Module Stdlib.Option

Options
Predicates and comparisons
Converting

Instructions: Use this module in your project

In the IDE (CLion, Visual Studio Code, Xcode, etc.) you use for your DkSDK project:

Add the following to your project's dependencies/CMakeLists.txt:

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DkSDKProject_DeclareAvailable(ocaml
    CONSTRAINT "= 4.14.0"
    FINDLIBS str unix runtime_events threads dynlink)
DkSDKProject_MakeAvailable(ocaml)

Add the Findlib::ocaml library to any desired targets in src/*/CMakeLists.txt:

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target_link_libraries(YourPackage_YourLibraryName
     # ... existing libraries, if any ...
     Findlib::ocaml)

Click your IDE's Build button

Not using DkSDK?

FIRST, do one or all of the following:

Run:
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```
opam install ocaml.4.14.0
```

Edit your dune-project and add:

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(package
  (name YourExistingPackage)
  (depends
  ; ... existing dependenices ...
  (ocaml (>= 4.14.0))))

Then run:

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dune build *.opam # if this fails, run: dune build

Edit your <package>.opam file and add:

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depends: [
  # ... existing dependencies ...
  "ocaml" {>= "4.14.0"}
]

Then run:

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opam install . --deps-only

FINALLY, add the library to any desired (library)and/or (executable) targets in your **/dune files:

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(library
  (name YourLibrary)
  ; ... existing library options ...
  (libraries
    ; ... existing libraries ...
    ))

(executable
  (name YourExecutable)
  ; ... existing executable options ...
  (libraries
    ; ... existing libraries ...
    ))

Options

type``'a t`` ='aoption`` =


| None

| Some of 'a

The type for option values. Either None or a value Some v.

valnone :'a option

none is None.

valsome :'a -> 'a option

some v is Some v.

valvalue :'aoption``-> ``default:'a -> 'a

value o ~default is v if o is Some v and default otherwise.

valget :'aoption``-> 'a

get o is v if o is Some v and raise otherwise.

raises Invalid_argument

if o is None.

valbind :'aoption``-> ``('a -> 'boption``)``-> 'b option

bind o f is f v if o is Some v and None if o is None.

valjoin :'aoption`` option``-> 'a option

join oo is Some v if oo is Some (Some v) and None otherwise.

val map : ``('a -> 'b)`` -> 'aoption``-> 'b option

map f o is None if o is None and Some (f v) is o is Some v.

val fold : ``none:'a -> ``some:``('b -> 'a)`` -> 'boption``-> 'a

fold ~none ~some o is none if o is None and some v if o is Some v.

val iter : ``('a ->unit)``-> 'aoption``-> unit

iter f o is f v if o is Some v and () otherwise.

Predicates and comparisons

valis_none :'aoption``-> bool

is_none o is true if and only if o is None.

valis_some :'aoption``-> bool

is_some o is true if and only if o is Some o.

val equal : ``('a -> 'a ->bool)``-> 'aoption``-> 'aoption``-> bool

equal eq o0 o1 is true if and only if o0 and o1 are both None or if they are Some v0 and Some v1 and eq v0 v1 is true.

val compare : ``('a -> 'a ->int)``-> 'aoption``-> 'aoption``-> int

compare cmp o0 o1 is a total order on options using cmp to compare values wrapped by Some _. None is smaller than Some _ values.

Converting

val to_result : ``none:'e -> 'aoption``-> ``('a, 'e)`` result

to_result ~none o is Ok v if o is Some v and Error none otherwise.

valto_list :'aoption``-> 'a list

to_list o is [] if o is None and [v] if o is Some v.

valto_seq :'aoption``-> 'a Seq.t

to_seq o is o as a sequence. None is the empty sequence and Some v is the singleton sequence containing v.

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