HOPE - Programming language

HOPE is a programming language created in 1978.

#906on PLDB

46Years Old

Hope is a small functional programming language developed in the 1970s at Edinburgh University. It predates Miranda and Haskell and is contemporaneous with ML (also developed at Edinburgh). Hope was derived from NPL, a simple functional language developed by Rod Burstall and John Darlington in their work on program transformation. Read more on Wikipedia...

Tags: programming language
Early development of HOPE happened in https://github.com/dmbaturin/hope/issues
Explore HOPE snippets on Rosetta Code
HOPE on HOPL
See also: (3 related languages) Haskell, ML, SNOBOL
Read more about HOPE on the web: 1.

Example from Wikipedia:

dec fact : num -> num;
--- fact 0 <= 1;
--- fact n <= n*fact(n-1);

HOPE Keywords

and or not char num div mod dec X # : -> ; --- if then else > <= + ( ) , infix - truval :: nil " <> == in where data ++ lambda

Language features

Feature	Supported	Example	Token
Conditionals	✓
Comments	✓	--- A comment
Line Comments	✓	--- A comment	---
Single-Type Arrays	✓	[1,2,3]
Letter-first Identifiers	✓
Anonymous Functions	✓	lambda(x,y) => x + y
Integers	✓
Infix Notation	✓	max(10,20) + max(1,max(2,3));
Pattern Matching	✓
Merges Whitespace	✓
hasUserDefinedOperators	✓	Hope enables us to use a function with two arguments as an infix operator. e must assign it a priority and use it as an infix operator everywhere, including the equations that define it. A bigger number in the infix declaration means a higher priority. Most of Hope's standard functions are supplied as infix operators. infix mult 8; dec mult : num # num - > num; ---xmulty<= ifY=0then0elsexmult(y-1)+x;
Semantic Indentation	X
While Loops	X