From 4649c12fa93a68d3b68c337e42c5628d458a78e9 Mon Sep 17 00:00:00 2001 From: "Wolfgang (Blub) Bumiller" Date: Mon, 19 Nov 2012 22:06:29 +0100 Subject: [PATCH] Parsing of switches --- parser.c | 160 +++++++++++++++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 156 insertions(+), 4 deletions(-) diff --git a/parser.c b/parser.c index 8dbd775..b45fe62 100644 --- a/parser.c +++ b/parser.c @@ -51,6 +51,7 @@ static bool parse_variable(parser_t *parser, ast_block *localblock, bool nofield static ast_block* parse_block(parser_t *parser, bool warnreturn); static bool parse_block_into(parser_t *parser, ast_block *block, bool warnreturn); static ast_expression* parse_statement_or_block(parser_t *parser); +static bool parse_statement(parser_t *parser, ast_block *block, ast_expression **out, bool allow_cases); static ast_expression* parse_expression_leave(parser_t *parser, bool stopatcomma); static ast_expression* parse_expression(parser_t *parser, bool stopatcomma); @@ -1331,7 +1332,10 @@ static ast_expression* parse_expression_leave(parser_t *parser, bool stopatcomma if (!parser_next(parser)) { goto onerr; } - if (parser->tok == ';' || (!parens && parser->tok == ']')) { + if (parser->tok == ';' || + (!parens && parser->tok == ']') || + parser->tok == ':') + { break; } } @@ -1734,7 +1738,142 @@ static bool parse_break_continue(parser_t *parser, ast_block *block, ast_express return true; } -static bool parse_statement(parser_t *parser, ast_block *block, ast_expression **out) +static bool parse_switch(parser_t *parser, ast_block *block, ast_expression **out) +{ + ast_expression *operand; + ast_switch *switchnode; + ast_switch_case swcase; + + lex_ctx ctx = parser_ctx(parser); + + /* parse over the opening paren */ + if (!parser_next(parser) || parser->tok != '(') { + parseerror(parser, "expected switch operand in parenthesis"); + return false; + } + + /* parse into the expression */ + if (!parser_next(parser)) { + parseerror(parser, "expected switch operand"); + return false; + } + /* parse the operand */ + operand = parse_expression_leave(parser, false); + if (!operand) + return false; + + switchnode = ast_switch_new(ctx, operand); + + /* closing paren */ + if (parser->tok != ')') { + ast_delete(switchnode); + parseerror(parser, "expected closing paren after 'switch' operand"); + return false; + } + + /* parse over the opening paren */ + if (!parser_next(parser) || parser->tok != '{') { + ast_delete(switchnode); + parseerror(parser, "expected list of cases"); + return false; + } + + if (!parser_next(parser)) { + ast_delete(switchnode); + parseerror(parser, "expected 'case' or 'default'"); + return false; + } + + /* case list! */ + while (parser->tok != '}') { + ast_block *block; + + if (parser->tok != TOKEN_KEYWORD) { + ast_delete(switchnode); + parseerror(parser, "expected 'case' or 'default'"); + return false; + } + if (!strcmp(parser_tokval(parser), "case")) { + if (!parser_next(parser)) { + ast_delete(switchnode); + parseerror(parser, "expected expression for case"); + return false; + } + swcase.value = parse_expression_leave(parser, false); + if (!swcase.value) { + ast_delete(switchnode); + parseerror(parser, "expected expression for case"); + return false; + } + } + else if (!strcmp(parser_tokval(parser), "default")) { + swcase.value = NULL; + if (!parser_next(parser)) { + ast_delete(switchnode); + parseerror(parser, "expected colon"); + return false; + } + } + + /* Now the colon and body */ + if (parser->tok != ':') { + if (swcase.value) ast_unref(swcase.value); + ast_delete(switchnode); + parseerror(parser, "expected colon"); + return false; + } + + if (!parser_next(parser)) { + if (swcase.value) ast_unref(swcase.value); + ast_delete(switchnode); + parseerror(parser, "expected statements or case"); + return false; + } + block = ast_block_new(parser_ctx(parser)); + if (!block) { + if (swcase.value) ast_unref(swcase.value); + ast_delete(switchnode); + return false; + } + swcase.code = (ast_expression*)block; + vec_push(switchnode->cases, swcase); + while (true) { + ast_expression *expr; + if (parser->tok == '}') + break; + if (parser->tok == TOKEN_KEYWORD) { + if (!strcmp(parser_tokval(parser), "case") || + !strcmp(parser_tokval(parser), "default")) + { + break; + } + } + if (!parse_statement(parser, block, &expr, true)) { + ast_delete(switchnode); + return false; + } + if (!expr) + continue; + vec_push(block->exprs, expr); + } + } + + /* closing paren */ + if (parser->tok != '}') { + ast_delete(switchnode); + parseerror(parser, "expected closing paren of case list"); + return false; + } + if (!parser_next(parser)) { + ast_delete(switchnode); + parseerror(parser, "parse error after switch"); + return false; + } + *out = (ast_expression*)switchnode; + return true; +} + +static bool parse_statement(parser_t *parser, ast_block *block, ast_expression **out, bool allow_cases) { if (parser->tok == TOKEN_TYPENAME || parser->tok == '.') { @@ -1801,6 +1940,19 @@ static bool parse_statement(parser_t *parser, ast_block *block, ast_expression * { return parse_break_continue(parser, block, out, true); } + else if (!strcmp(parser_tokval(parser), "switch")) + { + return parse_switch(parser, block, out); + } + else if (!strcmp(parser_tokval(parser), "case") || + !strcmp(parser_tokval(parser), "default")) + { + if (!allow_cases) { + parseerror(parser, "unexpected 'case' label"); + return false; + } + return true; + } parseerror(parser, "Unexpected keyword"); return false; } @@ -1864,7 +2016,7 @@ static bool parse_block_into(parser_t *parser, ast_block *block, bool warnreturn if (parser->tok == '}') break; - if (!parse_statement(parser, block, &expr)) { + if (!parse_statement(parser, block, &expr, false)) { /* parseerror(parser, "parse error"); */ block = NULL; goto cleanup; @@ -1916,7 +2068,7 @@ static ast_expression* parse_statement_or_block(parser_t *parser) ast_expression *expr = NULL; if (parser->tok == '{') return (ast_expression*)parse_block(parser, false); - if (!parse_statement(parser, NULL, &expr)) + if (!parse_statement(parser, NULL, &expr, false)) return NULL; return expr; } -- 2.39.2