Fix repo-less use of znap eval

Fixes marlonrichert#239.

README.md

@@ -51,6 +51,9 @@ To run `znap pull` on specific repos only, including ones you have set to be exc
 ## `.zshrc` optimization
 Using Znap to optimize your Zsh config can be as simple as this:
 ```sh
+[[ -r ~/Repos/znap/znap.zsh ]] ||
+    git clone --depth 1 -- https://github.com/marlonrichert/zsh-snap.git ~/Repos/znap
+
 # `znap prompt` makes your prompt visible in just 15-40ms!
 znap prompt sindresorhus/pure
 
@@ -74,13 +77,27 @@ file](.zshrc).
 Additionaly, Znap makes it so that you actually need to have _less_ in your `.zshrc` file, by
 automating several tasks for you.
 
+### Faster `eval`
+Use `znap eval ... <command>` to cache the output of `<command>`, compile it, and then `source` it (instead of `eval` it):
+```sh
+znal eval <name> '<command>'
+```
+This can be up 10 times faster than a regular `eval "$( <command> )"` statement!  If you pass a repo as the first
+argument, then Znap will `eval` the command output inside the given repo and will invalidate the cache whenever the repo
+is update.  Otherwise, the cache will be invalidated whenever `<command>` changes.  Caches are stored in
+`${XDG_CACHE_HOME:-$HOME/.cache}/zsh-snap/eval`.
+
 ### Automatic `compinit` and `bashcompinit`
 Note that the above example does not include any call to
 [`complist`](http://zsh.sourceforge.net/Doc/Release/Zsh-Modules.html#The-zsh_002fcomplist-Module),
 [`compinit`, or
 `bashcompinit`](http://zsh.sourceforge.net/Doc/Release/Completion-System.html#Initialization) in
 the `.zshrc` file. That is because Znap will run these for you as needed.
 
+Znap also regenerates your [comp dump
+file](http://zsh.sourceforge.net/Doc/Release/Completion-System.html#Use-of-compinit) automatically whenever you update a
+repo, install a repo, or change your `.zshrc` file.
+
 If necessary, you can let Znap pass arguments to `compinit` as follows:
 ```sh
 zstyle '*:compinit' arguments -D -i -u -C -w
@@ -98,18 +115,6 @@ zstyle ':znap:*' auto-compile no
 In any case, you can compile sources manually at any time with
 `znap compile [ <dir> | <file> ] ...`.
 
-### Automatic cache invalidation
-Znap automatically regenerates your [comp dump
-file](http://zsh.sourceforge.net/Doc/Release/Completion-System.html#Use-of-compinit) whenever you
-install or update a repo or change your `.zshrc` file.
-
-Znap also automatically regenerates its internal cache for each command when…
-* …a cache file is older than the Git index of its associated repo.
-* …the last argument of the `znap eval` statements that produced it has changed. So, if the last
-  argument to `znap eval` contains a variable, then its cached output will be regenerated whenever
-  the variable changes. See the [example `.zshrc` file](.zshrc) for a practical use of this.
-* …the cache file is missing. You can delete them manually from `$XDG_CACHE_HOME/zsh-snap/eval`.
-
 ## Automatic `git maintenance`
 When using `git` 2.31.0 or newer, Znap automatically enables `git maintenance` in each repo that it
 manages. This automatically optimizes your repos in the background, so that your `git` and `znap`

functions/.znap.eval

@@ -3,54 +3,48 @@
 # args: ( <repo> | <name> ) <command>
 zmodload -F zsh/files b:zf_mkdir
 
+# TODO: deprecate this and provide `znap cache <key> <command>` instead.
+
 if (( $# < 2 )); then
   print -u2 'znap eval: not enough arguments'
   .znap.help eval
   return $(( sysexits[(i)USAGE] + 63 ))
 fi
 
-.znap.eval.generate() {
-  (
-    private _P__repo=$1 _P__cache_file=$2
-    shift 2
-    private _P__header="#${(q)@}"
-
-    local __line
-    [[ -r $_P__cache_file ]] &&
-        IFS='' read -r __line < $_P__cache_file
-
-    if [[ $__line != $_P__header ||
-        ( -d $_P__repo && -f $_P__repo/${GIT_DIR:-.git}/index &&
-            $_P__repo/${GIT_DIR:-.git}/index -nt $_P__cache_file ) ]]; then
-      [[ -d $_P__repo ]] &&
-          cd -q -- $_P__repo
-      print -r -- "$_P__header" >| $_P__cache_file
-      eval "$@" >>| $_P__cache_file
-      .znap.compile $_P__cache_file
-    fi
-  )
-}
-
 local gitdir=''
 ..znap.repos-dir
 
 if [[ $1 == */* ]]; then
   .znap.clone $1 ||
       return
-fi
-
-private _P__repo=~[$1] __cache_dir=$XDG_CACHE_HOME/zsh-snap/eval
-shift
-
-zf_mkdir -pm 0700 $__cache_dir
-private _P__cache_file=$__cache_dir/${_P__repo:t}.zsh
-
-if [[ -r $_P__cache_file ]]; then
-  .znap.eval.generate "$_P__repo" "$_P__cache_file" "$@" &|
+  private _P__repo=~[$1]
+  private _P__name=${_P__repo#$gitdir}
 else
-  print -r "znap eval: generating cache for $*"
-  .znap.eval.generate "$_P__repo" "$_P__cache_file" "$@"
+  local _P__name=$1 _P__repo=
 fi
+private _P__cmd=$2
+
+private _P__cache_dir=$XDG_CACHE_HOME/zsh-snap/eval
+zf_mkdir -pm 0700 $_P__cache_dir
+private _P__cache_file=$_P__cache_dir/${_P__name}.zsh
+
+[[ -r $_P__cache_file ]] ||
+    print -r "znap eval: generating cache for ${(q+)_P__cmd}"
+
+private _P__line= _P__header="#${(q+)_P__cmd}" _P__index=$_P__repo/.git/index
+(
+  [[ -r $_P__cache_file ]] &&
+      IFS='' read -r _P__line < $_P__cache_file
+
+  if [[ $_P__line != $_P__header ]] ||
+      [[ -n $_P__repo && -f $_P__index && $_P__index -nt $_P__cache_file ]]; then
+    [[ -d $_P__repo ]] &&
+        cd -q -- $_P__repo
+    print -r -- "$_P__header" >! $_P__cache_file
+    eval "$_P__cmd" >>! $_P__cache_file
+    .znap.compile $_P__cache_file
+  fi
+)
 
 # Wrap in a named function for profiling purposes.
 .znap.eval:${_P__cache_file:t}() {