chickadee » simple-loops

simple-loops

This module exports some simple loop macros. The syntax of some of them has changed, but the earlier versions are still valid, albeit deprecated.

The routines

simple-loops

simple-loops #!optional symprocedure

documentation-procedure; returns the list of exported symbols if called with no symbol, otherwise the signature of that exported symbol sym.

do-for

(do-for (var start stop step) xpr . xprs)syntax
(do-for (var start stop) xpr . xprs)syntax
; deprecated
(do-for var (start stop step) xpr . xprs)syntax
(do-for var (start stop) xpr . xprs)syntax

for-loop: do xpr . xprs for var in [start stop[ with step defaulting to 1")

do-forever

(do-forever xpr . xprs)syntax

endless loop: executes body xpr . xprs until exit is called, a symbol being defined behind the scenes.

do-list

(do-list (var lst) xpr . xprs)syntax
; deprecated
(do-list var lst xpr . xprs)syntax

loop along a list: execute xpr . xprs for var in lst

do-times

(do-times (k upto) xpr . xprs)syntax
; deprecated
(do-times k upto xpr . xprs)syntax

loops a fixed number of times: execute xpr . xprs for k in [0 upto[

do-until

(do-until test? xpr . xprs)syntax

until-loop: execute xpr . xprs while test? is false

do-while

(do-while test? xpr . xprs)syntax

while-loop: execute xpr . xprs while test? is true

Requirements

none

Example

(import simple-loops)

    (let ((lst '()))
      (do-for (var 1 65 var) (set! lst (cons var lst)))
      (reverse lst))
    ;-> '(1 2 4 8 16 32 64)

    (let ((n 3) (lst '()))
      (do-forever
        (if (zero? n) (exit lst))
        (set! lst (cons 'a lst))
        (set! n (- n 1))))
    ;-> '(a a a)

    (let ((lst '()))
      (do-list (var '(1 2 3))
        (set! lst (cons var lst)))
      lst)
    ;-> '(3 2 1)

    (let ((lst '()))
      (do-times (k (+ 2 3))
        (set! lst (cons k lst)))
      lst)
    ;-> '(4 3 2 1 0)

    (let ((n 4) (lst '()))
      (do-until (> 0 n)
        (set! lst (cons n lst))
        (set! n (- n 1)))
      lst)
    ;-> '(0 1 2 3 4)

    (let ((n 4) (lst '()))
      (do-while (<= 0 n)
        (set! lst (cons n lst))
        (set! n (- n 1)))
      lst)
    ;-> '(0 1 2 3 4)

Last update

May 18, 2022

Author

Juergen Lorenz

License

Copyright (c) 2013-2022, Juergen Lorenz
All rights reserved.
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are
met:

Redistributions of source code must retain the above copyright
notice, this list of conditions and the following disclaimer.

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Version History

1.0
port from chicken-4
2.0
some loops with new syntax; the old syntax is deprecated

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