On Wed, 09 Sep 2009 11:05:53 -0400, John Cowan <[email protected]> wrote:
> Andre van Tonder scripsit:
>
>> This, however, makes it difficult to write program transformers (for
>> example macro expanders), that need to insert generated symbols for
>> which the requirement is that they cannot be typed in user programs.
>
> As others have posted, I think using a separate (and implementation
> specific) identifier type is now a win. At run time, gensyms are
> basically
> just strings that satisfy "symbol?" (and have p-lists, if your Scheme
> does p-lists), and if you need to play with such things, you are better
> off redefining "symbol?" or moving up to an informally-expressed union
> datatype of strings and true symbols.
Don't we already have an 'identifier?' procedure? We already have a system
that distinguishes symbols and syntax. I'm not sure what the problem is. I
may have missed the discussion...
Aaron W. Hsu
--
Of all tyrannies, a tyranny sincerely exercised for the good of its
victims may be the most oppressive. -- C. S. Lewis
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