[r6rs-discuss] [Formal] identifier macros with syntax-rules

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Name: David Van Horn
Email: dvanhorn_at_cs.brandeis.edu
Type: Enhancement
Priority: Major
R6RS component: Macros
Version of the report: 5.91
Summary of the issue
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It should be possible to define identifier macros using only the base 
library.
Full description
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The (r6rs syntax-case) library allows for identifier macros to be 
defined, however their specification is orthogonal to both non-hygienic 
macro expansion and the ability to evaluate arbitrary Scheme code at 
expansion time, thus it should be possible to define identifier macros 
in terms of syntax-rules.  This implies extending the <srpattern> 
production to include an underscore, having syntax-rules forms evaluate 
to transformers, and moving make-variable-transformer to the base library.