gh-131507: Add support for syntax highlighting in PyREPL (GH-133247)

Co-authored-by: Victorien <65306057+Viicos@users.noreply.github.com>
Co-authored-by: Hugo van Kemenade <1324225+hugovk@users.noreply.github.com>

Lib/_colorize.py

@@ -7,7 +7,22 @@ COLORIZE = True
 
 # types
 if False:
-    from typing import IO
+    from typing import IO, Literal
+
+    type ColorTag = Literal[
+        "PROMPT",
+        "KEYWORD",
+        "BUILTIN",
+        "COMMENT",
+        "STRING",
+        "NUMBER",
+        "OP",
+        "DEFINITION",
+        "SOFT_KEYWORD",
+        "RESET",
+    ]
+
+    theme: dict[ColorTag, str]
 
 
 class ANSIColors:
@@ -23,6 +38,7 @@ class ANSIColors:
     WHITE = "\x1b[37m"  # more like LIGHT GRAY
     YELLOW = "\x1b[33m"
 
+    BOLD = "\x1b[1m"
     BOLD_BLACK = "\x1b[1;30m"  # DARK GRAY
     BOLD_BLUE = "\x1b[1;34m"
     BOLD_CYAN = "\x1b[1;36m"
@@ -120,3 +136,28 @@ def can_colorize(*, file: IO[str] | IO[bytes] | None = None) -> bool:
         return os.isatty(file.fileno())
     except io.UnsupportedOperation:
         return hasattr(file, "isatty") and file.isatty()
+
+
+def set_theme(t: dict[ColorTag, str] | None = None) -> None:
+    global theme
+
+    if t:
+        theme = t
+        return
+
+    colors = get_colors()
+    theme = {
+        "PROMPT": colors.BOLD_MAGENTA,
+        "KEYWORD": colors.BOLD_BLUE,
+        "BUILTIN": colors.CYAN,
+        "COMMENT": colors.RED,
+        "STRING": colors.GREEN,
+        "NUMBER": colors.YELLOW,
+        "OP": colors.RESET,
+        "DEFINITION": colors.BOLD,
+        "SOFT_KEYWORD": colors.BOLD_BLUE,
+        "RESET": colors.RESET,
+    }
+
+
+set_theme()