On 2011-05-26, at 1:17 PM, Bradley Lucier wrote:
On Wed, 2011-05-25 at 16:37 -0400, Marc Feeley wrote:
The problem is related to the "absent" object, which is used in the handling of optional parameters. Note that there is no direct way to generate the absent object. The following macro, defined in lib/_gambit#.scm, must be used:
(##define-macro (macro-absent-obj) `',(##type-cast -6 2))
Marc:
People who write libraries could use (macro-absent-obj) quite fruitfully, see the code in
http://www.math.purdue.edu/~lucier/gambit-srfis/error-macros.scm
It would be good if (macro-absent-object) were exported by the runtime system, and not just defined in the compiler, so you could run code like this in gsi.
If the absent object is exported, then other things in Gambit will break (such as the handling of optional parameters).
In any case, you can get at the macro-absent-obj macro with:
(##include "~~lib/_gambit#.scm")
Marc