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wtd

Thu Mar 03, 2005 9:13 pm


Syntax Quickref: Turing <--> O'Caml

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O'Caml for the Turing Programmer

Input-Output

Printing to the standard output.

Turing
put "Hello"

O'Caml 
print_endline "Hello"

The same, without skipping to a newline.

Turing
put "Hello" ..

O'Caml
print_string "Hello"
   
Printing an integer.

Turing
put 42

O'Caml
print_int 42

Printing a floating point number.

Turing
put 42.3

O'Caml
print_float 42.3

Getting a line from the keyboard.

Turing
var line : string
get line : *

O'Caml
let line = read_line ()

Getting a single character from the keyboard.

Turing
var ch : string
get ch : 1

O'Caml
let ch = let str = read_line () in
  String.get str 0

Getting an integer from the keyboard.

Turing
var i : int
get i

O'Caml
let i = read_int ()
       
Getting a float from the keyboard.

Turing
var f : real
get f

O'Caml
let f = read_float ()
       
Math


Turing    | O'Caml      | Result
----------+-------------+---------
 4 + 3    |  4 + 3      |  7
 4 - 2    |  4 - 2      |  2
 2 * 3    |  2 * 3      |  6
 2 / 5    |  2 / 5      |  0
 6 div 4  |  6 / 4      |  1
 6 rem 4  |  (mod) 6 4  |  2
          |  6 mod 4    |
 3 ** 2   |  3. ** 2.   |  9.0
 sin      |  sin        | 
 cos      |  cos        |
          |  tan        | 
          |  asin       |
          |  acos       |
          |  atan       |
 
Comparisons

Turing  | O'Caml     
--------+----------
 =      |  =     
 not=   |  !=      
 =      
 not    |  not    
 and    |  && 
 or     |  ||, or

Conditional Statements/Expressions

Turing                      | O'Caml     
----------------------------+------------------------------
 if condition then          |  if condition
   statement1               |    then expression1
 elsif otherCondition then  |    else if otherCondition
   statement2               |      then expression2
 else                       |      else defaultExpression
   defaultStatement         |
 end if                     |
----------------------------+------------------------------
 case value of              |  match value with
   label 1: statement1      |    | 1 -> expression1
   label 2: statement2      |    | 2 -> expression2
   label: default           |    | _ -> default;;
 end case                   |

Function Definition

Turing                              | O'Caml     
------------------------------------+--------------------------------------------
 function fooBar : string           |  let fooBar = "foo, bar"
   result "foo, bar"                |  
 end fooBar                         |    
------------------------------------+--------------------------------------------
 function square (n : int) : float  |  let square n = n ** 2
   result n ** 2                    |  
 end square                         |  
                                    |  
------------------------------------+--------------------------------------------
 procedure greet (name : string)    |  let greet name = 
   put "Hello, " + name             |    print_endline ("Hello, " ^ name)
 end greet                          |  
                                    |    
------------------------------------+--------------------------------------------
 procedure greet (name : string)    |  let greet name =
   var greeting := "Hello, " + name |    let greeting = "Hello, " ^ name in
   put greeting                     |      print_endline greeting
 end greet                          |  
------------------------------------+--------------------------------------------
 function fact (n : int) : int      |  let rec fact n =
   if n = 0 then                    |    if n = 0 
     result 1                       |      then 0
   else                             |      else n * fact (n - 1)
     result n * fact (n - 1)        |  
   end if                           |  
 end fact                           |  

Comments

Turing      | O'Caml     
------------+-------------
 %          |  none      
 /* ... */  |  (* ... *)