This package provides DCG related utilities. It is organised into several modules:

library(dcg_core)

Provides predicates which can be used in DCGs where the threaded state variable can be of any type, not just lists of terminals as with applications to grammars in the linguistic sense.

library(dcg_codes)

Utilities for DCGs over sequences of character codes, ie, grammars in the linguistic sense. Note that only some of these can be used for both parsing and generation. The rules for writing Prolog values of various types can only be used for generation.

library(dcg_macros)

Provides goal expansions for some of the mapping predicates in library(dcg_core), similar to those in library(apply_macros).

library(dcg_progress)

Sequencing predicates that show progress information, for slow-running processes on sequences.

library(dcg_pair)

Operators for working with DCGs over pair states.

library(dcg_shell)

Provides a top-level read-eval-print loop similar to the Prolog top-level, but for running DCG goals and managing the current 'state'.

library(snobol)

A collection of SNOBOL inspired pattern matching predicates.

Prerequisites

SWI Prolog version at least 7.1.18 to get call_dcg/3.

Simple usage

Planned enhancements