type safety (was Re: FAQ terminology harmonisation)

[Peter-Henry Mander]

I was thinking of something like this (not compiled or tested, sorry) 
which I find kinda useful sometimes.

fn(#a_record{field=an_atom}) ->
     %% do stuff specific to a record with field=an_atom...
fn(Record=#a_record{field=Field}) ->
     %% do stuff for other values of field...
fn(Anything) ->
     %% do anything... Probably shouldn't!

But I have a feeling we may be thinking of different purposes. Sorry I 
can't elaborate right now, I've gotta scoot, family needs me.

Pete.

Chris Pressey wrote:
> On Fri, 04 Apr 2003 08:03:49 +0100
> Peter-Henry Mander <erlang@REDACTED> wrote:
> 
> 
>>Hmm... This emphasis on exact matching on type would potentially break
>>
>>an aspect of Erlang I have learnt to appreciate: pattern matching. I
>>can make a function match exactly or match with increasing degrees of 
>>generality. A special case function first, followed by general case.
>>If none match, an exception occurs. I can work with a bit of dicipline
>>and tag my tuples, and enforce that functions only acccept tagged
>>tuples.
>>
>>Pete.
> 
> 
> Do you mean you write functions like this?
> 
>   case Value of
>     Tuple when is_tuple(Tuple) ->
>       case Tuple of
>         Record when is_record(Record, my_record) ->
>           do_stuff(Record)
>       end
>   end
> 
> That seems silly.  You probably mean like this:
> 
>   case Value of
>     Record when is_record(Record, my_record) ->
>       do_stuff(Record);
>     Tuple when is_tuple(Tuple) ->
>       do_other_stuff(Tuple)
>   end
> 
> But if records were opaque, that sort of match wouldn't break, either.
> 
> -Chris
> 
> 
>