// Parse a statement.
//
// stmt -> block-stmt
// | declaration-stmt
// | expression-stmt
Stmt*
Parser::stmt()
{
switch (lookahead()) {
case semicolon_tok:
return empty_stmt();
case lbrace_tok:
return block_stmt();
case return_kw:
return return_stmt();
case if_kw:
return if_stmt();
case while_kw:
return while_stmt();
case break_kw:
return break_stmt();
case continue_kw:
return continue_stmt();
case var_kw:
case def_kw:
case foreign_kw:
return declaration_stmt();
default:
return expression_stmt();
}
}
static NODE * statement(void){
NODE *t = NULL;
switch (token.type){
case IF:
t = if_stmt();
break;
case WHILE:
t = while_stmt();
break;
case READ:
t = read();
break;
case VAR:
t = assign();
break;
case PRINT:
t = print();
break;
case BEGIN:
t = stmt_list();
break;
default:
syntax_error("Unexpected token ->");
token = getToken();
break;
}
return t;
}
static
stmt_code(stream, node, brk, cont, ret) {
/* Handle the null expression. */
if ( !node ) return;
auto op = node[0];
/* For debugging purposes, put a blank line between each statement. */
fputs("\n", stream);
if ( op == 'dcls' ) declaration( stream, node );
else if ( op == 'brea' ) branch( stream, brk );
else if ( op == 'cont' ) branch( stream, cont );
else if ( op == 'retu' ) return_stmt( stream, node, ret );
else if ( op == 'goto' ) goto_stmt( stream, node );
else if ( op == 'if' ) if_stmt( stream, node, brk, cont, ret );
else if ( op == 'whil' ) while_stmt( stream, node, brk, cont, ret );
else if ( op == 'for' ) for_stmt( stream, node, brk, cont, ret );
else if ( op == 'do' ) do_stmt( stream, node, brk, cont, ret );
else if ( op == 'swit' ) switch_stmt( stream, node, brk, cont, ret );
else if ( op == 'case'
|| op == 'defa' ) case_stmt( stream, node, brk, cont, ret );
else if ( op == ':' ) label_stmt( stream, node, brk, cont, ret );
else if ( op == '{}' ) do_block( stream, node, brk, cont, ret );
else expr_code( stream, node, 0 );
}
Stmt *Parser::stmt() {
if (lookahead_ == Token::IDENT)
return assign();
else if (lookahead_ == Token::IF)
return if_stmt();
else if (lookahead_ == Token::WHILE)
return while_stmt();
else
return action();
}
TreeNode * statement(void) //statement -> expression| if_stmt| while_stmt|for_stmt|var_stmt|assign_stmt
{ TreeNode * t = NULL;
switch (token) {
case IF : t = if_stmt(); break;
case FOR : t = for_stmt(); break;
case ID : t = assign_stmt(); break;
case WHILE : t = while_stmt(); break;
case INT :
case CHAR :
t = var_stmt(); break;
case RBRACE : match(RBRACE); break;
default : syntaxError("unexpected token -> ");
printToken(token,tokenString);
token = getToken();
break;
} /* end case */
return t;
}
