Name

fp − Functional Programming language compiler/interpreter

Syntax

fp

Description

The fp interpreter/compiler implements the applicative language proposed by John Backus.  It is written in FRANZ LISP . 

In a  functional programming language intent is expressed in  a mathematical style devoid of assignment statements and variables.  Functions compute by value only; there are no side-effects since  the result of a computation depends solely on the inputs. 

The fp programs consist of functional expressions − primitive and user-defined fp functions combined by functional forms.  These forms take functional arguments and return functional results.  For example, the composition operator ’@’ takes two functional arguments and returns a function which represents their composition. 

There exists a single operation in fp − application.  This operation causes the system to evaluate the indicated function using the single argument as input (all functions are monadic). 

Getting Started

fp invokes the system. fp compiles functions into lisp(1) source code; lisp(1) interprets this code (the user may compile this code using the liszt(1) compiler to gain a factor of 10 in performance). Ctrl D exits back to the shell. Break terminates any computation in progress  and resets any open file units.  )help provides a short summary of all user commands. 

Restrictions

If a non-terminating function is applied as the result of loading a file, then control is returned to the user immediately, everything after that position in the file is ignored. 

fp incorrectly marks the location of a syntax error on large, multi-line function definitions or applications. (Turing award lecture by John Backus).

Files

/usr/ucb/lispthe FRANZ LISP interpreter
/usr/ucb/lisztthe liszt compiler
/usr/doc/fpthe User’s Guide

See Also

lisp(1), liszt (1). 
"The FRANZ LISP Manual" in the Supplementary Documents, Volume 2: Programmer