gmqcc/parser.c

#include <stdio.h>
#include <stdarg.h>

#include "gmqcc.h"
#include "lexer.h"

typedef struct {
    lex_file *lex;
    int      tok;

    MEM_VECTOR_MAKE(ast_value*, globals);
} parser_t;

MEM_VEC_FUNCTIONS(parser_t, ast_value*, globals)

void parseerror(parser_t *parser, const char *fmt, ...)
{
	va_list ap;

    if (parser)
	    printf("error %s:%lu: ", parser->lex->tok->ctx.file, (unsigned long)parser->lex->tok->ctx.line);
	else
	    printf("error: ");

	va_start(ap, fmt);
	vprintf(fmt, ap);
	va_end(ap);

	printf("\n");
}

bool parser_next(parser_t *parser)
{
    /* lex_do kills the previous token */
    parser->tok = lex_do(parser->lex);
    if (parser->tok == TOKEN_EOF || parser->tok >= TOKEN_ERROR)
        return false;
    return true;
}

/* lift a token out of the parser so it's not destroyed by parser_next */
token *parser_lift(parser_t *parser)
{
    token *tok = parser->lex->tok;
    parser->lex->tok = NULL;
    return tok;
}

#define parser_tokval(p) (p->lex->tok->value)
#define parser_token(p)  (p->lex->tok)
#define parser_ctx(p)    (p->lex->tok->ctx)

ast_value* parser_find_global(parser_t *parser, const char *name)
{
    size_t i;
    for (i = 0; i < parser->globals_count; ++i) {
        if (!strcmp(parser->globals[i]->name, name))
            return parser->globals[i];
    }
    return NULL;
}

bool parser_do(parser_t *parser)
{
    if (parser->tok == TOKEN_TYPENAME)
    {
        ast_value *var;
        int       vtype = parser->lex->tok->constval.t;

        /* Declaring a variable */
        if (!parser_next(parser))
            return false;

        if (parser->tok != TOKEN_IDENT) {
            parseerror(parser, "expected variable name\n");
            return false;
        }

        var = parser_find_global(parser, parser_tokval(parser));

        if (var) {
            parseerror(parser, "global already exists: %s\n", parser_tokval(parser));
            return false;
        }

        var = ast_value_new(parser_ctx(parser), parser_tokval(parser), vtype);
        if (!parser_t_globals_add(parser, var))
            return false;

        /* Constant assignment */
        if (!parser_next(parser))
            return false;

        if (parser->tok == ';')
            return parser_next(parser);

        if (parser->tok != '=') {
            parseerror(parser, "expected '=' or ';'");
            return false;
        }

        /* '=' found, assign... */
        parseerror(parser, "TODO, const assignment");
        return false;
    }
    else if (parser->tok == TOKEN_KEYWORD)
    {
        /* handle 'var' and 'const' */
        return false;
    }
    else if (parser->tok == '.')
    {
        /* entity-member declaration */
        return false;
    }
    else
    {
        parseerror(parser, "unexpected token: %s", parser->lex->tok->value);
        return false;
    }
    return true;
}

bool parser_compile(const char *filename)
{
    size_t i;
    parser_t *parser;

    parser = (parser_t*)mem_a(sizeof(parser_t));
    if (!parser)
        return false;

    MEM_VECTOR_INIT(parser, globals);
    parser->lex = lex_open(filename);

    if (!parser->lex) {
        printf("failed to open file \"%s\"\n", filename);
        return false;
    }

    /* initial lexer/parser state */
    parser->lex->flags.noops = true;

    if (parser_next(parser))
    {
        while (parser->tok != TOKEN_EOF && parser->tok < TOKEN_ERROR)
        {
            if (!parser_do(parser)) {
                if (parser->tok == TOKEN_EOF)
                    break;
                printf("parse error\n");
                lex_close(parser->lex);
                mem_d(parser);
                return false;
            }
        }
    }

    lex_close(parser->lex);
    for (i = 0; i < parser->globals_count; ++i) {
        ast_value_delete(parser->globals[i]);
    }
    MEM_VECTOR_CLEAR(parser, globals);

    mem_d(parser);
    return true;
}