Corrected cursor positioning on inputs with full-width (2 column) characters (#817)

rybarczykj · web-flow · commit 8e25e01ef42e · 2020-07-13T18:38:36.000-06:00
- Added functionality for full-width character input
- Works with normal input and stdin input
- There still are issues with line wrapping when using full-width 
- Fix wide chars on input('...')
diff --git a/bpython/curtsiesfrontend/repl.py b/bpython/curtsiesfrontend/repl.py
@@ -19,6 +19,8 @@
 from bpython._py3compat import PythonLexer
 from pygments.formatters import TerminalFormatter
 
+from wcwidth import wcswidth
+
 import blessings
 
 import curtsies
@@ -1359,7 +1361,11 @@ def display_line_with_prompt(self):
 
     @property
     def current_cursor_line_without_suggestion(self):
-        """Current line, either output/input or Python prompt + code"""
+        """
+        Current line, either output/input or Python prompt + code
+
+        :returns: FmtStr
+        """
         value = self.current_output_line + (
             "" if self.coderunner.running else self.display_line_with_prompt
         )
@@ -1556,7 +1562,8 @@ def move_screen_up(current_line_start_row):
 
         if self.stdin.has_focus:
             cursor_row, cursor_column = divmod(
-                len(self.current_stdouterr_line) + self.stdin.cursor_offset,
+                wcswidth(self.current_stdouterr_line)
+                + wcswidth(self.stdin.current_line[: self.stdin.cursor_offset]),
                 width,
             )
             assert cursor_column >= 0, cursor_column
@@ -1574,12 +1581,12 @@ def move_screen_up(current_line_start_row):
                 len(self.current_line),
                 self.cursor_offset,
             )
-        else:
+        else: # Common case for determining cursor position
             cursor_row, cursor_column = divmod(
                 (
-                    len(self.current_cursor_line_without_suggestion)
-                    - len(self.current_line)
-                    + self.cursor_offset
+                    wcswidth(self.current_cursor_line_without_suggestion.s)
+                    - wcswidth(self.current_line)
+                    + wcswidth(self.current_line[: self.cursor_offset]) 
                 ),
                 width,
             )
diff --git a/setup.py b/setup.py
@@ -228,6 +228,7 @@ def initialize_options(self):
     "curtsies >=0.1.18",
     "greenlet",
     "six >=1.5",
+    "wcwidth"
 ]
 
 extras_require = {

Original file line number	Diff line number	Diff line change
`@@ -228,6 +228,7 @@ def initialize_options(self):`
`228`	`228`	`"curtsies >=0.1.18",`
`229`	`229`	`"greenlet",`
`230`	`230`	`"six >=1.5",`
	`231`	`+ "wcwidth"`
`231`	`232`	`]`
`232`	`233`
`233`	`234`	`extras_require = {`