91 lines
2.5 KiB
Scheme
91 lines
2.5 KiB
Scheme
;;; Copyright (c) 1994 by Olin Shivers
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;;; Add scsh conditions to s48.
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;;; A syscall-error condition-type:
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(define-condition-type 'syscall-error '(error))
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(define syscall-error? (condition-predicate 'syscall-error))
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(define (errno-error errno syscall . stuff)
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(let ((msg (errno-msg errno)))
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(apply signal 'syscall-error errno msg syscall stuff)))
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(define (with-errno-handler* handler thunk)
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(with-handler
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(lambda (condition more)
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(if (syscall-error? condition)
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(let ((stuff (condition-stuff condition)))
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(handler (car stuff) ; errno
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(cdr stuff)))) ; (msg syscall . packet)
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(more))
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thunk))
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;;; (with-errno-handler
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;;; ((errno data) ; These are vars bound in this scope.
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;;; ((errno/exist) . body1)
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;;; ((errno/wouldblock errno/again) . body2)
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;;; (else . body3))
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;;;
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;;; . body)
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(define-syntax with-errno-handler
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(lambda (exp rename compare)
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(let* ((%lambda (rename 'lambda))
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(%cond (rename 'cond))
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(%else (rename 'else))
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(%weh (rename 'with-errno-handler*))
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(%= (rename '=))
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(%begin (rename `begin))
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(%or (rename `or))
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(%call/cc (rename 'call-with-current-continuation))
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(%cwv (rename 'call-with-values))
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(%ret (rename 'ret)) ; I think this is the way to gensym.
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(err-var (caaadr exp))
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(data-var (car (cdaadr exp)))
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(clauses (cdadr exp))
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(body (cddr exp))
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(arms (map (lambda (clause)
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(let ((test (if (compare (car clause) %else)
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%else
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(let ((errs (car clause)))
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`(,%or . ,(map (lambda (err)
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`(,%= ,err ,err-var))
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errs))))))
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`(,test
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(,%cwv (,%lambda () . ,(cdr clause)) ,%ret))))
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clauses)))
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`(,%call/cc (,%lambda (,%ret)
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(,%weh
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(,%lambda (,err-var ,data-var)
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(,%cond . ,arms))
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(,%lambda () . ,body)))))))
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;;;; S48 already has this machinery, i.e., (SET-INTERACTIVE?! flag)
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;;;; Interactive => breakpoint on errors.
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;;;; Noninteractive => exit on errors.
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;
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;(define $interactive-errors? (make-fluid #f))
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;
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;(define (with-interactive-errors val thunk)
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; (let-fluid $interactive-errors? val thunk))
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;
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;(define (set-interactive-errors! val)
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; (set-fluid! $interactive-errors? val))
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;
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;;;; Just quit if non-interactive. Otherwise, punt to next handler.
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;;;; A hack, because we use the default handler for the interactive
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;;;; case.
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;
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;(define (scsh-error-handler condition more)
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; (if (and (error? condition)
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; (not (fluid $interactive-errors?)))
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; (begin (display condition (error-output-port))
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; (exit -1))
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; (more)))
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