Re: Equality operator overloading in ADA 83

[fjh@mundook.cs.mu.OZ.AU (Fergus Henderson)]

dewar@merv.cs.nyu.edu (Robert Dewar) writes:

>I still think that the utility is marginal in real programs, I looked for
>the elsif pattern that would correspond to this case sequence, and found
>*very* few examples in the millions of lines of code in our regression
>suite (always an interesting place to look, since it represents code from
>many places).

FWIW, I have some data that may be relevant.

The Mercury language includes support for the equivalent of
string case statements, and for switches that meet a minimum
size requirement (8 cases), the Mercury compiler generates
hash tables to index such switches.  I did a quick grep for
`hash_string' in the generated code, and found that for
the Mercury compiler itself (108 thousand lines of Mercury source,
or 80 thousand if you exclude whitespace and comment lines), there
where 15 such occurrences, spread over 12 of the 126 modules,
or about one for every 5 thousand non-comment non-whitespace line
of code.  (That figure doesn't count string switches with 7 or less
cases, for which the Mercury compiler currently generates code using
if-then-else chains.)

I leave it to the reader to judge what conclusions should be
drawn from this data.

--
Fergus Henderson <fjh@cs.mu.oz.au>   |  "I have always known that the pursuit
WWW: <http://www.cs.mu.oz.au/~fjh>   |  of excellence is a lethal habit"
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