Re: problems with identifiers and keywords...

Martin Ward wrote:
> On Wednesday 17 Nov 2004 4:36 pm, you wrote:
>
>>I am not sure I agree with this. Human languages are fairly hard
>>for machines to parse, yet presumably designed for humans to
>>understand. In a large number of cases, I don't believe humans have
>>problems with keywords used as identifiers,


> Humans very rarely use keywords as identifiers: how many (English)
> people do you know who are called "The" or "And"?
> "Pass me the the will you, And?" is not immediately obvious.
>
> More seriously, humans are good at pattern matching: with a small
> number of keywords (and properly indented code) a human can pick out
> the keywords instantly and work out the overall structure of a chunk
> of code very quickly. When keywords are also used as identifiers,
> this is not possible.
>
> So the real solution to the problem of lots of keywords (where a
> programmer might use an unfamiliar keyword as an identifier) is simply
> to define fewer keywords and *not* to use unique keywords for rarely
> used constructs in the language.


I fail to see the problem. Of course a rational programmer isn't
going to use "IF" and "ELSE" as variables, but the X11 example
recently given shows the obnoxiousness or having keywords as reserved
words. "CLASS" is a perfectly good name for a variable.


I hadn't really noticed too many problems parsing PL/I. Most
ambiguous cases require only a one- or two-token look-ahead to
resolve, rarely more.

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