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/*
* Copyright © 2018 Keith Packard <keithp@keithp.com>
*
* This program 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.
*
* This program 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.
*/
#include "snek.h"
snek_code_t *snek_stash_code;
snek_func_t *
snek_func_alloc(snek_code_t *code)
{
snek_func_t *func;
snek_stash_code = code;
func = snek_alloc(sizeof (snek_func_t) + snek_parse_nformal * sizeof (snek_id_t));
code = snek_stash_code;
snek_stash_code = NULL;
if (!func)
return NULL;
func->code = snek_pool_offset(code);
func->nformal = snek_parse_nformal;
func->nrequired = snek_parse_nformal - snek_parse_nnamed;
memcpy(func->formals, snek_parse_formals, snek_parse_nformal * sizeof (snek_id_t));
return func;
}
/*
* Assign a function formal from an actual value.
*
* Check to make sure there aren't duplicate assignments,
* e.g. a positional actual and named actual that end up
* naming the same formal.
*/
static bool __attribute__((noinline))
snek_func_actual(snek_id_t id, snek_poly_t value, uint8_t pos)
{
snek_variable_t *existing = &snek_frame->variables[snek_frame->nvariables-1];
snek_variable_t *insert = &snek_frame->variables[pos];
/* Check existing formals to see if we're duplicating one of
* those
*/
while (existing > insert) {
if (existing->id == id)
return false;
existing--;
}
/* All good, assign the name and value in the frame */
existing->id = id;
existing->value = value;
return true;
}
/*
* Make sure a named actual matches a known formal
*/
static bool
snek_func_check_formal(snek_id_t id, snek_func_t *func)
{
for (uint8_t f = 0; f < func->nformal; f++)
if (func->formals[f] == id)
return true;
return false;
}
/*
* Create a new frame holding all of the actuals
*/
bool
snek_func_push(uint8_t nposition, uint8_t nnamed, snek_offset_t ip)
{
/* Allocate the frame first so that
* nothing moves during the rest of the function
*/
uint8_t nparam = nposition + nnamed;
if (!snek_frame_push(ip, nparam))
return false;
snek_func_t *func = snek_poly_to_func(snek_a);
/* Check to make sure we don't pass more actuals by position
* than there are formals in the function
*/
if (nposition > func->nformal) {
snek_error_args(func->nformal, nposition);
goto fail_frame;
}
uint8_t pos = nparam;
snek_offset_t save_stackp = snek_stackp;
snek_poly_t value;
snek_id_t id;
/* Assign formals from actuals */
while (pos) {
pos--;
value = snek_stack_pop();
if (pos >= nposition) {
/* named actuals come last */
id = snek_stack_pop_soffset();
/* Make sure the actual matches a formal */
if (!snek_func_check_formal(id, func))
goto fail;
} else {
/* positional actuals come first */
id = func->formals[pos];
}
/* Insert into the frame, checking for duplicates */
if (!snek_func_actual(id, value, pos))
goto fail;
}
/* Make sure all required formals were given values */
for (pos = 0; pos < func->nrequired; pos++)
if (!snek_frame->variables[pos].id) {
id = func->formals[pos];
goto fail;
}
return true;
fail:
/* Restore stack and complain about the invalid actual */
snek_stackp = save_stackp;
snek_error_arg(id);
fail_frame:
/* Remove the invalid frame */
(void) snek_frame_pop();
return false;
}
snek_offset_t
snek_func_size(void *addr)
{
snek_func_t *func = addr;
return (snek_offset_t) sizeof (snek_func_t) + func->nformal * (snek_offset_t) sizeof (snek_id_t);
}
void
snek_func_mark(void *addr)
{
snek_func_t *func = addr;
snek_mark_offset(&snek_code_mem, func->code);
}
void
snek_func_move(void *addr)
{
snek_func_t *func = addr;
snek_move_offset(&snek_code_mem, &func->code);
}
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