Concatenative programming language

In concatenative programming languages, the concatenation of appropriate programs denotes the composition of the functions which the programs denote. Operations map an input stack into a results stack, and so it is possible to repeatedly concatenate a sequence of operations.

A programming language is concatenative (and not applicative) when:

• The elementary well-formed expressions of the language are monadic functions of a nameless data stack.
• If X and Y are well-formed expressions, then the concatenation of X and Y is well-formed.
• If Z is the concatenation of X and Y, then the value of Z is the composition of the values of X and Y.

Examples

The canonical examples of concatenative programming languages are Forth and Joy. In Joy, the program fragment:

2 7 +

Pushes "2" then "7" onto the stack. The "+" operator then replaces the stack with a new stack that contains the resulting sum "9".

The Category:Concatenative programming languages contains an exhaustive list of those known to AskFactMaster.Com.

External links

• A Note on Functional Programming in Joy and K (http://www.vector.org.uk/?submit=fetch&url=v203/fpjoy203.htm)
• Joy and Concatenative Programming (http://www.mail-archive.com/haskell-cafe@haskell.org/msg00907.html)

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