com.svincent.moksa
Class MiniPrologParser

java.lang.Object
  |
  +--com.svincent.moksa.WamObject
        |
        +--com.svincent.moksa.PrologParser
              |
              +--com.svincent.moksa.MiniPrologParser

public class MiniPrologParser

extends PrologParser

Parses a subset of the Prolog language, that I call 'Mini-Prolog'.

Moksa includes two Prolog parsers: this one, written entirely in Java, and another, which supports the entire ISO Prolog grammar, written in Prolog.

This parser may one day be extended to parse all of Prolog.

Mini-Prolog is defined as follows:

Clause

Head :- Body.

Clause

:- Body.

Clause

Head.

Head

Term

Body

TermList

TermList

Term (, Term)*

Term

(Term)

Term

Const

Term

Variable

Term

CompoundTerm

Term

List

CompoundTerm

ID (TermList)

List

[TermList(|Term)?]

Const

ID | INTEGER | REAL | STRING

Variable

VARIABLE

A pleasant property of this language is that it is LA(1). It never has to peek ahead more than one token.

Constructor Summary

MiniPrologParser(Io _io)

Method Summary

PrologTerm	parseClause(Io.PrologInput in) Parse a Prolog clause.
PrologTerm	parseTerm(Io.PrologInput in) Parse a Prolog term.

Methods inherited from class com.svincent.moksa.PrologParser

parseClause, parseFile, parseTerm

Methods inherited from class com.svincent.moksa.WamObject

tag, tag

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

MiniPrologParser

public MiniPrologParser(Io _io)

Method Detail

parseClause

public PrologTerm parseClause(Io.PrologInput in)
                       throws java.io.IOException,
                              PrologParseException

Description copied from class: PrologParser

Parse a Prolog clause. This ends at the next end ('.') character, and typically contains something of the form "Term :- Term, Term."

Returns null on EOF.

Overrides:

parseClause in class PrologParser

parseTerm

public PrologTerm parseTerm(Io.PrologInput in)
                     throws java.io.IOException,
                            PrologParseException

Description copied from class: PrologParser

Parse a Prolog term. This is the primitive term stuff we're all familiar with: atoms, integers, compound terms, floats, etc.

Returns null on EOF.

Overrides:

parseTerm in class PrologParser