Re: another take on hackers and painters

[John Clements <address@hidden>]

On Wednesday, May 21, 2003, at 03:02  PM, Dan Sugalski wrote:
>
> Erm, this argument, boiled down, turns into "people make logic errors 
> when writing perl, therefore perl makes people make logic errors". 
> Sure, perl's autoconversion can bite you, but so can checking objects 
> capabilities at runtime by looking for methods by name, containers 
> that are strictly typed, or the assumption that all strings are a 
> sequence of non-zero 8-bit characters with a null terminator.
>
> It may well be something that you, personally, aren't comfortable 
> with. That's fine. It's certainly something that people do, on 
> occasion, mess up, and that's fine too. (I sometimes swap < and >, but 
> that's not an argument for eliminating one or the other) It's a 
> language behaviour that is, in some circumstances, very useful, just 
> like almost any other language behaviour. Any feature may render a 
> language sub-optimal for some use or other, but no language is 
> universally appropriate.

I think you're being mushy.  The key difference between something like 
string->number conversion and the confusion between '<' and '>' is that 
there's no obvious way for the evaluator to check whether you meant < 
or >, whereas there is a very easy way to stave off the confusion of 
adding a string and a number; a way which nonetheless provides the 
programmer with an easy out should he wish to make such a conversion.

Put another way:  don't you want as much checking as you can possibly 
get at acceptable cost?

and

isn't having to write 'string->number' an acceptable cost?


john clements