at.jku.risc.stout.hoau.data

Class InputParser

java.lang.Object

at.jku.risc.stout.hoau.data.InputParser

public class InputParser
extends Object

Tiny term parser with the following rules: (The described rules use the default configuration. You can change the special symbols and/or the variable range.)

• The symbols A-Z, a-z, 1-9 are allowed for variable names and function names. Names can be of any length.
  
• If the first letter of the name is within [u,z] or [U,Z], then it is a free variable.
  
• The backslash "\" is used for the lambda symbol. The name followed by the lambda symbol will become a bound variable.
• The colon ":" is used to declare the type. Type specification is optional for every single symbol.
• The dash "-" is used as type constructor.

Author:

Alexander Baumgartner

Field Summary

Fields

Modifier and Type	Field and Description
static char	CLOSING_PARENTHESIS default = ')'.
static char	LAMBDA_NAME default = '\' => Any word after the '\' will become a bound variable.
static char	OPENING_PARENTHESIS default = '('.
static char	TYPE_CONSTRUCTOR default = '-'.
static char	VARIABLE_START default = 'u' => A word starting with 'u-z' will become a variable. VARIABLE_START has to be a lower case letter! Hedge variables are denoted by upper case letters.

Constructor Summary

Constructors

Constructor and Description
InputParser() Like InputParser(NodeFactory, boolean) with a new NodeFactory instance and forceType set to false.
InputParser(NodeFactory nodeFactory, boolean forceType) Constructor with the used NodeFactory.

Method Summary

Methods

Modifier and Type	Method and Description
<T extends Equation> void	parseEquation(Reader in1, Reader in2, EquationSystem<T> eqSys, int maxReduce)
<T extends Equation> void	parseEquationSystem(String in, EquationSystem<T> eqSys, int maxReduce) Parses a string and puts all the equations into the given equation system.
TermNode	parseSequence(Reader in) Parses a sequence of terms out of the given Reader and returns it.
TermNode	parseSequence(String in) Use parseSequence(Reader) if possible! It performs better and saves space by reading directly from the data stream;)
TermNode	parseTerm(Reader in) Parses a term out of the given Reader and returns it.
TermNode	parseTerm(String in) Use parseTerm(Reader) if possible! It performs better and saves space by reading directly from the data stream;)
void	tryBoundVarPrefix(String in, String... prefix) This method tries to find a suitable prefix for fresh bound variables.
void	tryFreeVarPrefix(String in, String... prefix) This method tries to find a suitable prefix for fresh free variables.

Methods inherited from class java.lang.Object

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

Field Detail

CLOSING_PARENTHESIS

public static char CLOSING_PARENTHESIS

default = ')'.

LAMBDA_NAME

public static char LAMBDA_NAME

default = '\' => Any word after the '\' will become a bound variable.

OPENING_PARENTHESIS

public static char OPENING_PARENTHESIS

default = '('.

TYPE_CONSTRUCTOR

public static char TYPE_CONSTRUCTOR

default = '-'.

VARIABLE_START

public static char VARIABLE_START

default = 'u' => A word starting with 'u-z' will become a variable.
VARIABLE_START has to be a lower case letter! Hedge variables are denoted by upper case letters.

Constructor Detail

InputParser

public InputParser()

Like InputParser(NodeFactory, boolean) with a new NodeFactory instance and forceType set to false.

InputParser

public InputParser(NodeFactory nodeFactory,
           boolean forceType)

Constructor with the used NodeFactory. If the second flag is set to true, then typing is mandatory.

Method Detail

parseEquation

public <T extends Equation> void parseEquation(Reader in1,
                                      Reader in2,
                                      EquationSystem<T> eqSys,
                                      int maxReduce)
                   throws NotNormalizableException,
                          MalformedTermException,
                          IOException

Throws:

NotNormalizableException

MalformedTermException

IOException

parseEquationSystem

public <T extends Equation> void parseEquationSystem(String in,
                                            EquationSystem<T> eqSys,
                                            int maxReduce)
                         throws IOException,
                                ControlledException

Parses a string and puts all the equations into the given equation system. Beta reduction is automatically called for every parsed term.

Throws:

IOException

ControlledException

parseSequence

public TermNode parseSequence(Reader in)
                       throws IOException,
                              MalformedTermException

Parses a sequence of terms out of the given Reader and returns it.

Throws:

IOException

MalformedTermException

parseSequence

public TermNode parseSequence(String in)
                       throws IOException,
                              MalformedTermException

Use parseSequence(Reader) if possible! It performs better and saves space by reading directly from the data stream;)

Throws:

IOException

MalformedTermException

parseTerm

public TermNode parseTerm(Reader in)
                   throws IOException,
                          MalformedTermException

Parses a term out of the given Reader and returns it.

Throws:

IOException

MalformedTermException

parseTerm

public TermNode parseTerm(String in)
                   throws IOException,
                          MalformedTermException

Use parseTerm(Reader) if possible! It performs better and saves space by reading directly from the data stream;)

Throws:

IOException

MalformedTermException

tryBoundVarPrefix

public void tryBoundVarPrefix(String in,
                     String... prefix)

This method tries to find a suitable prefix for fresh bound variables. Use this method carefully! (Or don't use it at all.)
The best way to go is to simply choose a special symbol for fresh variables which is guaranteed to never appear inside a term. (Just set NodeFactory.PREFIX_FreshBoundVar and don't use this method!)

tryFreeVarPrefix

public void tryFreeVarPrefix(String in,
                    String... prefix)

This method tries to find a suitable prefix for fresh free variables. Use this method carefully! (Or don't use it at all.)
The best way to go is to simply choose a special symbol for fresh variables which is guaranteed to never appear inside a term. (Just set NodeFactory.PREFIX_FreshFreeVar and don't use this method!)