REPL: transpose multiple lines at once when highlighted

base/repl/LineEdit.jl

@@ -219,7 +219,7 @@ command_group(command::Function) = command_group(Base.function_name(command))
 
 # return true if command should keep active a region
 function preserve_active(command::Symbol)
-    command == :edit_indent
+    command ∈ [:edit_indent, :edit_transpose_lines_down!, :edit_transpose_lines_up!]
 end
 
 function set_action!(s::MIState, command::Symbol)
@@ -953,37 +953,39 @@ function edit_transpose_words(buf::IOBuffer, mode=:emacs)
 end
 
 
-# swap current line with line above
-function edit_transpose_lines_up!(buf::IOBuffer)
-    b2 = beginofline(buf)
+# swap all lines intersecting the region with line above
+function edit_transpose_lines_up!(buf::IOBuffer, reg::Region)
+    b2 = beginofline(buf, first(reg))
     b2 == 0 && return false
     b1 = beginofline(buf, b2-1)
     # we do in this order so that the buffer's position is maintained in current line
     line1 = edit_splice!(buf, b1 => b2) # delete whole previous line
     line1 = '\n'*line1[1:end-1] # don't include the final '\n'
     pos = position(buf) # save pos in case it's at the end of line
-    b = endofline(buf)
+    b = endofline(buf, last(reg) - b2 + b1) # b2-b1 is the size of the removed line1
     edit_splice!(buf, b => b, line1)
     seek(buf, pos)
     true
 end
 
-# swap current line with line below
-function edit_transpose_lines_down!(buf::IOBuffer)
-    e1 = endofline(buf)
+# swap all lines intersecting the region with line below
+function edit_transpose_lines_down!(buf::IOBuffer, reg::Region)
+    e1 = endofline(buf, last(reg))
     e1 == buf.size && return false
     e2 = endofline(buf, e1+1)
     line2 = edit_splice!(buf, e1 => e2) # delete whole next line
     line2 = line2[2:end]*'\n' # don't include leading '\n'
-    b = beginofline(buf)
+    b = beginofline(buf, first(reg))
     edit_splice!(buf, b => b, line2)
     true
 end
 
+# return the region if active, or the current position as a Region otherwise
+region_if_active(s)::Region = is_region_active(s) ? region(s) : position(s)=>position(s)
 
 function edit_transpose_lines_up!(s::MIState)
     set_action!(s, :edit_transpose_lines_up!)
-    if edit_transpose_lines_up!(buffer(s))
+    if edit_transpose_lines_up!(buffer(s), region_if_active(s))
         refresh_line(s)
     else
         # beeping would be too noisy here
@@ -993,7 +995,7 @@ end
 
 function edit_transpose_lines_down!(s::MIState)
     set_action!(s, :edit_transpose_lines_down!)
-    if edit_transpose_lines_down!(buffer(s))
+    if edit_transpose_lines_down!(buffer(s), region_if_active(s))
         refresh_line(s)
     else
         :ignore

test/lineedit.jl

@@ -1,7 +1,7 @@
 # This file is a part of Julia. License is MIT: https://julialang.org/license
 
 using Base.LineEdit
-using Base.LineEdit: edit_insert, buffer, content, setmark, getmark
+using Base.LineEdit: edit_insert, buffer, content, setmark, getmark, region
 
 isdefined(Main, :TestHelpers) || @eval Main include(joinpath(dirname(@__FILE__), "TestHelpers.jl"))
 using Main.TestHelpers
@@ -802,19 +802,33 @@ end
 end
 
 @testset "edit_transpose_lines_{up,down}!" begin
+    transpose_lines_up!(buf) = LineEdit.edit_transpose_lines_up!(buf, position(buf)=>position(buf))
+    transpose_lines_up_reg!(buf) = LineEdit.edit_transpose_lines_up!(buf, region(buf))
+    transpose_lines_down!(buf) = LineEdit.edit_transpose_lines_down!(buf, position(buf)=>position(buf))
+    transpose_lines_down_reg!(buf) = LineEdit.edit_transpose_lines_down!(buf, region(buf))
+
     local buf
     buf = IOBuffer()
+
     write(buf, "l1\nl2\nl3")
     seek(buf, 0)
-    @test LineEdit.edit_transpose_lines_up!(buf) == false
-    @test transform!(LineEdit.edit_transpose_lines_up!, buf) == ("l1\nl2\nl3", 0, 0)
-    @test transform!(LineEdit.edit_transpose_lines_down!, buf) == ("l2\nl1\nl3", 3, 0)
-    @test LineEdit.edit_transpose_lines_down!(buf) == true
+    @test transpose_lines_up!(buf) == false
+    @test transform!(transpose_lines_up!, buf) == ("l1\nl2\nl3", 0, 0)
+    @test transform!(transpose_lines_down!, buf) == ("l2\nl1\nl3", 3, 0)
+    @test transpose_lines_down!(buf) == true
     @test String(take!(copy(buf))) == "l2\nl3\nl1"
-    @test LineEdit.edit_transpose_lines_down!(buf) == false
+    @test transpose_lines_down!(buf) == false
     @test String(take!(copy(buf))) == "l2\nl3\nl1" # no change
     LineEdit.edit_move_right(buf)
-    @test transform!(LineEdit.edit_transpose_lines_up!, buf) == ("l2\nl1\nl3", 4, 0)
+    @test transform!(transpose_lines_up!, buf) == ("l2\nl1\nl3", 4, 0)
     LineEdit.edit_move_right(buf)
-    @test transform!(LineEdit.edit_transpose_lines_up!, buf) == ("l1\nl2\nl3", 2, 0)
+    @test transform!(transpose_lines_up!, buf) == ("l1\nl2\nl3", 2, 0)
+
+    # multiline
+    @test transpose_lines_up_reg!(buf) == false
+    @test transform!(transpose_lines_down_reg!, buf) == ("l2\nl1\nl3", 5, 0)
+    Base.LineEdit.edit_exchange_point_and_mark(buf)
+    seek(buf, 1)
+    @test transpose_lines_up_reg!(buf) == false
+    @test transform!(transpose_lines_down_reg!, buf) == ("l3\nl2\nl1", 4, 8)
 end