💠 Introduction

What Are They?

They are extensions which increase functionality. Annexes can extend the functionality without adding unnecessary code to main application.

What Can They Do?

1. Add a new ZI subcommand (i.e. the command that’s placed after the function zi … when calling ZI).

2. Add new ice-modifiers.

3. Register four type of hooks:

   3.1. atclone hook – run after cloning any plugin or downloading any snippet.

   3.2. atpull hook – run after pulling new commits (i.e. updating) for any plugin / snippet.

   3.3. atinit hook – run before loading any plugin / snippet, after it has been set-up (i.e. downloaded).

   3.4. atload hook – run after loading any plugin / snippet.

4. Register hooks for generating help text, shown by the zi help subcommand.

Annex recommendations

Required for default functionality

1. z-a-bin-gem-node
2. z-a-readurl
3. z-a-patch-dl
4. z-a-rust

Recommeded for additional functionality

1. z-a-submods
2. z-a-unscope

tip

Install annexes as meta plugin

All required:

zi light-mode for z-shell/z-a-meta-plugins @annexes

All required + recommended:

zi light-mode for z-shell/z-a-meta-plugins @annexes+rec

How To Code Them?

Below is an example body of an atclone hook (taken from submods annex).

It shows how to:

1. Obtain the arguments passed to the hook.

2. Use an ice-modifier.

3. It also shows an useful snippet that will trim the whitespace in array elements (see # (4) … in the code).

4. Utilize the last hook argument – the plugin’s/snippet’s containing directory.

emulate -L zsh -o extendedglob -o warncreateglobal -o typesetsilent

[[ -z "${ZI_ICE[submods]}" ]] && return 0

# (1) – get arguments
[[ "$1" = plugin ]] && \
  local type="$1" user="$2" plugin="$3" id_as="$4" dir="$5" hook="$6" || \
  local type="$1" url="$2" id_as="$3" dir="$4" hook="$6" # type: snippet

# (2) – we're interested only in plugins/snippets
# which have the submods'' ice in their load command
[[ -z ${ZI_ICE[submods]} ]] && return 0

local -a mods parts
local mod

# (3) – process the submods'' ice
mods=( ${(@s.;.)ZI_ICE[submods]} )
for mod in "${mods[@]}"; do
    parts=( "${(@s:->:)mod}" )
    # (4) Remove only leading and trailing whitespace
    parts=( "${parts[@]//((#s)[[:space:]]##|[[:space:]]##(#e))/}" )

    print "\nCloning submodule: ${parts[1]} to dir: ${parts[2]}"
    parts[1]="https://github.com/${parts[1]}"
    # (5) – the use of the input argument: `$dir'
    command git -C "$dir" clone --progress "${parts[1]}" "${parts[2]}"
done

The recommended method of creating a hook is to place its body into a file that starts with a right arrow → (more information, and also a za- prefix, e.g. →za-myproject-atclone-hook and then to mark it for autoloading via autoload -Uz →za-myproject-atclone-hook. Then register the hook (presumably in the myproject.plugin.zsh file) with the API call:

@zi-register-annex:

@zi-register-annex myproject hook:atclone \
  →za-myproject-atclone-handler \
  →za-myproject-atclone-help-handler \
  "submods''" # register a new ice-mod: submods''

The general syntax of the API call is:

@zi-register-annex {project-name} \
  {hook: \
  {name-of-the-handler-function} \
  {name-of-the-HELP-handler-function} \
  "{ice-mod1}|{ice-mod2}|…" < hook-type >| subcommand: < new-subcommand-name > }

The last argument, i.e. the |-separated ice-list, is optional. That’s all! After this loading the plugin myproject will set up the new ice-modifier submods that will have syntax submods'{user}/{plugin} –> {output-dir}; …' and will clone submodules when installing the original plugin or snippet! Example real-world use of the ice-mod:

# Load the `zsh-autosuggestions' plugin via Prezto module: `autosuggestions'
zi ice svn submods'zsh-users/zsh-autosuggestions -> external'
zi snippet PZT::modules/autosuggestions

Checkout the project which fully implements this idea, z-a-submods. It e.g. also implements the atpull hook, i.e. supports automatic update of the submodules. The z-a-* prefix is recommended for projects that are being annexes.

Details

There are 2 or 3 subtypes for each of the hook:

1. atinit or !atinit – the ! version is ran before the atinit ice-mod (i.e. before zi ice atinit'echo this!'; …), while the normal version runs after it.

2. atload or !atload – analogous to the atinit case: the ! version runs before the atload ice-mod (while the normal version runs after it).

3. atclone or !atclone – analogous to the atinit and atload cases.

4. atpull, !atpull or %atpull – the first two are being ran only when there are new commits to be downloaded during the update. The % version is being always run, regardless if the update will pull any actual commits or not, and it is being ran after the atpull ice-mod.