main.sa

来自「Java写的词法/语法分析器。可生成JAVA语言或者是C++的词法和语法分析器。」· SA 代码 · 共 41 行

class MAIN is
   main ( args : ARRAY{STR} ) is

      if ( args.size < 2 ) then
	 #OUT + "usage " + args[0] + " <filename>\n";
	 return;
      end;
	 
      f : IFSTREAM := IFSTREAM::open_for_read( args[1] );

      if ( void(f) ) then
	 #OUT + "file \"" + args[1] + "\" not found\n";
	 return;
      end;

      protect
	 lexer  ::= #CALC_LEXER{ANTLR_COMMON_TOKEN}( f );
	 lexer.file_name( args[1] );

	 parser ::= #CALC_PARSER{ANTLR_COMMON_TOKEN, ANTLR_COMMON_AST}( lexer );
	 parser.file_name( args[1] );
	 
	 parser.expr;
	 
	 t : ANTLR_COMMON_AST := parser.ast;

	 #OUT + t.str_tree + "\n";
	 
	 walker ::= #CALC_TREE_WALKER{ANTLR_COMMON_AST};
	 r : FLT := walker.expr(t);
	 
	 #OUT + "value is " + r + "\n";
	 
      when $ANTLR_RECOGNITION_EXCEPTION then
	 #ERR + "exception: " + exception.str + "\n";	 
      end;
      
   end;
end;