dctg-logtalk

Definite Clause Translation Grammar (DCTG)

Definite Clause Translation Grammar rules (DCTGs) are represented as:

LeftPart ::= RightPart <:> Attributes ::- Semantics.

In this term, LeftPart ::= RightPart represents the rule syntax while Attributes ::- Semantics represents the rule semantics. As in DCGs, LeftPart is a non-terminal possibly followed by a list of terminals (aka a "push-back" list).

Usage

To load all the files, load the loader.lgt file in the main directory.

DCTG files must have a .dctg extension and must define the dctg_main/2 predicate where the first argument is the predicate indicator of the main DCTG predicate and the second argument is the predicate indicator of the evaluation predicate.

The major predicates are dctg::process/2, which translates a DCTG rule to a clause, and dctg::consult/2, which consults a file with DCTG rules.

Debugging

TBD.

History

This Logtalk implementation of the Definite Clause Translation Grammar is based on an implementation created by Lindsey Spratt in December, 1986, which in turn was based on the "Definite Clause Translation Grammars" paper by Harvey Abramson:

@inproceedings{SLP-1984-Abramson84,
	author    = "Harvey Abramson",
	booktitle = "{Proceedings of the First International Symposium on Logic Programming}",
	isbn      = "0-8186-0522-7",
	pages     = "233--240",
	publisher = "{IEEE-CS}",
	title     = "{Definite Clause Translation Grammars}",
	year      = 1984,
}

In Abramson's implementation, the dctg::term_expansion/2 predicate is called translate_rule/2.