> In the table of precedence in the original Report (now deleted in
> the revised Report), it makes it clear that a rightward-extending
> let, if, or lambda has a lower precedence than an infix operator,
> so for instance the parse
>
> h = (let op x y = y in (3 `op`))
>
> is correct and
>
> h = ((let op x y = y in 3) `op`)
>
> is not.
Actually the table claims that 'let' has a higher precedence than infix operators, so
your second example above would be the correct parse according to the table. This may
be one of the reasons it was removed, I can't remember now.
Also, the table wasn't supposed to contain any extra information that isn't already in
the grammar (Section 3: "As an aid to undertanding the grammar, Table 1 shows the
relative precedences..."), so if the table is required to understand a particular
parse, it would indicate a deficiency or ambiguity in the grammar.
On the other hand, one way to fix this problem *is* to specify the relative precedence
of 'let' & co. as compared to infix operators (namely that 'let' should have a lower
precedence). That would be a reasonable fix for the H98 report, IMO.
Cheers,
Simon
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