Re: early binding

[David Bartley <Bartley%ti-csl.csnet@CSNET-RELAY.ARPA>]

You've pretty well answered my questions, thanks...  I have one last
(small) question and comment on the following:

>Date: Wed, 16 Apr 86 20:57:31 EST
>From: Jonathan A Rees <JAR%mc.lcs.mit.edu@CSNET-RELAY.ARPA>
>
>    Date: Tue 15 Apr 86 13:17:22-CST
>    From: David Bartley <Bartley%ti-csl.csnet at CSNET-RELAY.ARPA>
>
>    (1) What do you do if Fi is a BEGIN?  For example, in
>
>       (FILE F1 F2 ... (BEGIN (DEFINE A ...)(FOO)(DEFINE B ...)) ... Fn),
>
>    are the DEFINEs for both A and B collected into a BIND by your pre-pass?
>
>Yes -- this is an extra bonus feature.
>
>    (2) Do you expand macros during the pre-pass?  What if a macro expands
>    into a DEFINE or a BEGIN containing a DEFINE?
>
>Yes, macros get expanded in the pre-pass, so it "works" for a macro to
>expand into (begin (define ...) ...).  Only the top level forms get
>macro expanded, not their subforms (lazy macroexpansion).

If only the top level forms get macro expanded, then a DEFINE at the
top level of a macro called FOO would not be recognized in the top
level form (BEGIN (FOO A)(FOO B)), right?  That is, if (FOO A)
macro-expands into (DEFINE A 42), we'd have (BEGIN (DEFINE A
42)(DEFINE B 42)), but you'd not catch these particular ``top level''
defines?

Similarly, suppose (BAR X Y Z) were a macro that expanded into 
(BEGIN X Y Z).  What would happen to (BAR (FOO A)(FOO B))?  Would it
be fully expanded into (BEGIN (DEFINE A 42)(DEFINE B 42)) in order
to catch the definitions?

The same question applies to macro expanding the bodies of lambdas in
order to detect ``top level'' DEFINEs to be collected into a LETREC.
To be honest, I'm not sure how deep my own PC Scheme goes in macro
expansion to detect such definitions.

Regards,
David Bartley
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