Pandora.NDRules
Class ExistsIntro

java.lang.Object
  Pandora.NDRules.NDRule
      Pandora.NDRules.ExistsIntro

public class ExistsIntro
extends NDRule

Implements the There Exists Introduction rule.
Extends abstract class Rule.

Field Summary

Fields inherited from class Pandora.NDRules.NDRule

firstLine

Constructor Summary

ExistsIntro(ProofBox proof)
Constructs an ExistsIntro.

Method Summary

void	addLine(ProofLine clickedLine) Adds the extra lines to the rule once the input line has been added.
void	apply() Called by the RuleController to apply the rule.
void	check() Called by the RuleController to check the input lines to the rule.
boolean	checkSignature(Term term) Returns false if the passed Term clashes with or is not included in the signature of the box this rule is applied in, true otherwise.
boolean	checkVarSub(Formula f) Only used when the rule is applied forwards to check if the passed formula can be reached by applying There Exists Introduction forwards on the selected line's formula.
protected Formula	getNewFormula(java.lang.String oldFormula, java.lang.String message) Takes as input a formula that was rejected because its atoms were not in the signature of the proof. Creates a dialog box asking the user to input a new formula. Parses the new formula and gives the user options of what to do if the atoms are not in the signature. The options are the add the atoms to the signature, cancel the rule or to type a new formula. Returns a formula entered by the user, whose atoms are now in the signature of the proof.
protected Term	getNewTerm(java.lang.String oldTerm, java.lang.String message, Formula f) This method is used only when There Exists Introduction rule is applied backwards, to get a term to substitute the There Exists variable formula. The returned Term must be in the signature of the box in which this rule is applied in.
protected Term	getTerm(java.lang.String oldTerm, java.lang.String message, Formula f) This method is used only when There Exists Introduction rule is applied forwards, to get a term to substitute the new There Exists formula's variable. The returned Term must appear free in the passed formula.
protected Var	getVar(java.lang.String oldTerm, java.lang.String message, Formula f) This method is used to get a new variable name for the newly introduced There Exists Formula The variable name must not clash with the signature of the box this rule is applied in. If the passed Formula already contains a quantifier formula, the returned variable must not be the same as its variables. I.e.
boolean	haveAll() Returns true if the rule has all of the required input lines.

Methods inherited from class Pandora.NDRules.NDRule

addInputLine, checkSignature

Methods inherited from class java.lang.Object

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

Constructor Detail

ExistsIntro

public ExistsIntro(ProofBox proof)

Constructs an ExistsIntro.

Parameters:

proof - ProofBox representing in which box the rule is being applied

Method Detail

addLine

public void addLine(ProofLine clickedLine)
             throws java.lang.Exception

Adds the extra lines to the rule once the input line has been added.

Specified by:

addLine in class NDRule

Parameters:

clickedLine - ProofLine which has been selected

Throws:

java.lang.Exception

haveAll

public boolean haveAll()

Returns true if the rule has all of the required input lines.

Specified by:

haveAll in class NDRule

check

public void check()
           throws java.lang.Exception

Called by the RuleController to check the input lines to the rule.

Specified by:

check in class NDRule

Throws:

java.lang.Exception

apply

public void apply()
           throws java.lang.Exception

Called by the RuleController to apply the rule.

Specified by:

apply in class NDRule

Throws:

java.lang.Exception

checkVarSub

public boolean checkVarSub(Formula f)
                    throws java.lang.Exception

Only used when the rule is applied forwards to check if the passed formula can be reached by applying There Exists Introduction forwards on the selected line's formula.

Parameters:

f - Formula represents the formula which is to be checked if is reachable.

Throws:

java.lang.Exception

checkSignature

public boolean checkSignature(Term term)

Returns false if the passed Term clashes with or is not included in the signature of the box this rule is applied in, true otherwise.

Parameters:

t - Term represents the Term which is to be checked against the signature.

getTerm

protected Term getTerm(java.lang.String oldTerm,
                       java.lang.String message,
                       Formula f)

This method is used only when There Exists Introduction rule is applied forwards,
to get a term to substitute the new There Exists formula's variable.
The returned Term must appear free in the passed formula.

Parameters:

oldTerm - String represents the previous invalid Term which has been input
and will appear as the default Term on the next dialog box.

message - String represents the question message to appear on the dialog box.

f - Formula represents the formula which must contain the returned Term as a free Term.

getNewTerm

protected Term getNewTerm(java.lang.String oldTerm,
                          java.lang.String message,
                          Formula f)

This method is used only when There Exists Introduction rule is applied backwards,
to get a term to substitute the There Exists variable formula.
The returned Term must be in the signature of the box in which this rule is applied in.

Parameters:

oldTerm - String represents the previous invalid Term which has been input
and will appear as the default Term on the next dialog box.

message - String represents the question message to appear on the dialog box.

f - Formula represents the There Exists formula whose variable is to be replaced by the returned Term.

getVar

protected Var getVar(java.lang.String oldTerm,
                     java.lang.String message,
                     Formula f)

This method is used to get a new variable name for the newly introduced There Exists Formula
The variable name must not clash with the signature of the box this rule is applied in.
If the passed Formula already contains a quantifier formula, the returned variable must not be the same as its variables.
I.e. Nested variables are not allowed.

Parameters:

oldTerm - String represents the previous invalid Term which has been input
and will appear as the default Term on the next dialog box.

message - String represents the question message to appear on the dialog box.

f - Formula represents the formula which There Exists quantifier is to be applied on.

getNewFormula

protected Formula getNewFormula(java.lang.String oldFormula,
                                java.lang.String message)
                         throws java.lang.Exception

Takes as input a formula that was rejected because its atoms were not in the signature of the proof.
Creates a dialog box asking the user to input a new formula.
Parses the new formula and gives the user options of what to do if the atoms are not in the signature.
The options are the add the atoms to the signature, cancel the rule or to type a new formula.
Returns a formula entered by the user, whose atoms are now in the signature of the proof.

Overrides:

getNewFormula in class NDRule

Parameters:

oldFormula - the formula with atoms that are not in the signature of the proof

Throws:

java.lang.Exception