Difference between revisions of "OCaml"
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This page aims to cover some of its differences from Haskell. |
This page aims to cover some of its differences from Haskell. |
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== Syntactic dictionary == |
== Syntactic dictionary == |
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{| class="wikitable" |
{| class="wikitable" |
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| − | | Language |
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| − | | Haskell |
+ | | '''Haskell''' |
| − | | OCaml |
+ | | '''OCaml''' |
| − | | Comments |
+ | | '''Comments''' |
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| Anonymous functions |
| Anonymous functions |
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int, bool, float * char, 'a |
int, bool, float * char, 'a |
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| − | | <tt>float</tt> is |
+ | | <tt>float</tt> is double-precision |
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| Type signatures |
| Type signatures |
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const : 'a -> 'b -> 'a |
const : 'a -> 'b -> 'a |
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| − | | Signatures usually omitted in OCaml |
+ | | Signatures usually omitted in OCaml implementations, may be provided separately in interface files |
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| Type declarations |
| Type declarations |
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| Parametrised types |
| Parametrised types |
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| − | data |
+ | data DList a = MkDList ([a] -> [a]) |
| − | data |
+ | data Either a b = Left a | Right b |
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| − | type 'a |
+ | type 'a dlist = MkDList of ('a list -> 'a list) |
| − | type ('a, 'b) |
+ | type ('a, 'b) either = Left of 'a | Right of 'b |
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| Pattern matching |
| Pattern matching |
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case x of |
case x of |
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| − | + | B x |
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| + | <nowiki>| x > 0 -> ... |
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| + | |</nowiki> otherwise -> ... |
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C a b -> ... |
C a b -> ... |
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| + | case Left () of |
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| + | Left x -> x |
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| + | Right x -> x |
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match x with |
match x with |
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| − | B x -> ... |
+ | B x when x > 0 -> ... |
| − | + | <nowiki>| B x -> ... |
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| + | |</nowiki> C (a, b) -> ... |
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| + | match Left () with |
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| + | Left x <nowiki>|</nowiki> Right x -> x |
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Latest revision as of 16:34, 15 May 2023
OCaml is a functional programming language in the ML family, an extension of the Caml language with object-oriented constructs.
This page aims to cover some of its differences from Haskell.
Conceptual differences
OCaml is strict by default, although it has some facility for introducing laziness.
OCaml's let is non-recursive by default, but has the form let rec for defining recursive functions.
OCaml is impure: although it makes heavy use of immutable data, it also has mutable references and arrays available, and IO is performed by ordinary functions.
Syntactic dictionary
| Haskell | OCaml | Comments | |
| Anonymous functions |
\x y -> ... |
fun x y -> ... |
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| Multiple assignments |
let x = 4 y = 5 in ... |
let x = 4 and y = 5 in ... |
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| Types |
Int, Bool, (Double, Char), a |
int, bool, float * char, 'a |
float is double-precision |
| Type signatures |
const :: a -> b -> a |
const : 'a -> 'b -> 'a |
Signatures usually omitted in OCaml implementations, may be provided separately in interface files |
| Type declarations |
data A = B Int | C Char Bool x = B 3 y = C 'a' True |
type a = B of int | C of char * bool
let x = B 3
and y = C ('a', true)
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| Parametrised types |
data DList a = MkDList ([a] -> [a]) data Either a b = Left a | Right b |
type 'a dlist = MkDList of ('a list -> 'a list)
type ('a, 'b) either = Left of 'a | Right of 'b
| |
| Pattern matching |
case x of
B x
| x > 0 -> ...
| otherwise -> ...
C a b -> ...
case Left () of Left x -> x Right x -> x |
match x with
B x when x > 0 -> ...
| B x -> ...
| C (a, b) -> ...
match Left () with Left x | Right x -> x |