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Re: Retrieving the string name of token
From: |
Hans Aberg |
Subject: |
Re: Retrieving the string name of token |
Date: |
Tue, 7 Mar 2006 07:22:55 +0100 |
On 7 Mar 2006, at 04:02, Frans Englich wrote:
Let's say I've declared the following token:
%token IMPORT_MODULE "import module"
Is it somehow possible to in code retrieve "import module" when
given the
IMPORT_MODULE define/enum? Is there a public function somewhere for
that? I
want to keep the descriptions centralized.
Bison writes (I think) an array into the parser with those names.
Check output parser source.
***
Also,
Please keep one topic per post, with descriptive subject for each.
sometimes I really feel like writing rules like this:
Rule: (A | B) C D
Which would allow A C D or B C D. What is the reason to that such
constructs
are not possible?
Simply because nobody has implemented it. I think some grads at
Berkeley made a Bison version with such constructs.
I think it would be possible if for example one ensured that A and
B had the
same types, or disallowed token values to be retrieved($N) if the
types were
incompatible.
Yes, I know the same can be expressed this way:
Rule: AorB C D
AorB: A
| B
I also guess that if Bison support the imaginary form above(if
that's at all
possible) it would rewrite into this latter, valid form.
My point being I find the first form much more readable.
One just expands it using standard rewrites (which I have posted here
before). In Bison, one would also enable the addition of suitable
actions.
Hans Aberg