local

  1. local
    1. Description
    2. Documentation
      1. locals
      2. local
      3. Examples
    3. Requirements
  2. Last update
  3. Author
  4. License
  5. Version History

Description

Besides the documentation procedure, this module exports only one macro, local, which is inspired by the equally named operator in ML. It exports a list of definitions, depending on another hidden list of definitions. So it can be used to implement procedures depending on a common state, something what define-values can do as well. In this new version, the hidden definitions can be macros as well, but that enforces a small syntax change: you have to add the keywords define, define-syntax or what have you.

Documentation

This documentation uses special ellipses meaning

locals

[procedure] (locals)

shows the definition of the local macro.

local

[syntax] (local (def ...) (var val)|((var . args) . body) ....)

exports procedures var ... depending on hidden procedures or macros def ...

Examples


;; fake example
(local (
  (define-syntax xx
    (syntax-rules ()
     ((_ x) (* x x))))
  (define (yy y) 1 2 3 (+ y y))
  (define zz 5)
  (define (uu u . us) #t)
  (define vv (lambda vs 10 20))
  (define (ww . ws) #f)
  )
  (aa (lambda (a) (+ zz (* 2 (xx a)))))
  ((bb b) 4 5 6 (* zz (* (xx b) (xx b))))
  (cc (* 2 zz))
  ((dd) (or (uu 10 20 30) (ww)))
  ((ee e) (vv #t #f)))

;; counter
(local (
  (state 0)
  )
  ((counter-ref) state)
  ((counter-add!)
   (set! state (+ state 1)))
  ((counter-reset!)
   (set! state 0)))

(counter-ref) ; -> 0
(counter-add!)
(counter-add!)
(counter-ref) ; -> 2
(counter-reset!)
(counter-ref) ; -> 0

Requirements

none

Last update

Dez 24, 2016

Author

Juergen Lorenz

License

Copyright (c) 2016, 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.

Redistributions in binary form must reproduce the above copyright
notice, this list of conditions and the following disclaimer in the
documentation and/or other materials provided with the distribution.
Neither the name of the author nor the names of its contributors may be
used to endorse or promote products derived from this software without
specific prior written permission. 
  
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

Version History

2.0
rewrite to accept macros
1.0
initial import