Tree-like construction while parsing the input file

[Ilyes Gouta]

Hi,

I'm writing a simple C header file parser using bison and I would like to
build a tree structure (a simplified AST) which will hold all the elements
of a given .h file.

Here is a snippet of my grammar:

input:
|   declaration input
;

item_list:
|   item_declaration item_list
;

enum_item:
    id                   { add_node_item(handle, &$1); }
|   id '=' expr          { add_node_item(handle, &$1); }
;

declaration:
    TYPEDEF ENUM { handle = add_node(TYPE_ENUM); } '{' enum_list '}' id ';'
{ set_node_name(handle, $6.text); check_stack(); }
|   STRUCT id { handle = add_node(TYPE_STRUCT); } '{' item_list '}' ';'
{ set_node_name(handle, $2.text); }

add_node(TYPE) will allocate the container as soon as we can tell if we're
processing a struct or an enum (for example). Now, I'd like the enum_listand
item_list rules to be able to "see" the allocated container so that I can
populate it when the parser hits those rules. I don't like to use global
variables (such as handle in this example) since declarations may be nested
and thus handle won't point to the correct container.

Any ideas?

Regards,
Ilyes Gouta.