source: mainline/uspace/app/sbi/src/parse.c@ 94d484a

/*
 * Copyright (c) 2010 Jiri Svoboda
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * - Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 * - Redistributions in binary form must reproduce the above copyright
 *   notice, this list of conditions and the following disclaimer in the
 *   documentation and/or other materials provided with the distribution.
 * - The name of the author may not be used to endorse or promote products
 *   derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

/** @file Parser
 *
 * Consumes a sequence of lexical elements and produces a syntax tree (stree).
 * Parsing primitives, module members, statements.
 */

#include <assert.h>
#include <stdlib.h>
#include "lex.h"
#include "list.h"
#include "mytypes.h"
#include "p_expr.h"
#include "p_type.h"
#include "stree.h"
#include "strtab.h"

#include "parse.h"

/*
 * Module members
 */
static stree_csi_t *parse_csi(parse_t *parse, lclass_t dclass);
static stree_csimbr_t *parse_csimbr(parse_t *parse, stree_csi_t *outer_csi);

static stree_fun_t *parse_fun(parse_t *parse);
static stree_var_t *parse_var(parse_t *parse);
static stree_prop_t *parse_prop(parse_t *parse);

static stree_fun_arg_t *parse_fun_arg(parse_t *parse);
static stree_arg_attr_t *parse_arg_attr(parse_t *parse);

/*
 * Statements
 */
static stree_block_t *parse_block(parse_t *parse);
static stree_stat_t *parse_stat(parse_t *parse);

static stree_vdecl_t *parse_vdecl(parse_t *parse);
static stree_if_t *parse_if(parse_t *parse);
static stree_while_t *parse_while(parse_t *parse);
static stree_for_t *parse_for(parse_t *parse);
static stree_raise_t *parse_raise(parse_t *parse);
static stree_return_t *parse_return(parse_t *parse);
static stree_wef_t *parse_wef(parse_t *parse);
static stree_exps_t *parse_exps(parse_t *parse);

static stree_except_t *parse_except(parse_t *parse);

void parse_init(parse_t *parse, stree_program_t *prog, struct lex *lex)
{
        parse->program = prog;
        parse->cur_mod = parse->program->module;
        parse->lex = lex;
        lex_next(parse->lex);
}

/** Parse module. */
void parse_module(parse_t *parse)
{
        stree_csi_t *csi;
        stree_modm_t *modm;
        stree_symbol_t *symbol;

        while (lcur_lc(parse) != lc_eof) {
                switch (lcur_lc(parse)) {
                case lc_class:
                case lc_struct:
                case lc_interface:
                        csi = parse_csi(parse, lcur_lc(parse));
                        modm = stree_modm_new(mc_csi);
                        modm->u.csi = csi;

                        symbol = stree_symbol_new(sc_csi);
                        symbol->u.csi = csi;
                        symbol->outer_csi = NULL;
                        csi->symbol = symbol;

                        list_append(&parse->cur_mod->members, modm);
                        break;
                default:
                        lunexpected_error(parse);
                        lex_next(parse->lex);
                        break;
                }

        }
}

/** Parse class, struct or interface declaration. */
static stree_csi_t *parse_csi(parse_t *parse, lclass_t dclass)
{
        stree_csi_t *csi;
        csi_class_t cc;
        stree_csimbr_t *csimbr;

        switch (dclass) {
        case lc_class: cc = csi_class; break;
        case lc_struct: cc = csi_struct; break;
        case lc_interface: cc = csi_interface; break;
        default: assert(b_false);
        }

        lskip(parse);

        csi = stree_csi_new(cc);
        csi->name = parse_ident(parse);
/*
        printf("parse_csi: csi=%p, csi->name = %p (%s)\n", csi, csi->name,
            strtab_get_str(csi->name->sid));
*/
        if (lcur_lc(parse) == lc_colon) {
                /* Inheritance list */
                lskip(parse);
                csi->base_csi_ref = parse_texpr(parse);
        } else {
                csi->base_csi_ref = NULL;
        }

        lmatch(parse, lc_is);
        list_init(&csi->members);

        /* Parse class, struct or interface members. */
        while (lcur_lc(parse) != lc_end) {
                csimbr = parse_csimbr(parse, csi);
                list_append(&csi->members, csimbr);
        }

        lmatch(parse, lc_end);

        return csi;
}

/** Parse class, struct or interface member. */
static stree_csimbr_t *parse_csimbr(parse_t *parse, stree_csi_t *outer_csi)
{
        stree_csimbr_t *csimbr;

        stree_csi_t *csi;
        stree_fun_t *fun;
        stree_var_t *var;
        stree_prop_t *prop;

        stree_symbol_t *symbol;

        switch (lcur_lc(parse)) {
        case lc_class:
        case lc_struct:
        case lc_interface:
                csi = parse_csi(parse, lcur_lc(parse));
                csimbr = stree_csimbr_new(csimbr_csi);
                csimbr->u.csi = csi;

                symbol = stree_symbol_new(sc_csi);
                symbol->u.csi = csi;
                symbol->outer_csi = outer_csi;
                csi->symbol = symbol;
                break;
        case lc_fun:
                fun = parse_fun(parse);
                csimbr = stree_csimbr_new(csimbr_fun);
                csimbr->u.fun = fun;

                symbol = stree_symbol_new(sc_fun);
                symbol->u.fun = fun;
                symbol->outer_csi = outer_csi;
                fun->symbol = symbol;
                break;
        case lc_var:
                var = parse_var(parse);
                csimbr = stree_csimbr_new(csimbr_var);
                csimbr->u.var = var;

                symbol = stree_symbol_new(sc_var);
                symbol->u.var = var;
                symbol->outer_csi = outer_csi;
                var->symbol = symbol;
                break;
        case lc_prop:
                prop = parse_prop(parse);
                csimbr = stree_csimbr_new(csimbr_prop);
                csimbr->u.prop = prop;

                symbol = stree_symbol_new(sc_prop);
                symbol->u.prop = prop;
                symbol->outer_csi = outer_csi;
                prop->symbol = symbol;
                break;
        default:
                lunexpected_error(parse);
                lex_next(parse->lex);
        }

        return csimbr;
}


/** Parse member function. */
static stree_fun_t *parse_fun(parse_t *parse)
{
        stree_fun_t *fun;
        stree_fun_arg_t *arg;

        fun = stree_fun_new();

        lmatch(parse, lc_fun);
        fun->name = parse_ident(parse);
        lmatch(parse, lc_lparen);

        list_init(&fun->args);

        if (lcur_lc(parse) != lc_rparen) {

                /* Parse formal parameters. */
                while (b_true) {
                        arg = parse_fun_arg(parse);
                        if (stree_arg_has_attr(arg, aac_packed)) {
                                fun->varg = arg;
                                break;
                        } else {
                                list_append(&fun->args, arg);
                        }

                        if (lcur_lc(parse) == lc_rparen)
                                break;

                        lmatch(parse, lc_scolon);
                }
        }

        lmatch(parse, lc_rparen);

        if (lcur_lc(parse) == lc_colon) {
                lskip(parse);
                fun->rtype = parse_texpr(parse);
        } else {
                fun->rtype = NULL;
        }

        lmatch(parse, lc_is);
        fun->body = parse_block(parse);
        lmatch(parse, lc_end);

        return fun;
}

/** Parse member variable. */
static stree_var_t *parse_var(parse_t *parse)
{
        stree_var_t *var;

        var = stree_var_new();

        lmatch(parse, lc_var);
        var->name = parse_ident(parse);
        lmatch(parse, lc_colon);
        var->type =  parse_texpr(parse);
        lmatch(parse, lc_scolon);

        return var;
}

/** Parse member property. */
static stree_prop_t *parse_prop(parse_t *parse)
{
        stree_prop_t *prop;

        prop = stree_prop_new();

        lmatch(parse, lc_prop);
        prop->name = parse_ident(parse);
        lmatch(parse, lc_colon);
        prop->type = parse_texpr(parse);
        lmatch(parse, lc_is);
        lmatch(parse, lc_end);

        return prop;
}

/** Parse formal function argument. */
static stree_fun_arg_t *parse_fun_arg(parse_t *parse)
{
        stree_fun_arg_t *arg;
        stree_arg_attr_t *attr;

        arg = stree_fun_arg_new();
        arg->name = parse_ident(parse);
        lmatch(parse, lc_colon);
        arg->type = parse_texpr(parse);

        list_init(&arg->attr);

        /* Parse attributes. */
        while (lcur_lc(parse) == lc_comma) {
                lskip(parse);
                attr = parse_arg_attr(parse);
                list_append(&arg->attr, attr);
        }

        return arg;
}

/** Parse argument attribute. */
static stree_arg_attr_t *parse_arg_attr(parse_t *parse)
{
        stree_arg_attr_t *attr;

        if (lcur_lc(parse) != lc_packed) {
                printf("Error: Unexpected attribute '");
                lem_print(lcur(parse));
                printf("'.\n");
                exit(1);
        }

        lskip(parse);

        attr = stree_arg_attr_new(aac_packed);
        return attr;
}

/** Parse statement block. */
static stree_block_t *parse_block(parse_t *parse)
{
        stree_block_t *block;
        stree_stat_t *stat;

        block = stree_block_new();
        list_init(&block->stats);

        while (terminates_block(lcur_lc(parse)) != b_true) {
                stat = parse_stat(parse);
                list_append(&block->stats, stat);
        }

        return block;
}

/** Parse statement. */
static stree_stat_t *parse_stat(parse_t *parse)
{
        stree_stat_t *stat;

        stree_vdecl_t *vdecl_s;
        stree_if_t *if_s;
        stree_while_t *while_s;
        stree_for_t *for_s;
        stree_raise_t *raise_s;
        stree_return_t *return_s;
        stree_wef_t *wef_s;
        stree_exps_t *exp_s;

        switch (lcur_lc(parse)) {
        case lc_var:
                vdecl_s = parse_vdecl(parse);
                stat = stree_stat_new(st_vdecl);
                stat->u.vdecl_s = vdecl_s;
                break;
        case lc_if:
                if_s = parse_if(parse);
                stat = stree_stat_new(st_if);
                stat->u.if_s = if_s;
                break;
        case lc_while:
                while_s = parse_while(parse);
                stat = stree_stat_new(st_while);
                stat->u.while_s = while_s;
                break;
        case lc_for:
                for_s = parse_for(parse);
                stat = stree_stat_new(st_for);
                stat->u.for_s = for_s;
                break;
        case lc_raise:
                raise_s = parse_raise(parse);
                stat = stree_stat_new(st_raise);
                stat->u.raise_s = raise_s;
                break;
        case lc_return:
                return_s = parse_return(parse);
                stat = stree_stat_new(st_return);
                stat->u.return_s = return_s;
                break;
        case lc_do:
        case lc_with:
                wef_s = parse_wef(parse);
                stat = stree_stat_new(st_wef);
                stat->u.wef_s = wef_s;
                break;
        default:
                exp_s = parse_exps(parse);
                stat = stree_stat_new(st_exps);
                stat->u.exp_s = exp_s;
                break;
        }

#ifdef DEBUG_PARSE_TRACE
        printf("Parsed statement %p\n", stat);
#endif
        return stat;
}

/** Parse variable declaration statement. */
static stree_vdecl_t *parse_vdecl(parse_t *parse)
{
        stree_vdecl_t *vdecl;

        vdecl = stree_vdecl_new();

        lmatch(parse, lc_var);
        vdecl->name = parse_ident(parse);
        lmatch(parse, lc_colon);
        vdecl->type = parse_texpr(parse);

        if (lcur_lc(parse) == lc_assign) {
                lskip(parse);
                (void) parse_expr(parse);
        }

        lmatch(parse, lc_scolon);

#ifdef DEBUG_PARSE_TRACE
        printf("Parsed vdecl for '%s'\n", strtab_get_str(vdecl->name->sid));
        printf("vdecl = %p, vdecl->name = %p, sid=%d\n",
            vdecl, vdecl->name, vdecl->name->sid);
#endif
        return vdecl;
}

/** Parse @c if statement, */
static stree_if_t *parse_if(parse_t *parse)
{
        stree_if_t *if_s;

        if_s = stree_if_new();

        lmatch(parse, lc_if);
        if_s->cond = parse_expr(parse);
        lmatch(parse, lc_then);
        if_s->if_block = parse_block(parse);

        if (lcur_lc(parse) == lc_else) {
                lskip(parse);
                if_s->else_block = parse_block(parse);
        } else {
                if_s->else_block = NULL;
        }

        lmatch(parse, lc_end);
        return if_s;
}

/** Parse @c while statement. */
static stree_while_t *parse_while(parse_t *parse)
{
        stree_while_t *while_s;

        while_s = stree_while_new();

        lmatch(parse, lc_while);
        while_s->cond = parse_expr(parse);
        lmatch(parse, lc_do);
        while_s->body = parse_block(parse);
        lmatch(parse, lc_end);

        return while_s;
}

/** Parse @c for statement. */
static stree_for_t *parse_for(parse_t *parse)
{
        stree_for_t *for_s;

        for_s = stree_for_new();

        lmatch(parse, lc_for);
        lmatch(parse, lc_ident);
        lmatch(parse, lc_colon);
        (void) parse_texpr(parse);
        lmatch(parse, lc_in);
        (void) parse_expr(parse);
        lmatch(parse, lc_do);
        for_s->body = parse_block(parse);
        lmatch(parse, lc_end);

        return for_s;
}

/** Parse @c raise statement. */
static stree_raise_t *parse_raise(parse_t *parse)
{
        stree_raise_t *raise_s;

        raise_s = stree_raise_new();
        lmatch(parse, lc_raise);
        raise_s->expr = parse_expr(parse);
        lmatch(parse, lc_scolon);

        return raise_s;
}

/** Parse @c return statement. */
static stree_return_t *parse_return(parse_t *parse)
{
        stree_return_t *return_s;

        return_s = stree_return_new();

        lmatch(parse, lc_return);
        return_s->expr = parse_expr(parse);
        lmatch(parse, lc_scolon);

        return return_s;
}

/* Parse @c with-except-finally statement. */
static stree_wef_t *parse_wef(parse_t *parse)
{
        stree_wef_t *wef_s;
        stree_except_t *except_c;

        wef_s = stree_wef_new();
        list_init(&wef_s->except_clauses);

        if (lcur_lc(parse) == lc_with) {
                lmatch(parse, lc_with);
                lmatch(parse, lc_ident);
                lmatch(parse, lc_colon);
                (void) parse_texpr(parse);
                lmatch(parse, lc_assign);
                (void) parse_expr(parse);
        }

        lmatch(parse, lc_do);
        wef_s->with_block = parse_block(parse);

        while (lcur_lc(parse) == lc_except) {
                except_c = parse_except(parse);
                list_append(&wef_s->except_clauses, except_c);
        }

        if (lcur_lc(parse) == lc_finally) {
                lmatch(parse, lc_finally);
                lmatch(parse, lc_do);
                wef_s->finally_block = parse_block(parse);
        } else {
                wef_s->finally_block = NULL;
        }

        lmatch(parse, lc_end);

        return wef_s;
}

/* Parse expression statement. */
static stree_exps_t *parse_exps(parse_t *parse)
{
        stree_expr_t *expr;
        stree_exps_t *exps;

        expr = parse_expr(parse);
        lmatch(parse, lc_scolon);

        exps = stree_exps_new();
        exps->expr = expr;

        return exps;
}

/* Parse @c except clause. */
static stree_except_t *parse_except(parse_t *parse)
{
        stree_except_t *except_c;

        except_c = stree_except_new();

        lmatch(parse, lc_except);
        except_c->evar = parse_ident(parse);
        lmatch(parse, lc_colon);
        except_c->etype = parse_texpr(parse);
        lmatch(parse, lc_do);

        except_c->block = parse_block(parse);

        return except_c;
}

/** Parse identifier. */
stree_ident_t *parse_ident(parse_t *parse)
{
        stree_ident_t *ident;

        lcheck(parse, lc_ident);
        ident = stree_ident_new();
        ident->sid = lcur(parse)->u.ident.sid;
        lskip(parse);

        return ident;
}

/** Return current lem. */
lem_t *lcur(parse_t *parse)
{
        return &parse->lex->current;
}

/** Retturn current lem lclass. */
lclass_t lcur_lc(parse_t *parse)
{
        return parse->lex->current.lclass;
}

/** Skip to next lem. */
void lskip(parse_t *parse)
{
        lex_next(parse->lex);
}

/** Verify that lclass of current lem is @a lc. */
void lcheck(parse_t *parse, lclass_t lc)
{
        if (lcur(parse)->lclass != lc) {
                lem_print_coords(lcur(parse));
                printf(" Error: expected '"); lclass_print(lc);
                printf("', got '"); lem_print(lcur(parse));
                printf("'.\n");
                exit(1);
        }
}

/** Verify that lclass of current lem is @a lc and go to next lem. */
void lmatch(parse_t *parse, lclass_t lc)
{
        lcheck(parse, lc);
        lskip(parse);
}

/** Display generic parsing error. */
void lunexpected_error(parse_t *parse)
{
        lem_print_coords(lcur(parse));
        printf(" Error: unexpected token '");
        lem_print(lcur(parse));
        printf("'.\n");
        exit(1);
}

/** Basically tells us whether @a lclass is in next(block). */
bool_t terminates_block(lclass_t lclass)
{
        switch (lclass) {
        case lc_else:
        case lc_end:
        case lc_except:
        case lc_finally:
                return b_true;
        default:
                return b_false;
        }
}