[fdiff.color] add support for ANSI escape code coloring of unified diff lines

Author: chrissimpkins

lib/fdiff/color.py

@@ -0,0 +1,32 @@
+ansicolors = {
+    "BLACK": "\033[30m",
+    "RED": "\033[31m",
+    "GREEN": "\033[32m",
+    "YELLOW": "\033[33m",
+    "BLUE": "\033[34m",
+    "MAGENTA": "\033[35m",
+    "CYAN": "\033[36m",
+    "WHITE": "\033[37m",
+    "BOLD": "\033[1m",
+    "RESET": "\033[0m",
+}
+
+green_start = ansicolors["GREEN"]
+red_start = ansicolors["RED"]
+cyan_start = ansicolors["CYAN"]
+reset = ansicolors["RESET"]
+
+
+def color_unified_diff_line(line):
+    if line[0:2] == "+ ":
+        return f"{green_start}{line}{reset}"
+    elif line[0:2] == "- ":
+        return f"{red_start}{line}{reset}"
+    elif line[0:3] == "@@ ":
+        return f"{cyan_start}{line}{reset}"
+    elif line[0:4] == "--- ":
+        return f"{red_start}{line}{reset}"
+    elif line[0:4] == "+++ ":
+        return f"{green_start}{line}{reset}"
+    else:
+        return line