78 lines
2.1 KiB
Scheme
78 lines
2.1 KiB
Scheme
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; Copyright (c) 1994 by Richard Kelsey. See file COPYING.
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; Expanding using the Scheme 48 expander.
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(define (scan-packages packages)
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(let ((definitions
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(fold (lambda (package definitions)
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(let ((cenv (package->environment package)))
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(fold (lambda (form definitions)
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(let ((node (expand-form form cenv)))
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(cond ((define-node? node)
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(cons (eval-define (expand node cenv)
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cenv)
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definitions))
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(else
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(eval-node (expand node cenv)
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global-ref
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global-set!
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eval-primitive)
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definitions))))
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(call-with-values
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(lambda ()
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(package-source package))
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(lambda (files.forms usual-transforms primitives?)
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(scan-forms (apply append (map cdr files.forms))
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cenv)))
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definitions)))
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packages
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'())))
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(reverse (map (lambda (var)
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(let ((value (variable-flag var)))
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(set-variable-flag! var #f)
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(cons var value)))
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definitions))))
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(define package->environment (structure-ref packages package->environment))
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(define define-node? (node-predicate 'define))
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(define (eval-define node cenv)
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(let* ((form (node-form node))
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(value (eval-node (caddr form)
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global-ref
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global-set!
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eval-primitive))
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(lhs (cadr form)))
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(global-set! lhs value)
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(name->variable-or-value lhs)))
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(define (global-ref name)
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(let ((thing (name->variable-or-value name)))
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(if (variable? thing)
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(variable-flag thing)
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thing)))
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(define (global-set! name value)
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(let ((thing (name->variable-or-value name)))
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(if (primitive? thing)
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(bug "trying to set the value of primitive ~S" thing)
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(set-variable-flag! thing value))))
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(define (name->variable-or-value name)
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(let ((binding (node-ref name 'binding)))
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(if (binding? binding)
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(let ((value (binding-place binding))
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(static (binding-static binding)))
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(cond ((primitive? static)
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static)
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((variable? value)
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value)
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((and (location? value)
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(constant? (contents value)))
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(contents value))
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(else
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(bug "global binding is not a variable, primitive or constant ~S" name))))
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(user-error "unbound variable ~S" (node-form name)))))
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