OpenEuphoria

Re: foperator overloading (was Re:fraclib.e)

• Posted by jbrown1050 at hotpop.com Jan 23, 2003
• 372 views

On Wed, Jan 22, 2003 at 11:28:59PM +0000, Pete Lomax wrote:
> 
> Someone, I forget who, wrote:

Me. :T

> 
> >> BTW, what would be really useful here, is a way to make a custom type
> >> which allows one to redefine the math operators, so I could do "f1 + f2"
> >> rather than "f_add(f1, f2)", but have the 2 mean the same thing.
> 
> Interesting. The syntax should(could) be something as trivial as:
> 
> include custom_type_redefine.e	-- global redefine()
> 
> function f_add(blah,
> blah,
> blah
> end function
> 
> -- <no difference to normal yet>
> 
> type ftype(blah...
> redefine("+","f_add")
> ...
> end type
> 
> ...
> ...
> ..
> 
> Somehow I realise there is true potential here, but a convincing
> example escapes me (hint, hint)

Perhaps for natural-looking OOP? (obj.method becomes call_method(obj, method),
and obj:var becomes getvar(obj, var), for example ...)

> 
> Pete

> PS as "+" is both a unary and binary operator, you might have to
> redefine({"+",2},{"f_add",2}). Other stuff too.

Actually, my parser, which is based on Dot, doesn't use a function, it adds
a new keyword, newoperator.

Example:

newoperator % remainder 2

Tells it to replace all "x % y" with "remainder(x , y)". (The last parameter
is the number of parameters the function takes, which is either 1 or 2.)

This works easily for all things, except '=', and slicing.

operator [] slice 1
operator .. multi_slice 2

I hacked my rewriter to be able to handling slicing, so s["1"] becomes
slice(s, "1") and s[1.."3"] becomes multi_slice(s, 1, "3"), for example.

However, my parser currently has a problem with '=', as its both assignment
and comparison operator. Still working on fixing that.

jbrown

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