mirror of
https://github.com/go-sylixos/elvish.git
synced 2024-12-05 03:17:50 +08:00
120 lines
2.3 KiB
Go
120 lines
2.3 KiB
Go
package eval
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import (
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"errors"
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"os"
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)
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// ErrNonExistentEnvVar is raised by the get-env command when the environment
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// variable does not exist.
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var ErrNonExistentEnvVar = errors.New("non-existent environment variable")
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//elvdoc:fn set-env
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//
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// ```elvish
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// set-env $name $value
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// ```
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//
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// Sets an environment variable to the given value. Calling `set-env VAR_NAME
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// value` is similar to `set E:VAR_NAME = value`, but allows the variable name
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// to be dynamic.
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//
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// Example:
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//
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// ```elvish-transcript
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// ~> set-env X foobar
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// ~> put $E:X
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// ▶ foobar
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// ```
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//
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// @cf get-env has-env unset-env
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//elvdoc:fn unset-env
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//
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// ```elvish
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// unset-env $name
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// ```
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//
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// Unset an environment variable. Calling `unset-env VAR_NAME` is similar to
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// `del E:VAR_NAME`, but allows the variable name to be dynamic.
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//
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// Example:
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//
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// ```elvish-transcript
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// ~> set E:X = foo
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// ~> unset-env X
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// ~> has-env X
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// ▶ $false
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// ~> put $E:X
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// ▶ ''
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// ```
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//
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// @cf has-env get-env set-env
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func init() {
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addBuiltinFns(map[string]any{
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"has-env": hasEnv,
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"get-env": getEnv,
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"set-env": os.Setenv,
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"unset-env": os.Unsetenv,
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})
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}
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//elvdoc:fn has-env
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//
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// ```elvish
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// has-env $name
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// ```
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//
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// Test whether an environment variable exists. This command has no equivalent
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// operation using the `E:` namespace (but see https://b.elv.sh/1026).
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//
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// Examples:
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//
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// ```elvish-transcript
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// ~> has-env PATH
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// ▶ $true
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// ~> has-env NO_SUCH_ENV
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// ▶ $false
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// ```
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//
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// @cf get-env set-env unset-env
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func hasEnv(key string) bool {
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_, ok := os.LookupEnv(key)
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return ok
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}
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//elvdoc:fn get-env
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//
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// ```elvish
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// get-env $name
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// ```
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//
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// Gets the value of an environment variable. Throws an exception if the
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// environment variable does not exist.
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//
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// Calling `get-env VAR_NAME` is similar to `put $E:VAR_NAME`, but allows the
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// variable name to be dynamic, and throws an exception instead of producing an
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// empty string for nonexistent environment variables.
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//
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// Examples:
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//
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// ```elvish-transcript
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// ~> get-env LANG
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// ▶ zh_CN.UTF-8
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// ~> get-env NO_SUCH_ENV
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// Exception: non-existent environment variable
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// [tty], line 1: get-env NO_SUCH_ENV
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// ```
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//
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// @cf has-env set-env unset-env
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func getEnv(key string) (string, error) {
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value, ok := os.LookupEnv(key)
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if !ok {
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return "", ErrNonExistentEnvVar
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}
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return value, nil
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}
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