Re: Is it really Ok to assert that the Ada syntax is a context-free grammar ?

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

Hibou57 (Yannick Duch�ne) wrote:
> On 20 f�v, 16:19, Niklas Holsti <niklas.hol...@tidorum.invalid> wrote:
> 
>>rule in ARM 9.6(4). Does that make you happy? But look, the
>>[...]
>>parsability of Ada, so I don't see what your problem is.
> 
> Why are you so sad ?

Be reassured, I don't feel sad .. I thought you did :-), but if 
that's not so, then we're both happy, good.

> I was just curious beceause I used to read that Ada and Pascal
> are exemples of unambigous grammar.

Compared to what? And what has that to do with context-freeness?

Perhaps the thing you read was about the bracketing of control 
structures, such as if-then-else-end if, where the parsing of 
nested structures was ambiguous in Algol and Pascal which do not 
have the "end if" bracket, but is unambiguous in Ada.

For sure the Ada *grammar* is ambiguous because you can 
syntactically parse some programs in many ways, for example 
programs that contain the famous fragment X(Y). The legality and 
static semantic rules are there to make all but one parse illegal, 
ensuring an unambigous meaning for the program.

-- 
Niklas Holsti
Tidorum Ltd
niklas holsti tidorum fi
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