• bioinfornatics (20/20) May 23 2014 I bask originally this qustion in this thread :
• bioinfornatics (29/52) May 23 2014 Sorry for typos they are severals.
• =?UTF-8?B?QWxpIMOHZWhyZWxp?= (33/38) May 26 2014 I was able to make that work if I used function instead of delegate:
• bioinfornatics (3/43) May 26 2014 thanks Ali nice works as usual :-)

"bioinfornatics" <bioifornatics fedoraproject.org> writes:

I bask originally this qustion in this thread :
http://forum.dlang.org/post/rsnswykpjfzenplivkhm forum.dlang.org

but another thread is better as that is not exactly same topic.


I would like to use custom annotate/attribute on members as:


struct A
{
          Parser(
                  start = "( word ) =>  word[0] == '>'",
                  end   = "( word ) =>  word[0] == '\n'" )
         string header;

}


but it seem we can't use curstom annotation in D and mxin in this
case are not easy.

This custom attribute is a metadata to explain how to retrieve
this field from a file. This will aloow to create a global parser
and give to this parrser data structure to get back.
Parser could to b an input range were
hront give currentfilled  struct and popfront will look foward in
buffer given by file.byChunk() using this metadata.
When all field are filled give the instance to front …

"bioinfornatics" <bioifornatics fedoraproject.org> writes:

On Friday, 23 May 2014 at 15:17:52 UTC, bioinfornatics wrote:
 I bask originally this qustion in this thread :
 http://forum.dlang.org/post/rsnswykpjfzenplivkhm forum.dlang.org

 but another thread is better as that is not exactly same topic.


 I would like to use custom annotate/attribute on members as:


 struct A
 {
          Parser(
                  start = "( word ) =>  word[0] == '>'",
                  end   = "( word ) =>  word[0] == '\n'" )
         string header;

 }


 but it seem we can't use curstom annotation in D and mxin in 
 this
 case are not easy.

 This custom attribute is a metadata to explain how to retrieve
 this field from a file. This will aloow to create a global 
 parser
 and give to this parrser data structure to get back.
 Parser could to b an input range were
 hront give currentfilled  struct and popfront will look foward 
 in
 buffer given by file.byChunk() using this metadata.
 When all field are filled give the instance to front …

Sorry for typos they are severals.


So to continue te code below is more close to D but do not build:

import std.stdio;

struct attribute { }

 attribute
struct section {
      bool delegate( string ) start;
      bool delegate( string ) end;

      this( in bool delegate( string ) start, in bool delegate(
string ) end)
      {
          this.start  = start,
          this.end    = end;
      }
}


struct A {
           section( ( word ) =>  word[0] == ' ', ( word ) =>
word[0] == '\n')
          int a;
}


int main(string[] args)
{
      A a;
      return 0;
}


testCustomAttributes.d(43): Error: delegate
testCustomAttributes.A.__lambda2!(string).__lambda2 function
literals cannot be class members

=?UTF-8?B?QWxpIMOHZWhyZWxp?= <acehreli yahoo.com> writes:

On 05/23/2014 09:09 AM, bioinfornatics wrote:

 struct A {
            section( ( word ) =>  word[0] == ' ', ( word ) =>
 word[0] == '\n')
           int a;
 }

I was able to make that work if I used function instead of delegate:

import std.stdio;

struct attribute { }

alias MatchFunc = bool function( string );

 attribute
struct section {
      MatchFunc start;
      MatchFunc end;

      this( in MatchFunc start,
            in MatchFunc end)
      {
          this.start  = start,
          this.end    = end;
      }
}

struct A {
      section((string word) => word[0] == ' ',
              (string word) => word[0] == '\n')
     int a;
}

import std.traits;

void main()
{
     auto aa = A();
     auto t = __traits(getAttributes, A.a);

     foreach (sect; t) {
         auto start_result = sect.start(" test");
         auto end_result = sect.end("\n");

         writefln("Results: %s and %s", start_result, end_result);
     }
}

Ali

"bioinfornatics" <bioifornatics fedoraproject.org> writes:

On Monday, 26 May 2014 at 19:50:29 UTC, Ali Çehreli wrote:
 On 05/23/2014 09:09 AM, bioinfornatics wrote:

 struct A {
            section( ( word ) =>  word[0] == ' ', ( word ) =>
 word[0] == '\n')
           int a;
 }

 I was able to make that work if I used function instead of 
 delegate:

 import std.stdio;

 struct attribute { }

 alias MatchFunc = bool function( string );

  attribute
 struct section {
      MatchFunc start;
      MatchFunc end;

      this( in MatchFunc start,
            in MatchFunc end)
      {
          this.start  = start,
          this.end    = end;
      }
 }

 struct A {
      section((string word) => word[0] == ' ',
              (string word) => word[0] == '\n')
     int a;
 }

 import std.traits;

 void main()
 {
     auto aa = A();
     auto t = __traits(getAttributes, A.a);

     foreach (sect; t) {
         auto start_result = sect.start(" test");
         auto end_result = sect.end("\n");

         writefln("Results: %s and %s", start_result, 
 end_result);
     }
 }

 Ali

thanks Ali nice works as usual :-)

it seem delegate will be suppoted into dmdfe 2.066