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@(#)fp.1 6.2 (Berkeley) 02/17/89
Fp is an interpreter/compiler that 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.
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).
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 (\*s) compiler to gain a factor of 10 in performance). Control 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.
/usr/ucb/liszt the liszt compiler
lisp(\*s), liszt(\*s).
The Berkeley FP user's manual, available on-line. The language is described in the August 1978 issue of CACM (Turing award lecture by John Backus).
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.