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author | C. Bess <cbess@company.com> | 2015-11-09 17:55:53 -0600 |
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committer | C. Bess <cbess@company.com> | 2015-11-09 17:55:53 -0600 |
commit | df0992d72c2a28f140e6ff9681c505f36e19249a (patch) | |
tree | 508aa3abe4c25b957dca442560d9c95c9b1fc97a /ocaml.html.markdown | |
parent | afc5ea14654e0e9cd11c7ef1b672639d12418bad (diff) | |
parent | c460e1fafa0e9b4edc6a5cb35b970bb5cc030a81 (diff) |
Merge remote-tracking branch 'adambard/master'
Conflicts:
swift.html.markdown
Diffstat (limited to 'ocaml.html.markdown')
-rw-r--r-- | ocaml.html.markdown | 35 |
1 files changed, 20 insertions, 15 deletions
diff --git a/ocaml.html.markdown b/ocaml.html.markdown index f9db7080..8faab297 100644 --- a/ocaml.html.markdown +++ b/ocaml.html.markdown @@ -34,13 +34,13 @@ For a source file you can use "ocamlc -i /path/to/file.ml" command to print all names and type signatures. ``` -$ cat sigtest.ml +$ cat sigtest.ml let inc x = x + 1 let add x y = x + y -let a = 1 +let a = 1 -$ ocamlc -i ./sigtest.ml +$ ocamlc -i ./sigtest.ml val inc : int -> int val add : int -> int -> int val a : int @@ -104,7 +104,7 @@ let fact_4 = factorial (5-1) ;; let sqr2 = sqr (-2) ;; (* Every function must have at least one argument. - Since some funcions naturally don't take any arguments, there's + Since some funcions naturally don't take any arguments, there's "unit" type for it that has the only one value written as "()" *) let print_hello () = print_endline "hello world" ;; @@ -144,11 +144,16 @@ x + y ;; (* Alternatively you can use "let ... and ... in" construct. This is especially useful for mutually recursive functions, with ordinary "let .. in" the compiler will complain about - unbound values. - It's hard to come up with a meaningful but self-contained - example of mutually recursive functions, but that syntax - works for non-recursive definitions too. *) -let a = 3 and b = 4 in a * b ;; + unbound values. *) +let rec + is_even = function + | 0 -> true + | n -> is_odd (n-1) +and + is_odd = function + | 0 -> false + | n -> is_even (n-1) +;; (* Anonymous functions use the following syntax: *) let my_lambda = fun x -> x * x ;; @@ -191,7 +196,7 @@ let (~/) x = 1.0 /. x ;; ~/4.0 (* = 0.25 *) -(*** Built-in datastructures ***) +(*** Built-in data structures ***) (* Lists are enclosed in square brackets, items are separated by semicolons. *) @@ -288,7 +293,7 @@ type int_list_list = int list_of_lists ;; (* Types can also be recursive. Like in this type analogous to built-in list of integers. *) type my_int_list = EmptyList | IntList of int * my_int_list ;; -let l = Cons (1, EmptyList) ;; +let l = IntList (1, EmptyList) ;; (*** Pattern matching ***) @@ -296,7 +301,7 @@ let l = Cons (1, EmptyList) ;; (* Pattern matching is somewhat similar to switch statement in imperative languages, but offers a lot more expressive power. - Even though it may look complicated, it really boils down to matching + Even though it may look complicated, it really boils down to matching an argument against an exact value, a predicate, or a type constructor. The type system is what makes it so powerful. *) @@ -315,7 +320,7 @@ let is_one = function ;; (* Matching predicates, aka "guarded pattern matching". *) -let abs x = +let abs x = match x with | x when x < 0 -> -x | _ -> x @@ -336,10 +341,10 @@ let say x = say (Cat "Fluffy") ;; (* "Fluffy says meow". *) -(** Traversing datastructures with pattern matching **) +(** Traversing data structures with pattern matching **) (* Recursive types can be traversed with pattern matching easily. - Let's see how we can traverse a datastructure of the built-in list type. + Let's see how we can traverse a data structure of the built-in list type. Even though the built-in cons ("::") looks like an infix operator, it's actually a type constructor and can be matched like any other. *) let rec sum_list l = |