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More doc. 

git-svn-id: http://caml.inria.fr/svn/ocaml/branches/extension_points@13363 f963ae5c-01c2-4b8c-9fe0-0dff7051ff02
master
Alain Frisch 2013-03-06 14:29:04 +00:00
parent 8055753e58
commit 9f8b148761
1 changed files with 37 additions and 2 deletions
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39
experimental/frisch/extension_points.txt
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@ -67,7 +67,7 @@ On items:
Note: item attributes are currently not supported on Pstr_eval Note: item attributes are currently not supported on Pstr_eval
and Pstr_value structure items. and Pstr_value structure items.
A fifth syntax exists for attributes which stands as signature or A fifth syntax exists for attributes which stand as signature or
structure item on their own (i.e. they are not attached to any other structure item on their own (i.e. they are not attached to any other
component): component):
@ -76,6 +76,40 @@ component):
([^^] and [@@] attributes cannot be attached to such a standalone attribute.) ([^^] and [@@] attributes cannot be attached to such a standalone attribute.)
=== Representation of attributes in the Parsetree
For attributes on expressions and similar categories, attributes are
just another possible constructor (one single attribute per node):
and expression_desc =
....
| Pexp_attribute of (expression * attribute)
Note: we currently don't distinguish between prefix and postfix attributes.
Similarly, attributes as standalone signature/structure items are represented
by a new constructor:
| Psig_attribute of attribute
| Pstr_attribute of attribute
For "declarations"-like items (type declarations, module declarations,
..., but also constructors and record labels), all attributes are stored
in an extra field in their record (again, without making the distinction
between prefix and postfix attributes):
and type_declaration = {
...
ptype_attributes: attribute list;
...
For other kinds of items (currently: open/include stataments,
exception rebind), the attributes are stored directly in the
constructor of the item:
| Pstr_open of Longident.t loc * attribute list
=== Extension nodes === Extension nodes
Extension nodes replace valid components in the syntax tree. They are Extension nodes replace valid components in the syntax tree. They are
@ -178,4 +212,5 @@ More self-documented, simplifies some code.
- Adapt Camlp4 (both its parser(s) and its internal representation of OCaml ASTs). - Adapt Camlp4 (both its parser(s) and its internal representation of OCaml ASTs).
- Propagate attributes to the Typedtree (so that they can be retrieved in .cmt/.cmti). - Propagate attributes to the Typedtree (so that they can be retrieved in .cmt/.cmti).
- Consider adding hooks to the type-checker so that custom extension expanders can be registered (a la OCaml Templates). - Consider adding hooks to the type-checker so that custom extension expanders can be registered (a la OCaml Templates).
- Quotations (i.e. string literals with custom delimiters and without any interpretation of special characters in them), and a syntax which combines extension nodes and quotations.
- More cleanups to the Parsetree + documentation.