jack-compiler/parser-expressions.c

#include <stdlib.h>
#include "util.h"
#include "parser-internal.h"
#include "parser-expressions.h"

TERM* parsetermnullified(PARSER* p);
TERM* parseterm(PARSER* p);
TERM* mkterm(TERMTYPE type);
TERM* parseint(PARSER* p);
TERM* parsestr(PARSER* p);
TERM* parsekeyword(PARSER* p);
TERM* parseunaryopterm(PARSER* p);
TERM* parseinnerexpression(PARSER* p);
TERM* parsecalltermnullified(PARSER* p);
TERM* parsearrayterm(PARSER* p);
TERM* parsevarterm(PARSER* p);
TERM* parseidentifierterm(PARSER* p);
bool isop(TOKEN* t);
SUBROUTCALL* nullsubroutcall(PARSER* p, SUBROUTCALL* c);
SUBROUTCALL* parsesubroutcallnullified(PARSER* p);

const char* keywordsarr[] = { "true", "false", "null", "this" };
const char* opsarr[] = { "+", "-", "*", "/", "&", "|", "<", ">", "=" };
mkstrlist(keywordconstants, keywordsarr);
mkstrlist(operators, opsarr);

TERM* parsetermnullified(PARSER* p) {
	TOKENTYPE type = p->current->type;
	if(type == integer) return parseint(p);
	if(type == string) return parsestr(p);
	if(type == keyword) return parsekeyword(p);
	if(type == identifier) return parseidentifierterm(p);
	if(equals(p, "-") || equals(p, "~")) return parseunaryopterm(p);
	if(equals(p, "(")) return parseinnerexpression(p);
	return NULL;
}

TERM* parseterm(PARSER* p) {
	TERM* t = parsetermnullified(p);
	if(t == NULL)
		unexpected(p);
	return t;
}

TERM* mkterm(TERMTYPE type) {
	TERM* t = (TERM*)malloc(sizeof(TERM));
	t->type = type;
	return t;
}

TERM* parseint(PARSER* p) {
	TERM* t = mkterm(intconstant);
	t->integer = atoi(p->current->token);
	next(p);
	return t;
}

TERM* parsestr(PARSER* p) {
	TERM* t = mkterm(stringconstant);
	t->string = p->current->token;
	next(p);
	return t;
}

TERM* parsekeyword(PARSER* p) {
	TERM* t = mkterm(keywordconstant);
	if(!existsinarray(&keywordconstants, p->current->token))
		unexpected(p);
	t->string = p->current->token;
	next(p);
	return t;
}

TERM* parseunaryopterm(PARSER* p) {
	TERM* t = mkterm(unaryopterm);
	next(p);
	t->expression = parseterm(p);
	t->expression->next = NULL;
	return t;
}

TERM* parseinnerexpression(PARSER* p) {
	TERM* t = mkterm(innerexpression);
	next(p);
	t->expression = parseexpression(p);
	checkcontent(p, ")");
	return t;
}

TERM* parsecalltermnullified(PARSER* p) {
	SUBROUTCALL* call = parsesubroutcallnullified(p);
	if(call == NULL)
		return NULL;
	TERM* t = mkterm(subroutcall);
	t->call == call;
	return t;
}

TERM* parsearrayterm(PARSER* p) {
	TERM* t = mkterm(arrayitem);
	t->string = p->current->token;
	next(p);
	checkcontent(p, "[");
	t->arrayexp = parseexpression(p);
	checkcontent(p, "]");
	return t;
}

TERM* parsevarterm(PARSER* p) {
	TERM* t = mkterm(varname);
	t->string = p->current->token;
	next(p);
	return t;
}

TERM* parseidentifierterm(PARSER* p) {
	TERM* t = parsecalltermnullified(p);
	if(t == NULL)
		if(nextequals(p, "["))
			return parsearrayterm(p);
		else
			return parsevarterm(p);
	else
		return t;
}

bool isop(TOKEN* t) {
	for(int i = 0; i < operators.size; i++)
		if(!strcmp(t->token, operators.items[i]))
			return true;
	return false;
}

TERM* parseexpressionnullified(PARSER* p) {
	TERM* head = parsetermnullified(p);
	TERM* current = head;
	TERM* nextt;
	while(isop(p->current)) {
		current->op = p->current->token[0]; 
		next(p);
		nextt = parseterm(p);
		current->next = nextt;
		current = nextt;
	}
	if(current != NULL)
		current->next = NULL;
	return head;
}

TERM* parseexpression(PARSER* p) {
	TERM* t = parseexpressionnullified(p);
	if(t == NULL)
		unexpected(p);
	return t;
}

SUBROUTCALL* nullsubroutcall(PARSER* p, SUBROUTCALL* c) {
	free(c);
	rewindparser(p);
	return NULL;
}

SUBROUTCALL* parsesubroutcallnullified(PARSER* p) {
	if(p->current->type != identifier)
		return NULL;

	anchorparser(p);
	SUBROUTCALL* c = (SUBROUTCALL*)malloc(sizeof(SUBROUTCALL));

	c->debug = getdebug(p);

	if(nextequals(p, ".")) {
		c->parentname = p->current->token;
		next(p);
		next(p);
	}
	else
		c->parentname = NULL;

	if(p->current->type != identifier)
		return nullsubroutcall(p, c);
	c->name = p->current->token;
	next(p);

	if(differs(p, "("))
		return nullsubroutcall(p, c);
	next(p);

	c->parameters = parseexpressionlist(p);

	if(differs(p, ")"))
		return nullsubroutcall(p, c);
	next(p);
	return c;
}

SUBROUTCALL* parsesubroutcall(PARSER* p) {
	SUBROUTCALL* c = (SUBROUTCALL*)malloc(sizeof(SUBROUTCALL));
	c->debug = getdebug(p);

	if(nextequals(p, ".")) {
		c->parentname = parseidentifier(p);
		next(p);
	}
	else
		c->parentname = NULL;

	c->name = parseidentifier(p);

	checkcontent(p, "(");

	c->parameters = parseexpressionlist(p);

	checkcontent(p, ")");
	return c;
}

EXPRESSIONLIST* parseexpressionlist(PARSER* p) {
	if(!strcmp(p->current->token, ")"))
		return NULL;
	EXPRESSIONLIST* head = (EXPRESSIONLIST*)malloc(sizeof(EXPRESSIONLIST));
	head->expression = parseexpressionnullified(p);
	EXPRESSIONLIST* current = head;
	EXPRESSIONLIST* nextls;
	while(!strcmp(p->current->token, ",")) {
		next(p);
		nextls = (EXPRESSIONLIST*)malloc(sizeof(EXPRESSIONLIST));
		nextls->expression = parseexpression(p);
		current->next = nextls;
		current = nextls;
	}
	if(current != NULL)
		current->next = NULL;
	return head;
}