Re: How to print current type of a SumType?

[Chris Piker via Digitalmars-d-learn]

We posted at the same time!  Thanks for help nonetheless.

I do hope over time, SumTypes get the Ali Çehreli treatment.  I 
keep his book open on my desk all the time.

Re: How to print current type of a SumType?

[Paul Backus via Digitalmars-d-learn]

On Sunday, 1 October 2023 at 01:17:50 UTC, Chris Piker wrote:

Hi D

I've a simple question but it's bedeviling me anyway.  How do I 
get a string representation of the current type of a SumType?  
I'm trying to avoid something like this:


```d
alias Vec3 = SumType!(void* /* invalid vector */, byte[3], 
short[3], char[][3]);


string prnType(Vec3 vec){

  return vec.match!(
 (void* _) => "void*",
 (byte[3] _) => "byte[3]",
 (short[3] _) => "short[3]",
 (char[][3] _) => "char[][3]"
  );
}
```

I'm sure there's a much easier way, especially once there's a 
largish number of vector types.


Thanks,


```d
return vec.match(value => typeof(value).stringof);
```

Re: How to print current type of a SumType?

[Chris Piker via Digitalmars-d-learn]

On Sunday, 1 October 2023 at 01:17:50 UTC, Chris Piker wrote:

```d
alias Vec3 = SumType!(void* /* invalid vector */, byte[3], 
short[3], char[][3]);


```



I know it's bad form to reply to my own question, but I think I 
found a reasonably simple way:


```d
string prnType(Vec3 vec){
   return vec.match!( t => typeof(t).stringof);
}
```

which is hardly worth making into a function of it's own.  Other 
suggestions are welcome of course.


SumTypes are really tripping me up.  Unlearning years of writing 
C takes more time then I'd prefer.

How to print current type of a SumType?

[Chris Piker via Digitalmars-d-learn]

Hi D

I've a simple question but it's bedeviling me anyway.  How do I 
get a string representation of the current type of a SumType?  
I'm trying to avoid something like this:


```d
alias Vec3 = SumType!(void* /* invalid vector */, byte[3], 
short[3], char[][3]);


string prnType(Vec3 vec){

  return vec.match!(
 (void* _) => "void*",
 (byte[3] _) => "byte[3]",
 (short[3] _) => "short[3]",
 (char[][3] _) => "char[][3]"
  );
}
```

I'm sure there's a much easier way, especially once there's a 
largish number of vector types.


Thanks,