• Charles Parker (24/24) Jun 02 2014 ./graph_structures.d(124): Error: class graph_structures.node(D,
• H. S. Teoh via Digitalmars-d-learn (11/16) Jun 02 2014 It usually means you tried to use an uninstantiated template as a type.
• Chris Cain (20/22) Jun 02 2014 Well one thing is that you don't need the type parameters on the
• Charles Parker (7/30) Jun 02 2014 Chris, that was it I needed to do both things. It then complained
• Jacob Carlborg (9/14) Jun 02 2014 You don't really need to allocate the arrays. You can just declare them

"Charles Parker" <j831526 gmail.com> writes:

./graph_structures.d(124): Error: class graph_structures.node(D,
E) is used as a type

I have no idea what this means:( Once we create a class, the
textbook examples show its use as a type which I believe is what
C++ & Java allow. Here's some code:

class node(D, E) {
      int nid;
      D data;
      E[] in_edges; // All edges for undirected graphs go here.
      E[] out_edges; // Only used by directed graphs

      this(D, E)(D data, int n) {
          this.data = data;
          nid = n;
          in_edges = new E[];
          out_edges = new E[];
      }

This is incomplete, but I believe the relevant stuff is my node
template uses 2 parameters corresponding to the data types for
the stored data and the edge types. Here's statement 124 in main:

      auto fee = new node(string, u_edge)("Suck Moose", 1);

I pass the 2 data types in the first parm list and the
constructor required arguments in the second list. I must be
missing something, but I don't see it:(

Thanx for any help - Charlie

"H. S. Teoh via Digitalmars-d-learn" <digitalmars-d-learn puremagic.com> writes:

On Tue, Jun 03, 2014 at 03:17:09AM +0000, Charles Parker via
Digitalmars-d-learn wrote:
 ./graph_structures.d(124): Error: class graph_structures.node(D,
 E) is used as a type
 
 I have no idea what this means:(

It usually means you tried to use an uninstantiated template as a type.


[...]
      auto fee = new node(string, u_edge)("Suck Moose", 1);

[...]

You're missing the compile-time argument "!" operator; this line should
be written as:

      auto fee = new node!(string, u_edge)("Suck Moose", 1);

Hope this helps.


T

-- 
Too many people have open minds but closed eyes.

"Chris Cain" <zshazz gmail.com> writes:

On Tuesday, 3 June 2014 at 03:17:10 UTC, Charles Parker wrote:
 ...
 Thanx for any help - Charlie

Well one thing is that you don't need the type parameters on the
this function. You're basically creating a templated this inside
the templated class which is not what you want.

try this:

      class node(D, E) {
          int nid;
          D data;
          E[] in_edges; // All edges for undirected graphs go here.
          E[] out_edges; // Only used by directed graphs

          this(D data, int n) {
              this.data = data;
              nid = n;
              in_edges = new E[];
              out_edges = new E[];
          }

Another thing is that you're missing the ! to instantiate

                         v
      auto fee = new node!(string, u_edge)("Suck Moose", 1);
                         ^

"Charles Parker" <j831526 gmail.com> writes:

On Tuesday, 3 June 2014 at 03:35:46 UTC, Chris Cain wrote:
 On Tuesday, 3 June 2014 at 03:17:10 UTC, Charles Parker wrote:
 ...
 Thanx for any help - Charlie

 Well one thing is that you don't need the type parameters on the
 this function. You're basically creating a templated this inside
 the templated class which is not what you want.

 try this:

      class node(D, E) {
          int nid;
          D data;
          E[] in_edges; // All edges for undirected graphs go 
 here.
          E[] out_edges; // Only used by directed graphs

          this(D data, int n) {
              this.data = data;
              nid = n;
              in_edges = new E[];
              out_edges = new E[];
          }

 Another thing is that you're missing the ! to instantiate

                         v
      auto fee = new node!(string, u_edge)("Suck Moose", 1);
                         ^

Chris, that was it I needed to do both things. It then complained
about trying to allocate the in_edges and out_edges arrays in the
constructor which is how I thought dynamic arrays are allocated
on the heap. I removed the 2 new statements, and both compile and
execution of my initial test worked.

Thanx - Charlie

Jacob Carlborg <doob me.com> writes:

On 03/06/14 05:57, Charles Parker wrote:

 Chris, that was it I needed to do both things. It then complained
 about trying to allocate the in_edges and out_edges arrays in the
 constructor which is how I thought dynamic arrays are allocated
 on the heap. I removed the 2 new statements, and both compile and
 execution of my initial test worked.

You don't really need to allocate the arrays. You can just declare them 
and start using them:

int[] foo;
foo ~= 4; // append 4 to the array

Arrays in D are a implemented as a struct with a pointer to the data and 
a field with the length of the array.

-- 
/Jacob Carlborg