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 ../../docs/library_index.html#grammars link in a web browser.


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

| ?- logtalk_load(grammars(loader)).


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

| ?- logtalk_load(grammars(tester)).


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