REPL: enable "redo" after "undo"

base/repl/LineEdit.jl

@@ -68,6 +68,7 @@ mutable struct PromptState <: ModeState
  p::Prompt
  input_buffer::IOBuffer
  undo_buffers::Vector{IOBuffer}
+ undo_idx::Int
  ias::InputAreaState
  # indentation of lines which do not include the prompt
  # if negative, the width of the prompt is used
@@ -1668,7 +1669,8 @@ AnyDict(
  # Meta Enter
  "\e\r" => (s,o...)->edit_insert_newline(s),
  "\e\n" => "\e\r",
- "^_" => (s,o...)->(pop_undo(s) ? refresh_line(s) : beep(terminal(s))),
+ "^_" => (s,o...)->edit_undo!(s),
+ "\e_" => (s,o...)->edit_redo!(s),
  # Simply insert it into the buffer by default
  "*" => (s,data,c)->(edit_insert(s, c)),
  "^U" => (s,o...)->edit_clear(s),
@@ -1856,7 +1858,7 @@ end
 run_interface(::Prompt) = nothing
 
 init_state(terminal, prompt::Prompt) =
- PromptState(terminal, prompt, IOBuffer(), IOBuffer[], InputAreaState(1, 1),
+ PromptState(terminal, prompt, IOBuffer(), IOBuffer[], 1, InputAreaState(1, 1),
  #=indent(spaces)=# -1)
 
 function init_state(terminal, m::ModalInterface)
@@ -1895,20 +1897,59 @@ position(s::Union{MIState,ModeState}) = position(buffer(s))
 
 function empty_undo(s::PromptState)
  empty!(s.undo_buffers)
+ s.undo_idx = 1
 end
+
 empty_undo(s) = nothing
 
-function push_undo(s::PromptState)
- push!(s.undo_buffers, copy(s.input_buffer))
+function push_undo(s::PromptState, advance=true)
+ resize!(s.undo_buffers, s.undo_idx)
+ s.undo_buffers[end] = copy(s.input_buffer)
+ advance && (s.undo_idx += 1)
 end
+
 push_undo(s) = nothing
 
+# must be called after a push_undo
 function pop_undo(s::PromptState)
- length(s.undo_buffers) > 0 || return false
- s.input_buffer = pop!(s.undo_buffers)
+ pop!(s.undo_buffers)
+ s.undo_idx -= 1
+end
+
+function edit_undo!(s::MIState)
+ s.last_action ∉ (:edit_redo!, :edit_undo!) && push_undo(s, false)
+ if edit_undo!(state(s))
+ :edit_undo!
+ else
+ beep(terminal(s))
+ :ignore
+ end
+end
+
+function edit_undo!(s::PromptState)
+ s.undo_idx > 1 || return false
+ s.input_buffer = s.undo_buffers[s.undo_idx -=1]
+ refresh_line(s)
+ true
+end
+edit_undo!(s) = nothing
+
+function edit_redo!(s::MIState)
+ if s.last_action ∈ (:edit_redo!, :edit_undo!) && edit_redo!(state(s))
+ :edit_redo!
+ else
+ beep(terminal(s))
+ :ignore
+ end
+end
+
+function edit_redo!(s::PromptState)
+ s.undo_idx < length(s.undo_buffers) || return false
+ s.input_buffer = s.undo_buffers[s.undo_idx += 1]
+ refresh_line(s)
  true
 end
-pop_undo(s) = nothing
+edit_redo!(s) = nothing
 
 keymap(s::PromptState, prompt::Prompt) = prompt.keymap_dict
 keymap_data(s::PromptState, prompt::Prompt) = prompt.keymap_func_data

test/lineedit.jl

@@ -22,8 +22,11 @@ charpos(buf, pos=position(buf)) = Base.unsafe_ind2chr(content(buf), pos+1)-1
 function transform!(f, s, i = -1) # i is char-based (not bytes) buffer position
  buf = buffer(s)
  i >= 0 && charseek(buf, i)
- f(s)
- content(buf), charpos(buf), charpos(buf, getmark(buf))
+ action = f(s)
+ if s isa LineEdit.MIState && action isa Symbol
+ s.last_action = action # simulate what happens in LineEdit.prompt!
+ end
+ content(s), charpos(buf), charpos(buf, getmark(buf))
 end
 
 
@@ -604,10 +607,11 @@ end
  @test s.kill_ring[end] == "a ≡ not"
  charseek(buf, 0)
  @test transform!(LineEdit.edit_yank, s) == ("a ≡ notçhing", 7, 0)
+ s.last_action = :unknown
  # next action will fail, as yank-pop doesn't know a yank was just issued
  @test transform!(LineEdit.edit_yank_pop, s) == ("a ≡ notçhing", 7, 0)
  s.last_action = :edit_yank
- # not this should work:
+ # now this should work:
  @test transform!(LineEdit.edit_yank_pop, s) == ("ça ≡ nothingçhing", 12, 0)
  @test s.kill_idx == 1
  LineEdit.edit_kill_line(s)
@@ -617,88 +621,78 @@ end
 
 @testset "undo" begin
  s = new_state()
+ edit!(f) = transform!(f, s)[1]
+ edit_undo! = LineEdit.edit_undo!
+ edit_redo! = LineEdit.edit_redo!
 
  edit_insert(s, "one two three")
 
- LineEdit.edit_delete_prev_word(s)
- @test content(s) == "one two "
- LineEdit.pop_undo(s)
- @test content(s) == "one two three"
+ @test edit!(LineEdit.edit_delete_prev_word) == "one two "
+ @test edit!(edit_undo!) == "one two three"
+ @test edit!(edit_redo!) == "one two "
+ @test edit!(edit_undo!) == "one two three"
 
  edit_insert(s, " four")
- edit_insert(s, " five")
- @test content(s) == "one two three four five"
- LineEdit.pop_undo(s)
- @test content(s) == "one two three four"
- LineEdit.pop_undo(s)
- @test content(s) == "one two three"
-
- LineEdit.edit_clear(s)
- @test content(s) == ""
- LineEdit.pop_undo(s)
- @test content(s) == "one two three"
+ @test edit!(s->edit_insert(s, " five")) == "one two three four five"
+ @test edit!(edit_undo!) == "one two three four"
+ @test edit!(edit_undo!) == "one two three"
+ @test edit!(edit_redo!) == "one two three four"
+ @test edit!(edit_redo!) == "one two three four five"
+ @test edit!(edit_undo!) == "one two three four"
+ @test edit!(edit_undo!) == "one two three"
+
+ @test edit!(LineEdit.edit_clear) == ""
+ @test edit!(edit_undo!) == "one two three"
 
  LineEdit.edit_move_left(s)
  LineEdit.edit_move_left(s)
- LineEdit.edit_transpose_chars(s)
- @test content(s) == "one two there"
- LineEdit.pop_undo(s)
- @test content(s) == "one two three"
+ @test edit!(LineEdit.edit_transpose_chars) == "one two there"
+ @test edit!(edit_undo!) == "one two three"
 
  LineEdit.move_line_start(s)
- LineEdit.edit_kill_line(s)
- @test content(s) == ""
- LineEdit.pop_undo(s)
- @test content(s) == "one two three"
+ @test edit!(LineEdit.edit_kill_line) == ""
+ @test edit!(edit_undo!) == "one two three"
 
  LineEdit.move_line_start(s)
  LineEdit.edit_kill_line(s)
  LineEdit.edit_yank(s)
- LineEdit.edit_yank(s)
- @test content(s) == "one two threeone two three"
- LineEdit.pop_undo(s)
- @test content(s) == "one two three"
- LineEdit.pop_undo(s)
- @test content(s) == ""
- LineEdit.pop_undo(s)
- @test content(s) == "one two three"
+ @test edit!(LineEdit.edit_yank) == "one two threeone two three"
+ @test edit!(edit_undo!) == "one two three"
+ @test edit!(edit_undo!) == ""
+ @test edit!(edit_undo!) == "one two three"
 
  LineEdit.move_line_end(s)
  LineEdit.edit_backspace(s)
  LineEdit.edit_backspace(s)
- LineEdit.edit_backspace(s)
- @test content(s) == "one two th"
- LineEdit.pop_undo(s)
- @test content(s) == "one two thr"
- LineEdit.pop_undo(s)
- @test content(s) == "one two thre"
- LineEdit.pop_undo(s)
- @test content(s) == "one two three"
+ @test edit!(LineEdit.edit_backspace) == "one two th"
+ @test edit!(edit_undo!) == "one two thr"
+ @test edit!(edit_undo!) == "one two thre"
+ @test edit!(edit_undo!) == "one two three"
 
  LineEdit.push_undo(s) # TODO: incorporate push_undo into edit_splice! ?
  LineEdit.edit_splice!(s, 4 => 7, "stott")
  @test content(s) == "one stott three"
- LineEdit.pop_undo(s)
- @test content(s) == "one two three"
+ s.last_action = :not_undo
+ @test edit!(edit_undo!) == "one two three"
 
  LineEdit.edit_move_left(s)
  LineEdit.edit_move_left(s)
  LineEdit.edit_move_left(s)
- LineEdit.edit_delete(s)
- @test content(s) == "one two thee"
- LineEdit.pop_undo(s)
- @test content(s) == "one two three"
+ @test edit!(LineEdit.edit_delete) == "one two thee"
+ @test edit!(edit_undo!) == "one two three"
 
  LineEdit.edit_move_word_left(s)
  LineEdit.edit_werase(s)
- LineEdit.edit_delete_next_word(s)
- @test content(s) == "one "
- LineEdit.pop_undo(s)
- @test content(s) == "one three"
- LineEdit.pop_undo(s)
- @test content(s) == "one two three"
+ @test edit!(LineEdit.edit_delete_next_word) == "one "
+ @test edit!(edit_undo!) == "one three"
+ @test edit!(edit_undo!) == "one two three"
+ @test edit!(edit_redo!) == "one three"
+ @test edit!(edit_redo!) == "one "
+ @test edit!(edit_redo!) == "one " # nothing more to redo (this "beeps")
+ @test edit!(edit_undo!) == "one three"
+ @test edit!(edit_undo!) == "one two three"
 
  # pop initial insert of "one two three"
- LineEdit.pop_undo(s)
- @test content(s) == ""
+ @test edit!(edit_undo!) == ""
+ @test edit!(edit_undo!) == "" # nothing more to undo (this "beeps")
 end