Good
Converts this Or to an Or with the same Good type and a Bad type consisting of
One parameterized by this Or's Bad type.
Converts this Or to an Or with the same Good type and a Bad type consisting of
One parameterized by this Or's Bad type.
For example, invoking the accumulating method on an Int Or ErrorMessage would convert it to an
Int Or One[ErrorMessage]. This result type, because the Bad type is an Every, can be used
with the mechanisms provided in trait Accumulation to accumulate errors.
Note that if this Or is already an accumulating Or, the behavior of this accumulating method does not change.
For example, if you invoke accumulating on an Int Or One[ErrorMessage] you will be rewarded with an
Int Or One[One[ErrorMessage]].
this Good, if this Or is a Good; or this Bad value wrapped in a One if
this Or is a Bad.
Returns this Good with the type widened to Or.
Returns this Good with the type widened to Or.
This widening method can useful when the compiler infers the more specific Good type and
you need the more general Or type. Here's an example that uses foldLeft on
a List[Int] to calculate a sum, so long as only odd numbers exist in a passed List:
scala> import org.scalactic._
import org.scalactic._
scala> def oddSum(xs: List[Int]): Int Or ErrorMessage =
| xs.foldLeft(Good(0).orBad[ErrorMessage]) { (acc, x) =>
| acc match {
| case Bad(_) => acc
| case Good(_) if (x % 2 == 0) => Bad(x + " is not odd")
| case Good(sum) => Good(sum + x)
| }
| }
<console>:13: error: constructor cannot be instantiated to expected type;
found : org.scalactic.Bad[G,B]
required: org.scalactic.Good[Int,org.scalactic.ErrorMessage]
case Bad(_) => acc
^
<console>:14: error: type mismatch;
found : org.scalactic.Bad[Nothing,String]
required: org.scalactic.Good[Int,org.scalactic.ErrorMessage]
case Good(_) if (x % 2 == 0) => Bad(x + " is not odd")
^
Because the compiler infers the type of the first parameter to foldLeft to be Good[Int, ErrorMessage],
it expects the same type to appear as the result type of function passed as the second, curried parameter. What you really want is
that both types be Int Or ErrorMessage, but the compiler thinks you want them to be the more specific
Good[Int, ErrorMessage]. You can use the asOr method to indicate you want the type to be Or
with minimal boilerplate:
scala> def oddSum(xs: List[Int]): Int Or ErrorMessage =
| xs.foldLeft(Good(0).orBad[ErrorMessage].asOr) { (acc, x) =>
| acc match {
| case Bad(_) => acc
| case Good(_) if (x % 2 == 0) => Bad(x + " is not odd")
| case Good(sum) => Good(sum + x)
| }
| }
oddSum: (xs: List[Int])org.scalactic.Or[Int,org.scalactic.ErrorMessage]
Now you can use the method to sum a List of odd numbers:
scala> oddSum(List(1, 2, 3)) res2: org.scalactic.Or[Int,org.scalactic.ErrorMessage] = Bad(2 is not odd) scala> oddSum(List(1, 3, 5)) res3: org.scalactic.Or[Int,org.scalactic.ErrorMessage] = Good(9)
Maps the given function to this Or's value if it is a Bad or returns this if it is a Good.
Returns true if this Or is a Good and the predicate p returns true when applied to this Good's value.
Returns true if this Or is a Good and the predicate p returns true when applied to this Good's value.
Note: The exists method will return the same result as forall if this Or is a Good, but the opposite
result if this Or is a Bad.
the predicate to apply to the Good value, if this is a Good
the result of applying the passed predicate p to the Good value, if this is a Good, else false
Returns this Or if either 1) it is a Bad or 2) it is a Good and applying the validation function f to this
Good's value returns Pass; otherwise,
returns a new Bad containing the error value contained in the Fail resulting from applying the validation
function f to this Good's value.
Returns this Or if either 1) it is a Bad or 2) it is a Good and applying the validation function f to this
Good's value returns Pass; otherwise,
returns a new Bad containing the error value contained in the Fail resulting from applying the validation
function f to this Good's value.
For examples of filter used in for expressions, see the main documentation for trait
Validation.
the validation function to apply
a Good if this Or is a Good that passes the validation function, else a Bad.
Returns the given function applied to the value contained in this Or if it is a Good,
or returns this if it is a Bad.
Returns the given function applied to the value contained in this Or if it is a Good,
or returns this if it is a Bad.
the function to apply
if this is a Good, the result of applying the given function to the contained value wrapped in a Good,
else this Bad is returned
Folds this Or into a value of type V by applying the given gf function if this is
a Good else the given bf function if this is a Bad.
Folds this Or into a value of type V by applying the given gf function if this is
a Good else the given bf function if this is a Bad.
the function to apply to this Or's Good value, if it is a Good
the function to apply to this Or's Bad value, if it is a Bad
the result of applying the appropriate one of the two passed functions, gf or bf, to this Or's value
Returns true if either this Or is a Bad or if the predicate p returns true when applied
to this Good's value.
Returns true if either this Or is a Bad or if the predicate p returns true when applied
to this Good's value.
Note: The forall method will return the same result as exists if this Or is a Good, but the opposite
result if this Or is a Bad.
the predicate to apply to the Good value, if this is a Good
the result of applying the passed predicate p to the Good value, if this is a Good, else true
Applies the given function f to the contained value if this Or is a Good; does nothing if this Or
is a Bad.
the “good” value
Returns the Or's value if it is a Good or throws NoSuchElementException if it is a Bad.
Returns, if this Or is Good, this Good's value; otherwise returns the result of evaluating default.
Indicates whether this Or is a Bad
Indicates whether this Or is a Bad
true if this Or is a Bad, false if it is a Good.
Indicates whether this Or is a Good
Maps the given function to this Or's value if it is a Good or returns this if it is a Bad.
Narrows the Bad type of this Good to the given type.
Narrows the Bad type of this Good to the given type.
Because Or has two types, but the Good factory method only takes a value of the “good” type, the Scala compiler will
infer Nothing for the Bad type:
scala> Good(3) res0: org.scalactic.Good[Int,Nothing] = Good(3)
Often Nothing will work fine, as it will be widened as soon as the compiler encounters a more specific Bad type.
Sometimes, however, you may need to specify it. In such situations you can use this orBad method, like this:
scala> Good(3).orBad[String] res1: org.scalactic.Good[Int,String] = Good(3)
Returns this Or if it is a Good, otherwise returns the result of evaluating the passed alternative.
Maps the given function to this Or's value if it is a Bad, transforming it into a Good, or returns
this if it is already a Good.
Maps the given function to this Or's value if it is a Bad, transforming it into a Good, or returns
this if it is already a Good.
the function to apply
if this is a Bad, the result of applying the given function to the contained value wrapped in a Good,
else this Good is returned
Maps the given function to this Or's value if it is a Bad, returning the result, or returns
this if it is already a Good.
Returns an Or with the Good and Bad types swapped: Bad becomes Good and Good
becomes Bad.
Returns an Or with the Good and Bad types swapped: Bad becomes Good and Good
becomes Bad.
Here's an example:
scala> val lyrics = Bad("Hey Jude, don't make it bad. Take a sad song and make it better.")
lyrics: org.scalactic.Bad[Nothing,String] =
Bad(Hey Jude, don't make it bad. Take a sad song and make it better.)
scala> lyrics.swap
res12: org.scalactic.Or[String,Nothing] =
Good(Hey Jude, don't make it bad. Take a sad song and make it better.)
Now that song will be rolling around in your head all afternoon. But at least it is a good song (thanks to swap).
if this Or is a Good, its Good value wrapped in a Bad; if this Or is
a Bad, its Bad value wrapped in a Good.
Returns an Either: a Right containing the Good value, if this is a Good; a Left
containing the Bad value, if this is a Bad.
Returns an Either: a Right containing the Good value, if this is a Good; a Left
containing the Bad value, if this is a Bad.
Note that values effectively “switch sides” when convering an Or to an Either. If the type of the
Or on which you invoke toEither is Or[Int, ErrorMessage] for example, the result will be an
Either[ErrorMessage, Int]. The reason is that the convention for Either is that Left is used for “bad”
values and Right is used for “good” ones.
this Good value, wrapped in a Right, or this Bad value, wrapped in a Left.
Returns a Some containing the Good value, if this Or is a Good, else None.
Returns an immutable IndexedSeq containing the Good value, if this Or is a Good, else an empty
immutable IndexedSeq.
Returns a Try: a Success containing the
Good value, if this is a Good; a Failure
containing the Bad value, if this is a Bad.
Returns a Try: a Success containing the
Good value, if this is a Good; a Failure
containing the Bad value, if this is a Bad.
Note: This method can only be called if the Bad type of this Or is a subclass
of Throwable (or Throwable itself).
Note that values effectively “switch sides” when converting an Or to an Either. If the type of the
Or on which you invoke toEither is Or[Int, ErrorMessage] for example, the result will be an
Either[ErrorMessage, Int]. The reason is that the convention for Either is that Left is used for “bad”
values and Right is used for “good” ones.
this Good value, wrapped in a Right, or this Bad value, wrapped in a Left.
Transforms this Or by applying the function gf to this Or's Good value if it is a Good,
or by applying bf to this Or's Bad value if it is a Bad.
Transforms this Or by applying the function gf to this Or's Good value if it is a Good,
or by applying bf to this Or's Bad value if it is a Bad.
the function to apply to this Or's Good value, if it is a Good
the function to apply to this Or's Bad value, if it is a Bad
the result of applying the appropriate one of the two passed functions, gf or bf, to this Or's value
Currently just forwards to filter, and therefore, returns the same result.
Currently just forwards to filter, and therefore, returns the same result.
Contains a “good” value.
You can decide what “good” means, but it is expected
Goodwill be commonly used to hold valid results for processes that may fail with an error instead of producing a valid result.the “good” value