assert()ing in elisp

assert()ing in elisp

[lalit mohan tripathi]

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Hi Everyone,

   I was wondering how I could write assert(condition) in elisp code, as I
can do in C by including assert.h?

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Re: assert()ing in elisp

[Kevin Rodgers]

lalit mohan tripathi wrote:
>    I was wondering how I could write assert(condition) in elisp code, as 
> I can do in C by including assert.h?

(require 'cl)
(assert CONDITION)

-- 
Kevin

Re: assert()ing in elisp

[Eric Hanchrow]

Here's one example:
(defun assert= (expected actual)
  (when (not (string-equal expected actual))
    (error "expected %S; got %S" expected actual)))
-- 
There is such a thing as American-ness.  ... [H]ackers ... come
closest of any group I know to embodying it.  Closer, probably, than
the men running our government.
        -- Paul Graham

Re: assert()ing in elisp

[Giorgos Keramidas]

On Thu, 29 Jun 2006 06:26:09 -0700, Eric Hanchrow <offby1@blarg.net> wrote:
> Here's one example:
> (defun assert= (expected actual)
>   (when (not (string-equal expected actual))
>     (error "expected %S; got %S" expected actual)))

Or you could use a macro, which can print the assertion
that failed too:

,----------------------------------------------------------------
| (defmacro assert (test-form)
|   `(when (not ,test-form)
|      (error "Assertion failed: %s" (format "%s" ',test-form))))
|
| (assert (equal t nil))
| =>
| Debugger entered--Lisp error: (error "Assertion failed: (equal t nil)")
|   signal(error ("Assertion failed: (equal t nil)"))
|   error("Assertion failed: %s" "(equal t nil)")
|   (progn (error "Assertion failed: %s" (format "%s" ...)))
|   (if (not (equal t nil)) (progn (error "Assertion failed: %s" ...)))
|   (when (not (equal t nil)) (error "Assertion failed: %s" (format "%s" ...)))
|   (assert (equal t nil))
|   eval((assert (equal t nil)))
|   eval-last-sexp-1(nil)
|   eval-last-sexp(nil)
|   call-interactively(eval-last-sexp)
`----------------------------------------------------------------