[I get permenant error on Help-Bison. This list eseem to work]
On 6 Dec 2006, at 10:55, Joel E. Denny wrote:
For verbatim strings:
%define "NAME" "STRING"
No, just one line. This why <code> had to be added.
Do you have a specific need for multiline strings that are not
parsed as
code?
I have the need for code to be added, therefore the feature was added
to %define. But, by the reason I gave, that is, output language
parsing, I think it is better to have a separate command %code for
adding code. This is a conclusion I came to rather recently, some
weeks ago. Before that, I still felt it would be better to have %code
for code, as it would look better, but I did not really care. So I
did not complain when it appeared in %define. But if you are going to
add a host %code like commands anyway, it seems better to have single
one with an argument. It will free up the Bison language name space -
fewer keywords needed.
As for other uses of %define, I have no such immediate needs. But I
think such needs may turn up, at least for others. Then I think it is
best to reserve it for verbatim macros. Macros that require special
parsing should be given special command names - that is the principle
I see.
For code that needs to be parsed:
%define "NAME" { CODE }
How does calling it %code in the second case solve the problem of
multiple
languages?
Because parsing of the code part needs to be changed according to
language.
For a macro define, that seems to be a poor practice.
So the issue isn't with multiple languages?
Yes: right now, the languages that are parsed have similar parsing
and the code additions are similar. But suppose the parsing becomes
more different, plus that there is a need for adding verbatim code.
Then %code should be used for regular code, and %define for the
verbatim code.
It's with parsing CODE at all
when the directive is named %define?
This doesn't bother me. { CODE } is always parsed no matter where it
appears in the Bison grammar file.
So, if %define is used to parsing code at all, I think it should not
parse comments, strings and characters, etc..
And, I think removing the redundant quotes around NAME is pretty
straightforward. There, I think Bison should admit '-" in macro
names, as it will look good in grammar rules, and therefore
elsewhere. - I do not know if M4 handles it.
Hans Aberg
