Fix bug causing characters to be lost.

diff --git a/v7/src/edwin/tterm.scm b/v7/src/edwin/tterm.scm
index b8f7e53c50df15bcdb6a427718ecd70666557015..d8fded65b137a431d5613ebafa7e36ef14d00802 100644 (file)
--- a/v7/src/edwin/tterm.scm
+++ b/v7/src/edwin/tterm.scm
@@ -1,6 +1,6 @@
 #| -*-Scheme-*-
 
-$Header: /Users/cph/tmp/foo/mit-scheme/mit-scheme/v7/src/edwin/tterm.scm,v 1.15 1992/02/25 23:32:03 cph Exp $
+$Header: /Users/cph/tmp/foo/mit-scheme/mit-scheme/v7/src/edwin/tterm.scm,v 1.16 1992/02/27 00:44:50 cph Exp $
 
 Copyright (c) 1990-92 Massachusetts Institute of Technology
 
@@ -151,53 +151,54 @@ MIT in each case. |#
     (let ((read-event
           (lambda (block?)
             (let ((event pending-event))
-              (if event
-                  (begin
-                    (set! pending-event false)
-                    event)
-                  (let loop ()
-                    (if block?
-                        (channel-blocking channel)
-                        (channel-nonblocking channel))
-                    (let ((n
-                           (channel-select-then-read
-                            channel string 0 input-buffer-size)))
-                      (cond ((not n)
-                             (if block?
-                                 (error "#F returned from blocking read"))
-                             false)
-                            ((fix:> n 0)
-                             (set! start 0)
-                             (set! end n)
-                             (if transcript-port
-                                 (output-port/write-substring
-                                  transcript-port string 0 n))
-                             (string-ref string 0))
-                            ((or (fix:= n event:process-output)
-                                 (fix:= n event:process-status))
-                             n)
-                            ((fix:= n event:interrupt)
-                             (if inferior-thread-changes? n (loop)))
-                            ((fix:= n 0)
-                             (error "Reached EOF in keyboard input."))
-                            (else
-                             (error "Illegal return value:" n))))))))))
+              (cond (event
+                     (set! pending-event false)
+                     event)
+                    ((fix:< start end)
+                     (string-ref string start))
+                    (else
+                     (let loop ()
+                       (if block?
+                           (channel-blocking channel)
+                           (channel-nonblocking channel))
+                       (let ((n
+                              (channel-select-then-read
+                               channel string 0 input-buffer-size)))
+                         (cond ((not n)
+                                (if block?
+                                    (error "#F returned from blocking read"))
+                                false)
+                               ((fix:> n 0)
+                                (set! start 0)
+                                (set! end n)
+                                (if transcript-port
+                                    (output-port/write-substring
+                                     transcript-port string 0 n))
+                                (string-ref string 0))
+                               ((or (fix:= n event:process-output)
+                                    (fix:= n event:process-status))
+                                n)
+                               ((fix:= n event:interrupt)
+                                (if inferior-thread-changes? n (loop)))
+                               ((fix:= n 0)
+                                (error "Reached EOF in keyboard input."))
+                               (else
+                                (error "Illegal return value:" n)))))))))))
       (let ((read-until-result
             (lambda (block?)
               (let loop ()
-                (or (fix:< start end)
-                    (let ((event
-                           (if block?
-                               (or (read-event false)
-                                   (begin
-                                     (update-screens! false)
-                                     (read-event true)))
-                               (read-event false))))
-                      (if (fix:fixnum? event)
-                          (begin
-                            (process-change-event event)
-                            (loop))
-                          event)))))))
+                (let ((event
+                       (if block?
+                           (or (read-event false)
+                               (begin
+                                 (update-screens! false)
+                                 (read-event true)))
+                           (read-event false))))
+                  (if (fix:fixnum? event)
+                      (begin
+                        (process-change-event event)
+                        (loop))
+                      event))))))
        (values
         (lambda ()                     ;halt-update?
           (or pending-event