#!/bin/sh

# CORMACKSCRIPT 
# written by daniel
#
# Usage: cormackscript [cmks file] [output file]
#
# IMPORTANT!
# Place the comments (important to get spaces right too):
# ; CMKS START
# ; CMKS END
# into your racket program, the 'assembled' code will be injected here.
#
# For extra niceness, if you have the racket program installed it will auto execute it your file.
#
# A CormackScript file contains 3 columns separated by whitespace in the format [opcode|target|source]  
# - The inc, print and read instructions read from the first column
# - The quit instruction can be standalone
# - you can comment with ;
# - extraneous whitespace is ignored
#
# Here's some sample code
# =-=-=-=-=-=-=-=-=-=-=-=-=-=-=
# ; setting up memory
# 6     ; [0]: first instruction
# 1     ; [1]: literal 1
# 2     ; [2]: literal 2
# 7     ; [3]: literal 7
# 0     ; [4]: n
# 0     ; [5]: acc
#
# ; actual instructions 
# read 4 ; input n
# addeq 00 4 ; skip next if n = 0
# add 00 2 ; skip next 2 instructions
# print 5 ; out acc
# quit
# add 05 04 ; acc = acc + n
# sub 04 01 ; n = n - 1
# sub 00 03 ; go back 7 (from next instr)
# =-=-=-=-=-=-=-=-=-=-=-=-=-=-=
#
# You can redefine these to whatever you want

inst0="inc"   # [tt] = [tt] + 1
inst1="add"   # [tt] = [tt] + [ss]
inst2="sub"   # [tt] = max([tt] - [ss], 0)
inst3="mov"   # [tt] = [ss]
inst4="addeq" # [tt] = [tt] + 1, if [ss] = 0
inst5="fetch" # [tt] = [[ss]]
inst6="store" # [[tt]] = [ss]
inst7="print" # display [ss]
inst8="read"  # read [tt]
inst9="quit"  # halt

# Config ends here =-=-=-=-=-=-=-=-=

[ "$#" -ne 2 ] && { echo "Usage: cormackscript [cmks file] [output file]" && exit 1; }
scriptfile="$1"; targetfile="$2"
[ -f "$scriptfile" ] && [ -f "$targetfile" ] || { echo "Either $scriptfile or $targetfile do not exist" && exit 1; }

tmp="$(mktemp 'tempXXX')"
cat "$scriptfile" |\
    sed -r "s/\s*;.*//g; /^\s*$/ d; s/\s+/ /g; s/^\s+//" |\
        awk "
                /^$inst0\s/ {printf \"0%02d00 ; [%02d] = [%02d] + 1\n\",\$2,\$2,\$2}
                /^$inst1\s/ {printf \"1%02d%02d ; [%02d] = [%02d] + [%02d]\n\",\$2,\$3,\$2,\$2,\$3}
                /^$inst2\s/ {printf \"2%02d%02d ; [%02d] = max([%02d] - [%02d], 0)\n\",\$2,\$3,\$2,\$2,\$3}
                /^$inst3\s/ {printf \"3%02d%02d ; [%02d] = [%02d]\n\",\$2,\$3,\$2,\$3}
                /^$inst4\s/ {printf \"4%02d%02d ; [%02d] = [%02d] + 1, if [%02d] = 0\n\",\$2,\$3,\$2,\$2,\$3}
                /^$inst5\s/ {printf \"5%02d%02d ; [%02d] = [[%02d]]\n\",\$2,\$3,\$2,\$3}
                /^$inst6\s/ {printf \"6%02d%02d ; [[%02d]] = [%02d]\n\",\$2,\$3,\$2,\$3}
                /^$inst7\s/ {printf \"700%02d ; display [%02d]\n\",\$2,\$2}
                /^$inst8\s/ {printf \"8%02d00 ; read [%02d]\n\",\$2,\$2}
                /^$inst9/ {print \"90000 ; halt\"}
                !/^$inst0\s|^$inst1\s|^$inst2\s|^$inst3\s|^$inst4\s|^$inst5\s|^$inst6\s|^$inst7\s|^$inst8\s|^$inst9/
            " >> "$tmp"
sed -i "/\; CMKS START/,/\; CMKS END/{/\; CMKS START/!{/\; CMKS END/!d}}; /\; CMKS START/r $tmp" "$targetfile"
rm "$tmp"

# If racket is installed run it directly
[ ! -z "$(command -v racket)" ] && racket "$targetfile" && echo ""