On 11 January 2012 00:39, UJWAL POTLURI <[email protected]> wrote:
> Can you please show me an example of how to do.
>
> On Tue, Jan 10, 2012 at 3:52 AM, Hans Aberg <[email protected]> wrote:
>
>>
>> On 10 Jan 2012, at 01:38, UJWAL POTLURI wrote:
>>
>> > I am new to Bison. I am able to parse the grammar using Bison but I
>> am
>> > unable to figure out how to generate the parse tree. I would be grateful
>> if
>> > anyone could help me out in this.
>>
>> You'll have to build it in the grammar actions.
>>
>> Hans
>>
>>
>>
>
>
> --
> Ujwal Potluri,
> Masters student,
> Computer Science,
> University of Connecticut,
> Connecticut, USA.
> _______________________________________________
> [email protected] https://lists.gnu.org/mailman/listinfo/help-bison
The bison manual has some good basic examples if i recall. But take
the general idea of something like:
x = 1 + 2;
The DAG of this would be something like:
=
/ \
x +
/ \
1 2
So you would have the grammar:
expr = identifier '=' expr
| expr '+' expr
...
| primary
So you could simply have the structure:
struct tree {
type T;
union {
int x;
char * s
struct tree * t;
} opa;
union {
int x;
.....
};
};
And you parse each thing in a simple way. Read on here
http://www.gnu.org/software/bison/manual/html_node/Infix-Calc.html#Infix-Calc
or read the dragon book and the Lex and Yacc o'reilly book is good.
Just make it in a way that makes things easy for you just think about
how the parser parsers things and you should get the idea.
--Phil
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