[Scheme-reports] equivalent rewrite of a sequence of (syntax) definitions?
Daniel Villeneuve 04 Jan 2013 03:03 UTC
Without syntax definitions, a sequence of definitions is
equivalent to a letrec* form (Section 5.3.2).
With syntax definitions, since this is explicitly not covered by Section
5.3.2,
the wording of Section 5.4 should be used. However, it is not said:
- what happens with too mutually recursive syntactic definitions;
- how to split subsequences of regular and syntactic definitions.
I would propose the following rewrite:
Given a sequence of definitions and syntax definitions at the start of
a <body>, let r_i be the identifier bound by the i^{th} definition v_i
and s_i be the identifier bound by the i^{th} syntax definition d_i.
Then, the entire sequence of definitions and syntax definitions
is equivalent to
(letrec-syntax ((s_i d_i) ...)
(letrec* ((r_i v_i) ...)
<expressions>+))
Is this a plausible rewrite?
I know it conflicts with the wording at the end of Section 5.4 which says
> Any use of a syntax keyword before its corresponding definition is
> an error.
but if the above rewrite is "correct", this error condition could be
dropped.
--
Daniel Villeneuve
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