.. _library_grammars:

``grammars``
============

This library provides Definite Clause Grammars (DCGs) for common parsing
tasks. The DCGs support parsing both lists of characters (aka chars) and
lists of character codes (aka codes).

Currently, four groups of DCGs are available, each defined in its own
file:

- blanks (``blank_grammars.lgt``)
- numbers (``number_grammars.lgt``)
- sequences (``sequence_grammars.lgt``)
- IP addresses (``ip_grammars.lgt``; depends on ``number_grammars.lgt``)

API documentation
-----------------

Open the
`../../apis/library_index.html#grammars <../../apis/library_index.html#grammars>`__
link in a web browser.

Loading
-------

To load all entities in this library, load the ``loader.lgt`` file:

::

   | ?- logtalk_load(grammars(loader)).

Testing
-------

Minimal tests for this library predicates can be run by loading the
``tester.lgt`` file:

::

   | ?- logtalk_load(grammars(tester)).

Usage
-----

The library uses (when necessary) parametric objects where the single
parameter can be either ``chars`` or ``codes``. The parameter must be
bound when using the DCGs. For example, when using implicit
message-sending:

::

   :- uses(blank_grammars(chars), [
       white_spaces//0, new_lines//0
   ]).
