New subject: [Spirit] Creating a vector of structs

2 Sep 2009


      ...
On Tue, Sep 1, 2009 at 4:38 PM, Lindley M French 
wrote:> I'm playing around with Spirit for a particular parsing 
task. I could do this manually, but I figured this was a good 
chance to learn what Spirit had to offer.
...
The trouble is this. While Spirit offers ready-made semantic
actions for parsing primitives, it doesn't seem to offer anything 
terribly useful for compound statements. As far as I can tell, you 
can define your own semantic actions but they simply take in the 
matched string as an argument----there's no way to get at the 
values parsed on that level.
...
For example, let's say I have a type
struct Person
{
? string name;
? double height;
? int age;
? Person(string n, double h, int a)
? : name(n), height(h), age(a)
};
And I have a document containing
5.5 15 Henry
4.6 32 Jane
6.1 21 Bob
I could parse this using
rule<> personrule = strict_real_p >> int_p >> ~eol_p;
parse(str, *(personrule[WhatGoesHere] >> eol_p) >> end_p);
But how can I build a vector<Person> out of this? I can write my
own functor to do the push_back, but I need to get at the parsed 
values of name, age, and height for each personrule somehow.
...
I suppose I *could* just run another parse() on the input the
semantic action for that specific person....but that really seems 
like it shouldn't be necessary.
You are using Spirit.Classic, you should use Spirit.QI (Boost trunk,
docs are at: 
http://svn.boost.org/svn/boost/trunk/libs/spirit/doc/html/index.html), then you can do it easy, like so:
BOOST_FUSION_ADAPT_STRUCT(Person
                        (double,height)
                        (int,age)
                        (string,name)
                        )
rule<YourIteratorType> personrule;
personrule %= double_ >> int_ >> raw[lexeme[*(char_-eol)]];
std::vector<Person> theVec;
parse(str.begin(),str.end(), *personrule, theVec);
This is also better to ask on the spirit mailing list.  :)
Unfortunately for the moment I'm stuck with Boost 1.35, which I don't believe has Spirit 2. I'll try asking on the Spirit list.

Re: [Boost-users] [Spirit] Creating a vector of structs

Lindley M French

OvermindDL1

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