Trait that defines abstract methods used to enforce compile-time type constraints for equality comparisons, and defines ===
and !==
operators
used by matchers.
The abstract methods of this trait are selectively implemented as implicit by subclasses to enable a spectrum of type constraints for the
===
and !==
operators. As an illustration, if in the expression, a === b
, the type of a
is A
and b
is B
, the following three levels of compile-time checking can be obtained from
TripleEqualsSupport
subtraits:
Unchecked - A
and B
can be any two types. This constraint level is available from
subtrait TripleEquals
.
Statically-checked - A
must be a subtype of B
, or vice versa, or must cooperate such that the
equality laws stated in the equals
contract are preserved.
This (intermediate) constraint level is available by using subtrait TripleEquals
and installing the SuperSafe Community Edition
Scala compiler plugin.
Type-checked - A
must be a subtype of B
, or vice versa.
(Both A
and B
can be the same type, because a type is considered a subtype
of itself.)
This (strongest) constraint level is available from subtrait TypeCheckedTripleEquals
.
This trait defines all methods that need to be defined implicitly by the subtraits so that if multiple subtraits are used together, the inner-most
subtrait in scope can not only enable the implicits it needs by overriding or hiding those methods (currently-in-scope as regular, non-implicit
methods) and making
them implicit, it can also disable any implicits enabled by its sibling subtraits in enclosing scopes. For example, if your test class mixes
in TypeCheckedTripleEquals
, inside your test class the following methods will be implicit:
-
convertToCheckingEqualizer
-
typeCheckedConstraint
-
lowPriorityTypeCheckedConstraint
-
convertEquivalenceToAToBConstraint
-
convertEquivalenceToBToAConstraint
If in the body of a test you want to turn off the type checking, you can import the members
of TripleEquals
in the body of that test. This will not only hide
non-implicit methods convertToEqualizer
unconstrainedEquality
of TypeCheckedTripleEquals
,
replacing those with implicit ones defined in TripleEquals
, it will also hide the three methods made implicit in TypeCheckedTripleEquals
(and listed above), replacing them by non-implicit ones.
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.
- Companion:
- object
- Source:
- TripleEqualsSupport.scala
Type members
Classlikes
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:
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))
- Value parameters:
- leftSide
An object to convert to
Equalizer
, which represents the value on the left side of a===
or!==
invocation.
- Source:
- TripleEqualsSupport.scala
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:
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))
- Value parameters:
- leftSide
An object to convert to
Equalizer
, which represents the value on the left side of a===
or!==
invocation.
- Source:
- TripleEqualsSupport.scala
Value members
Abstract methods
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.
- Value parameters:
- equivalenceOfB
an
Equivalence[B]
type class to which theConstraint.areEqual
method will delegate to determine equality.- ev
evidence that
A
is a subype of B
- Returns:
an
A CanEqual B
instance whoseareEqual
method delegates to theareEquivalent
method of the passedEquivalence[B]
.- Source:
- TripleEqualsSupport.scala
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.
- Value parameters:
- equalityOfA
an
Equivalence[A]
type class to which theConstraint.areEqual
method will delegate to determine equality.- ev
evidence that
B
is a subype of A
- Returns:
an
A CanEqual B
instance whoseareEqual
method delegates to theareEquivalent
method of the passedEquivalence[A]
.- Source:
- TripleEqualsSupport.scala
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 subtrait TypeCheckedTripleEquals
, and
overriden as non-implicit by the other subtraits in this package.
- Value parameters:
- left
the object whose type to convert to
CheckingEqualizer
.
- Throws:
- NullPointerException
if
left
isnull
.
- Source:
- TripleEqualsSupport.scala
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.
- Value parameters:
- left
the object whose type to convert to
Equalizer
.
- Throws:
- NullPointerException
if
left
isnull
.
- Source:
- TripleEqualsSupport.scala
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.
- Value parameters:
- equivalenceOfB
an
Equivalence[B]
type class to which theConstraint.areEqual
method will delegate to determine equality.- ev
evidence that
A
is a subype of B
- Returns:
an
A CanEqual B
instance whoseareEqual
method delegates to theareEquivalent
method of the passedEquivalence[B]
.- Source:
- TripleEqualsSupport.scala
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.
- Value parameters:
- equalityOfA
an
Equivalence[A]
type class to which theConstraint.areEqual
method will delegate to determine equality.- ev
evidence that
B
is a subype of A
- Returns:
an
A CanEqual B
instance whoseareEqual
method delegates to theareEquivalent
method of the passedEquivalence[A]
.- Source:
- TripleEqualsSupport.scala
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.
- Value parameters:
- equalityOfA
an
Equality[A]
type class to which theConstraint.areEqual
method will delegate to determine equality.
- Returns:
an
A CanEqual B
instance whoseareEqual
method delegates to theareEqual
method of the passedEquality[A]
.- Source:
- TripleEqualsSupport.scala
Concrete methods
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
.
- Value parameters:
- right
the right-hand side value for an equality assertion
- Returns:
a
TripleEqualsInvocation
wrapping the passed right value, withexpectingEqual
set tofalse
.- Source:
- TripleEqualsSupport.scala
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
.
- Value parameters:
- right
a null reference
- Returns:
a
TripleEqualsInvocation
wrapping the passednull
value, withexpectingEqual
set tofalse
.- Source:
- TripleEqualsSupport.scala
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
.
- Value parameters:
- right
the
Spread[T]
against which to compare the left-hand value
- Returns:
a
TripleEqualsInvocationOnSpread
wrapping the passedSpread[T]
value, withexpectingEqual
set tofalse
.- Source:
- TripleEqualsSupport.scala
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
.
- Value parameters:
- right
the right-hand side value for an equality assertion
- Returns:
a
TripleEqualsInvocation
wrapping the passed right value, withexpectingEqual
set totrue
.- Source:
- TripleEqualsSupport.scala
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
.
- Value parameters:
- right
a null reference
- Returns:
a
TripleEqualsInvocation
wrapping the passednull
value, withexpectingEqual
set totrue
.- Source:
- TripleEqualsSupport.scala
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
.
- Value parameters:
- right
the
Spread[T]
against which to compare the left-hand value
- Returns:
a
TripleEqualsInvocationOnSpread
wrapping the passedSpread[T]
value, withexpectingEqual
set totrue
.- Source:
- TripleEqualsSupport.scala
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 ==
.
- Returns:
a default
Equality
for typeA
- Source:
- TripleEqualsSupport.scala
Deprecated methods
The conversionCheckedConstraint
method has been deprecated and will be removed in a future version of Scalactic. It
is no longer needed now that the deprecation period of ConversionCheckedTripleEquals
has expired. It will not be replaced.
The conversionCheckedConstraint
method has been deprecated and will be removed in a future version of Scalactic. It
is no longer needed now that the deprecation period of ConversionCheckedTripleEquals
has expired. It will not be replaced.
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.
- Value parameters:
- cnv
an implicit conversion from
B
to A- equivalenceOfA
an
Equivalence[A]
type class to which theConstraint.areEqual
method will delegate to determine equality.
- Returns:
an
A CanEqual B
instance whoseareEqual
method delegates to theareEquivalent
method of the passedEquivalence[A]
.- Deprecated
- Source:
- TripleEqualsSupport.scala
The convertEquivalenceToAToBConversionConstraint
method has been deprecated and will be removed in a future version of Scalactic.
It is no longer needed now that the deprecation period of ConversionCheckedTripleEquals
has expired. It will not be replaced.
The convertEquivalenceToAToBConversionConstraint
method has been deprecated and will be removed in a future version of Scalactic.
It is no longer needed now that the deprecation period of ConversionCheckedTripleEquals
has expired. It will not be replaced.
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.
- Value parameters:
- cnv
an implicit conversion from
A
to B- equalityOfB
an
Equivalence[B]
type class to which theConstraint.areEqual
method will delegate to determine equality.
- Returns:
an
A CanEqual B
instance whoseareEqual
method delegates to theareEquivalent
method of the passedEquivalence[B]
.- Deprecated
- Source:
- TripleEqualsSupport.scala
The convertEquivalenceToBToAConversionConstraint
method has been deprecated and will be removed in a future version of Scalactic.
It is no longer needed now that the deprecation period of ConversionCheckedTripleEquals
has expired. It will not be replaced.
The convertEquivalenceToBToAConversionConstraint
method has been deprecated and will be removed in a future version of Scalactic.
It is no longer needed now that the deprecation period of ConversionCheckedTripleEquals
has expired. It will not be replaced.
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.
- Value parameters:
- cnv
an implicit conversion from
B
to A- equivalenceOfA
an
Equivalence[A]
type class to which theConstraint.areEqual
method will delegate to determine equality.
- Returns:
an
A CanEqual B
instance whoseareEqual
method delegates to theareEquivalent
method of the passedEquivalence[A]
.- Deprecated
- Source:
- TripleEqualsSupport.scala
The lowPriorityConversionCheckedConstraint
method has been deprecated and will be removed in a future version of Scalactic. It
is no longer needed now that the deprecation period of ConversionCheckedTripleEquals
has expired. It will not be replaced.
The lowPriorityConversionCheckedConstraint
method has been deprecated and will be removed in a future version of Scalactic. It
is no longer needed now that the deprecation period of ConversionCheckedTripleEquals
has expired. It will not be replaced.
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.
- Value parameters:
- cnv
an implicit conversion from
A
to B- equalityOfB
an
Equivalence[B]
type class to which theConstraint.areEqual
method will delegate to determine equality.
- Returns:
an
A CanEqual B
instance whoseareEqual
method delegates to theareEquivalent
method of the passedEquivalence[B]
.- Deprecated
- Source:
- TripleEqualsSupport.scala