smelly code in input.c

[Anthony Clayden]

(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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