scsh-0.6/scsh/syntax.scm

;;; Syntax definitions for scsh.
;;; Translating process forms into Scheme code.
;;; Copyright (c) 1993 by Olin Shivers.

(define-syntax define-simple-syntax
  (syntax-rules ()
    ((define-simple-syntax (name . pattern) result)
     (define-syntax name (syntax-rules () ((name . pattern) result))))))

;;; The three basic forms for running an extended process form:
;;; EXEC-EPF, &, and RUN. EXEC-EPF is the foundation.

;; This is used by the macro for the << redirection to prevent the temporary 
;; port from being closed by a GC before the process exec's
(define <<-port-holder)

(define-syntax exec-epf
  (lambda (form rename compare)
    (transcribe-extended-process-form (cdr form) rename compare)))

(define-simple-syntax (& . epf)
  (fork (lambda () (exec-epf . epf))))

(define-simple-syntax (run . epf)
  (wait (& . epf)))

;;; Sequencing operators:
;;;
;;; (|| pf1 ... pfn)
;;;     Run each proc until one completes successfully (i.e., exit status 0).
;;;     Return true if some proc completes successfully; otherwise #f.
;;;
;;; (&& pf1 ... pfn) 
;;;     Run each proc until one fails (i.e., exit status non-0).
;;;     Return true if all procs complete successfully; otherwise #f.

;;; WARNING: || is not a readable symbol in R4RS.

(define-simple-syntax (|| pf ...) (or  (zero? (run pf)) ...))
(define-simple-syntax (:or: pf ...) (or  (zero? (run pf)) ...))
(define-simple-syntax (&& pf ...) (and (zero? (run pf)) ...))

(define-simple-syntax (run/collecting fds . epf)
  (run/collecting* `fds (lambda () (exec-epf . epf))))

(define-simple-syntax (run/port+proc . epf)
  (run/port+proc* (lambda () (exec-epf . epf))))

(define-simple-syntax (run/port . epf)
  (run/port* (lambda () (exec-epf . epf))))

(define-simple-syntax (run/strings . epf)
  (run/strings* (lambda () (exec-epf . epf))))

(define-simple-syntax (run/file . epf)
  (run/file* (lambda () (exec-epf . epf))))

(define-simple-syntax (run/string . epf)
  (run/string* (lambda () (exec-epf . epf))))

(define-simple-syntax (run/sexp . epf)
  (run/sexp* (lambda () (exec-epf . epf))))

(define-simple-syntax (run/sexps . epf)
  (run/sexps* (lambda () (exec-epf . epf))))

(define-simple-syntax (run/pty . epf)
  (run/pty* (lambda () (exec-epf . epf))))

;(define (expand-mac transformer form)
;  (transformer form (lambda (x) x) eq?))

;(define-simple-syntax (test-mac trans . form)
;  (pp (expand-mac trans (quote form))))