Re: Type-checking trick

[Reuben Thomas <rrt@...>]

> I thought about a compiler extension. An optional type name before the
> parameter name.  Like:
> 
>   function(typename varname, ...)

I'd prefer varname : typename, both because it's easier to read, and 
because it doesn't use up syntactic concatenation, but otherwise, yes, I 
like this idea, and that it could work on assignments and declarations.

I hadn't been thinking about methods which involved changing the compiler.

> PS: I think, one needs another syntax to specify optional typed
> arguments (may be nil or of that type).  I.e. append an '?':
> function(FooType x?)

Another problem is how to keep the type of a value which is set to nil so 
that it can't be then be set to another type (assuming that you want to 
enforce types on names rather than just values).

-- 
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