#!/bin/ksh
# Read a ksh file, given as argument, and generate an HTML rendering of it to stdout
# Uses sed to prepare the HTML file from the shell script.  The sed scripts are complex
# and hard to maintain, but repetitive, so we generate them in scratch files.  This is inefficient if
# this script is called multiple times, so we cache them in /tmp and only regenerate them when
# needed.

# This is just text editing, not command parsing, so it can't handle all situations.
# 
# It works on Irix and TRU64.  Solaris has 3 versions of sed available.  
# /usr/xpg4/bin/sed and /usr/ucb/sed:
#   - need to have '^' '$' outside of a \(..\) RE in order to match EOL -- taken literally inside \( ..\)
# /usr/bin/sed 
#   - fails with "line too long"
#
# Using \<..\> to isolate words doesn't seem to work (IRIX, SOLARIS /usr/ucb/sed)
# Using [..]+, [..]* dont work in all sed.  [..]\{1,\} and [..]\{0,\} work properly.
#
# Sed will only accept about 200 commands in one file, so we generate multiple passes
#
# First version  2001/11/14  Richard Brittain,  Dartmouth College
#
# 2003/10/16 RB Rewrite to use dynamically generated sed scripts
# 2005/03/10 RB Added -i flag to create an HTML include file - no headers etc.
#               Change generated HTML to lower case.

# Make sure we get the XPG4 version of sed if we are on Solaris
PATH=/usr/xpg4/bin:$PATH; export PATH

htinc=
# Option -i = format for HTML include file (default is stand-alone HTML)
while getopts i o ; do
   case $o in
   i) htinc=1;;
   esac
done
shift $OPTIND-1

scriptname=$1

# Colours for HTML output
sh_keywords=DARKBLUE 
sh_comments=DARKGREEN
sh_commandsubs=PURPLE
sh_vars=BLACK
sh_lineno=GRAY
default_colour=DARKRED

seddir=/tmp/$USER/ksh2html
needscripts=0
if [[ -d $seddir && -w $seddir ]] ; then
   # Directory already exists and is writeable
   if [[ -r $seddir/pass1.sed && $0 -ot $seddir/pass1.sed ]]; then
      print -u2 "$0: using previously generated HTML generation scripts"
   else
      needscripts=1
   fi
elif [[ ! -d $seddir ]]; then
   if mkdir -p  $seddir ; then
      # We need to regenerate files
      needscripts=1
   else
      print -u2 "$0: Unable to create $seddir for editing scripts"
      exit 1
   fi
else
   print -u2 "$0: Unable to access $seddir for editing scripts"
   exit 1
fi

if [[ $needscripts -eq 1 ]]; then
   print -u2 "$0: generating HTML editing scripts"
   sed -e "s/sh_comments/$sh_comments/g" \
             -e "s/sh_commandsubs/$sh_commandsubs/g" \
             -e "s/sh_vars/$sh_vars/g" \
             -e "s/sh_keywords/$sh_keywords/g"   > $seddir/prelim.sed \
     <<"EndOfPrelim"
# first Protect all things that look like HTML tags - unfortunately that means I/O redirection too
s#&#\&amp;#g
s#<#\&lt;#g
s#>#\&gt;#g

# Detect comment lines and shuffle them off to the end so we don't interpret the contents
/^[     ]*\#/ b comment
# Terminating comments, following active code, are left so that we can interpret the code first.

# Variable references $var and ${var}
# Ideally we'd not include ones in 'quoted strings'
s#\(\$[a-zA-Z0-9_*@]\{1,\}\)#<font color=sh_vars>\1</font>#g
s#\(\${[a-zA-Z0-9_]\{1,\}.*}\)#<font color=sh_vars>\1</font>#g

# Command Substitution 
s#\$(\([^(].*\))#\$(<font color=sh_commandsubs>\1</font>)#g
s#`\(.*\)`#`<font color=sh_commandsubs>\1</font>`#g

# Variable assignment.  Only look for first thing on line (not really correct, but avoids getting
# similar things in quoted strings)
s#^\([  ]*\)\([A-Za-z_][A-Za-z0-9_]*=\)#\1<font color=sh_vars>\2</font>#

# Arithmetic operations $((..)) 
s#\(\$((.*))\)#<font color=sh_keywords>\1</font>#g

: comment
# Comment lines are italicised and coloured
# Multiple comment characters are additionally bolded
s#^\([  ]\{0,\}\)\(\#\#.*\)$#\1<font color=sh_comments><i><b>\2</b></i></font>#
s#^\([  ]\{0,\}\)\(\#.*\)$#\1<font color=sh_comments><i>\2</i></font>#

EndOfPrelim

   sed -e "s/sh_comments/$sh_comments/g" > $seddir/final.sed <<"EndOfFinal"
# Last pass - get only the end-of-line comments, possibly after other translations on the line
s#\([  ]\{1,\}\)\(\#\#.*\)$#\1<font color=sh_comments><i><b>\2</b></i></font>#
s#\([  ]\{1,\}\)\(\#.*\)$#\1<font color=sh_comments><i>\2</i></font>#

EndOfFinal

   # Use open filedescriptors instead of multiple open/append/close
   exec 3>$seddir/pass1.sed 4>$seddir/pass2.sed 5>$seddir/pass3.sed 6>$seddir/pass4.sed
   for shellcode in \
    if then elif else fi case esac for do done while until exec eval readonly typeset \
    integer unalias unset trap kill wait getopts let bg read test \\\[ exit cd export \
    alias break return echo print pwd shift times ulimit umask jobs fc : continue function
     do
     # ksh intrinsics - any location, Front anchor to ^ or ];&| with optional leading spaces
     #                                End anchor to space or $
  
     print -r -u3 's#^\([  ]\{0,\}\)\('$shellcode'[ ;]\)#\1<font color='$sh_keywords'>\2</font>#'    #  >>$seddir/pass1.sed
     print -r -u4 's#^\([  ]\{0,\}\)\('$shellcode'\)$#\1<font color='$sh_keywords'>\2</font>#'       #  >>$seddir/pass2.sed
     print -r -u5 's#\([];&|][  ]\{0,\}\)\('$shellcode' \)#\1<font color='$sh_keywords'>\2</font>#g' #  >>$seddir/pass3.sed
     print -r -u6 's#\([];&|][  ]\{0,\}\)\('$shellcode'\)$#\1<font color='$sh_keywords'>\2</font>#g' #  >>$seddir/pass4.sed

  done
  3>&- ; 4>&- ; 5>&- ; 6>&- 
fi

if [[ -z "$htinc" ]]; then
   # generate stand-alone HTML with headers
   print "<html>"
   print "<head>"
   print "<title>Script: $scriptname</title>"
   print "</head>"
   print "<body>"
   print "<h2>Example script: $scriptname</h2>"
fi
print "<pre><font color=$default_colour>"
sed -f $seddir/prelim.sed $scriptname |\
  sed -f $seddir/pass1.sed |\
  sed -f $seddir/pass2.sed |\
  sed -f $seddir/pass3.sed |\
  sed -f $seddir/pass4.sed |\
  sed -f $seddir/final.sed |\
  awk '{printf "<font color='$sh_lineno'>%4d:</font> %s\n",NR,$0}'
print "</font></pre>"
if [[ -z "$htinc" ]]; then
   print "</body>"
   print "</html>"
fi
exit 0