Change conda activation scripts to be a module (nushell#205)

virtual_environments/README.md

@@ -1,45 +1,28 @@
 # Virtual environment scripts
 
-The scripts in this directory activate virtual environments for Conda environments. They follow the pattern described in the [Nushell 0.32
-changelog](https://www.nushell.sh/blog/2021-06-01-nushell_0_32.html#environment-loading-lily-mara):
+The scripts in this directory activate virtual environments for Conda environments.
 
-```
-$ load-env (activate some-env)
-```
-
-A custom command (`activate`) creates a table with environment variables and
-`load-env` is used to load it into the shell's scope.
+## Usage
 
-In most cases, deactivation is a matter of restoring the PATH variable to the
-state before activating the env and removing any additional variables. There are
-no environment-specific elements to this, which is why the same deactivation
-script can be used for deactivating any environment of a specific type. For
-example, `source conda_deactivate.nu` will deactivate any Conda env, there are
-no input parameters.
+The activation and deactivation commands are exported from the `conda` module.
 
-## Expected Usage
-
-1. Source an activation script in your `config.nu`. For example, `conda.nu`.
- You'll then have the `conda-env` command available.
-2. Create an alias for sourcing the appropriate deactivation script:
- `alias conda-deactivate = source /path/to/conda_deactivate.nu`
-3. Activate with `load-env (conda-env env-name)`. You might want to define some
- shorter aliases for both commands, if typing that every time seems like a
- hassle.
-4. If you're using [Starship](https://starship.rs/), your prompt should reflect the activated env.
-5. When done, deactivate with your alias: `conda-deactivate`.
+```
+> use conda.nu
+> conda activate foo
+[foo] > conda deactivate
+>
+```
 
-Look at the script files to find the exact command name for creating an environment table.
+Do disable the prompt changes (e.g., to let [Starship](https://starship.rs) include its own), pass a `--no-prompt` flag to `activate`.
+The `activate` command includes custom completions for the environment names.
 
-## `conda.nu`
+## Limitations
 
-Limitations:
+_(old text, not tested)_
 
 - The "root_prefix" might not actually correspond to the correct path to the Conda envs. You can fix
  this for your setup by changing how the root prefix is found in the `conda-env` command.
 - Nested envs are not well supported. If you activate a Conda env while another one is
  activated, new elements will be appended to the PATH, but the other environment
  variables will be overwritten. There's no way to then restore the PATH to the state
  it was in before activating the *first* env (at least not with this script directly).
-- The prompt is not updated by the script. Consider using [Starship](https://starship.rs/)
- with the Python prompt element.

virtual_environments/conda.nu

@@ -1,20 +1,97 @@
-def conda-env [env-name] {
+# Activate conda environment
+export def-env activate [
+ env-name: string@'nu-complete conda envs' # name of the environment
+ --no-prompt # do not update the prompt
+] {
  let conda-info = (conda info --envs --json | from json)
- let suffix = (if $env-name == "base" {""} else {(["envs" $env-name] | path join)})
+
+ let suffix = if $env-name == "base" {
+ ""
+ } else {
+ ["envs" $env-name] | path join
+ }
+
  let env-dir = ([$conda-info.root_prefix $suffix] | path join)
- let old-path = ((system-path) | str collect (path-sep))
- let new-path = (if (windows?) { (conda-create-path-windows $env-dir) } else { (conda-create-path-unix $env-dir) })
- let new-env = {
+ let old-path = (system-path | str collect (char esep))
+
+ let new-path = if windows? {
+ conda-create-path-windows $env-dir
+ } else {
+ conda-create-path-unix $env-dir
+ }
+
+ let virtual-prompt = $'[($env-name)] '
+
+ let new-env = ({
  CONDA_DEFAULT_ENV: $env-name
  CONDA_PREFIX: $env-dir
- CONDA_PROMPT_MODIFIER: $"[($env-name)]"
+ CONDA_PROMPT_MODIFIER: $virtual-prompt
  CONDA_SHLVL: "1"
  CONDA_OLD_PATH: $old-path
+ } | merge { $new-path })
+
+ let new-env = if not $no-prompt {
+ let old_prompt_command = if (has-env CONDA_OLD_PROMPT_COMMAND) {
+ $env.CONDA_OLD_PROMPT_COMMAND
+ } else {
+ if (has-env 'PROMPT_COMMAND') {
+ $env.PROMPT_COMMAND
+ } else {
+ ''
+ }
+ }
+
+
+ let new-prompt = if (has-env 'PROMPT_COMMAND') {
+ if ($old_prompt_command | describe) == 'block' {
+ { $'($virtual-prompt)(do $old_prompt_command)' }
+ } else {
+ { $'($virtual-prompt)($old_prompt_command)' }
+ }
+ } else {
+ { $'($virtual-prompt)' }
+ }
+
+ $new-env
+ | insert CONDA_OLD_PROMPT_COMMAND $old_prompt_command
+ | insert PROMPT_COMMAND $new-prompt
+ } else {
+ $new-env
  }
- $new-env | merge { $new-path }
+
+ load-env $new-env
 }
 
-def conda-create-path-windows [env-dir] {
+# Deactivate currently active conda environment
+export def-env deactivate [] {
+ let path-name = if "PATH" in (env).name { "PATH" } else { "Path" }
+ let-env $path-name = $env.CONDA_OLD_PATH
+ let-env PROMPT_COMMAND = $env.CONDA_OLD_PROMPT_COMMAND
+
+ hide CONDA_PROMPT_MODIFIER
+ hide CONDA_PREFIX
+ hide CONDA_SHLVL
+ hide CONDA_DEFAULT_ENV
+ hide CONDA_OLD_PATH
+
+ let-env PROMPT_COMMAND = if 'CONDA_OLD_PROMPT_COMMAND' in (env).name {
+ $env.CONDA_OLD_PROMPT_COMMAND
+ } else {
+ $env.PROMPT_COMMAND
+ }
+
+ hide CONDA_OLD_PROMPT_COMMAND
+}
+
+def 'nu-complete conda envs' [] {
+ conda info --envs
+ | lines
+ | where not ($it | str starts-with '#')
+ | where not ($it | empty?)
+ | each {|entry| $entry | split row ' ' | get 0 }
+}
+
+def conda-create-path-windows [env-dir: path] {
  # Conda on Windows needs a few additional Path elements
  let env-path = [
  $env-dir
@@ -23,31 +100,34 @@ def conda-create-path-windows [env-dir] {
  ([$env-dir "Library" "bin"] | path join)
  ([$env-dir "Library" "usr" "bin"] | path join)
  ]
- let new-path = ([$env-path (system-path)] | flatten | str collect (path-sep))
- {
- PATH: $new-path
- }
+
+ let new-path = ([$env-path (system-path)]
+ | flatten
+ | str collect (char esep))
+
+ { PATH: $new-path }
 }
 
-def conda-create-path-unix [env-dir] {
+def conda-create-path-unix [env-dir: path] {
  let env-path = [
  ([$env-dir "bin"] | path join)
  ]
- let new-path = ([$env-path $env.PATH] | flatten | str collect (path-sep))
- {
- PATH: $new-path
- }
-}
 
+ let new-path = ([$env-path $env.PATH]
+ | flatten
+ | str collect (char esep))
+
+ { PATH: $new-path }
+}
 
 def windows? [] {
- (sys).host.name == "Windows"
+ ((sys).host.name | str downcase) == "windows"
 }
 
 def system-path [] {
  if "PATH" in (env).name { $env.PATH } else { $env.Path }
 }
 
-def path-sep [] {
- if (windows?) { ";" } else { ":" }
+def has-env [name: string] {
+ $name in (env).name
 }