Extending arithmetic

Bjorn Gustavsson <>
Mon Feb 10 12:29:01 CET 2003


Joe Armstrong <> writes:

> On Sat, 8 Feb 2003, Robert Virding wrote:
> 
> 
>   I entirely agree  - this violates the "principle  of least surprise"
> my intuitive  understanding of  "+" is  that it is  a thing  that adds
> *numbers* together - nothing else.
> 
>   <aside> Robert  and I  agonized for months  over whether  "+" should
> overload floats and integers -  we made (of course) the wrong decision
> allowing arbitrary mixing of  floats and integers with the appropriate
> coercions  where necessary.  This sucks  since coercing  a  very large
> integer (bignum) into a float can fail etc. - too late now.
> 

I think that "principle  of least surprise" says that you should be able
to freely mix integers and floats.

In my opinion, the decision was correct. It does make it harder to
write a compiler, but it makes it (a lot) easier for the user.

I find the overloading of the size/1 BIF (tuples/binaries) to be much
worse. It prevents optimizing most uses of size/1, and is not significantly
easier for the user than two separate size BIFs would be.

/Bjorn

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Björn Gustavsson            Ericsson Utvecklings AB
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