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Merge pull request #759 from dmbaturin/master

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Strings/character section and minor fixes in the OCaml tutorial.
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Nami-Doc 2014-09-11 17:22:09 +02:00
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@ -10,7 +10,7 @@ features.
Along with StandardML and its dialects it belongs to ML language family. Along with StandardML and its dialects it belongs to ML language family.
Just like StandardML, there are both a compiler and an interpreter Just like StandardML, there are both a compiler and an interpreter
for OCaml. The interpreter binary is normally called "ocaml" and for OCaml. The interpreter binary is normally called "ocaml" and
the compiler is "ocamlc.opt". There is also a bytecode compiler, "ocamlc", the compiler is "ocamlopt". There is also a bytecode compiler, "ocamlc",
but there are few reasons to use it. but there are few reasons to use it.
It is strongly and statically typed, but instead of using manually written It is strongly and statically typed, but instead of using manually written
@ -59,11 +59,19 @@ written in curried form.
(* Expressions can be separated by a double semicolon symbol, ";;". (* Expressions can be separated by a double semicolon symbol, ";;".
In many cases it's redundant, but in this tutorial we use it after In many cases it's redundant, but in this tutorial we use it after
every expression for easy pasting into the interpreter shell. *) every expression for easy pasting into the interpreter shell.
Unnecessary use of expression separators in source code files
is often considered to be a bad style. *)
(* Variable and function declarations use "let" keyword. *) (* Variable and function declarations use "let" keyword. *)
let x = 10 ;; let x = 10 ;;
(* OCaml allows single quote characters in identifiers.
Single quote doesn't have a special meaning in this case, it's often used
in cases when in other languages one would use names like "foo_tmp". *)
let foo = 1 ;;
let foo' = foo * 2 ;;
(* Since OCaml compiler infers types automatically, you normally don't need to (* Since OCaml compiler infers types automatically, you normally don't need to
specify argument types explicitly. However, you can do it if you want or need to. *) specify argument types explicitly. However, you can do it if you want or need to. *)
let inc_int (x: int) = x + 1 ;; let inc_int (x: int) = x + 1 ;;
@ -196,6 +204,39 @@ let my_array = [| 1; 2; 3 |] ;;
my_array.(0) ;; my_array.(0) ;;
(*** Strings and characters ***)
(* Use double quotes for string literals. *)
let my_str = "Hello world" ;;
(* Use single quotes for character literals. *)
let my_char = 'a' ;;
(* Single and double quotes are not interchangeable. *)
let bad_str = 'syntax error' ;; (* Syntax error. *)
(* This will give you a single character string, not a character. *)
let single_char_str = "w" ;;
(* Strings can be concatenated with the "^" operator. *)
let some_str = "hello" ^ "world" ;;
(* Strings are not arrays of characters.
You can't mix characters and strings in expressions.
You can convert a character to a string with "String.make 1 my_char".
There are more convenient functions for this purpose in additional
libraries such as Core.Std that may not be installed and/or loaded
by default. *)
let ocaml = (String.make 1 'O') ^ "Caml" ;;
(* There is a printf function. *)
Printf.printf "%d %s" 99 "bottles of beer" ;;
(* Unformatted read and write functions are there too. *)
print_string "hello world\n" ;;
print_endline "hello world" ;;
let line = read_line () ;;
(*** User-defined data types ***) (*** User-defined data types ***)