==

A type family to compute Boolean equality.
A type family to compute Boolean equality.
A type family to compute Boolean equality.
An infix alias for Equals.
Equality constraint, used as e.g. (x == 3) => _
Check if values are “the same”. Breaking from Elm, this relies on Haskell's Eq typeclass. For example:
data Foo = Bar | Baz deriving (Eq)
Like ==, but prints a counterexample when it fails.
Implication for properties: The resulting property holds if the first argument is False (in which case the test case is discarded), or if the given property holds. Note that using implication carelessly can severely skew test case distribution: consider using cover to make sure that your test data is still good quality.
Fails the test if the two arguments provided are not equal.
Check for equality.

Example usage

selectSPJ :: MonadIO m => ReaderT SqlBackend m [Entity User]
selectSPJ = selectList [UserName ==. "SPJ" ] []
The above query when applied on dataset-1, will produce this:
+-----+-----+-----+
|id   |name |age  |
+-----+-----+-----+
|1    |SPJ  |40   |
+-----+-----+-----+
The ==> operator can be used to express a restricting condition under which a property should hold. It corresponds to implication in the classical logic. Note that ==> resets the quantification context for its operands to the default (universal).
vertical concatenation
Place two diagrams (or other objects) vertically adjacent to one another, with the first diagram above the second. Since Haskell ignores whitespace in expressions, one can thus write
c
===
d

to place c above d. The local origin of the resulting combined diagram is the same as the local origin of the first. (===) is associative and has mempty as an identity. See the documentation of beside for more information.