RE: boost::spirit and boost in general for c++ people.

  • From: "Ken Perry" <whistler@xxxxxxxxxxxxx>
  • To: <programmingblind@xxxxxxxxxxxxx>
  • Date: Thu, 7 Apr 2011 10:53:05 -0400


Nah didn't have time to read all the code sorry good job.

Ken

-----Original Message-----
From: programmingblind-bounce@xxxxxxxxxxxxx
[mailto:programmingblind-bounce@xxxxxxxxxxxxx] On Behalf Of Littlefield,
Tyler
Sent: Thursday, April 07, 2011 10:36 AM
To: programmingblind@xxxxxxxxxxxxx
Subject: Re: boost::spirit and boost in general for c++ people.

um. did you read the code? I -did- use the spirit parser. but you still 
need an AST, which Spirit will create for you.
On 4/7/2011 8:07 AM, Ken Perry wrote:
> Oh for the calculator you really should use the boost spirit parser so you
> don't have to write your own.
>
> Ken
>
> -----Original Message-----
> From: programmingblind-bounce@xxxxxxxxxxxxx
> [mailto:programmingblind-bounce@xxxxxxxxxxxxx] On Behalf Of Littlefield,
> Tyler
> Sent: Thursday, April 07, 2011 9:09 AM
> To: programmingblind@xxxxxxxxxxxxx
> Subject: boost::spirit and boost in general for c++ people.
>
> hello all:
> Recently I got into using boost a bit and started finding uses for it
> all over the place. I would like to encourage those who haven't yet and
> use c++ to check it out; it is quite powerful and can eas some of your
> work and provide really cool features along the way. For example:
> boost::function lets you take callbacks in multiple forms; boost::bind
> will let you bind a functor to it's arguments and pass that as your
> callback, which means you can bind to a static member function, a member
> function (and pass the object with boost::ref), a global function and
> you can also use boost::lambda.
> There are many more utilities out there; I highly recommend checking out
> boost::asio, boost::fusion, boost::function and boost::bind.
> In the spirit of convincing you all, I wrote a small calculator program
> that does single operations (1+3, 3*5), etc and returns the result.
> My next step is to split up my parsing into different rulesets and then
> work on generating an AST so that I can handle larger more complex
> calculations.
> /*
> A simple calculator, supports multiplication, division, addition and
> subtraction.
> */
> #include<boost/spirit/include/qi.hpp>
> #include<boost/spirit/include/phoenix_core.hpp>
> #include<boost/spirit/include/phoenix_operator.hpp>
> #include<boost/spirit/include/phoenix_operator.hpp>
> #include<iostream>
> #include<string>
> #include<boost/fusion/include/adapt_struct.hpp>
> #include<boost/fusion/container/vector.hpp>
> #include<boost/fusion/container/vector/convert.hpp>
> #include<boost/fusion/include/io.hpp>
>
> namespace qi = boost::spirit::qi;
> namespace ascii = boost::spirit::ascii;
> namespace phoenix = boost::phoenix;
>
> struct calculation
> {
>     int a, b;
>     char op;
> };
> BOOST_FUSION_ADAPT_STRUCT(calculation, (int, a) (char, op) (int, b) )
>
> template<typename iterator>
> class CParser:public qi::grammar<iterator, calculation(),
> qi::ascii::space_type>
> {
>     qi::rule<iterator, calculation(), qi::ascii::space_type>  crule;
> public:
>     CParser():CParser::base_type(crule)
>     {
>       using qi::ascii::char_;
>       using qi::int_;
>
>       crule %= (int_>>
>                 (char_('+')|char_('-')|char_('*')|char_('/'))>>
>                 int_);
>     }
> };
>
> int main()
> {
>     CParser<std::string::iterator>  p;
>     std::string str;
>     calculation result;
>
>     std::cout<<  "Enter your calculation>";
> getline(std::cin, str);
>
>     bool r = phrase_parse(str.begin(), str.end(), p, qi::ascii::space,
> result);
>     if (r)
>       {
>         std::cout<<  "a: "<<  result.a<<  " b: "<<  result.b<<  " op: "
> <<  result.op<<  std::endl;
>         switch(result.op)
>           {
>           case '+':
>             std::cout<<  "Result: "<<  (result.a + result.b)<<  std::endl;
>             break;
>           case '-':
>             std::cout<<  "result: "<<  (result.a - result.b)<<  std::endl;
>             break;
>           case '*':
>             std::cout<<  "Result: "<<  (result.a * result.b)<<  std::endl;
>             break;
>           case '/':
>             if (result.a == 0)
>               {
>                 std::cout<<  "Division by zero error."<<  std::endl;
>                 break;
>               }
>             std::cout<<  "result: "<<  (result.a / result.b)<<  std::endl;
>             break;
>           default:
>             std::cout<<  "Invalid operation."<<  std::endl;
>           }
>       }
>     else
>       {
>         std::cout<<  "Invalid input."<<  std::endl;
>       }
>
>     return 0;
> }
>


-- 

Thanks,
Ty

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