Miranda - A Functional Language


Miranda is a functional programming language built for the UNIX environment. Developed between 1985 and 1986 by David Turner, Miranda was designed to produce a commercial version of a standard non-strict purely functional language. (Purists will note that it is pretty difficult to get a purely functional language, see referential transparency).


Miranda is an archaic language, and in the shadow of the mighty Haskell, has degenerated to a mere teaching language. But, in its prime, it was used:


Miranda is composed of some fairly basic data types:

num : Numbers, Miranda's basic number type is similar to the real number types in other languages.
char : Characters, single characters, such as 'A', 'a', '.' or '6'.
bool : Boolean, true or false.

Tuples : Sets of non-homogeneously typed values.
Lists : Sets of homogeneously typed values. Miranda can have lists of infinite length.

New types can be defined as follws:

string == [char]
(List of characters)

Functions are defined in this form:

FunctionName :: InputType1 -> InputType2 ->..-> InputTypeN -> OutputType
FunctionName Arg1 Arg2..ArgN = Statement

Notice functions can only EVER produce a single value as a result. However, this value can be a list. All functions in Miranda are curried (see: Currying Functions).


Using recursion:

>greenbottles :: num -> string
>greenbottles 0 		= 	"no green bottles standing on the wall.\n"
>greenbottles (x+1) 	= 	show (x+1) ++ " green bottles standing on the wall.\n" ++
>				show (x+1) ++ " green bottles standing on the wall,\n" ++
>				"and if one green bottle, should accidentally fall,\n" ++
>				"there'll be " ++ greenbottles x


A PC friendly version of Miranda is available, called "Amanda", and was developed by Dick Bruin.

For more info...

Information on Miranda is very hard to come by, as it is living in the shadows of the functional programming world. Haskell dominates, simply because it is more powerful. Everything that can be done in Miranda can be done in Haskell. Haskell also has Monads. However, because of it's limited functionality, Miranda does make a good teaching langauge. Take it from me, I had to learn about functional programming through Miranda on my University course.

Try here for some limited inforamtion about the Miranda language:http://www.engin.umd.umich.edu/CIS/course.des/cis400/miranda/miranda.html

Dick Bruin's homepage was last seen here: