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Expressions: Use BooleanExpression class for EQ, NE, LT, GT, LTE, and GTE operators.

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This commit is contained in:
Eivind Kvedalen 2016-03-04 01:01:55 +01:00 committed by wmayer
parent 26f4d1ae8e
commit ac79af0289
1 changed files with 43 additions and 14 deletions
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57
src/App/Expression.cpp
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@ -297,8 +297,34 @@ bool OperatorExpression::isTouched() const
return left->isTouched() || right->isTouched();
}
/* The following definitions are from The art of computer programming by Knuth
* (copied from http://stackoverflow.com/questions/17333/most-effective-way-for-float-and-double-comparison)
*/
/*
static bool approximatelyEqual(double a, double b, double epsilon)
{
return fabs(a - b) <= ( (fabs(a) < fabs(b) ? fabs(b) : fabs(a)) * epsilon);
}
*/
static bool essentiallyEqual(double a, double b, double epsilon)
{
return fabs(a - b) <= ( (fabs(a) > fabs(b) ? fabs(b) : fabs(a)) * epsilon);
}
static bool definitelyGreaterThan(double a, double b, double epsilon)
{
return (a - b) > ( (fabs(a) < fabs(b) ? fabs(b) : fabs(a)) * epsilon);
}
static bool definitelyLessThan(double a, double b, double epsilon)
{
return (b - a) > ( (fabs(a) < fabs(b) ? fabs(b) : fabs(a)) * epsilon);
}
/**
* Evalutate the expression. Returns a new NumberExpression with the result, or throws
* Evalutate the expression. Returns a new Expression with the result, or throws
* an exception if something is wrong, i.e the expression cannot be evaluated.
*/
@ -308,7 +334,8 @@ Expression * OperatorExpression::eval() const
NumberExpression * v1;
std::auto_ptr<Expression> e2(right->eval());
NumberExpression * v2;
NumberExpression * output;
Expression * output;
const double epsilon = std::numeric_limits<double>::epsilon();
v1 = freecad_dynamic_cast<NumberExpression>(e1.get());
v2 = freecad_dynamic_cast<NumberExpression>(e2.get());
@ -339,33 +366,35 @@ Expression * OperatorExpression::eval() const
break;
case EQ:
if (v1->getUnit() != v2->getUnit())
throw ExpressionError("Incompatible units for + operator");
output = new NumberExpression(owner, Quantity(fabs(v1->getValue() - v2->getValue()) < 1e-7));
throw ExpressionError("Incompatible units for the = operator");
output = new BooleanExpression(owner, essentiallyEqual(v1->getValue(), v2->getValue(), epsilon) );
break;
case NEQ:
if (v1->getUnit() != v2->getUnit())
throw ExpressionError("Incompatible units for + operator");
output = new NumberExpression(owner, Quantity(fabs(v1->getValue() - v2->getValue()) > 1e-7));
throw ExpressionError("Incompatible units for the != operator");
output = new BooleanExpression(owner, !essentiallyEqual(v1->getValue(), v2->getValue(), epsilon) );
break;
case LT:
if (v1->getUnit() != v2->getUnit())
throw ExpressionError("Incompatible units for + operator");
output = new NumberExpression(owner, Quantity(v1->getValue() < v2->getValue()));
throw ExpressionError("Incompatible units for the < operator");
output = new BooleanExpression(owner, definitelyLessThan(v1->getValue(), v2->getValue(), epsilon) );
break;
case GT:
if (v1->getUnit() != v2->getUnit())
throw ExpressionError("Incompatible units for + operator");
output = new NumberExpression(owner, Quantity(v1->getValue() > v2->getValue()));
throw ExpressionError("Incompatible units for the > operator");
output = new BooleanExpression(owner, definitelyGreaterThan(v1->getValue(), v2->getValue(), epsilon) );
break;
case LTE:
if (v1->getUnit() != v2->getUnit())
throw ExpressionError("Incompatible units for + operator");
output = new NumberExpression(owner, Quantity(v1->getValue() - v2->getValue() < 1e-7));
throw ExpressionError("Incompatible units for the <= operator");
output = new BooleanExpression(owner, definitelyLessThan(v1->getValue(), v2->getValue(), epsilon) ||
essentiallyEqual(v1->getValue(), v2->getValue(), epsilon));
break;
case GTE:
if (v1->getUnit() != v2->getUnit())
throw ExpressionError("Incompatible units for + operator");
output = new NumberExpression(owner, Quantity(v2->getValue() - v1->getValue()) < 1e-7);
throw ExpressionError("Incompatible units for the >= operator");
output = new BooleanExpression(owner, essentiallyEqual(v1->getValue(), v2->getValue(), epsilon) ||
definitelyGreaterThan(v1->getValue(), v2->getValue(), epsilon));
break;
case NEG:
output = new NumberExpression(owner, -v1->getQuantity() );