[erlang-questions] What is wrong with this list?

Dustin Sallings <>
Tue Sep 4 23:47:05 CEST 2007


On Sep 4, 2007, at 13:29 , Peter K Chan wrote:

> I think it would be nice if the compiler can output why a match  
> fails (e.g. {number, 1} does not equal {atom, java}).

	This could work as an error string along with the badmatch for the  
single case discussed, but what about a case (that is contrived, but  
probably similar to real code I've written somewhere) like this:

	Pid = some_function(),
	Pid = other_function().

	The error message wouldn't be all that useful to you either way  
because on the first line you're capturing a value into a variable,  
and on the second line you're validating the same Pid is returned.   
If it showed you the value, it'd probably be meaningless to you.  It  
would basically be showing you two different values and saying  
they're not the same.

	You have the same issue in a case, receive, function definition,  
etc... for which you have no matching case.  You don't want to list  
every possible pattern.

-- 
Dustin Sallings


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