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digitalmars.D.learn - using __traits to get line number of a member

reply forkit <forkit gmail.com> writes:
Code below is self explanatory.

Any assistance on how to get the line number is welcome ;-)


// ++++++++++++++++++++++++++

module test;

import std;

class myClass{ void foo(){}}

void myFunction1(){}

void main()
{
     // list the first user defined member of this module (other 
than main)

     int i;
     foreach(m; __traits(allMembers, mixin(__MODULE__)))
     {
         // we can ignore these members
         // "std" and "object" are created by the compiler, and 
"main" I'm not interested in.
         if(m == "std" || m == "object" || m == "main")
         {
             i = 1;
             continue;
         }

         writefln("The name of the first user member is: %s", m);

         // On this next line, m.lineNumber is just a stub holder 
till an actual solution is found
         //writefln("The line number on which that member begins, 
is: %s, m.lineNumber);

         if(i == 1)
             break;
     }

     //writeln("Nothing to see here.");
}


void myFunction2(){}

// +++++++++++++++++++++++++
Nov 12 2021
parent reply Stanislav Blinov <stanislav.blinov gmail.com> writes:
On Saturday, 13 November 2021 at 05:31:51 UTC, forkit wrote:

 Code below is self explanatory.

 Any assistance on how to get the line number is welcome ;-)


https://dlang.org/spec/traits.html#getLocation

That?
Nov 12 2021
parent reply forkit <forkit gmail.com> writes:
On Saturday, 13 November 2021 at 06:05:37 UTC, Stanislav Blinov 
wrote:

 On Saturday, 13 November 2021 at 05:31:51 UTC, forkit wrote:

 Code below is self explanatory.

 Any assistance on how to get the line number is welcome ;-)


 https://dlang.org/spec/traits.html#getLocation

 That?


Thanks. That seems to be the one, except:

writeln(__traits(getLocation, m)[1]); // nope. writes the line 
no. of the foreach loop

writeln(__traits(getLocation, myClass)[1]); // yes, but I have to 
provide the name manually here, which i would not know.

I would have thought m referred to myClass at this point in the 
loop. But that doesn't seem to be the case.
Nov 12 2021
parent reply =?UTF-8?Q?Ali_=c3=87ehreli?= <acehreli yahoo.com> writes:
On 11/12/21 11:00 PM, forkit wrote:


 // nope. writes the line no. of the foreach loop


mixin(m) seems to solve the issue, which I think necessitates 'static if':

     static foreach(m; __traits(allMembers, mixin(__MODULE__)))
     {
         static if(m == "std" || m == "object" || m == "main")
         {
           // Ignore
         } else {
           writefln("The name of the first user member is: %s", m);
           writeln(__traits(getLocation, mixin(m))[1]);  // <-- HERE
         }
     }

It works because we mix-in the value of the string 'm', which becomes a 
symbol.

('foreach' instead of 'static foreach' works as well.)

Ali
Nov 12 2021
parent reply forkit <forkit gmail.com> writes:
On Saturday, 13 November 2021 at 07:20:14 UTC, Ali Çehreli wrote:

 It works because we mix-in the value of the string 'm', which 
 becomes a symbol.

 ('foreach' instead of 'static foreach' works as well.)

 Ali


Thanks. Really appreciate the help provided in this thread :-)

Final working code below:

//===================================

module test;

import std;

class myClass{ void foo(){}}

void myFunction1(){}

void main()
{
     // list the first user defined member of this module (other 
than main)

     int i;
     foreach(m; __traits(allMembers, mixin(__MODULE__)))
     {
         // ignore these members
         static if(m == "std" || m == "object" || m == "main" || m 
== "_d_run_main" || m == "_Dmain"  )
         {
            i = 1;
            continue;
         }
         else
         {
             writefln("The name of the first user member is: %s", 
m);

             // getLocation returns a tuple. See note below
             writefln("%s begins on line number: %s", m, 
__traits(getLocation, mixin(m))[1]);
         }

         if(i == 1) break;
     }
}


void myFunction2(){}


/*
     https://dlang.org/spec/traits.html#getLocation

     get the location of a symbol where the argument was declared.

     getLocation Returns a tuple(string, int, int) whose entries 
correspond to
     [0] string -> the filename
     [1] int -> line number
     [2] int -> column number
*/

// ======================================
Nov 13 2021
parent reply Stanislav Blinov <stanislav.blinov gmail.com> writes:
On Saturday, 13 November 2021 at 08:04:56 UTC, forkit wrote:


     int i;
     foreach(m; __traits(allMembers, mixin(__MODULE__)))
     // ...
     __traits(getLocation, mixin(m))[1]);


What you really should be doing is this:

```d
static import mod = mixin(__MODULE__);
foreach (i, name; __traits(allMembers, mod))
{
    // ...
    __traits(getLocation, __traits(getMember, mod, i));
    // ...
}
```

Otherwise you might run into name conflicts, and get location of 
a wrong symbol.

Also if you really want to be generic you should couple it with 
`__traits(getOverloads)`, like the docs for getLocation suggest.
Nov 13 2021
parent reply forkit <forkit gmail.com> writes:
On Saturday, 13 November 2021 at 17:22:16 UTC, Stanislav Blinov 
wrote:

 On Saturday, 13 November 2021 at 08:04:56 UTC, forkit wrote:


     int i;
     foreach(m; __traits(allMembers, mixin(__MODULE__)))
     // ...
     __traits(getLocation, mixin(m))[1]);


 What you really should be doing is this:

 ```d
 static import mod = mixin(__MODULE__);
 foreach (i, name; __traits(allMembers, mod))
 {
    // ...
    __traits(getLocation, __traits(getMember, mod, i));
    // ...
 }
 ```

 Otherwise you might run into name conflicts, and get location 
 of a wrong symbol.

 Also if you really want to be generic you should couple it with 
 `__traits(getOverloads)`, like the docs for getLocation suggest.


static import mod = mixin(__MODULE__);

That statement above would not compile. After spending way too 
much time trying to work out, I gave up, and used what i have, 
which works.

I just want to know, which members in my module are functions, 
and which are classes. I got the isFunction  (that method exists)

However, there is no isClass method. Why not?

How do I determine if a member is a class.. I wonder...

e.g.

//=========================
module test;

import std;

class myClass{} // nothing to see here

void main()
{
     alias allMembersOfThisModule = __traits(allMembers, 
mixin(__MODULE__));
     string memberFile() { return `__traits(getLocation, 
mixin(member))[0]`; }
     string memberLocation() { return `__traits(getLocation, 
mixin(member))[1]`; }

     foreach(member; allMembersOfThisModule)
     {
         static if(member == "std" || member == "object")
         {
             continue;
         }
         else
         {
             writefln("\nHere is a member: %s", member);

             // what kind of member is it?
             if(isFunction!(mixin(member)))
                 writeln("This is a function.");
             //else
             //if(isClass!(mixin(member)))
                //writeln("This is a class.");
             else
                 writeln("Not really sure what type of member this 
is..");

             writefln("%s is located in file: %s", member, 
mixin(memberFile));
             writefln("%s begins on line number: %s", member, 
mixin(memberLocation));
         }
     }
}

void myFunction(){} // nothing to see here

// =========================================
Nov 13 2021
next sibling parent reply Stanislav Blinov <stanislav.blinov gmail.com> writes:
On Sunday, 14 November 2021 at 04:05:45 UTC, forkit wrote:


 However, there is no isClass method. Why not?

 How do I determine if a member is a class.. I wonder...


```
static if (is(something == class)) { /* ... */ }
```

or, if member is an instance

```
static if (is(typeof(something) == class)) { /* ... */ }
```

Ditto for interfaces, structs, unions.
Nov 13 2021
parent forkit <forkit gmail.com> writes:
On Sunday, 14 November 2021 at 04:24:09 UTC, Stanislav Blinov 
wrote:

 On Sunday, 14 November 2021 at 04:05:45 UTC, forkit wrote:


 However, there is no isClass method. Why not?

 How do I determine if a member is a class.. I wonder...


 ```
 static if (is(something == class)) { /* ... */ }
 ```

 or, if member is an instance

 ```
 static if (is(typeof(something) == class)) { /* ... */ }
 ```

 Ditto for interfaces, structs, unions.


thanks :-)

works now...

if((is(mixin(member) == class)))
                writeln("This is a class.");
Nov 13 2021
prev sibling parent =?UTF-8?Q?Ali_=c3=87ehreli?= <acehreli yahoo.com> writes:
On 11/13/21 8:05 PM, forkit wrote:


 static import mod = mixin(__MODULE__);

 That statement above would not compile.


I don't understand myself but all of it as a single string works:

mixin("static import mod = " ~ __MODULE__ ~ ";");

Ali
Nov 14 2021