Package net.sf.tweety.logics.fol.parser

Class FolParser

  • public class FolParser
extends Parser<FolBeliefSet,​FolFormula>
    This class implements a parser for first-order logic. The BNF for a first-order knowledge base is given by (starting symbol is KB)

    KB ::== SORTSDEC DECLAR FORMULAS
    DECLAR ::== (FUNCTORDEC | PREDDEC)*
    SORTSDEC ::== ( SORTNAME "=" "{" (CONSTANTNAME ("," CONSTANTNAME)*)? "}" "\n" )*
    PREDDEC ::== "type" "(" PREDICATENAME ("(" SORTNAME ("," SORTNAME)* ")")? ")" "\n"
    FUNCTORDEC ::== "type" "(" SORTNAME "=" FUNCTORNAME "(" (SORTNAME ("," SORTNAME)*)? ")" ")" "\n"
    FORMULAS ::== ( "\n" FORMULA)*
    FORMULA ::== ATOM | "forall" VARIABLENAME ":" "(" FORMULA ")" | "exists" VARIABLENAME ":" "(" FORMULA ")" |
    "(" FORMULA ")" | FORMULA "&&" FORMULA | FORMULA "||" FORMULA | "!" FORMULA | "+" | "-" |
    FORMULA "=>" FORMULA | FORMULA "<=>" FORMULA | FORMULA "==" FORMULA | FORMULA "/==" FORMULA |
    FORMULA "^^" FORMULA
    ATOM ::== PREDICATENAME ("(" TERM ("," TERM)* ")")?
    TERM ::== VARIABLENAME | CONSTANTNAME | FUNCTORNAME "(" (TERM ("," TERM)*)? ")"

    where SORTNAME, PREDICATENAME, CONSTANTNAME and FUNCTORNAME are sequences of
    symbols from {a,...,z,A,...,Z,0,...,9} with a letter at the beginning and VARIABLENAME
    is a sequence of symbols from {a,...,z,A,...,Z,0,...,9} with an uppercase letter at the beginning.

    Note: Equality/Inequality predicates (== and /==) can only be parsed if the parser is given a FolSignature
    with equality (which is not the case by default).
    Author:
    Matthias Thimm, Anna Gessler

    • Constructor Summary

      Constructors 
      Constructor Description
      FolParser()
      Creates a new FolParser
      FolParser​(boolean ignoreUndeclaredConstants)
      Creates a new FolParser

    • Method Summary

      Modifier and Type Method Description
      FolSignature getSignature()
      Returns the signature of this parser.
      java.util.Map<java.lang.String,​Variable> getVariables()  
      FolBeliefSet parseBeliefBase​(java.io.Reader reader)
      Parses the given reader into a belief base of the given type.
      FolFormula parseFormula​(java.io.Reader reader)
      Parses the given reader into a formula of the given type.
      FolSignature parseSignature​(java.lang.String s)
      This function parses only the sorts declaration and type declaration parts of a belief base.
      void parseSortDeclaration​(java.lang.String s, FolSignature sig)
      Parses a sort declaration of the form "SORTNAME "=" "{" (CONSTANTNAME ("," CONSTANTNAME)*)? "}"" and modifies the given signature accordingly.
      void parseTypeDeclaration​(java.lang.String s, FolSignature sig)
      Parses a predicate declaration of the form "type" "(" PREDICATENAME "(" (SORTNAME ("," SORTNAME)*)? ")" ")" or a functor declaration of the form "type" "(" SORTNAME "=" FUNCTORNAME "(" (SORTNAME ("," SORTNAME)*)? ")" ")" and modifies the given signature accordingly.
      void setSignature​(FolSignature signature)
      Sets the signature for this parser.
      void setVariables​(java.util.Map<java.lang.String,​Variable> variables)  

      • Methods inherited from class java.lang.Object

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

    • Constructor Detail

      • FolParser

        public FolParser()
        Creates a new FolParser

      • FolParser

        public FolParser​(boolean ignoreUndeclaredConstants)
        Creates a new FolParser
        Parameters:
        ignoreUndeclaredConstants - Do not raise exceptions when encountering new constants, all new constants are treated as THING

    • Method Detail

      • parseBeliefBase

        public FolBeliefSet parseBeliefBase​(java.io.Reader reader)
                             throws java.io.IOException,
                                    ParserException
        Description copied from class: Parser
        Parses the given reader into a belief base of the given type.
        Specified by:
        parseBeliefBase in class Parser<FolBeliefSet,​FolFormula>
        Parameters:
        reader - a reader
        Returns:
        a belief base
        Throws:
        java.io.IOException - if some IO issue occurred.
        ParserException - some parsing exceptions may be added here.

      • parseSortDeclaration

        public void parseSortDeclaration​(java.lang.String s,
                                 FolSignature sig)
                          throws ParserException
        Parses a sort declaration of the form "SORTNAME "=" "{" (CONSTANTNAME ("," CONSTANTNAME)*)? "}"" and modifies the given signature accordingly.
        Parameters:
        s - a string
        sig - a signature
        Throws:
        ParserException - if parsing fails

      • parseTypeDeclaration

        public void parseTypeDeclaration​(java.lang.String s,
                                 FolSignature sig)
                          throws ParserException
        Parses a predicate declaration of the form "type" "(" PREDICATENAME "(" (SORTNAME ("," SORTNAME)*)? ")" ")" or a functor declaration of the form "type" "(" SORTNAME "=" FUNCTORNAME "(" (SORTNAME ("," SORTNAME)*)? ")" ")" and modifies the given signature accordingly.
        Parameters:
        s - a string
        sig - a signature
        Throws:
        ParserException - if parsing fails

      • parseFormula

        public FolFormula parseFormula​(java.io.Reader reader)
                        throws java.io.IOException,
                               ParserException
        Description copied from class: Parser
        Parses the given reader into a formula of the given type.
        Specified by:
        parseFormula in class Parser<FolBeliefSet,​FolFormula>
        Parameters:
        reader - a reader
        Returns:
        a formula
        Throws:
        java.io.IOException - if some IO issue occurred.
        ParserException - some parsing exceptions may be added here.

      • parseSignature

        public FolSignature parseSignature​(java.lang.String s)
        This function parses only the sorts declaration and type declaration parts of a belief base.
        Parameters:
        s - the signature as a string
        Returns:
        the parsed fol signature

      • setSignature

        public void setSignature​(FolSignature signature)
        Sets the signature for this parser.
        Parameters:
        signature - a fol signature.

      • getSignature

        public FolSignature getSignature()
        Returns the signature of this parser.
        Returns:
        the signature of this parser.

      • getVariables

        public java.util.Map<java.lang.String,​Variable> getVariables()

      • setVariables

        public void setVariables​(java.util.Map<java.lang.String,​Variable> variables)