Time-bounded properties with equal lower/upper bounds, e.g. P=?[ F[T,T] target ], can be specified as P=?[ F=T target ], for convenience.

git-svn-id: https://www.prismmodelchecker.org/svn/prism/prism/trunk@4710 bbc10eb1-c90d-0410-af57-cb519fbb1720

prism/src/parser/PrismParser.jj

@@ -322,8 +322,6 @@ public class PrismParser
 	// A few classes for temporary storage of bits of the AST
 	//-----------------------------------------------------------------------------------
 	
-	static class TimeBound { public Expression lBound = null; public Expression uBound = null; public boolean lBoundStrict = false; public boolean uBoundStrict = false; }
-	
 	static class ExpressionPair { public Expression expr1 = null; public Expression expr2 = null; }
 }
 
@@ -1039,7 +1037,6 @@ Expression ExpressionTemporalBinary(boolean prop, boolean pathprop) :
 {
 	Expression ret, expr;
 	ExpressionTemporal exprTemp;
-	TimeBound tb = null;
 	Token begin = null;
 }
 {
@@ -1051,7 +1048,7 @@ Expression ExpressionTemporalBinary(boolean prop, boolean pathprop) :
 		( <U> { exprTemp.setOperator(ExpressionTemporal.P_U); }
 		| <W> { exprTemp.setOperator(ExpressionTemporal.P_W); }
 		| <R> { exprTemp.setOperator(ExpressionTemporal.P_R); } )
-		( tb = TimeBound() { exprTemp.setLowerBound(tb.lBound, tb.lBoundStrict); exprTemp.setUpperBound(tb.uBound, tb.uBoundStrict); } )?
+		( TimeBound(exprTemp) )?
 		expr = ExpressionTemporalUnary(prop, pathprop)
 		{ exprTemp.setOperand2(expr); exprTemp.setPosition(begin, getToken(0)); ret = exprTemp; }
 	]
@@ -1062,7 +1059,6 @@ Expression ExpressionTemporalUnary(boolean prop, boolean pathprop) :
 {
 	Expression ret, expr;
 	ExpressionTemporal exprTemp;
-	TimeBound tb = null;
 	Token begin = null;
 }
 {
@@ -1073,7 +1069,7 @@ Expression ExpressionTemporalUnary(boolean prop, boolean pathprop) :
 		( <X> { exprTemp.setOperator(ExpressionTemporal.P_X); }
 		| <F> { exprTemp.setOperator(ExpressionTemporal.P_F); }
 		| <G> { exprTemp.setOperator(ExpressionTemporal.P_G); } )
-		( tb = TimeBound() { exprTemp.setLowerBound(tb.lBound, tb.lBoundStrict); exprTemp.setUpperBound(tb.uBound, tb.uBoundStrict); } )?
+		( TimeBound(exprTemp) )?
 		expr = ExpressionTemporalUnary(prop, pathprop)
 		{ exprTemp.setOperand2(expr); exprTemp.setPosition(begin, getToken(0)); ret = exprTemp; }
 	|
@@ -1085,17 +1081,18 @@ Expression ExpressionTemporalUnary(boolean prop, boolean pathprop) :
 // Time bound for temporal operators
 // (see ExpressionTemporal production for lookahead explanation)
 
-TimeBound TimeBound() :
+void TimeBound(ExpressionTemporal exprTemp) :
 {
-	TimeBound tb = new TimeBound();
+	Expression lBound, uBound;
 }
 {
-	( <LE> ( LOOKAHEAD(IdentifierExpression() <LPARENTH>) tb.uBound = IdentifierExpression() | tb.uBound = Expression(false, false) )
-	| <LT> {tb.uBoundStrict=true;} ( LOOKAHEAD(IdentifierExpression() <LPARENTH>) tb.uBound = IdentifierExpression() | tb.uBound = Expression(false, false) )
-	| <GE> ( LOOKAHEAD(IdentifierExpression() <LPARENTH>) tb.lBound = IdentifierExpression() | tb.lBound = Expression(false, false) )
-	| <GT> {tb.lBoundStrict=true;} ( LOOKAHEAD(IdentifierExpression() <LPARENTH>) tb.lBound = IdentifierExpression() | tb.lBound = Expression(false, false) )
-	| <LBRACKET> tb.lBound = Expression(false, false) <COMMA> tb.uBound = Expression(false, false) <RBRACKET> )
-	{ return tb; }
+	( ( <LE> ( LOOKAHEAD(IdentifierExpression() <LPARENTH>) uBound = IdentifierExpression() | uBound = Expression(false, false) ) { exprTemp.setUpperBound(uBound, false); } )
+	| ( <LT> ( LOOKAHEAD(IdentifierExpression() <LPARENTH>) uBound = IdentifierExpression() | uBound = Expression(false, false) ) { exprTemp.setUpperBound(uBound, true); } )
+	| ( <GE> ( LOOKAHEAD(IdentifierExpression() <LPARENTH>) lBound = IdentifierExpression() | lBound = Expression(false, false) ) { exprTemp.setLowerBound(lBound, false); } )
+	| ( <GT> ( LOOKAHEAD(IdentifierExpression() <LPARENTH>) lBound = IdentifierExpression() | lBound = Expression(false, false) ) { exprTemp.setLowerBound(lBound, true); } )
+	| ( <LBRACKET> lBound = Expression(false, false) <COMMA> uBound = Expression(false, false) <RBRACKET> { exprTemp.setLowerBound(lBound, false); exprTemp.setUpperBound(uBound, false); } )
+	| ( <EQ> lBound = Expression(false, false) { exprTemp.setEqualBounds(lBound); } )
+	)
 }
 
 // Expression: if-then-else, i.e. "cond ? then : else"

prism/src/parser/ast/ExpressionTemporal.java

@@ -27,7 +27,7 @@
 package parser.ast;
 
 import parser.EvaluateContext;
-import parser.visitor.*;
+import parser.visitor.ASTVisitor;
 import prism.PrismLangException;
 
 public class ExpressionTemporal extends Expression
@@ -57,6 +57,8 @@ public class ExpressionTemporal extends Expression
 	// Strictness of (time) bounds
 	protected boolean lBoundStrict = false; // true: >, false: >= 
 	protected boolean uBoundStrict = false; // true: <, false: <=
+	// Display as =T rather than [T,T] ?
+	protected boolean equals = false;
 
 	// Constructors
 
@@ -88,16 +90,8 @@ public class ExpressionTemporal extends Expression
 		operand2 = e2;
 	}
 
-	public int getNumOperands()
-	{
-		if (operand1 == null)
-			return 0;
-		else
-			return (operand2 == null) ? 1 : 2;
-	}
-
 	/**
-	 * Set lower timer bound to be of form >= e
+	 * Set lower time bound to be of form >= e
 	 * (null denotes no lower bound, i.e. zero)
 	 */
 	public void setLowerBound(Expression e)
@@ -106,7 +100,7 @@ public class ExpressionTemporal extends Expression
 	}
 
 	/**
-	 * Set lower timer bound to be of form >= e or > e
+	 * Set lower time bound to be of form >= e or > e
 	 * (null denotes no lower bound, i.e. zero)
 	 */
 	public void setLowerBound(Expression e, boolean strict)
@@ -116,7 +110,7 @@ public class ExpressionTemporal extends Expression
 	}
 
 	/**
-	 * Set upper timer bound to be of form <= e
+	 * Set upper time bound to be of form <= e
 	 * (null denotes no upper bound, i.e. infinity)
 	 */
 	public void setUpperBound(Expression e)
@@ -125,7 +119,7 @@ public class ExpressionTemporal extends Expression
 	}
 
 	/**
-	 * Set upper timer bound to be of form <= e or < e
+	 * Set upper time bound to be of form <= e or < e
 	 * (null denotes no upper bound, i.e. infinity)
 	 */
 	public void setUpperBound(Expression e, boolean strict)
@@ -134,6 +128,18 @@ public class ExpressionTemporal extends Expression
 		uBoundStrict = strict;
 	}
 
+	/**
+	 * Set both lower/upper time bound to e, i.e. "=e".
+	 */
+	public void setEqualBounds(Expression e)
+	{
+		lBound = e;
+		lBoundStrict = false;
+		uBound = e;
+		uBoundStrict = false;
+		equals = true;
+	}
+
 	// Get methods
 
 	public int getOperator()
@@ -156,6 +162,14 @@ public class ExpressionTemporal extends Expression
 		return operand2;
 	}
 
+	public int getNumOperands()
+	{
+		if (operand1 == null)
+			return 0;
+		else
+			return (operand2 == null) ? 1 : 2;
+	}
+
 	public boolean hasBounds()
 	{
 		return lBound != null || uBound != null;
@@ -181,6 +195,14 @@ public class ExpressionTemporal extends Expression
 		return uBoundStrict;
 	}
 
+	/**
+	 * Returns true if lower/upper bound are equal and should be displayed as =T 
+	 */
+	public boolean getEquals()
+	{
+		return equals;
+	}
+
 	// Methods required for Expression:
 
 	/**
@@ -236,7 +258,10 @@ public class ExpressionTemporal extends Expression
 			if (uBound == null) {
 				s += ">" + (lBoundStrict ? "" : "=") + lBound;
 			} else {
-				s += "[" + lBound + "," + uBound + "]";
+				if (equals)
+					s += "=" + lBound;
+				else
+					s += "[" + lBound + "," + uBound + "]";
 			}
 		}
 		if (operand2 != null)
@@ -257,6 +282,7 @@ public class ExpressionTemporal extends Expression
 			expr.setOperand2(operand2.deepCopy());
 		expr.setLowerBound(lBound == null ? null : lBound.deepCopy(), lBoundStrict);
 		expr.setUpperBound(uBound == null ? null : uBound.deepCopy(), uBoundStrict);
+		expr.equals = equals;
 		expr.setType(type);
 		expr.setPosition(this);
 		return expr;
@@ -280,6 +306,7 @@ public class ExpressionTemporal extends Expression
 			exprTemp = new ExpressionTemporal(P_U, op1, operand2);
 			exprTemp.setLowerBound(lBound, lBoundStrict);
 			exprTemp.setUpperBound(uBound, uBoundStrict);
+			exprTemp.equals = equals;
 			return exprTemp;
 		case P_G:
 			// G a == !(true U !a)
@@ -288,6 +315,7 @@ public class ExpressionTemporal extends Expression
 			exprTemp = new ExpressionTemporal(P_U, op1, op2);
 			exprTemp.setLowerBound(lBound, lBoundStrict);
 			exprTemp.setUpperBound(uBound, uBoundStrict);
+			exprTemp.equals = equals;
 			return Expression.Not(exprTemp);
 		case P_W:
 			// a W b == !(a&!b U !a&!b)
@@ -296,6 +324,7 @@ public class ExpressionTemporal extends Expression
 			exprTemp = new ExpressionTemporal(P_U, op1, op2);
 			exprTemp.setLowerBound(lBound, lBoundStrict);
 			exprTemp.setUpperBound(uBound, uBoundStrict);
+			exprTemp.equals = equals;
 			return Expression.Not(exprTemp);
 		case P_R:
 			// a R b == !(!a U !b)
@@ -304,6 +333,7 @@ public class ExpressionTemporal extends Expression
 			exprTemp = new ExpressionTemporal(P_U, op1, op2);
 			exprTemp.setLowerBound(lBound, lBoundStrict);
 			exprTemp.setUpperBound(uBound, uBoundStrict);
+			exprTemp.equals = equals;
 			return Expression.Not(exprTemp);
 		}
 		throw new PrismLangException("Cannot convert " + getOperatorSymbol() + " to until form");