PATCH: Fiddling with colors

["Bart Schaefer" <schaefer@xxxxxxxxxxxxxxxxxxxxxxx>]

This discussion of a more understandable way to set the list-colors style
got me looking at the `colors' function, `dircolors --print-database` and
the docs for an ANSI terminal emulator.  In the process I noticed several
glitches with the themed prompt system (none of which were mentioned in
sourceforge bug #104884).

After this patch the `colors' function creates an associative array `color'
(and copies it to `colour' for the color-blind) that maps ANSI code numbers
to descriptive words and vice-versa.  (Calling these all colors is a bit of
a misnomer; "text properties" as in emacs would be better, but ...)

The {f,b}g{,{,_no}_bold} arrays are then filled in by looping over indices
in $color.  I removed the fg_zzzz and bg_zzzz parameters, which were only
there to clean up the output of `typeset`, and instead typeset parameters
that contain escape sequences with -H so the values aren't shown.  This is
something that probably should be done throughout Functions/Prompts/, but
I didn't get that ambitious.

BTW, see the note in `colors' about black and white, to see why the themed
prompt system is a bit strange in its use of the term "grey".

The promptinit patch adds `psvar' to the variables that are preserved when
previewing prompt settings and adds a `prompt_preview_safely' wrapper that
preserves those values around individual prompt previewings as well.  It's
a bit of overkill in the current situation because everything utimately goes
through `prompt_preview_theme', which I also modified to preserve the same
parameters, but I did it anyway in case somebody writes a prompt_xxx_preview
function that behaves badly.

An unrelated thing that this patch points up is how painful it is to create
a local *copy* of an array parameter; see the lines marked "Ick" below.

I also fixed a problem with simulation of preexec in `prompt_preview_theme';
and I put the themes in alphabetical rather than reverse-alphabetical order
for previewing, just because.

Index: Functions/Misc/colors
===================================================================
@@ -1,85 +1,79 @@
-# Put standard ANSI color codes in environment for easy use
-reset_color=$'\e[0m'
-bold_color=$'\e[1m'
+# Put standard ANSI color codes in shell parameters for easy use.
+# Note that some terminals do not support all combinations.
 
-# Foreground
+typeset -Ag color colour
 
-typeset -Ag fg
-fg=(
-  grey      $'\e[30m'
-  red       $'\e[31m'
-  green     $'\e[32m'
-  yellow    $'\e[33m'
-  blue      $'\e[34m'
-  magenta   $'\e[35m'
-  cyan      $'\e[36m'
-  white     $'\e[37m'
-)
-fg_zzzz="$reset_color"
+color=(
+# Attribute codes:
+  00 none
+  01 bold
+  02 faint                  22 normal
+  03 standout               23 no-standout
+  04 underline              24 no-underline
+  05 blink                  25 no-blink
+  07 reverse                27 no-reverse
+  08 conceal
 
-typeset -Ag fg_no_bold
-fg_no_bold=(
-  grey      $'\e[0;30m'
-  red       $'\e[0;31m'
-  green     $'\e[0;32m'
-  yellow    $'\e[0;33m'
-  blue      $'\e[0;34m'
-  magenta   $'\e[0;35m'
-  cyan      $'\e[0;36m'
-  white     $'\e[0;37m'
+# Text color codes:
+  30 black                  40 bg-black
+  31 red                    41 bg-red
+  32 green                  42 bg-green
+  33 yellow                 43 bg-yellow
+  34 blue                   44 bg-blue
+  35 magenta                45 bg-magenta
+  36 cyan                   46 bg-cyan
+  37 white                  47 bg-white
+  39 default                49 bg-default
 )
-fg_no_bold_zzzz="$reset_color"
 
-typeset -Ag fg_bold
-fg_bold=(
-  grey      $'\e[1;30m'
-  red       $'\e[1;31m'
-  green     $'\e[1;32m'
-  yellow    $'\e[1;33m'
-  blue      $'\e[1;34m'
-  magenta   $'\e[1;35m'
-  cyan      $'\e[1;36m'
-  white     $'\e[1;37m'
-)
-fg_bold_zzzz="$reset_color"
+# A word about black and white:  The "normal" shade of white is really a
+# very pale grey on many terminals; to get truly white text, you have to
+# use bold white, and to get a truly white background you have to use
+# bold reverse white bg-xxx where xxx is your desired foreground color
+# (and which means the foreground is also bold).
 
-# Background
+# Map in both directions; could do this with e.g. ${(k)colors[(i)normal]},
+# but it's clearer to include them all both ways.
 
-typeset -Ag bg
-bg=(
-  grey      $'\e[40m'
-  red       $'\e[41m'
-  green     $'\e[42m'
-  yellow    $'\e[43m'
-  blue      $'\e[44m'
-  magenta   $'\e[45m'
-  cyan      $'\e[46m'
-  white     $'\e[47m'
-)
-bg_zzzz="$reset_color"
+local k
+for k in ${(k)color}; do color[${color[$k]}]=$k; done
 
-typeset -Ag bg_no_bold
-bg_no_bold=(
-  grey      $'\e[0;40m'
-  red       $'\e[0;41m'
-  green     $'\e[0;42m'
-  yellow    $'\e[0;43m'
-  blue      $'\e[0;44m'
-  magenta   $'\e[0;45m'
-  cyan      $'\e[0;46m'
-  white     $'\e[0;47m'
-)
-bg_no_bold_zzzz="$reset_color"
+# Add "fg-" keys for all the text colors, for clarity.
 
-typeset -Ag bg_bold
-bg_bold=(
-  grey      $'\e[1;40m'
-  red       $'\e[1;41m'
-  green     $'\e[1;42m'
-  yellow    $'\e[1;43m'
-  blue      $'\e[1;44m'
-  magenta   $'\e[1;45m'
-  cyan      $'\e[1;46m'
-  white     $'\e[1;47m'
-)
-bg_bold_zzzz="$reset_color"
+for k in ${color[(I)3?]}; do color[fg-${color[$k]}]=$k; done
+
+# This is inaccurate, but the prompt theme system needs it.
+
+color[grey]=${color[black]}
+color[fg-grey]=${color[grey]}
+color[bg-grey]=${color[bg-black]}
+
+# Assistance for the color-blind.
+
+colour=(${(kv)color})	# A case where ksh namerefs would be useful ...
+
+# The following are terminal escape sequences used by colored prompt themes.
+
+local lc=$'\e[' rc=m	# Standard ANSI terminal escape values
+
+typeset -Hg reset_color bold_color
+reset_color="$lc${color[none]}$rc"
+bold_color="$lc${color[bold]}$rc"
+
+# Foreground
+
+typeset -AHg fg fg_bold fg_no_bold
+for k in ${(v)color[(I)fg-*]}; do
+    fg[${color[$k]}]="$lc$k$rc"
+    fg_bold[${color[$k]}]="$lc${color[bold]};$k$rc"
+    fg_no_bold[${color[$k]}]="$lc${color[normal]};$k$rc"
+done
+
+# Background
+
+typeset -AHg bg bg_bold bg_no_bold
+for k in ${(v)color[(I)bg-*]}; do
+    bg[${color[$k]}]="$lc$k$rc"
+    bg_bold[${color[$k]}]="$lc${color[bold]};$k$rc"
+    bg_no_bold[${color[$k]}]="$lc${color[normal]};$k$rc"
+done
Index: Functions/Prompts/promptinit
===================================================================
@@ -20,7 +20,7 @@
     if [[ $theme == */prompt_(#b)(*)_setup ]]; then
       name="$match[1]"
       if [[ -r "$theme" ]]; then
-        prompt_themes=($name $prompt_themes)
+        prompt_themes=($prompt_themes $name)
         autoload -U prompt_${name}_setup
       else
         print "Couldn't read file $theme containing theme $name."
@@ -38,6 +38,29 @@
   prompt_newline=$'\n%{\r%}'
 }
 
+prompt_preview_safely() {
+  print $reset_color
+  if [[ -z "$prompt_themes[(r)$1]" ]]; then
+    print "Unknown theme: $1"
+    return
+  fi
+
+  local -a psv; psv=($psvar); local -a +h psvar; psvar=($psv) # Ick
+  local +h PS1=$PS1 PS2=$PS2 PS3=$PS3 PS4=$PS4 RPS1=$RPS1
+  trap "${$(functions precmd):-:} ; ${$(functions preexec):-:}" 0
+
+  # The next line is a bit ugly.  It (perhaps unnecessarily)
+  # runs the prompt theme setup function to ensure that if
+  # the theme has a _preview function that it's been autoloaded.
+  prompt_${1}_setup
+
+  if typeset +f prompt_${1}_preview >&/dev/null; then
+    prompt_${1}_preview "$@[2,-1]"
+  else
+    prompt_preview_theme "$@"
+  fi
+}
+
 set_prompt() {
   emulate -L zsh
   local opt preview theme usage old_theme
@@ -59,6 +82,7 @@
       setopt localtraps
       if [[ -z "$prompt_theme[1]" ]]; then
         # Not using a prompt theme; save settings
+        local -a psv; psv=($psvar); local -a +h psvar; psvar=($psv) # Ick
 	local +h PS1=$PS1 PS2=$PS2 PS3=$PS3 PS4=$PS4 RPS1=$RPS1
 	trap "${$(functions precmd):-:} ; ${$(functions preexec):-:}" 0
       else
@@ -102,26 +126,10 @@
     p) preview=( $prompt_themes )
        (( $#* > 1 )) && preview=( "$@[2,-1]" )
        for theme in $preview; do
-         theme_args=( "$=theme" )
          [[ "$theme" == "$prompt_theme[*]" ]] && continue
-         if [[ -z "$prompt_themes[(r)$theme_args[1]]" ]]; then
-           print "\nUnknown theme: $theme_args[1]"
-           continue
-         fi
-         print
-
-         # The next line is a bit ugly.  It (perhaps unnecessarily)
-         # runs the prompt theme setup function to ensure that if
-         # the theme has a _preview function that it's been autoloaded.
-         prompt_${theme_args[1]}_setup
-
-         if functions prompt_${theme_args[1]}_preview >&/dev/null; then
-           prompt_${theme_args[1]}_preview "${(@)theme_args[2,-1]}"
-         else
-           prompt_preview_theme "${(@)theme_args}"
-         fi
+         prompt_preview_safely "$=theme"
        done
-       print
+       print $reset_color
        ;;
     s) print "Set and save not yet implemented.  Please ensure your ~/.zshrc"
        print "contains something similar to the following:\n"
@@ -167,14 +175,17 @@
 }
 
 prompt_preview_theme () {
+  local -a psv; psv=($psvar); local -a +h psvar; psvar=($psv) # Ick
+  local +h PS1=$PS1 PS2=$PS2 PS3=$PS3 PS4=$PS4 RPS1=$RPS1
+  trap "${$(functions precmd):-:} ; ${$(functions preexec):-:}" 0
+
   print -n "$1 theme"
   (( $#* > 1 )) && print -n " with parameters \`$*[2,-1]'"
   print ":"
   prompt_${1}_setup "$@[2,-1]"
   precmd
-  print -n -P "${PS1}"
+  print -P "${PS1}command arg1 arg2 ... argn"
   preexec
-  print "command arg1 arg2 ... argn"
 }
 
 [[ -o kshautoload ]] || promptinit "$@"

-- 
Bart Schaefer                                 Brass Lantern Enterprises
http://www.well.com/user/barts              http://www.brasslantern.com

Zsh: http://www.zsh.org | PHPerl Project: http://phperl.sourceforge.net