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call-with-environment-variables

Set up and take down environment vars

call-with-environment-variables

[procedure] (call-with-environment-variables variables thunk) → unspecified

Sets up environment variable via dynamic-wind which are taken down after thunk.

variables

An alist of the form '(("var" . "value") ...)

thunk

The thunk to execute with a modified environment

(define (call-with-environment-variables variables thunk)
  (let ((pre-existing-variables
          (map (lambda (var-value)
                 (let ((var (car var-value)))
                   (cons var (get-environment-variable var))))
               variables)))
    (dynamic-wind
      (lambda () (void))
      (lambda ()
        (use posix)
        (for-each
          (lambda (var-value) (setenv (car var-value) (cdr var-value)))
          variables)
        (thunk))
      (lambda ()
        (for-each
          (lambda (var-value)
            (let ((var (car var-value)) (value (cdr var-value)))
              (if value (setenv var value) (unsetenv var))))
          pre-existing-variables)))))

About this egg

Author

Peter Danenberg

Repository

https://github.com/klutometis/call-with-environment-variables

License

BSD

Dependencies

• hahn
• setup-helper

Versions

0.1

Initial release

0.1.1

Add the actual code.

0.1.2

Fix versions.

0.1.3

Update docs.

0.1.4

With a note about cock-utils

0.1.5

Docs

0.1.6

Use hahn.

0.1.7

Specify hahn-version.

Colophon

Documented by hahn.