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From: "Randy Brukardt" <randy@rrsoftware.com>
Newsgroups: comp.lang.ada
Subject: Re: Ada grammar rules for names too permissive?
Date: Sat, 5 Jan 2019 02:45:26 -0600
Organization: JSA Research & Innovation
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Date: 2019-01-05T02:45:26-06:00
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"Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de> wrote in message 
news:q0n77h$2e4$1@gioia.aioe.org...
> On 2019-01-03 23:39, olivermkellogg@gmail.com wrote:
>> On Tuesday, January 1, 2019 at 9:44:17 AM UTC+1, Dmitry A. Kazakov wrote:
>>> [...]
>>>        Never push semantic rules into syntax.
>>
>> I'm not so sure about that:
>> A nice feature of ANTLR is that is supports semantic predicates which can 
>> be embedded in the grammar.
>> For example, using sem preds on the basis of symbol tables would permit 
>> discerning among indexed_component, type_conversion, function_call.
>
> In presence of overloading, really? Anyway, I see no use in such a 
> distinction in general.

Right. That might work in other languages, but in Ada that is a very complex 
algorithm. You'd think that the lack of object overloading would help, and 
it does, but not enough, since you can have a function that returns an array 
that is then indexed, as opposed to a function that returns an 
access-to-function. They both could look like:
     F (1) (2)

And you don't want the grammar to be too smart, simply because hand-written 
error messages are almost always better than automatically generated ones, 
once you get past the trivial (missing punctuation).

                          Randy.