok": vars.NewReadOnly(OK),
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"nil": vars.NewReadOnly(nil),
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"true": vars.NewReadOnly(true),
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"false": vars.NewReadOnly(false),
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"buildinfo": vars.NewReadOnly(buildinfo.Value),
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"version": vars.NewReadOnly(buildinfo.Value.Version),
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"paths": vars.NewEnvListVar("PATH"),
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"nop" + FnSuffix: vars.NewReadOnly(nopGoFn),
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})
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func addBuiltinFns(fns map[string]any) {
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builtinNs.AddGoFns(fns)
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}
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