From 63038285e563c453d89a3fdaea2afc4f0c5a3d41 Mon Sep 17 00:00:00 2001
From: Max New <maxsnew@gmail.com>
Date: Mon, 9 Mar 2015 17:12:43 -0500
Subject: [PATCH] Delete trailing whitespace on return

---
 gui-doc/scribblings/framework/racket.scrbl |  1 +
 gui-lib/framework/private/racket.rkt       | 36 ++++++++++++--------
 gui-test/framework/tests/racket.rkt        | 38 ++++++++++++++++++++++
 3 files changed, 61 insertions(+), 14 deletions(-)

diff --git a/gui-doc/scribblings/framework/racket.scrbl b/gui-doc/scribblings/framework/racket.scrbl
index 6364f77d..6ba0f0f0 100644
--- a/gui-doc/scribblings/framework/racket.scrbl
+++ b/gui-doc/scribblings/framework/racket.scrbl
@@ -86,6 +86,7 @@
   @defmethod*[(((insert-return) void?))]{
     Inserts a newline into the buffer.  If @method[racket:text<%>
     tabify-on-return?] returns @racket[#t], this will tabify the new line.
+    Deletes any trailing whitespace from the old line.
   }
 
   @defmethod*[(((box-comment-out-selection
diff --git a/gui-lib/framework/private/racket.rkt b/gui-lib/framework/private/racket.rkt
index 38662f20..c0d86887 100644
--- a/gui-lib/framework/private/racket.rkt
+++ b/gui-lib/framework/private/racket.rkt
@@ -756,20 +756,28 @@
     
     (define (tabify-all) (tabify-selection 0 (last-position)))
     (define (insert-return)
-      (if (tabify-on-return?)
-          (begin 
-            (begin-edit-sequence #t #f)
-            (insert #\newline)
-            (tabify (get-start-position))
-            (set-position 
-             (let loop ([new-pos (get-start-position)])
-               (if (let ([next (get-character new-pos)])
-                     (and (char-whitespace? next)
-                          (not (char=? next #\newline))))
-                   (loop (add1 new-pos))
-                   new-pos)))
-            (end-edit-sequence))
-          (insert #\newline)))
+      (begin-edit-sequence #t #f)
+      (define end-of-whitespace (get-start-position))
+      (define start-cutoff
+        (paragraph-start-position (position-paragraph end-of-whitespace)))
+      (define start-of-whitespace
+        (let loop ([pos end-of-whitespace])
+          (if (and (> pos start-cutoff)
+                   (char-whitespace? (get-character (sub1 pos))))
+              (loop (sub1 pos))
+              pos)))
+      (delete start-of-whitespace end-of-whitespace)
+      (insert #\newline)
+      (when (and (tabify-on-return?)
+                 (tabify (get-start-position)))
+        (set-position
+         (let loop ([new-pos (get-start-position)])
+           (if (let ([next (get-character new-pos)])
+                 (and (char-whitespace? next)
+                      (not (char=? next #\newline))))
+               (loop (add1 new-pos))
+               new-pos))))
+      (end-edit-sequence))
     
     (define (calc-last-para last-pos)
       (let ([last-para (position-paragraph last-pos #t)])
diff --git a/gui-test/framework/tests/racket.rkt b/gui-test/framework/tests/racket.rkt
index 9239f8b0..ce2799ff 100644
--- a/gui-test/framework/tests/racket.rkt
+++ b/gui-test/framework/tests/racket.rkt
@@ -185,6 +185,44 @@
 (test-magic-square-bracket 'for/fold1 "(for/fold (" "(for/fold ([")
 (test-magic-square-bracket 'for/fold2 "(for/fold ([x 1]) (" "(for/fold ([x 1]) ([")
 
+(define (test-insert-return/proc line before-txt before-pos after-txt after-pos #:tabify? [tabify? #t])
+  (test
+   (string->symbol (format "racket:test-insert-return ~a" line))
+   (λ (x)
+     (and (equal? (car x) after-pos)
+          (equal? (cadr x) after-txt)))
+   (λ ()
+    (queue-sexp-to-mred
+     `(let ()
+       (define t (new (class racket:text%
+                            (define/override (tabify-on-return?) ,tabify?)
+                            (super-new))))
+       (send t insert ,before-txt)
+       (send t set-position ,before-pos)
+       (send t insert-return)
+       (list (send t get-start-position)
+             (send t get-text)))))))
+
+(define-syntax (test-insert-return stx)
+  (syntax-case stx ()
+    [(_  before-txt before-pos after-txt after-pos . args)
+     (with-syntax ([line (syntax-line stx)])
+       #'(test-insert-return/proc line before-txt before-pos after-txt after-pos . args))]))
+
+(test-insert-return "" 0 "\n" 1)
+(test-insert-return "" 0 "\n" 1 #:tabify? #f)
+(test-insert-return " " 1 "\n" 1)
+(test-insert-return " " 1 "\n" 1 #:tabify? #f)
+(test-insert-return "( " 2 "(\n " 3)
+(test-insert-return "( " 2 "(\n" 2 #:tabify? #f)
+(test-insert-return "hellothere" 5 "hello\nthere" 6)
+(test-insert-return "hellothere" 5 "hello\nthere" 6 #:tabify? #f)
+(test-insert-return "#lang racket\n(+ 123 456)\n 4"      20 "#lang racket\n(+ 123\n  456)\n 4" 22)
+(test-insert-return "#lang racket\n(+ 123 456)\n 4"      20 "#lang racket\n(+ 123\n456)\n 4" 20 #:tabify? #f)
+(test-insert-return "#lang racket\n(+ 123      456)\n 4" 22 "#lang racket\n(+ 123\n  456)\n 4" 22)
+(test-insert-return "#lang racket\n(+ 123      456)\n 4" 22 "#lang racket\n(+ 123\n   456)\n 4" 20 #:tabify? #f)
+(test-insert-return "#lang racket\n(+ 123 \n   456)\n 4" 22 "#lang racket\n(+ 123 \n\n  456)\n 4" 24)
+(test-insert-return "#lang racket\n(+ 123 \n   456)\n 4" 22 "#lang racket\n(+ 123 \n\n  456)\n 4" 22 #:tabify? #f)
 
 (define (test-message-send/proc line before expected pos msg
                                 #:check-result? [check-result? #f]