[regex,input_field]: Add/clarify wide char support (fixes #98, #126)

InputField in its current form can't support wide characters, but other
things now do. Real length also uses `wcswidth` now on top of stripping
ANSI.

Credit to @qoft with #118.

pyproject.toml

@@ -15,7 +15,7 @@ description = """\
 license = {text = "MIT"}
 
 requires-python = ">=3.8"
-dependencies = ["typing_extensions"]
+dependencies = ["wcwidth", "typing_extensions"]
 
 keywords = [
     "terminal",

pytermgui/regex.py

@@ -4,6 +4,8 @@
 from functools import lru_cache
 from typing import Match
 
+from wcwidth import wcswidth
+
 RE_LINK = re.compile(r"(?:\x1b\]8;;([^\\]*)\x1b\\([^\\]*?)\x1b\]8;;\x1b\\)")
 RE_ANSI_NEW = re.compile(rf"(\x1b\[(.*?)[mH])|{RE_LINK.pattern}|(\x1b_G(.*?)\x1b\\)")
 RE_ANSI = re.compile(r"(?:\x1b\[(.*?)[mH])|(?:\x1b\](.*?)\x1b\\)|(?:\x1b_G(.*?)\x1b\\)")
@@ -69,7 +71,7 @@ def real_length(text: str) -> int:
         The display-length of text.
     """
 
-    return len(strip_ansi(text))
+    return wcswidth(strip_ansi(text))
 
 
 def escape_markup(text: str) -> str:

pytermgui/widgets/input_field.py

@@ -7,6 +7,8 @@
 from dataclasses import dataclass
 from typing import Any, Iterator, Literal
 
+from wcwidth import wcwidth
+
 from ..ansi_interface import MouseAction, MouseEvent
 from ..enums import HorizontalAlignment
 from ..helpers import break_line
@@ -83,6 +85,9 @@ def __init__(
         if "width" not in attrs:
             self.width = len(value)
 
+        if any(wcwidth(char) > 1 for char in value):
+            raise ValueError("InputField doesn't support wide unicode characters.")
+
         self.prompt = prompt
         self.height = 1
         self.tablength = tablength
@@ -431,6 +436,7 @@ def move_cursor(self, new: tuple[int, int], *, absolute: bool = False) -> None:
         row, col = self.cursor
 
         line = self._lines[row]
+        width = len(line)
 
         # Going left, possibly upwards
         if col < 0:
@@ -440,17 +446,17 @@ def move_cursor(self, new: tuple[int, int], *, absolute: bool = False) -> None:
             else:
                 self.cursor.row -= 1
                 line = self._lines[self.cursor.row]
-                self.cursor.col = len(line)
+                self.cursor.col = width
 
         # Going right, possibly downwards
-        elif col > len(line) and line != "":
+        elif col > width and line != "":
             if len(self._lines) > row + 1:
                 self.cursor.row += 1
                 self.cursor.col = 0
 
             line = self._lines[self.cursor.row]
 
-        self.cursor.col = max(0, min(self.cursor.col, len(line)))
+        self.cursor.col = max(0, min(self.cursor.col, width))
 
     def get_lines(self) -> list[str]:
         """Builds the input field's lines."""