colorize: add ability to colorize multiple files into less (#7662)

cless is an alias for a colorized less wrappper: colorize_via_pygmentize_less.
Note that cless opens many files as independent files, navigatable with `:n` and `:p`.

plugins/colorize/README.md

@@ -2,6 +2,10 @@
 
 With this plugin you can syntax-highlight file contents of over 300 supported languages and other text formats.
 
+Colorize will highlight the content based on the filename extension. If it can't find a syntax-highlighting
+method for a given extension, it will try to find one by looking at the file contents. If no highlight method
+is found it will just cat the file normally, without syntax highlighting.
+
 To use it, add colorize to the plugins array of your zshrc file:
 ```
 plugins=(... colorize)
@@ -9,9 +13,16 @@ plugins=(... colorize)
 
 ## Usage
 
-* `ccat <file> [files]`: colorize the contents of the file (or files, if more than one are provided). If no arguments are passed it will colorize the standard input or stdin.
+* `ccat  <file> [files]`: colorize the contents of the file (or files, if more than one are provided). 
+  If no arguments are passed it will colorize the standard input or stdin.
+
+* `cless <file> [files]`: colorize the contents of the file (or files, if more than one are provided) and
+  open less. If no arguments are passed it will colorize the standard input or stdin.
 
-Colorize will highlight the content based on the filename extension. If it can't find a syntax-highlighting method for a given extension, it will try to find one by looking at the file contents. If no highlight method is found it will just cat the file normally, without syntax highlighting.
+Note that `cless` will behave as less when provided more than one file: you have to navigate files with
+the commands `:n` for next and `:p` for previous. The downside is that less options are not supported.
+But you can circumvent this by either using the LESS environment variable, or by running `ccat file1 file2|less --opts`.
+In the latter form, the file contents will be concatenated and presented by less as a single file.
 
 ## Requirements
 

plugins/colorize/colorize.plugin.zsh

 # easier alias to use the plugin
 alias ccat='colorize_via_pygmentize'
+alias cless='colorize_via_pygmentize_less'  
 
 colorize_via_pygmentize() {
     if ! (( $+commands[pygmentize] )); then
@@ -16,7 +17,7 @@ colorize_via_pygmentize() {
     # guess lexer from file extension, or
     # guess it from file contents if unsuccessful
     local FNAME lexer
-    for FNAME in $@
+    for FNAME in "$@"
     do
         lexer=$(pygmentize -N "$FNAME")
         if [[ $lexer != text ]]; then
@@ -26,3 +27,23 @@ colorize_via_pygmentize() {
         fi
     done
 }
+
+colorize_via_pygmentize_less() (   
+    # this function is a subshell so tmp_files can be shared to cleanup function
+    declare -a tmp_files 
+    
+    cleanup () {
+        [[ ${#tmp_files} -gt 0 ]] && rm -f "${tmp_files[@]}"
+        exit
+    }
+    trap 'cleanup' EXIT HUP TERM INT
+    
+    while (( $# != 0 )); do     #TODO: filter out less opts
+        tmp_file="$(mktemp --tmpdir "tmp.colorize.XXXX.$(sed 's/\//./g' <<< "$1")")"
+        tmp_files+=("$tmp_file")
+        colorize_via_pygmentize "$1" > "$tmp_file"
+        shift 1
+    done
+
+    less -f "${tmp_files[@]}"
+)