(docs) Adding an example of a closure that contains mutable state in Mutable State & Imperative Tutorial #2046
Conversation
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
cuihtlauac
requested changes
Feb 12, 2024
There was a problem hiding this comment.
Thanks @The-Amoghavarsha. We need more details, this example is more profound that it may looks.
Comment on lines
534
to
536
| let counter () = | ||
| let n = ref 0 in | ||
| fun () -> incr n; !n;; |
There was a problem hiding this comment.
Suggested change
| let counter () = | |
| let n = ref 0 in | |
| fun () -> incr n; !n;; | |
| # let create_counter () = | |
| let n = ref 0 in | |
| fun () -> incr n; !n;; | |
| val create_counter : unit -> unit -> int = <fun> | |
| # let c1 = create_counter ();; | |
| val c1 : unit -> int = <fun> | |
| # let c2 = create_counter ();; | |
| val c2 : unit -> int = <fun> | |
| # c1 ();; | |
| - : int = 1 | |
| # c1 ();; | |
| - : int = 2 | |
| # c2 ();; | |
| - : int = 1 | |
| # c1 ();; | |
| - : int = 3 |
| @@ -526,6 +526,18 @@ The following example uses the `get_char` function we defined earlier (in the se | |||
|
|
|||
| This `while` loop echoes characters typed on the keyboard. When the ASCII `Escape` character is read, the `Exit` exception is thrown, which terminates the iteration and displays the REPL reply: `- : unit = ()`. | |||
|
|
|||
| ### Closures | |||
There was a problem hiding this comment.
Suggested change
| ### Closures | |
| ### References Inside Closures |
| @@ -526,6 +526,18 @@ The following example uses the `get_char` function we defined earlier (in the se | |||
|
|
|||
| This `while` loop echoes characters typed on the keyboard. When the ASCII `Escape` character is read, the `Exit` exception is thrown, which terminates the iteration and displays the REPL reply: `- : unit = ()`. | |||
|
|
|||
| ### Closures | |||
|
|
|||
| A closure is a function bundled together with its surrounding state, including any variables or references from the enclosing scope that it references. This bundled function-state package allows for the creation of self-contained units of behavior that can maintain internal state across multiple invocations. | |||
There was a problem hiding this comment.
Refer to the definition of closures from Values & Functios.
This example is meant to illustrate it is possible to “hide” a reference in a closure returned by a function. Which is a neat way to produce an "effectful function" (maybe we should say somewhere such a thing is not a all function, in the math sense).
sabine
changed the title
|
Also, checks are failing because the formatting was broken upstream. Please rebase. |
cuihtlauac
approved these changes
Feb 13, 2024
There was a problem hiding this comment.
This looks good to me.
@christinerose, is this ok for you too?
sabine
changed the title
sabine
approved these changes
Feb 16, 2024
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
Closes #2035