/*
 * Mesa 3-D graphics library
 * Version:  6.3
 *
 * Copyright (C) 2005  Brian Paul   All Rights Reserved.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included
 * in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
 * BRIAN PAUL BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
 * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */

/**
 * \file slang_compile.c
 * slang front-end compiler
 * \author Michal Krol
 */

#include "imports.h" 
#include "slang_compile.h"
#include "grammar_mesa.h"

/*
	This is a straightforward implementation of the slang front-end compiler.
	Lots of error-checking functionality is missing but every well-formed shader source should
	compile successfully and execute as expected. However, some semantically ill-formed shaders
	may be accepted resulting in undefined behaviour.
*/

void slang_alloc_free (void *ptr)
{
	_mesa_free (ptr);
}

void *slang_alloc_malloc (unsigned int size)
{
	return _mesa_malloc (size);
}

void *slang_alloc_realloc (void *ptr, unsigned int old_size, unsigned int size)
{
	return _mesa_realloc (ptr, old_size, size);
}

int slang_string_compare (const char *str1, const char *str2)
{
	return _mesa_strcmp (str1, str2);
}

char *slang_string_copy (char *dst, const char *src)
{
	return _mesa_strcpy (dst, src);
}

char *slang_string_concat (char *dst, const char *src)
{
	return _mesa_strcpy (dst + _mesa_strlen (dst), src);
}

char *slang_string_duplicate (const char *src)
{
	return _mesa_strdup (src);
}

static void slang_variable_construct (slang_variable *);
static int slang_variable_copy (slang_variable *, const slang_variable *);
static void slang_struct_construct (slang_struct *);
static void slang_struct_destruct (slang_struct *);
static int slang_struct_copy (slang_struct *, const slang_struct *);
static int slang_struct_equal (const slang_struct *, const slang_struct *);
static void slang_variable_destruct (slang_variable *);

/* slang_type_specifier */

static void slang_type_specifier_construct (slang_type_specifier *spec)
{
	spec->type = slang_spec_void;
	spec->_struct = NULL;
	spec->_array = NULL;
}

static void slang_type_specifier_destruct (slang_type_specifier *spec)
{
	if (spec->_struct != NULL)
	{
		slang_struct_destruct (spec->_struct);
		slang_alloc_free (spec->_struct);
	}
	if (spec->_array != NULL)
	{
		slang_type_specifier_destruct (spec->_array);
		slang_alloc_free (spec->_array);
	}
}

static int slang_type_specifier_copy (slang_type_specifier *x, const slang_type_specifier *y)
{
	slang_type_specifier_destruct (x);
	slang_type_specifier_construct (x);
	x->type = y->type;
	if (x->type == slang_spec_struct)
	{
		x->_struct = (slang_struct *) slang_alloc_malloc (sizeof (slang_struct));
		slang_struct_construct (x->_struct);
		return slang_struct_copy (x->_struct, y->_struct);
	}
	if (x->type == slang_spec_array)
	{
		x->_array = (slang_type_specifier *) slang_alloc_malloc (sizeof (slang_type_specifier));
		slang_type_specifier_construct (x->_array);
		return slang_type_specifier_copy (x->_array, y->_array);
	}
	return 1;
}

static int slang_type_specifier_equal (const slang_type_specifier *x, const slang_type_specifier *y)
{
	if (x->type != y->type)
		return 0;
	if (x->type == slang_spec_struct)
		return slang_struct_equal (x->_struct, y->_struct);
	if (x->type == slang_spec_array)
		return slang_type_specifier_equal (x->_array, y->_array);
	return 1;
}

/* slang_fully_specified_type */

static void slang_fully_specified_type_construct (slang_fully_specified_type *type)
{
	type->qualifier = slang_qual_none;
	slang_type_specifier_construct (&type->specifier);
}

static void slang_fully_specified_type_destruct (slang_fully_specified_type *type)
{
	slang_type_specifier_destruct (&type->specifier);
}

static int slang_fully_specified_type_copy (slang_fully_specified_type *x,
	const slang_fully_specified_type *y)
{
	slang_fully_specified_type_construct (x);
	slang_fully_specified_type_destruct (x);
	x->qualifier = y->qualifier;
	return slang_type_specifier_copy (&x->specifier, &y->specifier);
}

/* slang_variable_scope */

static void slang_variable_scope_construct (slang_variable_scope *scope)
{
	scope->variables = NULL;
	scope->num_variables = 0;
	scope->outer_scope = NULL;
}

static void slang_variable_scope_destruct (slang_variable_scope *scope)
{
	unsigned int i;
	for (i = 0; i < scope->num_variables; i++)
		slang_variable_destruct (scope->variables + i);
	slang_alloc_free (scope->variables);
}

static int slang_variable_scope_copy (slang_variable_scope *x, const slang_variable_scope *y)
{
	unsigned int i;
	slang_variable_scope_destruct (x);
	slang_variable_scope_construct (x);
	x->variables = (slang_variable *) slang_alloc_malloc (y->num_variables * sizeof (
		slang_variable));
	if (x->variables == NULL)
		return 0;
	x->num_variables = y->num_variables;
	for (i = 0; i < x->num_variables; i++)
		slang_variable_construct (x->variables + i);
	for (i = 0; i < x->num_variables; i++)
		if (!slang_variable_copy (x->variables + i, y->variables + i))
			return 0;
	x->outer_scope = y->outer_scope;
	return 1;
}

/* slang_operation */
/* XXX mem! */
static void slang_operation_construct (slang_operation *oper)
{
	oper->type = slang_oper_none;
	oper->children = NULL;
	oper->num_children = 0;
	oper->literal = (float) 0;
	oper->identifier = NULL;
	oper->locals = (slang_variable_scope *) slang_alloc_malloc (sizeof (slang_variable_scope));
	slang_variable_scope_construct (oper->locals);
}

static void slang_operation_destruct (slang_operation *oper)
{
	unsigned int i;
	for (i = 0; i < oper->num_children; i++)
		slang_operation_destruct (oper->children + i);
	slang_alloc_free (oper->children);
	slang_alloc_free (oper->identifier);
	slang_variable_scope_destruct (oper->locals);
	slang_alloc_free (oper->locals);
}

static int slang_operation_copy (slang_operation *x, const slang_operation *y)
{
	unsigned int i;
	slang_operation_destruct (x);
	slang_operation_construct (x);
	x->type = y->type;
	x->children = (slang_operation *) slang_alloc_malloc (y->num_children * sizeof (
		slang_operation));
	if (x->children == NULL)
		return 0;
	x->num_children = y->num_children;
	for (i = 0; i < x->num_children; i++)
		slang_operation_construct (x->children + i);
	for (i = 0; i < x->num_children; i++)
		if (!slang_operation_copy (x->children + i, y->children + i))
			return 0;
	x->literal = y->literal;
	if (y->identifier != NULL)
	{
		x->identifier = slang_string_duplicate (y->identifier);
		if (x->identifier == NULL)
			return 0;
	}
	if (!slang_variable_scope_copy (x->locals, y->locals))
		return 0;
	return 1;
}

/* slang_variable */

static void slang_variable_construct (slang_variable *var)
{
	slang_fully_specified_type_construct (&var->type);
	var->name = NULL;
	var->array_size = NULL;
	var->initializer = NULL;
}

static void slang_variable_destruct (slang_variable *var)
{
	slang_fully_specified_type_destruct (&var->type);
	slang_alloc_free (var->name);
	if (var->array_size != NULL)
	{
		slang_operation_destruct (var->array_size);
		slang_alloc_free (var->array_size);
	}
	if (var->initializer != NULL)
	{
		slang_operation_destruct (var->initializer);
		slang_alloc_free (var->initializer);
	}
}

static int slang_variable_copy (slang_variable *x, const slang_variable *y)
{
	slang_variable_destruct (x);
	slang_variable_construct (x);
	if (!slang_fully_specified_type_copy (&x->type, &y->type))
		return 0;
	if (y->name != NULL)
	{
		x->name = slang_string_duplicate (y->name);
		if (x->name == NULL)
			return 0;
	}
	if (y->array_size != NULL)
		if (!slang_operation_copy (x->array_size, y->array_size))
			return 0;
	if (y->initializer != NULL)
		if (!slang_operation_copy (x->initializer, y->initializer))
			return 0;
	return 1;
}

/* slang_struct_scope */

static void slang_struct_scope_construct (slang_struct_scope *scope)
{
	scope->structs = NULL;
	scope->num_structs = 0;
	scope->outer_scope = NULL;
}

static void slang_struct_scope_destruct (slang_struct_scope *scope)
{
	unsigned int i;
	for (i = 0; i < scope->num_structs; i++)
		slang_struct_destruct (scope->structs + i);
	slang_alloc_free (scope->structs);
}

static int slang_struct_scope_copy (slang_struct_scope *x, const slang_struct_scope *y)
{
	unsigned int i;
	slang_struct_scope_destruct (x);
	slang_struct_scope_construct (x);
	x->structs = (slang_struct *) slang_alloc_malloc (y->num_structs * sizeof (slang_struct));
	if (x->structs == NULL)
		return 0;
	x->num_structs = y->num_structs;
	for (i = 0; i < x->num_structs; i++)
		slang_struct_construct (x->structs + i);
	for (i = 0; i < x->num_structs; i++)
		if (!slang_struct_copy (x->structs + i, y->structs + i))
			return 0;
	x->outer_scope = y->outer_scope;
	return 1;
}

static slang_struct *slang_struct_scope_find (slang_struct_scope *stru, const char *name,
	int all_scopes)
{
	unsigned int i;
	for (i = 0; i < stru->num_structs; i++)
		if (slang_string_compare (name, stru->structs[i].name) == 0)
			return stru->structs + i;
	if (all_scopes && stru->outer_scope != NULL)
		return slang_struct_scope_find (stru->outer_scope, name, 1);
	return NULL;
}

/* slang_struct */
/* XXX mem! */
static void slang_struct_construct (slang_struct *stru)
{
	stru->name = NULL;
	stru->fields = (slang_variable_scope *) slang_alloc_malloc (sizeof (slang_variable_scope));
	slang_variable_scope_construct (stru->fields);
	stru->structs = (slang_struct_scope *) slang_alloc_malloc (sizeof (slang_struct_scope));
	slang_struct_scope_construct (stru->structs);
}

static void slang_struct_destruct (slang_struct *stru)
{
	slang_alloc_free (stru->name);
	slang_variable_scope_destruct (stru->fields);
	slang_alloc_free (stru->fields);
	slang_struct_scope_destruct (stru->structs);
	slang_alloc_free (stru->structs);
}

static int slang_struct_copy (slang_struct *x, const slang_struct *y)
{
	slang_struct_destruct (x);
	slang_struct_construct (x);
	if (y->name != NULL)
	{
		x->name = slang_string_duplicate (y->name);
		if (x->name == NULL)
			return 0;
	}
	if (!slang_variable_scope_copy (x->fields, y->fields))
		return 0;
	if (!slang_struct_scope_copy (x->structs, y->structs))
		return 0;
	return 1;
}

static int slang_struct_equal (const slang_struct *x, const slang_struct *y)
{
	unsigned int i;
	if (x->fields->num_variables != y->fields->num_variables)
		return 0;
	for (i = 0; i < x->fields->num_variables; i++)
	{
		slang_variable *varx = x->fields->variables + i;
		slang_variable *vary = y->fields->variables + i;
		if (slang_string_compare (varx->name, vary->name) != 0)
			return 0;
		if (!slang_type_specifier_equal (&varx->type.specifier, &vary->type.specifier))
			return 0;
		if (varx->type.specifier.type == slang_spec_array)
		{
			/* TODO compare array sizes */
		}
	}
	return 1;
}

/* slang_function */
/* XXX mem! */
static void slang_function_construct (slang_function *func)
{
	func->kind = slang_func_ordinary;
	slang_variable_construct (&func->header);
	func->parameters = (slang_variable_scope *) slang_alloc_malloc (sizeof (slang_variable_scope));
	slang_variable_scope_construct (func->parameters);
	func->body = NULL;
}

static void slang_function_destruct (slang_function *func)
{
	slang_variable_destruct (&func->header);
	slang_variable_scope_destruct (func->parameters);
	slang_alloc_free (func->parameters);
	if (func->body != NULL)
	{
		slang_operation_destruct (func->body);
		slang_alloc_free (func->body);
	}
}

/* slang_function_scope */

static void slang_function_scope_construct (slang_function_scope *scope)
{
	scope->functions = NULL;
	scope->num_functions = 0;
	scope->outer_scope = NULL;
}

static void slang_function_scope_destruct (slang_function_scope *scope)
{
	unsigned int i;
	for (i = 0; i < scope->num_functions; i++)
		slang_function_destruct (scope->functions + i);
	slang_alloc_free (scope->functions);
}

static slang_function *slang_function_scope_find (slang_function_scope *funcs, slang_function *fun,
	int all_scopes)
{
	unsigned int i;
	for (i = 0; i < funcs->num_functions; i++)
	{
		slang_function *f = funcs->functions + i;
		unsigned int j;
		if (slang_string_compare (fun->header.name, f->header.name) != 0)
			continue;
		if (fun->param_count != f->param_count)
			continue;
		for (j = 0; j < fun->param_count; j++)
		{
			if (!slang_type_specifier_equal (&fun->parameters->variables[j].type.specifier,
				&f->parameters->variables[j].type.specifier))
			{
				break;
			}
		}
		if (j == fun->param_count)
			return f;
	}
	if (all_scopes && funcs->outer_scope != NULL)
		return slang_function_scope_find (funcs->outer_scope, fun, 1);
	return NULL;
}

/* slang_translation_unit */
/* XXX mem! */
static void slang_translation_unit_construct (slang_translation_unit *unit)
{
	unit->globals = (slang_variable_scope *) slang_alloc_malloc (sizeof (slang_variable_scope));
	slang_variable_scope_construct (unit->globals);
	slang_function_scope_construct (&unit->functions);
	unit->structs = (slang_struct_scope *) slang_alloc_malloc (sizeof (slang_struct_scope));
	slang_struct_scope_construct (unit->structs);
}

static void slang_translation_unit_destruct (slang_translation_unit *unit)
{
	slang_variable_scope_destruct (unit->globals);
	slang_alloc_free (unit->globals);
	slang_function_scope_destruct (&unit->functions);
	slang_struct_scope_destruct (unit->structs);
	slang_alloc_free (unit->structs);
}

static int parse_identifier (const byte **I, char **id)
{
	*id = slang_string_duplicate ((const char *) *I);
	if (*id == NULL)
		return 0;
	*I += strlen ((const char *) *I) + 1;
	return 1;
}

static int parse_number (const byte **I, int *number)
{
	const int radix = (int) (*(*I)++);
	*number = 0;
	while (**I != '\0')
	{
		int digit;
		if (**I >= '0' && **I <= '9')
			digit = (int) (**I - '0');
		else if (**I >= 'A' && **I <= 'Z')
			digit = (int) (**I - 'A') + 10;
		else
			digit = (int) (**I - 'a') + 10;
		*number = *number * radix + digit;
		(*I)++;
	}
	(*I)++;
	return 1;
}

static int parse_float (const byte **I, float *number)
{
	char *integral = NULL;
	char *fractional = NULL;
	char *exponent = NULL;
	char *whole = NULL;

	if (!parse_identifier (I, &integral))
		return 0;

	if (!parse_identifier (I, &fractional))
	{
		slang_alloc_free (integral);
		return 0;
	}

	if (!parse_identifier (I, &exponent))
	{
		slang_alloc_free (fractional);
		slang_alloc_free (integral);
		return 0;
	}

	whole = (char *) (slang_alloc_malloc ((strlen (integral) + strlen (fractional) + strlen (
		exponent) + 3) * sizeof (char)));
	if (whole == NULL)
	{
		slang_alloc_free (exponent);
		slang_alloc_free (fractional);
		slang_alloc_free (integral);
		return 0;
	}

	slang_string_copy (whole, integral);
	slang_string_concat (whole, ".");
	slang_string_concat (whole, fractional);
	slang_string_concat (whole, "E");
	slang_string_concat (whole, exponent);

	*number = (float) (atof (whole));

	slang_alloc_free (whole);
	slang_alloc_free (exponent);
	slang_alloc_free (fractional);
	slang_alloc_free (integral);
	return 1;
}

/* revision number - increment after each change affecting emitted output */
#define REVISION 2

static int check_revision (const byte **I)
{
	if (**I != REVISION)
		return 0;
	(*I)++;
	return 1;
}

static int parse_statement (const byte **, slang_operation *, slang_variable_scope *,
	slang_struct_scope *);
static int parse_expression (const byte **, slang_operation *, slang_variable_scope *,
	slang_struct_scope *);

/* type qualifier */
#define TYPE_QUALIFIER_NONE 0
#define TYPE_QUALIFIER_CONST 1
#define TYPE_QUALIFIER_ATTRIBUTE 2
#define TYPE_QUALIFIER_VARYING 3
#define TYPE_QUALIFIER_UNIFORM 4
#define TYPE_QUALIFIER_FIXEDOUTPUT 5
#define TYPE_QUALIFIER_FIXEDINPUT 6

static int parse_type_qualifier (const byte **I, slang_type_qualifier *qual)
{
	switch (*(*I)++)
	{
	case TYPE_QUALIFIER_NONE:
		*qual = slang_qual_none;
		break;
	case TYPE_QUALIFIER_CONST:
		*qual = slang_qual_const;
		break;
	case TYPE_QUALIFIER_ATTRIBUTE:
		*qual = slang_qual_attribute;
		break;
	case TYPE_QUALIFIER_VARYING:
		*qual = slang_qual_varying;
		break;
	case TYPE_QUALIFIER_UNIFORM:
		*qual = slang_qual_uniform;
		break;
	case TYPE_QUALIFIER_FIXEDOUTPUT:
		*qual = slang_qual_fixedoutput;
		break;
	case TYPE_QUALIFIER_FIXEDINPUT:
		*qual = slang_qual_fixedinput;
		break;
	default:
		return 0;
	}
	return 1;
}

/* type specifier */
#define TYPE_SPECIFIER_VOID 0
#define TYPE_SPECIFIER_BOOL 1
#define TYPE_SPECIFIER_BVEC2 2
#define TYPE_SPECIFIER_BVEC3 3
#define TYPE_SPECIFIER_BVEC4 4
#define TYPE_SPECIFIER_INT 5
#define TYPE_SPECIFIER_IVEC2 6
#define TYPE_SPECIFIER_IVEC3 7
#define TYPE_SPECIFIER_IVEC4 8
#define TYPE_SPECIFIER_FLOAT 9
#define TYPE_SPECIFIER_VEC2 10
#define TYPE_SPECIFIER_VEC3 11
#define TYPE_SPECIFIER_VEC4 12
#define TYPE_SPECIFIER_MAT2 13
#define TYPE_SPECIFIER_MAT3 14
#define TYPE_SPECIFIER_MAT4 15
#define TYPE_SPECIFIER_SAMPLER1D 16
#define TYPE_SPECIFIER_SAMPLER2D 17
#define TYPE_SPECIFIER_SAMPLER3D 18
#define TYPE_SPECIFIER_SAMPLERCUBE 19
#define TYPE_SPECIFIER_SAMPLER1DSHADOW 20
#define TYPE_SPECIFIER_SAMPLER2DSHADOW 21
#define TYPE_SPECIFIER_STRUCT 22
#define TYPE_SPECIFIER_TYPENAME 23

/* structure field */
#define FIELD_NONE 0
#define FIELD_NEXT 1
#define FIELD_ARRAY 2

static int parse_type_specifier (const byte **I, slang_type_specifier *spec,
	slang_struct_scope *structs, slang_variable_scope *scope)
{
	switch (*(*I)++)
	{
	case TYPE_SPECIFIER_VOID:
		spec->type = slang_spec_void;
		break;
	case TYPE_SPECIFIER_BOOL:
		spec->type = slang_spec_bool;
		break;
	case TYPE_SPECIFIER_BVEC2:
		spec->type = slang_spec_bvec2;
		break;
	case TYPE_SPECIFIER_BVEC3:
		spec->type = slang_spec_bvec3;
		break;
	case TYPE_SPECIFIER_BVEC4:
		spec->type = slang_spec_bvec4;
		break;
	case TYPE_SPECIFIER_INT:
		spec->type = slang_spec_int;
		break;
	case TYPE_SPECIFIER_IVEC2:
		spec->type = slang_spec_ivec2;
		break;
	case TYPE_SPECIFIER_IVEC3:
		spec->type = slang_spec_ivec3;
		break;
	case TYPE_SPECIFIER_IVEC4:
		spec->type = slang_spec_ivec4;
		break;
	case TYPE_SPECIFIER_FLOAT:
		spec->type = slang_spec_float;
		break;
	case TYPE_SPECIFIER_VEC2:
		spec->type = slang_spec_vec2;
		break;
	case TYPE_SPECIFIER_VEC3:
		spec->type = slang_spec_vec3;
		break;
	case TYPE_SPECIFIER_VEC4:
		spec->type = slang_spec_vec4;
		break;
	case TYPE_SPECIFIER_MAT2:
		spec->type = slang_spec_mat2;
		break;
	case TYPE_SPECIFIER_MAT3:
		spec->type = slang_spec_mat3;
		break;
	case TYPE_SPECIFIER_MAT4:
		spec->type = slang_spec_mat4;
		break;
	case TYPE_SPECIFIER_SAMPLER1D:
		spec->type = slang_spec_sampler1D;
		break;
	case TYPE_SPECIFIER_SAMPLER2D:
		spec->type = slang_spec_sampler2D;
		break;
	case TYPE_SPECIFIER_SAMPLER3D:
		spec->type = slang_spec_sampler3D;
		break;
	case TYPE_SPECIFIER_SAMPLERCUBE:
		spec->type = slang_spec_samplerCube;
		break;
	case TYPE_SPECIFIER_SAMPLER1DSHADOW:
		spec->type = slang_spec_sampler1DShadow;
		break;
	case TYPE_SPECIFIER_SAMPLER2DSHADOW:
		spec->type = slang_spec_sampler2DShadow;
		break;
	case TYPE_SPECIFIER_STRUCT:
		spec->type = slang_spec_struct;
		{
			char *name;
			if (!parse_identifier (I, &name))
				return 0;
			if (*name != '\0' && slang_struct_scope_find (structs, name, 0) != NULL)
			{
				slang_alloc_free (name);
				return 0;		/* error: duplicate names */
			}
			spec->_struct = (slang_struct *) slang_alloc_malloc (sizeof (slang_struct));
			if (spec->_struct == NULL)
			{
				slang_alloc_free (name);
				return 0;
			}
			slang_struct_construct (spec->_struct);
			spec->_struct->name = name;
			spec->_struct->structs->outer_scope = structs;
		}
		do
		{
			slang_type_specifier sp;
			slang_type_specifier_construct (&sp);
			if (!parse_type_specifier (I, &sp, spec->_struct->structs, scope))
			{
				slang_type_specifier_destruct (&sp);
				return 0;
			}
			do
			{
				slang_variable *var;
				spec->_struct->fields->variables = (slang_variable *) slang_alloc_realloc (
					spec->_struct->fields->variables,
					spec->_struct->fields->num_variables * sizeof (slang_variable),
					(spec->_struct->fields->num_variables + 1) * sizeof (slang_variable));
				if (spec->_struct->fields->variables == NULL)
				{
					slang_type_specifier_destruct (&sp);
					return 0;
				}
				var = spec->_struct->fields->variables + spec->_struct->fields->num_variables;
				spec->_struct->fields->num_variables++;
				slang_variable_construct (var);
				if (!slang_type_specifier_copy (&var->type.specifier, &sp))
				{
					slang_type_specifier_destruct (&sp);
					return 0;
				}
				if (!parse_identifier (I, &var->name))
				{
					slang_type_specifier_destruct (&sp);
					return 0;
				}
				switch (*(*I)++)
				{
				case FIELD_NONE:
					break;
				case FIELD_ARRAY:
					var->array_size = (slang_operation *) slang_alloc_malloc (sizeof (
						slang_operation));
					if (var->array_size == NULL)
					{
						slang_type_specifier_destruct (&sp);
						return 0;
					}
					slang_operation_construct (var->array_size);
					if (!parse_expression (I, var->array_size, scope, structs))
					{
						slang_type_specifier_destruct (&sp);
						return 0;
					}
					break;
				default:
					slang_type_specifier_destruct (&sp);
					return 0;
				}
			}
			while (*(*I)++ != FIELD_NONE);
		}
		while (*(*I)++ != FIELD_NONE);
		if (*spec->_struct->name != '\0')
		{
			slang_struct *s;
			structs->structs = (slang_struct *) slang_alloc_realloc (structs->structs,
				structs->num_structs * sizeof (slang_struct),
				(structs->num_structs + 1) * sizeof (slang_struct));
			if (structs->structs == NULL)
				return 0;
			s = structs->structs + structs->num_structs;
			structs->num_structs++;
			slang_struct_construct (s);
			if (!slang_struct_copy (s, spec->_struct))
				return 0;
		}
		break;
	case TYPE_SPECIFIER_TYPENAME:
		spec->type = slang_spec_struct;
		{
			char *name;
			slang_struct *stru;
			if (!parse_identifier (I, &name))
				return 0;
			stru = slang_struct_scope_find (structs, name, 1);
			slang_alloc_free (name);
			if (stru == NULL)
				return 0;
			spec->_struct = (slang_struct *) slang_alloc_malloc (sizeof (slang_struct));
			if (spec->_struct == NULL)
				return 0;
			slang_struct_construct (spec->_struct);
			if (!slang_struct_copy (spec->_struct, stru))
				return 0;
		}
		break;
	default:
		return 0;
	}
	return 1;
}

static int parse_fully_specified_type (const byte **I, slang_fully_specified_type *type,
	slang_struct_scope *structs, slang_variable_scope *scope)
{
	if (!parse_type_qualifier (I, &type->qualifier))
		return 0;
	return parse_type_specifier (I, &type->specifier, structs, scope);
}

/* operation */
#define OP_END 0
#define OP_BLOCK_BEGIN_NO_NEW_SCOPE 1
#define OP_BLOCK_BEGIN_NEW_SCOPE 2
#define OP_DECLARE 3
#define OP_ASM 4
#define OP_BREAK 5
#define OP_CONTINUE 6
#define OP_DISCARD 7
#define OP_RETURN 8
#define OP_EXPRESSION 9
#define OP_IF 10
#define OP_WHILE 11
#define OP_DO 12
#define OP_FOR 13
#define OP_PUSH_VOID 14
#define OP_PUSH_BOOL 15
#define OP_PUSH_INT 16
#define OP_PUSH_FLOAT 17
#define OP_PUSH_IDENTIFIER 18
#define OP_SEQUENCE 19
#define OP_ASSIGN 20
#define OP_ADDASSIGN 21
#define OP_SUBASSIGN 22
#define OP_MULASSIGN 23
#define OP_DIVASSIGN 24
/*#define OP_MODASSIGN 25*/
/*#define OP_LSHASSIGN 26*/
/*#define OP_RSHASSIGN 27*/
/*#define OP_ORASSIGN 28*/
/*#define OP_XORASSIGN 29*/
/*#define OP_ANDASSIGN 30*/
#define OP_SELECT 31
#define OP_LOGICALOR 32
#define OP_LOGICALXOR 33
#define OP_LOGICALAND 34
/*#define OP_BITOR 35*/
/*#define OP_BITXOR 36*/
/*#define OP_BITAND 37*/
#define OP_EQUAL 38
#define OP_NOTEQUAL 39
#define OP_LESS 40
#define OP_GREATER 41
#define OP_LESSEQUAL 42
#define OP_GREATEREQUAL 43
/*#define OP_LSHIFT 44*/
/*#define OP_RSHIFT 45*/
#define OP_ADD 46
#define OP_SUBTRACT 47
#define OP_MULTIPLY 48
#define OP_DIVIDE 49
/*#define OP_MODULUS 50*/
#define OP_PREINCREMENT 51
#define OP_PREDECREMENT 52
#define OP_PLUS 53
#define OP_MINUS 54
/*#define OP_COMPLEMENT 55*/
#define OP_NOT 56
#define OP_SUBSCRIPT 57
#define OP_CALL 58
#define OP_FIELD 59
#define OP_POSTINCREMENT 60
#define OP_POSTDECREMENT 61

static int parse_child_operation (const byte **I, slang_operation *oper, int statement,
	slang_variable_scope *scope, slang_struct_scope *structs)
{
	oper->children = (slang_operation *) slang_alloc_realloc (oper->children,
		oper->num_children * sizeof (slang_operation),
		(oper->num_children + 1) * sizeof (slang_operation));
	if (oper->children == NULL)
		return 0;
	slang_operation_construct (oper->children + oper->num_children);
	oper->num_children++;
	if (statement)
		return parse_statement (I, oper->children + oper->num_children - 1, scope, structs);
	return parse_expression (I, oper->children + oper->num_children - 1, scope, structs);
}

static int parse_declaration (const byte **, slang_variable_scope *, slang_struct_scope *,
	slang_function_scope *);

static int parse_statement (const byte **I, slang_operation *oper, slang_variable_scope *scope,
	slang_struct_scope *structs)
{
	oper->locals->outer_scope = scope;
	switch (*(*I)++)
	{
	case OP_BLOCK_BEGIN_NO_NEW_SCOPE:
		oper->type = slang_oper_block_no_new_scope;
		while (**I != OP_END)
			if (!parse_child_operation (I, oper, 1, scope, structs))
				return 0;
		(*I)++;
		break;
	case OP_BLOCK_BEGIN_NEW_SCOPE:
		oper->type = slang_oper_block_new_scope;
		while (**I != OP_END)
			if (!parse_child_operation (I, oper, 1, oper->locals, structs))
				return 0;
		(*I)++;
		break;
	case OP_DECLARE:
		oper->type = slang_oper_variable_decl;
		{
			const unsigned int first_var = scope->num_variables;
			if (!parse_declaration (I, scope, structs, NULL))
				return 0;
			if (first_var < scope->num_variables)
			{
				const unsigned int num_vars = scope->num_variables - first_var;
				unsigned int i;
				oper->children = (slang_operation *) slang_alloc_malloc (num_vars * sizeof (
					slang_operation));
				if (oper->children == NULL)
					return 0;
				for (i = 0; i < num_vars; i++)
					slang_operation_construct (oper->children + i);
				oper->num_children = num_vars;
				for (i = first_var; i < scope->num_variables; i++)
				{
					slang_operation *o = oper->children + i - first_var;
					o->type = slang_oper_identifier;
					o->locals->outer_scope = scope;
					o->identifier = slang_string_duplicate (scope->variables[i].name);
					if (o->identifier == NULL)
						return 0;
				}
			}
		}
		break;
	case OP_ASM:
		oper->type = slang_oper_asm;
		if (!parse_identifier (I, &oper->identifier))
			return 0;
		while (**I != OP_END)
			if (!parse_child_operation (I, oper, 0, scope, structs))
				return 0;
		(*I)++;
		break;
	case OP_BREAK:
		oper->type = slang_oper_break;
		break;
	case OP_CONTINUE:
		oper->type = slang_oper_continue;
		break;
	case OP_DISCARD:
		oper->type = slang_oper_discard;
		break;
	case OP_RETURN:
		oper->type = slang_oper_return;
		if (!parse_child_operation (I, oper, 0, scope, structs))
			return 0;
		break;
	case OP_EXPRESSION:
		oper->type = slang_oper_expression;
		if (!parse_child_operation (I, oper, 0, scope, structs))
			return 0;
		break;
	case OP_IF:
		oper->type = slang_oper_if;
		if (!parse_child_operation (I, oper, 0, scope, structs))
			return 0;
		if (!parse_child_operation (I, oper, 1, scope, structs))
			return 0;
		if (!parse_child_operation (I, oper, 1, scope, structs))
			return 0;
		break;
	case OP_WHILE:
		oper->type = slang_oper_while;
		if (!parse_child_operation (I, oper, 1, oper->locals, structs))
			return 0;
		if (!parse_child_operation (I, oper, 1, oper->locals, structs))
			return 0;
		break;
	case OP_DO:
		oper->type = slang_oper_do;
		if (!parse_child_operation (I, oper, 1, scope, structs))
			return 0;
		if (!parse_child_operation (I, oper, 0, scope, structs))
			return 0;
		break;
	case OP_FOR:
		oper->type = slang_oper_for;
		if (!parse_child_operation (I, oper, 1, oper->locals, structs))
			return 0;
		if (!parse_child_operation (I, oper, 1, oper->locals, structs))
			return 0;
		if (!parse_child_operation (I, oper, 0, oper->locals, structs))
			return 0;
		if (!parse_child_operation (I, oper, 1, oper->locals, structs))
			return 0;
		break;
	default:
		return 0;
	}
	return 1;
}

static int handle_trinary_expression (slang_operation *op, slang_operation **ops,
	unsigned int *num_ops)
{
	op->num_children = 3;
	op->children = (slang_operation *) slang_alloc_malloc (3 * sizeof (slang_operation));
	if (op->children == NULL)
		return 0;
	op->children[0] = (*ops)[*num_ops - 4];
	op->children[1] = (*ops)[*num_ops - 3];
	op->children[2] = (*ops)[*num_ops - 2];
	(*ops)[*num_ops - 4] = (*ops)[*num_ops - 1];
	*num_ops -= 3;
	*ops = (slang_operation *) slang_alloc_realloc (*ops, (*num_ops + 3) * sizeof (slang_operation),
		*num_ops * sizeof (slang_operation));
	if (*ops == NULL)
		return 0;
	return 1;
}

static int handle_binary_expression (slang_operation *op, slang_operation **ops,
	unsigned int *num_ops)
{
	op->num_children = 2;
	op->children = (slang_operation *) slang_alloc_malloc (2 * sizeof (slang_operation));
	if (op->children == NULL)
		return 0;
	op->children[0] = (*ops)[*num_ops - 3];
	op->children[1] = (*ops)[*num_ops - 2];
	(*ops)[*num_ops - 3] = (*ops)[*num_ops - 1];
	*num_ops -= 2;
	*ops = (slang_operation *) slang_alloc_realloc (*ops, (*num_ops + 2) * sizeof (slang_operation),
		*num_ops * sizeof (slang_operation));
	if (*ops == NULL)
		return 0;
	return 1;
}

static int handle_unary_expression (slang_operation *op, slang_operation **ops, 
	unsigned int *num_ops)
{
	op->num_children = 1;
	op->children = (slang_operation *) slang_alloc_malloc (sizeof (slang_operation));
	if (op->children == NULL)
		return 0;
	op->children[0] = (*ops)[*num_ops - 2];
	(*ops)[*num_ops - 2] = (*ops)[*num_ops - 1];
	(*num_ops)--;
	*ops = (slang_operation *) slang_alloc_realloc (*ops, (*num_ops + 1) * sizeof (slang_operation),
		*num_ops * sizeof (slang_operation));
	if (*ops == NULL)
		return 0;
	return 1;
}

static int parse_expression (const byte **I, slang_operation *oper, slang_variable_scope *scope,
	slang_struct_scope *structs)
{
	slang_operation *ops = NULL;
	unsigned int num_ops = 0;
	int number;

	while (**I != OP_END)
	{
		slang_operation *op;
		const unsigned int op_code = *(*I)++;
		ops = (slang_operation *) slang_alloc_realloc (ops,
			num_ops * sizeof (slang_operation), (num_ops + 1) * sizeof (slang_operation));
		if (ops == NULL)
			return 0;
		op = ops + num_ops;
		num_ops++;
		slang_operation_construct (op);
		op->locals->outer_scope = scope;
		switch (op_code)
		{
		case OP_PUSH_VOID:
			op->type = slang_oper_void;
			break;
		case OP_PUSH_BOOL:
			op->type = slang_oper_literal_bool;
			if (!parse_number (I, &number))
				return 0;
			op->literal = (float) number;
			break;
		case OP_PUSH_INT:
			op->type = slang_oper_literal_int;
			if (!parse_number (I, &number))
				return 0;
			op->literal = (float) number;
			break;
		case OP_PUSH_FLOAT:
			op->type = slang_oper_literal_float;
			if (!parse_float (I, &op->literal))
				return 0;
			break;
		case OP_PUSH_IDENTIFIER:
			op->type = slang_oper_identifier;
			if (!parse_identifier (I, &op->identifier))
				return 0;
			break;
		case OP_SEQUENCE:
			op->type = slang_oper_sequence;
			if (!handle_binary_expression (op, &ops, &num_ops))
				return 0;
			break;
		case OP_ASSIGN:
			op->type = slang_oper_assign;
			if (!handle_binary_expression (op, &ops, &num_ops))
				return 0;
			break;
		case OP_ADDASSIGN:
			op->type = slang_oper_addassign;
			if (!handle_binary_expression (op, &ops, &num_ops))
				return 0;
			break;
		case OP_SUBASSIGN:
			op->type = slang_oper_subassign;
			if (!handle_binary_expression (op, &ops, &num_ops))
				return 0;
			break;
		case OP_MULASSIGN:
			op->type = slang_oper_mulassign;
			if (!handle_binary_expression (op, &ops, &num_ops))
				return 0;
			break;
		case OP_DIVASSIGN:
			op->type = slang_oper_divassign;
			if (!handle_binary_expression (op, &ops, &num_ops))
				return 0;
			break;
		/*case OP_MODASSIGN:*/
		/*case OP_LSHASSIGN:*/
		/*case OP_RSHASSIGN:*/
		/*case OP_ORASSIGN:*/
		/*case OP_XORASSIGN:*/
		/*case OP_ANDASSIGN:*/
		case OP_SELECT:
			op->type = slang_oper_select;
			if (!handle_trinary_expression (op, &ops, &num_ops))
				return 0;
			break;
		case OP_LOGICALOR:
			op->type = slang_oper_logicalor;
			if (!handle_binary_expression (op, &ops, &num_ops))
				return 0;
			break;
		case OP_LOGICALXOR:
			op->type = slang_oper_logicalxor;
			if (!handle_binary_expression (op, &ops, &num_ops))
				return 0;
			break;
		case OP_LOGICALAND:
			op->type = slang_oper_logicaland;
			if (!handle_binary_expression (op, &ops, &num_ops))
				return 0;
			break;
		/*case OP_BITOR:*/
		/*case OP_BITXOR:*/
		/*case OP_BITAND:*/
		case OP_EQUAL:
			op->type = slang_oper_equal;
			if (!handle_binary_expression (op, &ops, &num_ops))
				return 0;
			break;
		case OP_NOTEQUAL:
			op->type = slang_oper_notequal;
			if (!handle_binary_expression (op, &ops, &num_ops))
				return 0;
			break;
		case OP_LESS:
			op->type = slang_oper_less;
			if (!handle_binary_expression (op, &ops, &num_ops))
				return 0;
			break;
		case OP_GREATER:
			op->type = slang_oper_greater;
			if (!handle_binary_expression (op, &ops, &num_ops))
				return 0;
			break;
		case OP_LESSEQUAL:
			op->type = slang_oper_lessequal;
			if (!handle_binary_expression (op, &ops, &num_ops))
				return 0;
			break;
		case OP_GREATEREQUAL:
			op->type = slang_oper_greaterequal;
			if (!handle_binary_expression (op, &ops, &num_ops))
				return 0;
			break;
		/*case OP_LSHIFT:*/
		/*case OP_RSHIFT:*/
		case OP_ADD:
			op->type = slang_oper_add;
			if (!handle_binary_expression (op, &ops, &num_ops))
				return 0;
			break;
		case OP_SUBTRACT:
			op->type = slang_oper_subtract;
			if (!handle_binary_expression (op, &ops, &num_ops))
				return 0;
			break;
		case OP_MULTIPLY:
			op->type = slang_oper_multiply;
			if (!handle_binary_expression (op, &ops, &num_ops))
				return 0;
			break;
		case OP_DIVIDE:
			op->type = slang_oper_divide;
			if (!handle_binary_expression (op, &ops, &num_ops))
				return 0;
			break;
		/*case OP_MODULUS:*/
		case OP_PREINCREMENT:
			op->type = slang_oper_preincrement;
			if (!handle_unary_expression (op, &ops, &num_ops))
				return 0;
			break;
		case OP_PREDECREMENT:
			op->type = slang_oper_predecrement;
			if (!handle_unary_expression (op, &ops, &num_ops))
				return 0;
			break;
		case OP_PLUS:
			op->type = slang_oper_plus;
			if (!handle_unary_expression (op, &ops, &num_ops))
				return 0;
			break;
		case OP_MINUS:
			op->type = slang_oper_minus;
			if (!handle_unary_expression (op, &ops, &num_ops))
				return 0;
			break;
		case OP_NOT:
			op->type = slang_oper_not;
			if (!handle_unary_expression (op, &ops, &num_ops))
				return 0;
			break;
		/*case OP_COMPLEMENT:*/
		case OP_SUBSCRIPT:
			op->type = slang_oper_subscript;
			if (!handle_binary_expression (op, &ops, &num_ops))
				return 0;
			break;
		case OP_CALL:
			op->type = slang_oper_call;
			if (!parse_identifier (I, &op->identifier))
				return 0;
			while (**I != OP_END)
				if (!parse_child_operation (I, op, 0, scope, structs))
					return 0;
			(*I)++;
			break;
		case OP_FIELD:
			op->type = slang_oper_field;
			if (!parse_identifier (I, &op->identifier))
				return 0;
			if (!handle_unary_expression (op, &ops, &num_ops))
				return 0;
			break;
		case OP_POSTINCREMENT:
			op->type = slang_oper_postincrement;
			if (!handle_unary_expression (op, &ops, &num_ops))
				return 0;
			break;
		case OP_POSTDECREMENT:
			op->type = slang_oper_postdecrement;
			if (!handle_unary_expression (op, &ops, &num_ops))
				return 0;
			break;
		default:
			return 0;
		}
	}
	(*I)++;
	*oper = *ops;
	slang_alloc_free (ops);
	return 1;
}

/* parameter qualifier */
#define PARAM_QUALIFIER_IN 0
#define PARAM_QUALIFIER_OUT 1
#define PARAM_QUALIFIER_INOUT 2

/* function parameter array presence */
#define PARAMETER_ARRAY_NOT_PRESENT 0
#define PARAMETER_ARRAY_PRESENT 1

static int parse_parameter_declaration (const byte **I, slang_variable *param,
	slang_struct_scope *structs, slang_variable_scope *scope)
{
	if (!parse_type_qualifier (I, &param->type.qualifier))
		return 0;
	switch (*(*I)++)
	{
	case PARAM_QUALIFIER_IN:
		if (param->type.qualifier != slang_qual_const && param->type.qualifier != slang_qual_none)
			return 0;	/* error: type qualifier is invalid */
		break;
	case PARAM_QUALIFIER_OUT:
		if (param->type.qualifier == slang_qual_none)
			param->type.qualifier = slang_qual_out;
		else
			return 0;	/* error: type qualifier is invalid */
		break;
	case PARAM_QUALIFIER_INOUT:
		if (param->type.qualifier == slang_qual_none)
			param->type.qualifier = slang_qual_inout;
		else
			return 0;	/* error: type qualifier is invalid */
		break;
	default:
		return 0;
	}
	if (!parse_type_specifier (I, &param->type.specifier, structs, scope))
		return 0;
	if (!parse_identifier (I, &param->name))
		return 0;
	if (*(*I)++ == PARAMETER_ARRAY_PRESENT)
	{
		param->array_size = (slang_operation *) slang_alloc_malloc (sizeof (slang_operation));
		slang_operation_construct (param->array_size);
		if (!parse_expression (I, param->array_size, scope, structs))
			return 0;
	}
	return 1;
}

/* function type */
#define FUNCTION_ORDINARY 0
#define FUNCTION_CONSTRUCTOR 1
#define FUNCTION_OPERATOR 2

/* function parameter */
#define PARAMETER_NONE 0
#define PARAMETER_NEXT 1

/* operator type */
#define OPERATOR_ASSIGN 1
#define OPERATOR_ADDASSIGN 2
#define OPERATOR_SUBASSIGN 3
#define OPERATOR_MULASSIGN 4
#define OPERATOR_DIVASSIGN 5
/*#define OPERATOR_MODASSIGN 6*/
/*#define OPERATOR_LSHASSIGN 7*/
/*#define OPERATOR_RSHASSIGN 8*/
/*#define OPERATOR_ANDASSIGN 9*/
/*#define OPERATOR_XORASSIGN 10*/
/*#define OPERATOR_ORASSIGN 11*/
#define OPERATOR_LOGICALXOR 12
/*#define OPERATOR_BITOR 13*/
/*#define OPERATOR_BITXOR 14*/
/*#define OPERATOR_BITAND 15*/
#define OPERATOR_EQUAL 16
#define OPERATOR_NOTEQUAL 17
#define OPERATOR_LESS 18
#define OPERATOR_GREATER 19
#define OPERATOR_LESSEQUAL 20
#define OPERATOR_GREATEREQUAL 21
/*#define OPERATOR_LSHIFT 22*/
/*#define OPERATOR_RSHIFT 23*/
#define OPERATOR_MULTIPLY 24
#define OPERATOR_DIVIDE 25
/*#define OPERATOR_MODULUS 26*/
#define OPERATOR_INCREMENT 27
#define OPERATOR_DECREMENT 28
#define OPERATOR_PLUS 29
#define OPERATOR_MINUS 30
/*#define OPERATOR_COMPLEMENT 31*/
#define OPERATOR_NOT 32

/* these must match with slang_type_specifier_type enum */
static const char *type_specifier_names[] = {
	"void",
	"bool",
	"bvec2",
	"bvec3",
	"bvec4",
	"int",
	"ivec2",
	"ivec3",
	"ivec4",
	"float",
	"vec2",
	"vec3",
	"vec4",
	"mat2",
	"mat3",
	"mat4",
	"sampler1D",
	"sampler2D",
	"sampler3D",
	"samplerCube",
	"sampler1DShadow",
	"sampler2DShadow"
};

static const struct {
	unsigned int o_code;
	const char *o_name;
} operator_names[] = {
	{ OPERATOR_INCREMENT, "++" },
	{ OPERATOR_ADDASSIGN, "+=" },
	{ OPERATOR_PLUS, "+" },
	{ OPERATOR_DECREMENT, "--" },
	{ OPERATOR_SUBASSIGN, "-=" },
	{ OPERATOR_MINUS, "-" },
	{ OPERATOR_NOTEQUAL, "!=" },
	{ OPERATOR_NOT, "!" },
	{ OPERATOR_MULASSIGN, "*=" },
	{ OPERATOR_MULTIPLY, "*" },
	{ OPERATOR_DIVASSIGN, "/=" },
	{ OPERATOR_DIVIDE, "/" },
	{ OPERATOR_LESSEQUAL, "<=" },
	/*{ OPERATOR_LSHASSIGN, "<<=" },*/
	/*{ OPERATOR_LSHIFT, "<<" },*/
	{ OPERATOR_LESS, "<" },
	{ OPERATOR_GREATEREQUAL, ">=" },
	/*{ OPERATOR_RSHASSIGN, ">>=" },*/
	/*{ OPERATOR_RSHIFT, ">>" },*/
	{ OPERATOR_GREATER, ">" },
	{ OPERATOR_EQUAL, "==" },
	{ OPERATOR_ASSIGN, "=" },
	/*{ OPERATOR_MODASSIGN, "%=" },*/
	/*{ OPERATOR_MODULUS, "%" },*/
	/*{ OPERATOR_ANDASSIGN, "&=" },*/
	/*{ OPERATOR_BITAND, "&" },*/
	/*{ OPERATOR_ORASSIGN, "|=" },*/
	/*{ OPERATOR_BITOR, "|" },*/
	/*{ OPERATOR_COMPLEMENT, "~" },*/
	/*{ OPERATOR_XORASSIGN, "^=" },*/
	{ OPERATOR_LOGICALXOR, "^^" }/*,*/
	/*{ OPERATOR_BITXOR, "^" }*/
};

static int parse_operator_name (const byte **I, char **pname)
{
	unsigned int i;
	for (i = 0; i < sizeof (operator_names) / sizeof (*operator_names); i++)
		if (operator_names[i].o_code == (unsigned int) (**I))
		{
			*pname = slang_string_duplicate (operator_names[i].o_name);
			if (*pname == NULL)
				return 0;
			(*I)++;
			return 1;
		}
	return 0;
}

static int parse_function_prototype (const byte **I, slang_function *func,
	slang_struct_scope *structs, slang_variable_scope *scope)
{
	if (!parse_fully_specified_type (I, &func->header.type, structs, scope))
		return 0;
	switch (*(*I)++)
	{
	case FUNCTION_ORDINARY:
		func->kind = slang_func_ordinary;
		if (!parse_identifier (I, &func->header.name))
			return 0;
		break;
	case FUNCTION_CONSTRUCTOR:
		func->kind = slang_func_constructor;
		if (func->header.type.specifier.type == slang_spec_struct)
			return 0;
		func->header.name = slang_string_duplicate (
			type_specifier_names[func->header.type.specifier.type]);
		if (func->header.name == NULL)
			return 0;
		break;
	case FUNCTION_OPERATOR:
		func->kind = slang_func_operator;
		if (!parse_operator_name (I, &func->header.name))
			return 0;
		break;
	default:
		return 0;
	}
	func->parameters->outer_scope = scope;
	while (*(*I)++ == PARAMETER_NEXT)
	{
		func->parameters->variables = (slang_variable *) slang_alloc_realloc (
			func->parameters->variables,
			func->parameters->num_variables * sizeof (slang_variable),
			(func->parameters->num_variables + 1) * sizeof (slang_variable));
		if (func->parameters->variables == NULL)
			return 0;
		slang_variable_construct (func->parameters->variables + func->parameters->num_variables);
		func->parameters->num_variables++;
		if (!parse_parameter_declaration (I, func->parameters->variables +
			func->parameters->num_variables - 1, structs, scope))
			return 0;
	}
	func->param_count = func->parameters->num_variables;
	return 1;
}

static int parse_function_definition (const byte **I, slang_function *func,
	slang_struct_scope *structs, slang_variable_scope *scope)
{
	if (!parse_function_prototype (I, func, structs, scope))
		return 0;
	func->body = (slang_operation *) slang_alloc_malloc (sizeof (slang_operation));
	if (func->body == NULL)
		return 0;
	slang_operation_construct (func->body);
	if (!parse_statement (I, func->body, func->parameters, structs))
		return 0;
	return 1;
}

/* init declarator list */
#define DECLARATOR_NONE 0
#define DECLARATOR_NEXT 1

/* variable declaration */
#define VARIABLE_NONE 0
#define VARIABLE_IDENTIFIER 1
#define VARIABLE_INITIALIZER 2
#define VARIABLE_ARRAY_EXPLICIT 3
#define VARIABLE_ARRAY_UNKNOWN 4

static int parse_init_declarator (const byte **I, const slang_fully_specified_type *type,
	slang_variable_scope *vars, slang_struct_scope *structs)
{
	slang_variable *var;

	if (*(*I)++ == VARIABLE_NONE)
		return 1;
	vars->variables = (slang_variable *) slang_alloc_realloc (vars->variables,
		vars->num_variables * sizeof (slang_variable),
		(vars->num_variables + 1) * sizeof (slang_variable));
	if (vars->variables == NULL)
		return 0;
	var = vars->variables + vars->num_variables;
	vars->num_variables++;
	slang_variable_construct (var);
	var->type.qualifier = type->qualifier;
	if (!parse_identifier (I, &var->name))
		return 0;
	switch (*(*I)++)
	{
	case VARIABLE_NONE:
		if (!slang_type_specifier_copy (&var->type.specifier, &type->specifier))
			return 0;
		break;
	case VARIABLE_INITIALIZER:
		if (!slang_type_specifier_copy (&var->type.specifier, &type->specifier))
			return 0;
		var->initializer = (slang_operation *) slang_alloc_malloc (sizeof (slang_operation));
		if (var->initializer == NULL)
			return 0;
		slang_operation_construct (var->initializer);
		if (!parse_expression (I, var->initializer, vars, structs))
			return 0;
		break;
	case VARIABLE_ARRAY_UNKNOWN:
		var->type.specifier.type = slang_spec_array;
		var->type.specifier._array = (slang_type_specifier *) slang_alloc_malloc (sizeof (
			slang_type_specifier));
		if (var->type.specifier._array == NULL)
			return 0;
		slang_type_specifier_construct (var->type.specifier._array);
		if (!slang_type_specifier_copy (var->type.specifier._array, &type->specifier))
			return 0;
		break;
	case VARIABLE_ARRAY_EXPLICIT:
		var->type.specifier.type = slang_spec_array;
		var->type.specifier._array = (slang_type_specifier *) slang_alloc_malloc (sizeof (
			slang_type_specifier));
		if (var->type.specifier._array == NULL)
			return 0;
		slang_type_specifier_construct (var->type.specifier._array);
		if (!slang_type_specifier_copy (var->type.specifier._array, &type->specifier))
			return 0;
		var->array_size = (slang_operation *) slang_alloc_malloc (sizeof (slang_operation));
		if (var->array_size == NULL)
			return 0;
		slang_operation_construct (var->array_size);
		if (!parse_expression (I, var->array_size, vars, structs))
			return 0;
		break;
	default:
		return 0;
	}
	return 1;
}

static int parse_init_declarator_list (const byte **I, slang_variable_scope *vars,
	slang_struct_scope *structs)
{
	slang_fully_specified_type type;

	slang_fully_specified_type_construct (&type);
	if (!parse_fully_specified_type (I, &type, structs, vars))
	{
		slang_fully_specified_type_destruct (&type);
		return 0;
	}
	do
	{
		if (!parse_init_declarator (I, &type, vars, structs))
		{
			slang_fully_specified_type_destruct (&type);
			return 0;
		}
	}
	while (*(*I)++ == DECLARATOR_NEXT);
	slang_fully_specified_type_destruct (&type);
	return 1;
}

static int parse_function (const byte **I, int definition, slang_struct_scope *structs,
	slang_function_scope *funcs, slang_variable_scope *scope)
{
	slang_function parsed_func, *found_func;

	slang_function_construct (&parsed_func);
	if (definition)
	{
		if (!parse_function_definition (I, &parsed_func, structs, scope))
		{
			slang_function_destruct (&parsed_func);
			return 0;
		}
	}
	else
	{
		if (!parse_function_prototype (I, &parsed_func, structs, scope))
		{
			slang_function_destruct (&parsed_func);
			return 0;
		}
	}
	found_func = slang_function_scope_find (funcs, &parsed_func, 0);
	if (found_func == NULL)
	{
		funcs->functions = (slang_function *) slang_alloc_realloc (funcs->functions,
			funcs->num_functions * sizeof (slang_function), (funcs->num_functions + 1) * sizeof (
			slang_function));
		if (funcs->functions == NULL)
		{
			slang_function_destruct (&parsed_func);
			return 0;
		}
		funcs->functions[funcs->num_functions] = parsed_func;
		funcs->num_functions++;
	}
	else
	{
		/* TODO check function return type qualifiers and specifiers */
		if (definition)
		{
			if (found_func->body != NULL)
			{
				slang_function_destruct (&parsed_func);
				return 0;		/* error: second definition */
			}
			slang_function_destruct (found_func);
			*found_func = parsed_func;
		}
		else
		{
			slang_function_destruct (&parsed_func);
		}
	}
	return 1;
}

/* declaration */
#define DECLARATION_FUNCTION_PROTOTYPE 1
#define DECLARATION_INIT_DECLARATOR_LIST 2

static int parse_declaration (const byte **I, slang_variable_scope *scope,
	slang_struct_scope *structs, slang_function_scope *funcs)
{
	switch (*(*I)++)
	{
	case DECLARATION_INIT_DECLARATOR_LIST:
		if (!parse_init_declarator_list (I, scope, structs))
			return 0;
		break;
	case DECLARATION_FUNCTION_PROTOTYPE:
		if (!parse_function (I, 0, structs, funcs, scope))
			return 0;
		break;
	default:
		return 0;
	}
	return 1;
}

/* external declaration */
#define EXTERNAL_NULL 0
#define EXTERNAL_FUNCTION_DEFINITION 1
#define EXTERNAL_DECLARATION 2

static int parse_translation_unit (const byte **I, slang_translation_unit *unit)
{
	while (**I != EXTERNAL_NULL)
	{
		switch (*(*I)++)
		{
		case EXTERNAL_FUNCTION_DEFINITION:
			if (!parse_function (I, 1, unit->structs, &unit->functions, unit->globals))
				return 0;
			break;
		case EXTERNAL_DECLARATION:
			if (!parse_declaration (I, unit->globals, unit->structs, &unit->functions))
				return 0;
			break;
		default:
			return 0;
		}
	}
	(*I)++;
	return 1;
}

static int compile_with_grammar (grammar id, const char *source, slang_translation_unit *unit,
	slang_unit_type type)
{
	byte *prod, *I;
	unsigned int size;

	slang_translation_unit_construct (unit);
	unit->type = type;
	if (!grammar_fast_check (id, (const byte *) source, &prod, &size, 65536))
		return 0;
	I = prod;
	if (!check_revision (&I))
	{
		grammar_alloc_free (prod);
		return 0;
	}
	if (!parse_translation_unit (&I, unit))
	{
		slang_translation_unit_destruct (unit);
		grammar_alloc_free (prod);
		return 0;
	}
	grammar_alloc_free (prod);
	return 1;
}

static const char *slang_shader_syn =
#include "library/slang_shader_syn.h"
;

int _slang_compile (const char *source, slang_translation_unit *unit, slang_unit_type type)
{
	grammar id;

	id = grammar_load_from_text ((const byte *) slang_shader_syn);
	if (id == 0)
		return 0;

	grammar_set_reg8 (id, (const byte *) "parsing_builtin", 1);
	if (type == slang_unit_fragment_shader)
		grammar_set_reg8 (id, (const byte *) "shader_type", 1);
	else
		grammar_set_reg8 (id, (const byte *) "shader_type", 2);

	if (!compile_with_grammar (id, source, unit, type))
	{
		grammar_destroy (id);
		return 0;
	}

	grammar_destroy (id);
	return 1;
}