/*

████████╗██╗  ██╗██╗   ██╗███╗   ██╗
╚══██╔══╝██║  ██║██║   ██║████╗  ██║
   ██║   ███████║██║   ██║██╔██╗ ██║
   ██║   ██╔══██║██║   ██║██║╚██╗██║
   ██║   ██║  ██║╚██████╔╝██║ ╚████║
   ╚═╝   ╚═╝  ╚═╝ ╚═════╝ ╚═╝  ╚═══╝

Copyright © 2023 Simon Forman

This file is part of Thun

Thun is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.

Thun is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with Thun.  If not see <http://www.gnu.org/licenses/>.

*/
#include <stddef.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <setjmp.h>

#include <gc.h>
#include <gmp.h>

#include "joy.h"
#include "definitions.h"
#include "uthash.h"
#include "linenoise.h"


static jmp_buf jbuf;

const char *BLANKS = " \t";
const char *FALSE = "false";
const char *TRUE = "true";

JoyType loop_symbol = {joySymbol, {"loop"}};
JoyType JoyTrueVal = {joyTrue, {NULL}};
JoyType JoyFalseVal = {joyFalse, {NULL}};

JoyTypePtr JoyTrue = &JoyTrueVal;
JoyTypePtr JoyFalse = &JoyFalseVal;


void*
reallocate_function (void *ptr, __attribute__((unused)) size_t old_size, size_t new_size)
{
	return GC_REALLOC(ptr, new_size);
}


void
deallocate_function (void *ptr, __attribute__((unused)) size_t size)
{
	GC_FREE(ptr);
}


void
my_callback(GC_PTR void_obj, __attribute__((unused)) GC_PTR void_environment)
{
	mpz_t *obj = (mpz_t*)void_obj;
	mpz_clear(*obj);
}





struct user_def {
	char *name;/* key */
	JoyList body;
	UT_hash_handle hh;         /* makes this structure hashable */
};

struct user_def *user_defs = NULL;


/*
██╗   ██╗████████╗██╗██╗     ███████╗
██║   ██║╚══██╔══╝██║██║     ██╔════╝
██║   ██║   ██║   ██║██║     ███████╗
██║   ██║   ██║   ██║██║     ╚════██║
╚██████╔╝   ██║   ██║███████╗███████║
 ╚═════╝    ╚═╝   ╚═╝╚══════╝╚══════╝
*/


#define PUSH(node, stack) (node)->tail = *(stack); *(stack) = (node);


JoyList
make_non_list_node(char *text, size_t size)
{
	char *sym;
	const struct dict_entry *interned;
	JoyList node = newJoyList;

	interned = in_word_set(text, size);
	if (interned) {
		/* TODO: pre-compute and reuse whole JoyType in wordlist? */
		node->head = newJoyType;
		node->head->kind = joySymbol;
		node->head->value.symbol = interned->name;
		return node;
	}

	sym = GC_malloc(size + 1);  /* one more for the zero, right? */
	strncat(sym, text, size);

	if (!strcmp(sym, FALSE)) {
		node->head = JoyFalse;
	} else if (!strcmp(sym, TRUE)) {
		node->head = JoyTrue;
	} else {
		node->head = newJoyType;
		if (mpz_init_set_str(node->head->value.i, sym, 10)) {
			/* Non-zero (-1) return value means the string is not an int. */
			mpz_clear(node->head->value.i);
			node->head->kind = joySymbol;
			node->head->value.symbol = sym;

		} else {
			node->head->kind = joyInt;
			GC_register_finalizer(node->head->value.i, my_callback, NULL, NULL, NULL);
		}
	}

	return node;
}


/* Create a new list_node with a joyList head. */
JoyList
make_list_node(JoyList el)
{
	JoyList node = newJoyList;
	node->head = newJoyType;
	node->head->kind = joyList;
	node->head->value.el = el;
	return node;
}


void
push_quote(JoyList el, JoyListPtr stack)
{
	JoyList node = make_list_node(el);
	PUSH(node, stack)
}


JoyList
pop_any(JoyListPtr stack)
{
	JoyList result;
	if (!(*stack)) {
		fprintf(stderr, "Not enough values on stack.\n");
		longjmp(jbuf, 1);
	}
	result = *stack;
	*stack = (*stack)->tail;
	return result;
}


mpz_t *
pop_int(JoyListPtr stack)
{
	JoyList node = pop_any(stack);
	switch (node->head->kind) {
	case joyInt:
		return &(node->head->value.i);
	default:
		fprintf(stderr, "Not an integer.\n");
		longjmp(jbuf, 1);
	}
}


int
pop_bool(JoyListPtr stack)
{
	JoyList node = pop_any(stack);
	/* TODO: Look for just the singletons? */
	switch (node->head->kind) {
	case joyTrue:
		return 1;
	case joyFalse:
		return 0;
	default:
		fprintf(stderr, "Not a Boolean value.\n");
		longjmp(jbuf, 1);
	}
}


JoyList
pop_list_node(JoyListPtr stack)
{
	JoyList node;
	node = pop_any(stack);
	switch (node->head->kind) {
	case joyList:
		return node;
	default:
		fprintf(stderr, "Not a list.\n");
		longjmp(jbuf, 1);
	}
}


JoyList
pop_list(JoyListPtr stack)
{
	return pop_list_node(stack)->head->value.el;
}


JoyList
newIntNode(void)
{
	JoyList node = newJoyList;
	node->head = newJoyType;
	node->head->kind = joyInt;
	mpz_init(node->head->value.i);
	GC_register_finalizer(node->head->value.i, my_callback, NULL, NULL, NULL);
	return node;
}


void
push_thing(JoyTypePtr term, JoyListPtr stack)
{
	JoyList node = newJoyList;
	node->head = term;
	PUSH(node, stack)
}


JoyList
concat_lists(JoyList a, JoyList b)
{
	JoyList node;
	if (!a) return b;
	if (!b) return a;
	node = newJoyList;
	node->head = a->head;
	node->tail = concat_lists(a->tail, b);
	return node;
}


/*
?- gronk("fn", `[+] step`).

    def fn(stack, expression, dictionary):
        (s1, (i1, stack)) = stack
        while s1:
            (i2, s1) = s1
            i1 += i1 + i2
        return (i1, stack), expression, dictionary
*/

void
fn(JoyListPtr stack, __attribute__((unused)) JoyListPtr expression)
{
	JoyList s1 = pop_list(stack);
	JoyListPtr s1Ptr = &s1;
	mpz_t *i1 = pop_int(stack);
	JoyList node = newIntNode();
	mpz_set(node->head->value.i, *i1);
	while (*s1Ptr) {
		i1 = pop_int(s1Ptr);
		mpz_add(node->head->value.i, node->head->value.i, *i1);
	}
	PUSH(node, stack)
}



/*
██████╗ ██████╗ ██╗███╗   ██╗████████╗███████╗██████╗
██╔══██╗██╔══██╗██║████╗  ██║╚══██╔══╝██╔════╝██╔══██╗
██████╔╝██████╔╝██║██╔██╗ ██║   ██║   █████╗  ██████╔╝
██╔═══╝ ██╔══██╗██║██║╚██╗██║   ██║   ██╔══╝  ██╔══██╗
██║     ██║  ██║██║██║ ╚████║   ██║   ███████╗██║  ██║
╚═╝     ╚═╝  ╚═╝╚═╝╚═╝  ╚═══╝   ╚═╝   ╚══════╝╚═╝  ╚═╝
*/


/* Pre-declare so we can use it in print_node(). */
void
print_list(JoyList el);


void
print_node(JoyType j)
{
	switch (j.kind) {
	case joyInt:
		gmp_printf("%Zd", j.value.i);
		break;
	case joySymbol:
		printf("%s", j.value.symbol);
		break;
	case joyTrue:
		printf("true");
		break;
	case joyFalse:
		printf("false");
		break;
	case joyList:
		printf("[");
		print_list(j.value.el);
		printf("]");
		break;
	default:
		printf("wtf");
	}
}


void
print_list(JoyList el)
{
	while (NULL != el) {
		print_node(*(el->head));
		el = el->tail;
		if (NULL != el) {
			printf(" ");
		}
	}
}


void
print_stack(JoyList el)
{
	if (el) {
		if (el->tail) {
			print_stack(el->tail);
			printf(" ");
		}
		print_node(*(el->head));
	}
}


/*
██████╗  █████╗ ██████╗ ███████╗███████╗██████╗
██╔══██╗██╔══██╗██╔══██╗██╔════╝██╔════╝██╔══██╗
██████╔╝███████║██████╔╝███████╗█████╗  ██████╔╝
██╔═══╝ ██╔══██║██╔══██╗╚════██║██╔══╝  ██╔══██╗
██║     ██║  ██║██║  ██║███████║███████╗██║  ██║
╚═╝     ╚═╝  ╚═╝╚═╝  ╚═╝╚══════╝╚══════╝╚═╝  ╚═╝
*/


char *
trim_leading_blanks(char *str)
{
	size_t offset = strspn(str, BLANKS);
	return (offset == strlen(str)) ? NULL : (str + offset);
}


JoyList
parse_list(char **text)
{
	/*
	 * Extract terms from the text until a closing bracket is found.
	 */
	char *rest;
	ptrdiff_t diff;
	JoyList result = EMPTY_LIST;

	/* NULL string input? */
	if (NULL == *text) {
		fprintf(stderr, "Missing ']' bracket. A\n");
		longjmp(jbuf, 1);
	};

	*text = trim_leading_blanks(*text);

	if (NULL == *text) {
		fprintf(stderr, "Missing ']' bracket. B\n");
		longjmp(jbuf, 1);
	};

	/* Look for blanks or brackets. */
	rest = strpbrk(*text, " []");
	/* rest now points to a space or '[' or ']' after a term, -or- it
	 * is NULL if the rest of the string is a single term with no
	 * spaces nor brackets.  If that's the case then we're missing a
	 * closing bracket!
	 */

	if (NULL == rest) {
		fprintf(stderr, "Missing ']' bracket. C\n");
		longjmp(jbuf, 1);
	};

	/* How many chars have we got? */
	diff = rest - *text;

	if (diff) {
		result = make_non_list_node(*text, diff);
		*text = rest;
	} else if ('[' == rest[0]) {
		*text = ++rest;
		result = make_list_node(parse_list(text));
	} else if (']' == rest[0]) {
		*text = ++rest;
		return result;
	}
	result->tail = parse_list(text);
	return result;
}


/*
Get the next node from the text, updating text
to point to the rest of the, uh, text.
*/
JoyList
parse_node(char **text)
{
	char *rest;
	ptrdiff_t diff;
	JoyList thing;

	/* NULL string input? */
	if (NULL == *text) return EMPTY_LIST;

	*text = trim_leading_blanks(*text);

	/* All blanks? */
	if (NULL == *text) return EMPTY_LIST;

	/* Look for blanks or brackets. */
	rest = strpbrk(*text, " []");
	/*
	rest now points to a space or '[' or ']' after a term,
	-or- it is NULL if the rest of the string is a single term
	with no spaces nor brackets.  If that's the case then we're
	done, and we can just return a list with one symbol in it.
	*/
	if (NULL == rest) {
		thing = make_non_list_node(*text, strlen(*text));
		*text = rest;
		return thing;
	}

	/* How many chars have we got? */
	diff = rest - *text;

	if (diff) {
		thing = make_non_list_node(*text, diff);
		*text = rest;
		return thing;
	}
	if ('[' == rest[0]) {
		*text = ++rest;
		return make_list_node(parse_list(text));
	}
	if (']' == rest[0]) {
		fprintf(stderr, "Extra ']' bracket.\n");
		longjmp(jbuf, 1);
	}
	fprintf(stderr, "Should be unreachable.");
	exit(1);
}


JoyList
text_to_expression(char *text)
{
	JoyList result, head, tail;

	result = parse_node(&text);
	head = result;
	tail = parse_node(&text);
	while (NULL != tail) {
		head->tail = tail;
		head = tail;
		tail = parse_node(&text);
	}
	return result;
}


/*
███████╗██╗  ██╗██████╗ ██████╗ ███████╗███████╗███████╗██╗ ██████╗ ███╗   ██╗
██╔════╝╚██╗██╔╝██╔══██╗██╔══██╗██╔════╝██╔════╝██╔════╝██║██╔═══██╗████╗  ██║
█████╗   ╚███╔╝ ██████╔╝██████╔╝█████╗  ███████╗███████╗██║██║   ██║██╔██╗ ██║
██╔══╝   ██╔██╗ ██╔═══╝ ██╔══██╗██╔══╝  ╚════██║╚════██║██║██║   ██║██║╚██╗██║
███████╗██╔╝ ██╗██║     ██║  ██║███████╗███████║███████║██║╚██████╔╝██║ ╚████║
╚══════╝╚═╝  ╚═╝╚═╝     ╚═╝  ╚═╝╚══════╝╚══════╝╚══════╝╚═╝ ╚═════╝ ╚═╝  ╚═══╝

As elegant as it is to model the expression as a stack, it's not very
efficient, as concatenating definitions and other quoted programs to
the expression is a common and expensive operation.

Instead, let's keep a stack of sub-expressions, reading from them
one-by-one, and prepending new sub-expressions to the stack rather than
concatenating them.

*/


void
push_quote_onto_expression(JoyList el, JoyListPtr expression)
{
	JoyList node;
	if (!el) return;
	node = make_list_node(el);
	PUSH(node, expression)
}


void
push_thing_onto_expression(JoyTypePtr term, JoyListPtr expression)
{
	JoyList node = newJoyList;
	node->head = term;
	node->tail = EMPTY_LIST;
	push_quote_onto_expression(node, expression);
}


JoyTypePtr
next_term(JoyListPtr expression)
{
	JoyList quote;
	JoyTypePtr term;
	if (!(*expression)) {
		fprintf(stderr, "Do not call next_term on an empty expression.\n");
		exit(1);
	}
	quote = pop_list(expression);
	if (!quote) {
		fprintf(stderr, "How did an empty list get onto the expression!?\n");
		exit(1);
	}
	term = quote->head;
	quote = quote->tail;
	if (quote) {
		push_quote_onto_expression(quote, expression);
	}
	return term;
}


/*
 ██████╗ ██████╗ ██████╗ ███████╗    ██╗    ██╗ ██████╗ ██████╗ ██████╗ ███████╗
██╔════╝██╔═══██╗██╔══██╗██╔════╝    ██║    ██║██╔═══██╗██╔══██╗██╔══██╗██╔════╝
██║     ██║   ██║██████╔╝█████╗      ██║ █╗ ██║██║   ██║██████╔╝██║  ██║███████╗
██║     ██║   ██║██╔══██╗██╔══╝      ██║███╗██║██║   ██║██╔══██╗██║  ██║╚════██║
╚██████╗╚██████╔╝██║  ██║███████╗    ╚███╔███╔╝╚██████╔╝██║  ██║██████╔╝███████║
 ╚═════╝ ╚═════╝ ╚═╝  ╚═╝╚══════╝     ╚══╝╚══╝  ╚═════╝ ╚═╝  ╚═╝╚═════╝ ╚══════╝
*/


#define BINARY_MATH_OP(name) \
void \
name(JoyListPtr stack, __attribute__((unused)) JoyListPtr expression) \
{ \
	mpz_t *a, *b; \
	JoyList node; \
	b = pop_int(stack); \
	a = pop_int(stack); \
	node = newIntNode(); \
	mpz_ ## name(node->head->value.i, *a, *b); \
	node->tail = *stack; \
	*stack = node; \
}

BINARY_MATH_OP(add)
BINARY_MATH_OP(sub)
BINARY_MATH_OP(mul)
BINARY_MATH_OP(fdiv_q)
BINARY_MATH_OP(fdiv_r)


void
lshift(JoyListPtr stack, __attribute__((unused)) JoyListPtr expression)
{
	mpz_t *a, *b;
	JoyList node;
	b = pop_int(stack);
	if (-1 == mpz_sgn(*b)) {
		fprintf(stderr, "Negative shift count.\n");
		longjmp(jbuf, 1);
	}
	a = pop_int(stack);
	node = newIntNode();
	mpz_mul_2exp(node->head->value.i, *a, mpz_get_ui(*b));
	PUSH(node, stack)
}


void
rshift(JoyListPtr stack, __attribute__((unused)) JoyListPtr expression)
{
	mpz_t *a, *b;
	JoyList node;
	b = pop_int(stack);
	if (-1 == mpz_sgn(*b)) {
		fprintf(stderr, "Negative shift count.\n");
		longjmp(jbuf, 1);
	}
	a = pop_int(stack);
	node = newIntNode();
	mpz_fdiv_q_2exp(node->head->value.i, *a, mpz_get_ui(*b));
	PUSH(node, stack)
}


/*
With mpz_cmp we can implement the rest of the comparison functions as definitions:

     G       E       L
 eq [false] [true] [false] cmp
 gt [true] [false] [false] cmp
 lt [false] [false] [true] cmp
neq [true] [false] [true] cmp
 le [false] [true] [true] cmp
 ge [true] [true] [false] cmp
*/
void
cmp_joyfunc(JoyListPtr stack, JoyListPtr expression)
{
	JoyList L = pop_list(stack);
	JoyList E = pop_list(stack);
	JoyList G = pop_list(stack);
	mpz_t *b = pop_int(stack);
	mpz_t *a = pop_int(stack);
	int hmm = mpz_cmp(*a, *b);
	push_quote_onto_expression(((hmm > 0) ? G : (hmm < 0) ? L : E), expression);
}


void
i_joyfunc(JoyListPtr stack, JoyListPtr expression)
{
	push_quote_onto_expression(pop_list(stack), expression);
}


void
branch(JoyListPtr stack, JoyListPtr expression)
{
	JoyList T = pop_list(stack);
	JoyList F = pop_list(stack);
	push_quote_onto_expression((pop_bool(stack) ? T : F), expression);
}


void
loop(JoyListPtr stack, JoyListPtr expression)
{
	JoyList body = pop_list(stack);
	JoyList x = EMPTY_LIST;

	if (pop_bool(stack)) {
		JoyListPtr xPtr = &x;
		push_thing(&loop_symbol, xPtr);
		push_quote(body, xPtr);
		push_quote_onto_expression(*xPtr, expression);
		push_quote_onto_expression(body, expression);
	}
}


void
clear(JoyListPtr stack, __attribute__((unused)) JoyListPtr expression)
{
	*stack = EMPTY_LIST;
}


void
cons(JoyListPtr stack, __attribute__((unused)) JoyListPtr expression)
{
	JoyList quote = pop_list(stack);
	JoyListPtr qPtr = &quote;
	JoyList node = pop_any(stack);
	push_thing(node->head, qPtr);
	push_quote(*qPtr, stack);
}


void
pop(JoyListPtr stack, __attribute__((unused)) JoyListPtr expression)
{
	if (!(*stack)) {
		fprintf(stderr, "Cannot pop empty stack.\n");
		longjmp(jbuf, 1);
	}
	pop_any(stack);
}


void
swaack(JoyListPtr stack, __attribute__((unused)) JoyListPtr expression)
{
	JoyList quote = pop_list(stack);
	JoyListPtr qPtr = &quote;
	push_quote(*stack, qPtr);
	*stack = *qPtr;
}


void
stack(JoyListPtr stack, __attribute__((unused)) JoyListPtr expression)
{
	push_quote(*stack, stack);
}


void
swap(JoyListPtr stack, __attribute__((unused)) JoyListPtr expression)
{
	JoyList a = pop_any(stack);
	JoyList b = pop_any(stack);
	push_thing(a->head, stack);
	push_thing(b->head, stack);
}


void
concat(JoyListPtr stack, __attribute__((unused)) JoyListPtr expression)
{
	JoyList b = pop_list(stack);
	JoyList a = pop_list(stack);
	push_quote(concat_lists(a, b), stack);
}


void
first(JoyListPtr stack, __attribute__((unused)) JoyListPtr expression)
{
	JoyList quote = pop_list(stack);
	if (!quote) {
		fprintf(stderr, "Cannot take first of empty list.\n");
		longjmp(jbuf, 1);
	}
	push_thing(quote->head, stack);
}


void
rest(JoyListPtr stack, __attribute__((unused)) JoyListPtr expression)
{
	JoyList quote = pop_list(stack);
	if (!quote) {
		fprintf(stderr, "Cannot take rest of empty list.\n");
		longjmp(jbuf, 1);
	}
	push_quote(quote->tail, stack);
}


void
dip(JoyListPtr stack, JoyListPtr expression)
{
	JoyList quote = pop_list(stack);
	JoyList node = pop_any(stack);
	push_thing_onto_expression(node->head, expression);
	push_quote_onto_expression(quote, expression);
}


void
dup(JoyListPtr stack, __attribute__((unused)) JoyListPtr expression)
{
	JoyList s = *stack;
	JoyList node = pop_any(stack);
	*stack = s;
	push_thing(node->head, stack);
}


void
truthy(JoyListPtr stack, __attribute__((unused)) JoyListPtr expression)
{
	/*
	Keep the original stack in case	the top item is already a Boolean value.
	*/
	JoyList s = *stack;
	JoyList node = pop_any(stack);
	switch (node->head->kind) {
	case joyTrue:
		*stack = s;
		break;
	case joyFalse:
		*stack = s;
		break;
	case joyInt:
		if mpz_cmp_si(node->head->value.i, 0) {
			push_thing(JoyTrue, stack);
		} else {
			push_thing(JoyFalse, stack);
		}
		break;
	case joyList:
		if (node->head->value.el) {
			push_thing(JoyTrue, stack);
		} else {
			push_thing(JoyFalse, stack);
		}
		break;
	default:
		fprintf(stderr, "Cannot Boolify.\n");
		longjmp(jbuf, 1);
	}
}


/*
 *User definitions with inscribe command.
 */

void
add_user_def(char *name, JoyList body)
{
	struct user_def *s;
	HASH_FIND_STR(user_defs, name, s);
	if (!s) {
		s = GC_malloc(sizeof *s);
		s->name = name;
		HASH_ADD_KEYPTR(hh, user_defs, s->name, strlen(s->name), s);
	}
	s->body = body;
}


void
inscribe(JoyListPtr stack, __attribute__((unused)) JoyListPtr expression)
{
	JoyList quote = pop_list(stack);
	if (!quote) return;
	if (joySymbol != quote->head->kind) return;
	add_user_def(quote->head->value.symbol, quote->tail);
}


/*
██╗███╗   ██╗████████╗███████╗██████╗ ██████╗ ██████╗ ███████╗████████╗███████╗██████╗
██║████╗  ██║╚══██╔══╝██╔════╝██╔══██╗██╔══██╗██╔══██╗██╔════╝╚══██╔══╝██╔════╝██╔══██╗
██║██╔██╗ ██║   ██║   █████╗  ██████╔╝██████╔╝██████╔╝█████╗     ██║   █████╗  ██████╔╝
██║██║╚██╗██║   ██║   ██╔══╝  ██╔══██╗██╔═══╝ ██╔══██╗██╔══╝     ██║   ██╔══╝  ██╔══██╗
██║██║ ╚████║   ██║   ███████╗██║  ██║██║     ██║  ██║███████╗   ██║   ███████╗██║  ██║
╚═╝╚═╝  ╚═══╝   ╚═╝   ╚══════╝╚═╝  ╚═╝╚═╝     ╚═╝  ╚═╝╚══════╝   ╚═╝   ╚══════╝╚═╝  ╚═╝
*/


void
dispatch(char *sym, JoyListPtr stack, JoyListPtr expression)
{
	struct user_def *s;
	const struct dict_entry *word = in_word_set(sym, strlen(sym));
	if (word) {
		word->func(stack, expression);
		return;
	}
	HASH_FIND_STR(user_defs, sym, s);
	if (s) {
		push_quote_onto_expression(s->body, expression);
		return;
	}
	fprintf(stderr, "Unknown: %s\n", sym);
	longjmp(jbuf, 1);
}


void
joy(JoyListPtr stack, JoyListPtr expression)
{
	JoyTypePtr term;
	JoyList e = EMPTY_LIST;
	JoyListPtr ePtr = &e;
	push_quote_onto_expression(*expression, ePtr);
	expression = ePtr;

	while (*expression) {
		term = next_term(expression);
		switch (term->kind) {
		case joyInt:
		case joyTrue:
		case joyFalse:
		case joyList:
			push_thing(term, stack);
			break;
		case joySymbol:
			dispatch(term->value.symbol, stack, expression);
		}
	}
}


/* Set quiet mode by "-q" as only command line option. */
int quiet = 0;

#define SHH(message) \
if (!quiet) { \
	printf(message); \
}


int
main(int argc, char *argv[])
{
	char *line;
	JoyList stack = EMPTY_LIST;
	JoyList expression = EMPTY_LIST;
	JoyList s;

	mp_set_memory_functions(
		&GC_malloc,
		&reallocate_function,
		&deallocate_function
	);

	init_defs();

	quiet = ((2 == argc) && (!strcmp("-q", argv[1])));

	while (1) {
		line = linenoise(quiet? "" : "joy? ");
		if (NULL == line) {
			SHH("\n")
			break;
		}
		linenoiseHistoryAdd(line);
		s = stack;
		if (!setjmp(jbuf)) {
			expression = text_to_expression(line);
			joy(&stack, &expression);
		} else {
			/* err */
			stack = s;
		}
		free(line);
		print_stack(stack);
		printf("\n");
	}
	return 0;
}