#!/bin/sh
# com [-n] [FILE...] - compile anything

##% echo this is com % \#
##% echo $FILE $STEM

# Inspired by a tool of Tom Duff (http://www.iq0.com/duffgram/com.c).
#
# com looks for the sequence ##% (without preceding whitespace)
# in each file, and sends the rest of the line off to the shell.  The
# variable $FILE is set to the filename, and $STEM is set to the
# filename without suffix.  Used to allow information about how to
# compile a program to be stored with the program.  The -n flag causes
# com not to act, but to print out the action it would have taken.
#
# Public domain, 14apr2015  +chris+

CMD="sh -e -u -x"
if [ "$1" = -n ]; then
  CMD=cat
  shift
fi

if [ $# -eq 0 ]; then
  if [ -r .comfile ]; then
    set -- $(cat .comfile)
  else
    echo "Usage: $0 [-n] [FILE...]" 1>&2
    exit 1
  fi
elif [ "$CMD" != cat ]; then
  echo "$@" >.comfile
fi

export FILE STEM
for FILE; do
  STEM=${FILE%.*}
  if ! grep -q '^[^ ]*##%' "$FILE"; then
    echo "File '$FILE' contains no ##% instructions."
    exit 1
  fi
  sed -n '/^[^ ]*##%/s:^[^ ]*##% *::gp' "$FILE" |$CMD
done