#!/usr/bin/awk -f
# SQU.AWK --- a lisp in awk
# (C) 2022 Case Duckworth <acdw@acdw.net>

### Commentary:

# Why am I doing this?

### Code:
BEGIN {
	nested = 0
	buffer = ""
	OFS = "\t"
	STDERR = "/dev/stderr"
	PRGN = "squawk"
}

{
	buffer = buffer $0 "\n"
}

END {
	read(buffer, ast)
	eval(ast)
}


function die(message, errcode)
{
	eprint(PRGN " ERROR" (message ? ": " message : ""))
	exit (errcode ? errcode : 1)
}

function eprint(message)
{
	# Print MESSAGE to STDERR.
	print(message) > STDERR
}

function eval(ast)
{
	# Evaluate multi-dimensional array AST.
	for (w in ast) {
		print ast[w]
	}
}

function read(buf, ast)
{
	# Read string BUF into multi-dimensional array AST.
	split(buf, b, "")
	w = 1
	word = ""
	# Tokenize
	for (c in b) {
		# print c, b[c]
		if (b[c] == "\\") {
			word = word b[c++]
		} else if (b[c] == "(") {
			if (word) {
				ast[w++] = word
				word = ""
			}
			ast[w++] = "(" nested++
		} else if (b[c] == ")") {
			if (word) {
				ast[w++] = word
				word = ""
			}
			ast[w++] = ")" --nested
		} else if (b[c] ~ /[ \t\r\n\f\v]/) {
			if (word) {
				ast[w++] = word
				word = ""
			}
		} else {
			word = word b[c]
		}
		if (nested < 0) {
			die("Unmatched paren at " c)
		}
	}
}