TripleEquals
Related Docs:
object TripleEquals
| package scalactic
Class used via an implicit conversion to enable two objects to be compared with
=== and !== with a Boolean result and an enforced type constraint between
two object types.
Class used via an implicit conversion to enable two objects to be compared with
=== and !== with a Boolean result and an enforced type constraint between
two object types. For example:
assert(a === b) assert(c !== d)
You can also check numeric values against another with a tolerance. Here are some examples:
assert(a === (2.0 +- 0.1)) assert(c !== (2.0 +- 0.1))
Class used via an implicit conversion to enable any two objects to be compared with
=== and !== with a Boolean result and no enforced type constraint between
two object types.
Class used via an implicit conversion to enable any two objects to be compared with
=== and !== with a Boolean result and no enforced type constraint between
two object types. For example:
assert(a === b) assert(c !== d)
You can also check numeric values against another with a tolerance. Here are some examples:
assert(a === (2.0 +- 0.1)) assert(c !== (2.0 +- 0.1))
Returns a TripleEqualsInvocationOnSpread[T], given an Spread[T], to facilitate
the “<left> should !== (<pivot> +- <tolerance>)”
syntax of Matchers.
Returns a TripleEqualsInvocationOnSpread[T], given an Spread[T], to facilitate
the “<left> should !== (<pivot> +- <tolerance>)”
syntax of Matchers.
the Spread[T] against which to compare the left-hand value
a TripleEqualsInvocationOnSpread wrapping the passed Spread[T] value, with
expectingEqual set to false.
Returns a TripleEqualsInvocation[Null], given a null reference, to facilitate
the “<left> should !== null” syntax
of Matchers.
Returns a TripleEqualsInvocation[Null], given a null reference, to facilitate
the “<left> should !== null” syntax
of Matchers.
a null reference
a TripleEqualsInvocation wrapping the passed null value, with expectingEqual
set to false.
Returns a TripleEqualsInvocation[T], given an object of type T, to facilitate
the “<left> should !== <right>” syntax
of Matchers.
Returns a TripleEqualsInvocation[T], given an object of type T, to facilitate
the “<left> should !== <right>” syntax
of Matchers.
the right-hand side value for an equality assertion
a TripleEqualsInvocation wrapping the passed right value, with expectingEqual
set to false.
Returns a TripleEqualsInvocationOnSpread[T], given an Spread[T], to facilitate
the “<left> should === (<pivot> +- <tolerance>)”
syntax of Matchers.
Returns a TripleEqualsInvocationOnSpread[T], given an Spread[T], to facilitate
the “<left> should === (<pivot> +- <tolerance>)”
syntax of Matchers.
the Spread[T] against which to compare the left-hand value
a TripleEqualsInvocationOnSpread wrapping the passed Spread[T] value, with
expectingEqual set to true.
Returns a TripleEqualsInvocation[Null], given a null reference, to facilitate
the “<left> should === null” syntax
of Matchers.
Returns a TripleEqualsInvocation[Null], given a null reference, to facilitate
the “<left> should === null” syntax
of Matchers.
a null reference
a TripleEqualsInvocation wrapping the passed null value, with expectingEqual
set to true.
Returns a TripleEqualsInvocation[T], given an object of type T, to facilitate
the “<left> should === <right>” syntax
of Matchers.
Returns a TripleEqualsInvocation[T], given an object of type T, to facilitate
the “<left> should === <right>” syntax
of Matchers.
the right-hand side value for an equality assertion
a TripleEqualsInvocation wrapping the passed right value, with expectingEqual
set to true.
Provides an A CanEqual B instance for any two types A and B, enforcing the type constraint that B is
implicitly convertible to A, given an implicit Equivalence[A].
Provides an A CanEqual B instance for any two types A and B, enforcing the type constraint that B is
implicitly convertible to A, given an implicit Equivalence[A].
The returned Constraint's areEqual method uses the implicitly passed Equivalence[A]'s
areEquivalent method to determine equality.
This method is overridden and made implicit by subtraits
ConversionCheckedTripleEquals) and
overriden as non-implicit by the other subtraits in this package.
an Equivalence[A] type class to which the Constraint.areEqual method will delegate to determine equality.
an implicit conversion from B to A
an A CanEqual B instance whose areEqual method delegates to the areEquivalent method of
the passed Equivalence[A].
Provides a A CanEqual B for any two types A and B, enforcing the type constraint
that A must be a subtype of B, given an explicit Equivalence[B].
Provides a A CanEqual B for any two types A and B, enforcing the type constraint
that A must be a subtype of B, given an explicit Equivalence[B].
This method is used to enable the Explicitly DSL for
TypeCheckedTripleEquals by requiring an explicit Equivalance[B], but
taking an implicit function that provides evidence that A is a subtype of B.
The returned Constraint's areEqual method uses the implicitly passed Equivalence[B]'s
areEquivalent method to determine equality.
This method is overridden and made implicit by subtraits
LowPriorityTypeCheckedConstraint (extended by
TypeCheckedTripleEquals), and
overriden as non-implicit by the other subtraits in this package.
an Equivalence[B] type class to which the Constraint.areEqual method
will delegate to determine equality.
evidence that A is a subype of B
an A CanEqual B instance whose areEqual method delegates to the
areEquivalent method of the passed Equivalence[B].
Provides an A CanEqual B instance for any two types A and B, enforcing the type constraint that A is
implicitly convertible to B, given an explicit Equivalence[B].
Provides an A CanEqual B instance for any two types A and B, enforcing the type constraint that A is
implicitly convertible to B, given an explicit Equivalence[B].
This method is used to enable the Explicitly DSL for
ConversionCheckedTripleEquals by requiring an explicit Equivalance[B], but
taking an implicit function that converts from A to B.
The returned Constraint's areEqual method uses the implicitly passed Equivalence[B]'s
areEquivalent method to determine equality.
This method is overridden and made implicit by subtraits
LowPriorityConversionCheckedConstraint (extended by
ConversionCheckedTripleEquals), and
overriden as non-implicit by the other subtraits in this package.
an A CanEqual B instance whose areEqual method delegates to the areEquivalent method of
the passed Equivalence[B].
Provides an A CanEqual B instance for any two types A and B, enforcing the type constraint
that B must be a subtype of A, given an explicit Equivalence[A].
Provides an A CanEqual B instance for any two types A and B, enforcing the type constraint
that B must be a subtype of A, given an explicit Equivalence[A].
This method is used to enable the Explicitly DSL for
TypeCheckedTripleEquals by requiring an explicit Equivalance[B], but
taking an implicit function that provides evidence that A is a subtype of B. For example, under TypeCheckedTripleEquals,
this method (as an implicit method), would be used to compile this statement:
def closeEnoughTo1(num: Double): Boolean = (num === 1.0)(decided by forgivingEquality)
The returned Constraint's areEqual method uses the implicitly passed Equivalence[A]'s
areEquivalent method to determine equality.
This method is overridden and made implicit by subtraits
TypeCheckedTripleEquals) and
overriden as non-implicit by the other subtraits in this package.
evidence that B is a subype of A
an A CanEqual B instance whose areEqual method delegates to the areEquivalent method of
the passed Equivalence[A].
Provides an A CanEqual B instance for any two types A and B, enforcing the type constraint that B is
implicitly convertible to A, given an explicit Equivalence[A].
Provides an A CanEqual B instance for any two types A and B, enforcing the type constraint that B is
implicitly convertible to A, given an explicit Equivalence[A].
This method is used to enable the Explicitly DSL for
ConversionCheckedTripleEquals by requiring an explicit Equivalance[A], but
taking an implicit function that converts from B to A. For example, under ConversionCheckedTripleEquals,
this method (as an implicit method), would be used to compile this statement:
def closeEnoughTo1(num: Double): Boolean = (num === 1.0)(decided by forgivingEquality)
The returned Constraint's areEqual method uses the implicitly passed Equivalence[A]'s
areEquivalent method to determine equality.
This method is overridden and made implicit by subtraits
ConversionCheckedTripleEquals) and
overriden as non-implicit by the other subtraits in this package.
an Equivalence[A] type class to which the Constraint.areEqual method will delegate to determine equality.
an A CanEqual B instance whose areEqual method delegates to the areEquivalent method of
the passed Equivalence[A].
Converts to an CheckingEqualizer that provides === and !== operators
that result in Boolean and enforce a type constraint.
Converts to an CheckingEqualizer that provides === and !== operators
that result in Boolean and enforce a type constraint.
This method is overridden and made implicit by subtraits TypeCheckedTripleEquals and
ConversionCheckedTripleEquals, and overriden as
non-implicit by the other subtraits in this package.
the object whose type to convert to CheckingEqualizer.
NullPointerException if left is null.
Converts to an Equalizer that provides === and !== operators that
result in Boolean and enforce no type constraint.
Converts to an Equalizer that provides === and !== operators that
result in Boolean and enforce no type constraint.
This method is overridden and made implicit by subtrait TripleEquals and overriden as non-implicit by the other
subtraits in this package.
the object whose type to convert to Equalizer.
NullPointerException if left is null.
Returns an Equality[A] for any type A that determines equality
by first calling .deep on any Array (on either the left or right side),
then comparing the resulting objects with ==.
Returns an Equality[A] for any type A that determines equality
by first calling .deep on any Array (on either the left or right side),
then comparing the resulting objects with ==.
a default Equality for type A
Provides an A CanEqual B instance for any two types A and B, enforcing the type constraint that A is
implicitly convertible to B, given an implicit Equivalence[B].
Provides an A CanEqual B instance for any two types A and B, enforcing the type constraint that A is
implicitly convertible to B, given an implicit Equivalence[B].
The returned Constraint's areEqual method uses the implicitly passed Equivalence[B]'s
areEquivalent method to determine equality.
This method is overridden and made implicit by subtraits
LowPriorityConversionCheckedConstraint (extended by
ConversionCheckedTripleEquals), and
overriden as non-implicit by the other subtraits in this package.
an implicit conversion from A to B
an A CanEqual B instance whose areEqual method delegates to the areEquivalent method of
the passed Equivalence[B].
Provides an A CanEqual B for any two types A and B, enforcing the type constraint
that A must be a subtype of B, given an implicit Equivalence[B].
Provides an A CanEqual B for any two types A and B, enforcing the type constraint
that A must be a subtype of B, given an implicit Equivalence[B].
The returned Constraint's areEqual method uses the implicitly passed Equivalence[A]'s
areEquivalent method to determine equality.
This method is overridden and made implicit by subtraits
LowPriorityTypeCheckedConstraint (extended by
TypeCheckedTripleEquals), and
overriden as non-implicit by the other subtraits in this package.
an Equivalence[B] type class to which the Constraint.areEqual method
will delegate to determine equality.
evidence that A is a subype of B
an A CanEqual B instance whose areEqual method delegates to the
areEquivalent method of the passed Equivalence[B].
Provides an A CanEqual B instance for any two types A and B, enforcing the type constraint
that B must be a subtype of A, given an implicit Equivalence[A].
Provides an A CanEqual B instance for any two types A and B, enforcing the type constraint
that B must be a subtype of A, given an implicit Equivalence[A].
The returned Constraint's areEqual method uses the implicitly passed Equivalence[A]'s
areEquivalent method to determine equality.
This method is overridden and made implicit by subtraits
TypeCheckedTripleEquals) and
overriden as non-implicit by the other subtraits in this package.
evidence that B is a subype of A
an A CanEqual B instance whose areEqual method delegates to the areEquivalent method of
the passed Equivalence[A].
Provides an A CanEqual B instance for any two types A and B, with no type constraint enforced, given an
implicit Equality[A].
Provides an A CanEqual B instance for any two types A and B, with no type constraint enforced, given an
implicit Equality[A].
The returned Constraint's areEqual method uses the implicitly passed Equality[A]'s
areEqual method to determine equality.
This method is overridden and made implicit by subtraits TripleEquals and
overriden as non-implicit by the other subtraits in this package.
an Equality[A] type class to which the Constraint.areEqual method will delegate to determine equality.
an A CanEqual B instance whose areEqual method delegates to the areEqual method of
the passed Equality[A].
Provides
===and!==operators that returnBoolean, delegate the equality determination to anEqualitytype class, and require no relationship between the types of the two values compared.TripleEqualsis useful (in both production and test code) when you need determine equality for a type of object differently than itsequalsmethod: either you can't change theequalsmethod, or theequalsmethod is sensible generally, but you are in a special situation where you need something else. You can use the SuperSafe Community Edition compiler plugin to get a compile-time safety check of types being compared with===. In situations where you need a stricter type check, you can useTypeCheckedTripleEquals.This trait will override or hide implicit methods defined by its sibling traits,
ConversionCheckedTripleEqualsorTypeCheckedTripleEquals, and can therefore be used to temporarily turn of type checking in a limited scope. Here's an example, in whichTypeCheckedTripleEqualswill cause a compiler error:Because
IntandLongare not in a subtype/supertype relationship, comparing1and1Lin the context ofTypeCheckedTripleEqualswill generate a compiler error:Example.scala:9: error: types Int and Long do not adhere to the equality constraint selected for the === and !== operators; they must either be in a subtype/supertype relationship, or, if ConversionCheckedTripleEquals is in force, implicitly convertible in one direction or the other; the missing implicit parameter is of type org.scalactic.Constraint[Int,Long] if (a === b) 0 // This line won't compile ^ one error foundYou can “turn off” the type checking locally by importing the members of
TripleEqualsin a limited scope:With the above change, the
Example.scalafile compiles fine. Type checking is turned off only inside the firstcmpmethod that takes anIntand aLong.TypeCheckedTripleEqualsis still enforcing its type constraint, for example, for thes === texpression in the other overloadedcmpmethod that takes strings.Because the methods in
TripleEquals(and its siblings)override all the methods defined in supertypeTripleEqualsSupport, you can achieve the same kind of nested tuning of equality constraints whether you mix in traits, import from companion objects, or use some combination of both.In short, you should be able to select a primary constraint level via either a mixin or import, then change that in nested scopes however you want, again either through a mixin or import, without getting any implicit conversion ambiguity. The innermost constraint level in scope will always be in force.