Skip to content

Add transform and flip methods. #1864

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
Shadowfiend merged 15 commits into from
Sep 25, 2017
Merged

Add transform and flip methods. #1864

Show file tree
Hide file tree
Changes from 1 commit
Commits
Show all changes
15 commits
Select commit Hold shift + click to select a range
e2150e7
Add collect and mapFailure methods. WIP
Bhashit Jun 17, 2017
f9ecab8
Remove duplicated collect method
Bhashit Jun 17, 2017
ba011d3
Tests for the mapFailure method
Bhashit Jun 25, 2017
5c607f9
change mapFailure tests to use a valid Failure param when testing wit…
Bhashit Jun 26, 2017
42bbf08
Change the collect function to be a bit more readable. Add tests for …
Bhashit Jun 26, 2017
a5b3972
Corrected spacing
Bhashit Jun 26, 2017
2cc1ac8
Initial pass at `collectFailure` method
Bhashit Jul 9, 2017
b797621
Merge branch 'master' into issue-1856-box-combinator-and-other-improv…
Bhashit Jul 9, 2017
a10b78e
Correction in collectFailure method signature.
Bhashit Jul 10, 2017
d90ccff
Redefine the `collect` method to use an existing `apply` function.
Bhashit Jul 23, 2017
52e6f17
Implement `flip` to take a partial-function.
Bhashit Aug 6, 2017
833abfa
Remvoed a typo
Bhashit Aug 6, 2017
94cc62c
Implement `transform` method to transform a Box into another Box.
Bhashit Sep 10, 2017
f504a82
Rollback 'or' to use its own simpler implementation.
Bhashit Sep 11, 2017
783bf6e
Put backticks around the method-name links
Bhashit Sep 11, 2017
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
6 changes: 1 addition & 5 deletions core/common/src/main/scala/net/liftweb/common/Box.scala
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -797,11 +797,7 @@ sealed abstract class Box[+A] extends Product with Serializable{
* If the partial function is defined at the current Box's value, apply the
* partial function.
*/
final def collect[B](pf: PartialFunction[A, B]): Box[B] = {
flatMap(value =>
if (pf.isDefinedAt(value)) Full(pf(value))
else Empty)
}
final def collect[B](pf: PartialFunction[A, B]): Box[B] = filter(pf.isDefinedAt).map(pf)

@Bhashit Bhashit Jun 26, 2017 •
edited
Loading

Copy link
Copy Markdown
Contributor Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

@Shadowfiend thought this was more readable than

final def collect[B](pf: PartialFunction[A, B]): Box[B] = flatMap { value =>
  pf.andThen(Full.apply).applyOrElse(value, _ => Empty)
}

@Shadowfiend Shadowfiend Jul 22, 2017

Copy link
Copy Markdown
Member

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

I do think this version will result in a double-application of the PartialFunction guards/pattern matches (a problem that the previous version in the repo also shared):

@ def slap(in: String) = println(s"Uh-oh ${in}"); false 
defined function slap
@ val booyan: PartialFunction[String, Int] = { case "boom" if slap("jam") => 5; case _ => 8 } 
booyan: PartialFunction[String, Int] = <function1>

@ Full("boom").filter(booyan.isDefinedAt).map(booyan) 
Uh-oh jam
Uh-oh jam
res13: Box[Int] = Full(8)
@ booyan.andThen(Full.apply).applyOrElse("boom", { _: String => Empty }) 
Uh-oh jam
res12: Box[Int] = Full(8)

So while I agree this is slightly more readable, I think you nailed it with the original alternative formulation.


/**
* An alias for `collect`.
Expand Down
14 changes: 14 additions & 0 deletions core/common/src/test/scala/net/liftweb/common/BoxSpec.scala
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -156,6 +156,14 @@ class BoxSpec extends Specification with ScalaCheck with BoxGenerator {
val failure = Failure("new-error", Empty, Empty)
Full(1).mapFailure(_ => failure) must_== Full(1)
}

@Shadowfiend Shadowfiend Jul 23, 2017

Copy link
Copy Markdown
Member

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

This looks like it's a duplicate of one below?

@Shadowfiend Shadowfiend Jul 23, 2017

Copy link
Copy Markdown
Member

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Oh wait jk I just remembered how this spec is structured heh.

"define a 'collect' method that takes a PartialFunction to transform its contents" in {
"If the partial-function is defined for the contents of this box, returns a full box containing the result of applying that partial function to this Box's contents" in {
Full("Albus") collect { case "Albus" => "Dumbledore"} must_== Full("Dumbledore")
}
"If the partial-function is not defined for the contents of this box, returns Empty" in {
Full("Hermione") collect { case "Albus" => "Dumbledore"} must beEmpty
}
}
"define an 'elements' method returning an iterator containing its value" in {
Full(1).elements.next must_== 1
}
Expand Down Expand Up @@ -306,6 +314,9 @@ class BoxSpec extends Specification with ScalaCheck with BoxGenerator {
val failure = Failure("new-error", Empty, Empty)
Empty.mapFailure(_ => failure) must beEmpty
}
"define a 'collect' method returning Empty" in {
Empty collect { case _ => "Some Value"} must beEmpty
}
"define an 'elements' method returning an empty iterator" in {
Empty.elements.hasNext must beFalse
}
Expand Down Expand Up @@ -370,6 +381,9 @@ class BoxSpec extends Specification with ScalaCheck with BoxGenerator {
val exception = new Exception("transformed")
Failure("error", Empty, Empty) mapFailure { _ => Failure("new-error", Full(exception), Empty) } must_== Failure("new-error", Full(exception), Empty)
}
"define a 'collect' method returning itself" in {
Failure("error", Empty, Empty) collect { case _ => "Some Value"} must_== Failure("error", Empty, Empty)
}
"return itself when asked for its status with the operator ?~" in {
Failure("error", Empty, Empty) ?~ "nothing" must_== Failure("error", Empty, Empty)
}
Expand Down