Re: Accessing members of template class

From:

red floyd <no.spam@here.dude>

Newsgroups:

comp.lang.c++

Date:

Tue, 13 May 2008 12:35:24 -0700

Message-ID:

<N3mWj.1538$r82.38@nlpi069.nbdc.sbc.com>

Lucas Kanebley Tavares wrote:

Ok, I found a lot of similar errors to this on the net (and here), but
none just like it.

What I have is a bunch of classes that define a few members, for
isntance:

class ds_node {
____public:
________typedef typename std::map<ds_node, bool> old_nodes;
________static ds_node *first(fsm_core &m);
________static ds_node *next(fsm_core &m, ds_node &node, int input);
..... (a bunch of stuff goes here) ...
};

and another templated class which is suppose to use those previously
defined classes.

template <class T>
class suc_tree {
____public:
____void run(fsm_core &m);
....
};

template <class T>
void suc_tree<T>::run(fsm_core &m) {
____T::old_nodes old_node;

____T *cur = T::first(m);
.....
}

and I was wondering if this is doable without using inheritance and/or
what would be the suggested methods to go about doing this. The error
I'm getting is:
suctree.hpp|47|error: expected `;' before "old_node" (line 47 =
old_node declaration).
suctree.hpp|64|error: `old_node' was not declared in this scope (line
64 = old_node first use)

After that I get a LOT of STL related errors, but I suppose that once
these are fixed they'll go away. And as I get no errors from calling
first or next, I suppose that I shouldn't get any while declaring
old_node.

Your cut&paste really bad, with the leading underscores, and you didn't
follow FAQ 5.8
(http://www.parashift.com/c++-faq-lite/how-to-post.html#faq-5.8), by
posting complete compileable (except for the error) code.

However, this is a fairly common error (FAQ 35.18 --
http://www.parashift.com/c++-faq-lite/templates.html#faq-35.18)

old_nodes is a *dependent* name -- to wit, the compiler can't know that
it's a type without some help from you. Change the line in question to:

typename T::old_nodes old_node;