expr.cpp.par

%!language      "C++";

%whitespaces    ' \t';
%lexeme         int;
%default action	[* @@ = @1 *];

%left           '+' '-';
%left           '*' '/';

%prologue		[*
    #include <stdlib.h>
    #include <stdio.h>
    #include <string.h>
    #include <locale.h>
    #include <iostream>
*];

calc$           : expr                 [* std::cout << "= " <<
                                            @expr << std::endl *]
                ;

expr            : expr:a '+' expr:b    [* @@ = @a + @b *]
                | expr:a '-' expr:b    [* @@ = @a - @b *]
                | expr:a '*' expr:b    [* @@ = @a * @b *]
                | expr:a '/' expr:b    [* @@ = @a / @b *]
                | '(' expr ')'         [* @@ = @expr *]
                | int
                ;

int             : '0-9'                [* @@ = @1 - '0' *]
                | int '0-9'            [* @@ = @int * 10 + @2 - '0' *]
                ;