Re: [sqlite] Questions regarding Lemon
> > %type course_plot { std::vector* }
> >
> > course_plot(V) ::= COURSE_PLOT_BEG course_plot_sector(A) .
> > {
> >
> The issue is more what V is when the vector isn't created.
>
>
> Igmar
lemon is not going to initialize anything for you. You need to design
your parser such that you can control the creation and deletion of your
own objects.
*** untested pseudo-c code ***
%type assigments { struct llist *}
main ::= zero_or_more_statments.
zero_or_more_statements ::= .
zero_or_more_statements ::= zero_or_more_statements one_statement.
one_statement ::= assignments(L). { dostuff(*L); free(L); }
assignments(A) ::= ASSIGNMENT_BEGIN assignment(B). { A = malloc(...);
A->add(B); }
assignments(A) ::= assignments(L) assignment(B). { A = L; A->add(B); }
RW
Ron Wilson, Engineering Project Lead
(o) 434.455.6453, (m) 434.851.1612, www.harris.com
HARRIS CORPORATION | RF Communications Division
assuredcommunications(tm)
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Re: [sqlite] Questions regarding Lemon
> %type course_plot { std::vector* }
>
> course_plot(V) ::= COURSE_PLOT_BEG course_plot_sector(A) .
> {
>
The issue is more what V is when the vector isn't created.
Igmar
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Re: [sqlite] Questions regarding Lemon
You have to initialize the variable yourself, e.g.
%type course_plot { std::vector* }
course_plot(V) ::= COURSE_PLOT_BEG course_plot_sector(A) .
{
V = new std::vector;
V->push_back(A);
}
course_plot(V) ::= course_plot(L) COURSE_PLOT_GT course_plot_sector(A) .
{
V = L;
V->push_back(A);
}
And yes, I parse TradeWars 2002 with lemon. /bow
Ron Wilson, Engineering Project Lead
(o) 434.455.6453, (m) 434.851.1612, www.harris.com
HARRIS CORPORATION | RF Communications Division
assuredcommunications(tm)
> -Original Message-
> From: sqlite-users-boun...@sqlite.org [mailto:sqlite-users-
> boun...@sqlite.org] On Behalf Of Igmar Palsenberg
> Sent: Monday, February 22, 2010 7:39 AM
> To: sqlite-users@sqlite.org
> Subject: [sqlite] Questions regarding Lemon
>
>
> Hi,
>
> After a decode or so I've begun to program in C again. I've writing a
> parser, and Lemon seems like the right tool for the job. SQLite itself
> is an excellent read when starting with lemon.
> However, a few questions remain unanswered :
>
> - How do variables get initialized ? For example :
>
> %type assigments { struct llist *}
>
> assignments(A) ::= assignments assignment(B). { /* . */ }
> assignments(A) ::= assignment(B). {/* */ }
>
> Can I assume that A, when the rule is executed the first time, is NULL ?
>
> - What is the meaning of @ in an assignment ? From the sqlite parse.y
> source :
>
> transtype(A) ::= DEFERRED(X). {A = @X;}
>
> Thanx in advance for all the hints :)
>
>
> Regards,
>
>
> Igmar
>
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[sqlite] Questions regarding Lemon
Hi,
After a decode or so I've begun to program in C again. I've writing a
parser, and Lemon seems like the right tool for the job. SQLite itself
is an excellent read when starting with lemon.
However, a few questions remain unanswered :
- How do variables get initialized ? For example :
%type assigments { struct llist *}
assignments(A) ::= assignments assignment(B). { /* . */ }
assignments(A) ::= assignment(B). {/* */ }
Can I assume that A, when the rule is executed the first time, is NULL ?
- What is the meaning of @ in an assignment ? From the sqlite parse.y
source :
transtype(A) ::= DEFERRED(X). {A = @X;}
Thanx in advance for all the hints :)
Regards,
Igmar
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