Add an is_line_max function to clarify right ward motions

- Change `s` to be a synonym, rather than its own function
- swap ordering of `at_junction_type` params so that the last arg can be more flexible (different number of args)

Author: caleb-allen

src/buffer.jl

@@ -1,7 +1,7 @@
 module Buffer
 import REPL.LineEdit as LE
 export VimBuffer, mode, VimMode, normal_mode, insert_mode, testbuf, readall, freeze,
-    BufferRecord, chars, peek_left, peek_right, read_left, read_right
+    BufferRecord, chars, peek_left, peek_right, peek_two_right, read_left, read_right
 
 @enum VimMode begin
     normal_mode
@@ -125,6 +125,19 @@ function peek_right(buf::IO)::Union{Char,Nothing}
     return nothing
 end
 
+"""
+Read up to 2 valid UTF-8 character right of the current position and leave the buffer in the same position.
+
+Returns a tuple with each successful character (or nothing for a character not read successfully)
+"""
+function peek_two_right(buf::IO)
+    origin = position(buf)
+    c1 = read_right(buf)
+    c2 = read_right(buf)
+    seek(buf, origin)
+    return (c1, c2)
+end
+
 """
 Read 1 valid UTF-8 character right of the current position.
 

src/execute.jl

@@ -37,8 +37,13 @@ function execute(buf, command::MotionCommand)::Union{VimMode,ReplAction,Nothing}
                 nothing
             end
         else
-            # execute the motion object
-            motion(buf)
+            k = key(command)
+            if !(k == 'l' && is_line_max(buf))
+                # we shouldn't move past the last character of the line
+
+                # execute the motion object
+                motion(buf)
+            end
         end
     end
     return repl_action
@@ -89,9 +94,6 @@ const insert_functions = Dict{Char,Function}(
             motion
         end
     end,
-    's' => buf -> begin
-        delete(buf, right(buf))
-    end
     # _ => gen_motion(buf, command)
 )
 
@@ -119,7 +121,7 @@ function execute(buf, command::OperatorCommand)::Union{VimMode,Nothing}
     # see vim help :h cw regarding this exception
     if command.operator == 'c' && command.action.name in ['w', 'W']
         # in the middle of a word
-        if at_junction_type(buf, In{>:Word}) || at_junction_type(buf, Start{>:Word})
+        if at_junction_type(In{>:Word}, buf) || at_junction_type(Start{>:Word}, buf)
             new_name = if command.action.name == 'w'
                 'e'
             else
@@ -172,7 +174,8 @@ function execute(buf, command::SynonymCommand)::Union{VimMode,Nothing}
         'X' => "dh",
         'C' => "c\$",
         'D' => "d\$",
-        'S' => "cc"
+        'S' => "cc",
+        's' => "cl",
     )
     new_command = parse_command("$(command.r1)$(synonyms[command.operator])")
 

src/motion.jl

@@ -113,7 +113,7 @@ end
 
 function left(buf::IO)::Motion
     start = position(buf)
-    @loop_guard while position(buf) > 0
+    @loop_guard while position(buf) > 0 && !is_line_start(buf)
         seek(buf, position(buf) - 1)
         c = peek(buf)
         (((c & 0x80) == 0) || ((c & 0xc0) == 0xc0)) && break

src/parse.jl

@@ -53,8 +53,8 @@ end
 const UNDO_REDO = "(?|(u)|(\x12))"
 const TEXTOBJECT = "$REPEAT[ai][wWsp]"
 const PARTIALTEXTOBJECT = "$REPEAT[ai]([wWsp])?"
-const DELETECHARS = "[xXDCS]"
-const INSERTCHARS = "[aAiIoOs]"
+const DELETECHARS = "[xXDCSs]"
+const INSERTCHARS = "[aAiIoO]"
 const OPERATOR = "[ydc]"
 const RULES = TupleDict(
     "^(?<c>$INSERTCHARS)\$" |> Regex => InsertCommand, # insert commands

src/textutils.jl

@@ -1,3 +1,6 @@
+"""
+Getting carried away with types and multiple dispatch: text utility style
+"""
 module TextUtils
 import Base: *
 using REPL
@@ -9,33 +12,41 @@ export is_newline, is_whitespace, is_word_char, TextChar, WordChar, WhitespaceCh
     chars_by_cursor, junction_type, at_junction_type, Text, Object, Word, Line, Whitespace, Junction, Start, End, In,
     is_alphanumeric, is_alphabetic, is_uppercase, is_lowercase, is_punctuation, is_line_start, is_line_end,
     is_word_end, is_word_start, is_object_start, is_object_end, is_in_object, is_whitespace_end, is_whitespace_start, is_in_word, chars,
-    peek_left, peek_right, read_left, read_right
+    peek_left, peek_right, read_left, read_right, is_line_max
 
 """
     Determine whether the buffer is currently at the start of a text object.
     Whitespace is not included as a text object.
 """
-is_word_start(buf) = at_junction_type(buf, Start{>:Word})
-is_whitespace_start(buf) = at_junction_type(buf, Start{>:Whitespace})
+is_word_start(buf) = at_junction_type(Start{>:Word}, buf)
+is_whitespace_start(buf) = at_junction_type(Start{>:Whitespace}, buf)
 """
 Whether the buffer is currently at the start of a non-whitespace
 block
 """
-is_object_start(buf) = at_junction_type(buf, Start{>:Object})
+is_object_start(buf) = at_junction_type(Start{>:Object}, buf)
 
 """
     Whether the buffer is currently at the end of a text object. Whitespace is not included as a text object.
 """
-is_word_end(buf) = at_junction_type(buf, End{>:Word})
-is_object_end(buf) = at_junction_type(buf, End{>:Object})
-is_whitespace_end(buf) = at_junction_type(buf, End{>:Whitespace})
+is_word_end(buf) = at_junction_type(End{>:Word}, buf)
+is_object_end(buf) = at_junction_type(End{>:Object}, buf)
+is_whitespace_end(buf) = at_junction_type(End{>:Whitespace}, buf)
 
 """
     Whether the buffer is at the start of a line, in the literal sense
     In other words, is the char before the cursor a newline
 """
-is_line_start(buf) = at_junction_type(buf, Start{>:Line})
-is_line_end(buf) = at_junction_type(buf, End{>:Line})
+is_line_start(buf) = at_junction_type(Start{>:Line}, buf)
+is_line_end(buf) = at_junction_type(End{>:Line}, buf)
+
+"""
+Whether the buffer's location is the right-most that the cursor is allowed to go; the "end of the line" so that the cursor does not get placed at a newline where there is not actually a character to operate on.
+"""
+function is_line_max(buf)
+    c1, c2 = peek_two_right(buf)
+    return at_junction_type(End{>:Line}, c1, c2)
+end
 
 
 """
@@ -44,10 +55,10 @@ Whether the buffer is currently in an object of a continuous type (not between t
 function is_in_word(buf)
     a, b = chars_by_cursor(buf)
     typeof(a) == typeof(b) || return false
-    at_junction_type(buf, In{>:Word})
+    at_junction_type(In{>:Word}, buf)
 end
 
-is_in_object(buf) = at_junction_type(buf, In{<:Object})
+is_in_object(buf) = at_junction_type(In{<:Object}, buf)
 
 """
 Get the 
@@ -183,8 +194,15 @@ junction_type(char1::T, char2::T) where {T<:SpaceChar} = Set([In{Whitespace}()])
 """
 Whether the given buffer is currently at a junction of type junc
 """
-function at_junction_type(buf, junc_type)
-    for junc in junction_type(buf)
+function at_junction_type(junc_type, obj::Vararg)
+    juncs = junction_type(obj...)
+    # return at_junction_type(junction_type(obj, junc_type...))
+    return at_junction_type(junc_type, juncs)
+end
+
+function at_junction_type(junc_type, juncs::Set)
+    # TODO nuke this whole thing
+    for junc in juncs
         if junc isa junc_type
             @debug "at_junction_type?" junc_type chars_by_cursor(buf) at_junction_type = true
             return true

test/command.jl

@@ -41,7 +41,8 @@ end
 @testset "basic movements" begin
     @test run("asdf|", "h") == testbuf("asd|f")
     @test run("asdf|", "l") == testbuf("asdf|")
-    @test run("asd|f", "l") == testbuf("asdf|")
+    @test run("asd|f", "l") == testbuf("asd|f")
+    @test run("|asdf", "l") == testbuf("a|sdf")
     @test run("a|sdf", "\$") == testbuf("asd|f")
     @test run("asd|f", "\$") == testbuf("asd|f")
 
@@ -69,6 +70,9 @@ end
     @test run("|asdf", "dh") == testbuf("|asdf")
     @test run("asd|f", "X") == testbuf("as|f")
     @test run("asd|f", "x") == testbuf("as|d")
+    
+    @test run("|asdf", "s") == testbuf("|i|sdf")
+    @test run("asd|f", "s") == testbuf("asd|i|")
 end
 
 @testset "de" begin
@@ -152,6 +156,7 @@ end
 
 @testset "unicode" begin
     # https://github.com/caleb-allen/VimBindings.jl/issues/95
+    @test run("fo|o", "x") == testbuf("f|o")
     @test run("(0b0000 ⊻ 0b000|0)", "x") == testbuf("(0b0000 ⊻ 0b000|)")
     @test run("0b0000 ⊻ 0b000|0", "x") == testbuf("0b0000 ⊻ 0b00|0")
 

test/textutils.jl

@@ -128,7 +128,7 @@ end
     @test is_in_object(testbuf("hello%%|%%")) == true
     @test is_in_object(testbuf("|hello%%%%")) == false
 end
-@testset "is line start " begin
+@testset "start and end of lines" begin
     @test is_line_end(testbuf("|\n")) == true
     @test is_line_end(testbuf("one line\t|\nhello")) == true
     @test is_line_end(testbuf("one line\t\nhello|")) == true
@@ -141,6 +141,18 @@ end
     @test is_line_start(testbuf("one line|\nhello")) == false
     @test is_line_start(testbuf("one line \n|hello")) == true
 
+    @test is_line_max(testbuf("""
+    |hello world!
+    """)) == false
+
+    @test is_line_max(testbuf("""
+    hello world|!
+    """)) == true
+    
+    @test is_line_max(testbuf("|")) == true
+    @test is_line_max(testbuf("foo|")) == true
+    @test is_line_max(testbuf("fo|o")) == true
+    @test is_line_max(testbuf("f|oo")) == false
 end
 
 @testset "test buffer" begin