On 02/01/2013 09:39 AM, Tim Brown wrote:
On 01/02/13 13:13, Matthias Felleisen wrote:
Actually what does it mean to access syntactic extensions at run-time?
Just a thought, but is there a case for pulling the syntaxes into a
"run-time" test suite ("raco test", or even the GUI tester?) and testing
them there... e.g. do they transform a list of datums or a string of code
into an expected output of datums? Equally interesting, given an invalid
form (as a list of datums), to the macros fail, but without busting the
test environment because there has been a syntax error.
One way to do that would be to construct a namespace and use 'eval'.
When dealing with macros, you need to think *terms* (really,
expressions, definitions, etc), not *values*.
In a previous discussion(*), I have seen "positive" tests for macros...
I input a form and when run, the output displays the runtime-evaluated
result of the transformed macro.
Say we have:
(module+ test (require rackunit))
(define-syntax-rule
(define/test (f x ...) (#:tests t ...) e ...)
(begin
(module+ test
t ...)
(define (f x ...) e ...)))
(define/test (add-two a) (#:tests (check-= (add-two 2) 4 0)) (+ 2 a))
(define/test (add-three a) (#:tests (check-= (add-three 2) 5 0)) (+ 2 a))
I get no test results (i.e. success) for add-two. I get a test fails for
add-three. But if I now want to ensure/document (via a test) that the
following is an invalid syntax (all define/test forms should have a
#:tests form:
(define/test (add-four a) (check-= (add-four 2) 6 0) (+ 4 a))
This won't compile; I can't get off the starting line.
I have an outstanding question about "unit-testing" syntactic extensions
from a couple of weeks ago. What do the heavier users of syntaxes use to
unit test their macros?
Either construct a namespace and use 'eval' or wrap the invalid syntax
in something that catches compile-time exceptions and produces code that
raises the same exception at run time.
The error tests for syntax-parse, for example, use the second technique.
See tests/stxparse/test-error; the macro that turns compile-time
exceptions into run-time exceptions is 'convert-syntax-errors' in
tests/stxparse/setup. IIRC, Eli's test macro does this by default, and
that's probably where I got the idea from.
Ryan
* http://lists.racket-lang.org/users/archive/2013-January/055983.html
On Feb 1, 2013, at 2:57 AM, Dan Grossman wrote:
Cody and I would love an answer to this question from 1.5 months ago if
anybody can point us in the right direction and/or ask us to clarify the
question. Or if the answer is "that is not possible" then we'll do
something else.
Much thanks!
--Dan
On Mon, Dec 17, 2012 at 9:20 PM, Cody Schroeder <codeblac...@gmail.com
<mailto:codeblac...@gmail.com>> wrote:
I'm in a position that I would like to use dynamic-require
<http://docs.racket-lang.org/reference/Module_Names_and_Loading.html#(def._((quote._~23~25kernel)._dynamic-require))>
to
gain access to all of the provides in a module. This is quite
straightforward for normal procedures, but I also want this to
include syntax. However, I get this error when trying to
dynamically
require the blah macro from my test module:
(dynamic-require "test.rkt" 'blah)
blah: use does not match pattern: (blah body) in: blah
From the spec, it says that "If the module exports provided as
syntax, then a use of the binding is expanded and evaluated in a
fresh namespace to which the module is attached" when using
dynamic-require. I don't understand how it's being used, though.
Is there a way to use dynamic-require how I want? Is there a
better way?
Cody
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