smelly code in input.c

[Iavor Diatchki]

Hi,

I don't not know that code either, but looking at the comments and the
surrounding code, my guess is that the 2nd `c0` should be `c1`,
and it is checking for something like `.` followed by either a lower case
or upper case or symbol operator.

-Iavor



On Mon, Jun 14, 2021 at 3:48 AM Anthony Clayden <anthony.d.clayden at gmail.com>
wrote:

> (I can't say for sure I have a bug, because I don't grok the code well
> enough to figure out how to make something go wrong, but ...)
>
> In /src/input.c line 1714
> https://github.com/FranklinChen/hugs98-plus-Sep2006/blob/master/src/input.c#L1714
> ,
>
> >     if (c0=='.' && isIn(c0,(SMALL|LARGE|SYMBOL))) {
>
> It looks wrong to be testing `c0` twice, that test will always come out
> False. (Or if '.' counts as a SYMBOL, then always True.) I guess the second
> test should be lookahead `isIn(c1, ...)`. That follows the code pattern
> nearby above line 1688, and especially 1698.
>
> I think it'll mean the compiler won't handle multi-qualified names like
> `Mod1.Sub2.Subsub3.Foo`. Whereas `Prelude.True` (just a single qualifier)
> is ok.
>
> Can anyone confirm my suspicion and/or suggest a definitive test?
>
> (Reason for asking: I'm trying to persuade Hugs to differentiate
> tight-binding dot as an operator vs space-surrounded dot as function
> composition. In particular so I can write `record.label` as field access.
> I'd also like to write `record.#label` as a TRex field access.)
>
> AntC
>
>
>
>
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