Returns a TripleEqualsInvocationOnInterval[T]
, given an Interval[T]
, to facilitate
the “<left> should !== (<pivot> +- <tolerance>)
”
syntax of Matchers
.”“
Returns a TripleEqualsInvocationOnInterval[T]
, given an Interval[T]
, to facilitate
the “<left> should !== (<pivot> +- <tolerance>)
”
syntax of Matchers
.
the Interval[T]
against which to compare the left-hand value
a TripleEqualsInvocationOnInterval
wrapping the passed Interval[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 TripleEqualsInvocationOnInterval[T]
, given an Interval[T]
, to facilitate
the “<left> should === (<pivot> +- <tolerance>)
”
syntax of Matchers
.”“
Returns a TripleEqualsInvocationOnInterval[T]
, given an Interval[T]
, to facilitate
the “<left> should === (<pivot> +- <tolerance>)
”
syntax of Matchers
.
the Interval[T]
against which to compare the left-hand value
a TripleEqualsInvocationOnInterval
wrapping the passed Interval[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 EqualityConstraint[A, B]
class for any two types A
and B
, enforcing the type constraint that B
is implicitly convertible to A
, given an implicit Equality[A]
.
Provides an EqualityConstraint[A, B]
class for any two types A
and B
, enforcing the type constraint that B
is implicitly convertible to A
, given an implicit Equality[A]
.
The implicitly passed Equality[A]
must be used to determine equality by the returned EqualityConstraint
's
areEqual
method.
This method is overridden and made implicit by subtraits
ConversionCheckedTripleEquals
) and
ConversionCheckedLegacyTripleEquals
, and
overriden as non-implicit by the other subtraits in this package.
an Equality[A]
type class to which the EqualityConstraint.areEqual
method will delegate to determine equality.
an implicit conversion from B
to A
an EqualityConstraint[A, B]
whose areEqual
method delegates to the areEqual
method of
the passed Equality[A]
.
Convert to an CheckingEqualizer
that provides ===
and !==
operators that result in Boolean
and enforce a type constraint.
Convert 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
.
Convert to an Equalizer
that provides ===
and !==
operators that
result in Boolean
and enforce no type constraint.
Convert 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
.
Convert to a LegacyCheckingEqualizer
that provides ===
and !==
operators that result in Option[String]
and
enforce a type constraint.
Convert to a LegacyCheckingEqualizer
that provides ===
and !==
operators that result in Option[String]
and
enforce a type constraint.
This method is overridden and made implicit by subtraits TypeCheckedLegacyTripleEquals
and ConversionCheckedLegacyTripleEquals
, and
overriden as non-implicit by the other subtraits in this package.
the object whose type to convert to LegacyCheckingEqualizer
.
Convert to a LegacyEqualizer
that provides ===
and !==
operators that
result in Option[String]
and enforce no type constraint.
Convert to a LegacyEqualizer
that provides ===
and !==
operators that
result in Option[String]
and enforce no type constraint.
This method is overridden and made implicit by subtrait LegacyTripleEquals
and overriden as non-implicit by the other subtraits in this package.
the object whose type to convert to LegacyEqualizer
.
Return an Equality[A]
for any type A
that determines equality via the ==
operator on type A
.
Return an Equality[A]
for any type A
that determines equality via the ==
operator on type A
.
a DefaultEquality
for type A
Provides an EqualityConstraint[A, B]
class for any two types A
and B
, enforcing the type constraint that A
is implicitly convertible to B
, given an implicit Equality[A]
.
Provides an EqualityConstraint[A, B]
class for any two types A
and B
, enforcing the type constraint that A
is implicitly convertible to B
, given an implicit Equality[A]
.
The implicitly passed Equality[A]
must be used to determine equality by the returned EqualityConstraint
's
areEqual
method.
This method is overridden and made implicit by subtraits
LowPriorityConversionCheckedConstraint
(extended by
ConversionCheckedTripleEquals
), and
LowPriorityConversionCheckedLegacyConstraint
(extended by
ConversionCheckedLegacyTripleEquals
), and
overriden as non-implicit by the other subtraits in this package.
an implicit conversion from A
to B
an EqualityConstraint[A, B]
whose areEqual
method delegates to the areEqual
method of
the passed Equality[A]
.
Provides an EqualityConstraint[A, B]
class for any two types A
and B
, enforcing the type constraint that A
must be a subtype of B
, given an implicit Equality[A]
.
Provides an EqualityConstraint[A, B]
class for any two types A
and B
, enforcing the type constraint that A
must be a subtype of B
, given an implicit Equality[A]
.
The implicitly passed Equality[A]
must be used to determine equality by the returned EqualityConstraint
's
areEqual
method.
This method is overridden and made implicit by subtraits
LowPriorityTypeCheckedConstraint
(extended by
TypeCheckedTripleEquals
), and
LowPriorityTypeCheckedLegacyConstraint
(extended by
TypeCheckedLegacyTripleEquals
), and
overriden as non-implicit by the other subtraits in this package.
an Equality[A]
type class to which the EqualityConstraint.areEqual
method
will delegate to determine equality.
evidence that A
is a subype of B
an EqualityConstraint[A, B]
whose areEqual
method delegates to the
areEqual
method of the passed Equality[A]
.
Provides an EqualityConstraint[A, B]
class for any two types A
and B
, enforcing the type constraint that B
must be a subtype of A
, given an implicit Equality[A]
.
Provides an EqualityConstraint[A, B]
class for any two types A
and B
, enforcing the type constraint that B
must be a subtype of A
, given an implicit Equality[A]
.
The implicitly passed Equality[A]
must be used to determine equality by the returned EqualityConstraint
's
areEqual
method.
This method is overridden and made implicit by subtraits
TypeCheckedTripleEquals
) and
TypeCheckedLegacyTripleEquals
, and
overriden as non-implicit by the other subtraits in this package.
an Equality[A]
type class to which the EqualityConstraint.areEqual
method will delegate to determine equality.
evidence that B
is a subype of A
an EqualityConstraint[A, B]
whose areEqual
method delegates to the areEqual
method of
the passed Equality[A]
.
Provides an EqualityConstraint[A, B]
class for any two types A
and B
, with no type constraint enforced, given an
implicit Equality[A]
.
Provides an EqualityConstraint[A, B]
class for any two types A
and B
, with no type constraint enforced, given an
implicit Equality[A]
.
The implicitly passed Equality[A]
must be used to determine equality by the returned EqualityConstraint
's
areEqual
method.
This method is overridden and made implicit by subtraits TripleEquals
and LegacyTripleEquals
, and
overriden as non-implicit by the other subtraits in this package.
an Equality[A]
type class to which the EqualityConstraint.areEqual
method will delegate to determine equality.
an EqualityConstraint[A, B]
whose areEqual
method delegates to the areEqual
method of
the passed Equality[A]
.
Provides
===
and!==
operators that returnBoolean
, delegate the equality determination to anEquality
type class, and require the types of the two values compared to be in a subtype/supertype relationship.TypeCheckedTripleEquals
is useful (in both production and test code) when you need determine equality for a type of object differently than itsequals
method—either you can't change theequals
method, or theequals
method is sensible generally, but you're in a special situation where you need something else—and/or you want to enforce at compile-time that the types of the compared values are in a subtype/supertype relationship.This trait is the strictest of the three triple equals traits, enforcing a stronger constraint than both
TripleEquals
(the most lenient) andConversionCheckedTripleEquals
(the middle ground). IfTripleEquals
is mixed in or imported, the===
can be used with any two types and still compile. IfTypeCheckedTripleEquals
is mixed in or imported, however, only types in a subtype or supertype relationship with each other (including when both types are exactly the same) will compile.ConversionCheckedTripleEquals
is slightly more accomodating, because in addition to compiling any use of===
that will compile under TypeCheckedTripleEquals, it will also compile type types that would be rejected byTypeCheckedTripleEquals
, so long as an implicit conversion (in either direction) from one type to another is available.For example, under
TypeCheckedTripleEquals
, the following use of===
will not compile, becauseInt
andLong
are not in a subtype/supertype relationship. (I.e.,Int
is not a subtype or supertype ofLong
):Trait
TypeCheckedTripleEquals
rejects typesInt
andLong
because they are not directly related via subtyping. However, an implicit widening conversion fromInt
to Long does exist (imported implicitly fromscala.Predef
), soConversionCheckedTripleEquals
will allow it:The implicit conversion can go in either direction: from the left type to the right type, or vice versa. In the above expression the implicit conversion goes from left to right (the
Int
on the left to theLong
on the right). It also works the other way:This trait will override or hide implicit methods defined by its sibling traits,
TripleEquals
orTypeCheckedTripleEquals
, and can therefore be used to temporarily turn on or off conversion checking in a limited scope. Here's an example, in whichTypeCheckedTripleEquals
will cause a compiler error:Because
Int
andLong
are not in a subtype/supertype relationship, comparing1
and1L
in the context ofTypeCheckedTripleEquals
will generate a compiler error:You can “relax” the type checking (i.e., by additionally allowing implicitly convertible types) locally by importing the members of
ConversionCheckedTripleEquals
in a limited scope:With the above change, the
Example.scala
file compiles fine. Conversion checking is enabled only inside the firstcmp
method that takes anInt
and aLong
.TypeCheckedTripleEquals
is still enforcing its type constraint, for example, for thes === t
expression in the other overloadedcmp
method that takes strings.Because the methods in
ConversionCheckedTripleEquals
(and its siblings) override all the methods defined in supertypeEqualityConstraints
, 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.
An alternative way to solve an unwanted compiler error caused by an over-zealous equality type constraint is to convert one side or the other to type
Any
. BecauseAny
is a supertype of everything, any level of equality type constraint will be satisfied. TheAsAny
trait offers a convenient syntax, theasAny
method, for this purpose: