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Implicit renaming macros
This module contains some macros to make the use of low-level implicit renaming macros easyier. Recall that those macros are implemented as a transformer routine, which is a three-parameter procedure
(lambda (form inject compare?) ...)
which has to be enclosed by an ir-macro-transformer call. The programmer's job is to destructure the macro-code, form. All symbols of the macro-expression not protected by inject are transparently renamed in the background to achieve hygiene. If no symbol is injected, the macro is automatically hygienic.
The job of destructuring the macro-code is tedious and error prone, it can be done by a tool, bind from the contracts module, for example. Based on that, a macro ir-macro-rules has been implemented there. It mimics syntax-rules by design. The other job, compare? literal symbols supplied by the macro's client with those renamed behind the scene, something which is needed to use symbols like else and => in the cond macro, remains to be done. Hence ir-macro-rules is unhygienic by design. It exports compare? and inject to its local scope, the latter in case the macro has to export unrenamed symbols.
All macros in this module are unhygienic by design, since the evaluate to ir-macro-rules. They pollute the local (!) namespace with the symbols compare? and inject. But the macros implemented with those macros can be - and are in most cases - hygienic.
ir-macros[procedure] (ir-macros sym)
where sym is optional.
This is the documentation dispatcher provided for all modules written in the Design-by-Contract style. Without a symbol, it lists all exported symbols of the module, with one of these symbols it prints the contract of the symbol.
ir-macro-define[syntax] (ir-macro-define (name . args) . body)
defines a macro with macro-code (name . args) by means of body, which is either a sequence of expressions xpr . xprs which generate a template, or a list of the form (with-injected (sym ...) xpr . xprs). In the latter case the macro is unhygienic and pollutes its local namespace with sym ..., in the former case it is hygienic.
Note, that this macro in its hygienic form has exactly the same syntax as define-macro of Chicken-3 and other Schemes!
ir-macro-define-with-syntax[syntax] (ir-macro-define-with-syntax (name . args) [docstring] . body)
a contract-checked version of ir-macro-define.
ir-macro-let[syntax] (ir-macro-let ((code0 . body0) ...) . body)
where code0 ... is the macro-code (name0 . args0) ... of a local macro and body0 ... the corresponding body which generates a template. As in ir-macro-define this must either be a sequence of expressions, xpr0 . xprs0, or a list of the form (with-injected (sym0 ...) xpr0 . xprs0). In the latter case the local macros are unhygienic. These macros are locally defined in parallel and in there scope body is executed.
ir-macro-letrec[syntax] (ir-macro-letrec ((code0 body0) ...) . body)
recursive version of ir-macro-let, i.e. the local macros have access to each other.
(import ir-macros contracts) (import-for-syntax (only contracts syntax-contract ir-macro-rules))
(define-syntax my-or (ir-macro-rules () ((_) #f) ((_ arg . args) `(if ,arg ,arg (my-or ,@args)))))
Copyright (c) 2011, Juergen Lorenz All rights reserved.
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- Bug in ir-macro-define-with-contract corrected
- ir-macro-define-with-contract added, aliases without ir- prefix removed
- All macros in this egg made unhygienic by design
- changed syntax of [ir-]macro-rules, thanks to Moritz Heidkamp
- added additional inject argument to all transformers
- initial import
Jul 22, 2011