Re: Latest suggestion for 202x

[Niklas Holsti <niklas.holsti@tidorum.invalid>]

On 19-06-24 08:40 , Paul Rubin wrote:
> "J-P. Rosen" <rosen@adalog.fr> writes:
>> Case sensitivity brings nothing but confusion.  The principle for any
>> decent language is that if two identifiers mean the same thing in the
>> brain of the reader, then they must correspond to the same entity. And
>> the meaning of a word is not changed by casing.

Yes... most of the time. I recall, as a young programmer several decades 
ago, being stumped for an embarrassingly long time by a compilation 
error from the Burroughs Algol compiler, which would not accept the code

    real IF;
    ...
    if IF > limit then ...

In a case-insensitive language, of course "IF" is just another form of 
the reserved word "if". But my brain insisted that "IF" is an identifier 
that is an acronym / abbreviation for "Intermediate_Frequency"... even 
when "if" and "IF" were adjacent as above!

(That was in the main-frame punch-card ages, when one did not want to 
use long identifiers because of (a) the 80-column (or 72-column) limit, 
and (b) the high risk of spelling the identifier incorrectly and having 
to punch a new card, after waiting an hour or so for the compiler's 
snide error messages.)

> I don't find this in Haskell.  The names of types and of data
> constructors begin with upper-case letters, and the names of ordinary
> variables begin with lower-case letters.  So you could have
>
>    string = "hello"
>
> and that is separate from the type String.  That might not be great
> style but the language lets you tell the two apart.

Formally true, and usually harmless in today's programming styles where 
identifiers are usually longish words.

Ada's case-insensitivity (which I do prefer, in spite of my anecdote 
above) was, I believe, meant to prevent errors such as having two 
variables called respectively "x" and "X" and confusing between them.

Even if "X" is a type identifier and "x" a variable name, there could be 
confusion between, say, x'Size and X'Size, which look very similar but 
can have different values.

That said, I do find it a little irksome that Ada's rules force one to 
invent different, case-insensitive names for types on the one hand, and 
variables on the other. This leads to conventions such as adding "_T" to 
all type names, which seem ugly and cumbersome at first. But I don't 
have any suggestions for a better solution.

-- 
Niklas Holsti
Tidorum Ltd
niklas holsti tidorum fi
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