Fix handling of ctrl key in legacy mode

Also change the glfw constants used for the modifiers to match those
used in the terminal encoding. Less likely to make mistakes translating
that way.

gen-key-constants.py

@@ -3,7 +3,8 @@
 # License: GPLv3 Copyright: 2021, Kovid Goyal <kovid at kovidgoyal.net>
 
 import string
-from typing import Dict, List
+from typing import Dict, List, Any
+from pprint import pformat
 
 functional_key_defs = '''# {{{
 # kitty                     XKB                         macOS
@@ -141,6 +142,14 @@ for line in functional_key_defs.splitlines():
     if parts[1] != '-':
         name_to_xkb[name] = parts[1]
 last_code = start_code + len(functional_key_names) - 1
+ctrl_mapping = {
+    ' ': 0, '@': 0, 'a': 1, 'b': 2, 'c': 3, 'd': 4, 'e': 5, 'f': 6, 'g': 7,
+    'h': 8, 'i': 9, 'j': 10, 'k': 11, 'l': 12, 'm': 13, 'n': 14, 'o': 15, 'p': 16,
+    'q': 17, 'r': 18, 's': 19, 't': 20, 'u': 21, 'v': 22, 'w': 23, 'x': 24,
+    'y': 25, 'z': 26, '[': 27, '\\': 28, ']': 29, '^': 30, '~': 30, '/': 31,
+    '_': 31, '?': 127, '0': 48, '1': 49, '2': 0, '3': 27, '4': 28,
+    '5': 29, '6': 30, '7': 31, '8': 127, '9': 57
+}
 
 
 def patch_file(path: str, what: str, text: str, start_marker: str = '/* ', end_marker: str = ' */') -> None:
@@ -167,6 +176,10 @@ def patch_file(path: str, what: str, text: str, start_marker: str = '/* ', end_m
         f.write(raw)
 
 
+def serialize_dict(x: dict) -> str:
+    return pformat(x, indent=4).replace('{', '{\n ', 1)
+
+
 def generate_glfw_header() -> None:
     lines = [
         'typedef enum {',
@@ -205,10 +218,13 @@ def generate_functional_table() -> None:
         ''
     ]
     enc_lines = []
+    tilde_trailers = set()
     for name, code in name_to_code.items():
         if name in functional_encoding_overrides or name in different_trailer_functionals:
-            code = oc = functional_encoding_overrides.get(name, code)
             trailer = different_trailer_functionals.get(name, '~')
+            if trailer == '~':
+                tilde_trailers.add(code)
+            code = oc = functional_encoding_overrides.get(name, code)
             code = code if trailer in '~u' else 1
             enc_lines.append((' ' * 8) + f"case GLFW_FKEY_{name.upper()}: S({code}, '{trailer}');")
             if code == 1 and name not in ('up', 'down', 'left', 'right'):
@@ -220,6 +236,16 @@ def generate_functional_table() -> None:
     lines.append('')
     patch_file('docs/keyboard-protocol.rst', 'functional key table', '\n'.join(lines), start_marker='.. ', end_marker='')
     patch_file('kitty/key_encoding.c', 'special numbers', '\n'.join(enc_lines))
+    code_to_name = {v: k.upper() for k, v in name_to_code.items()}
+    csi_map = {v: name_to_code[k] for k, v in functional_encoding_overrides.items()}
+    letter_trailer_codes = {
+        v: functional_encoding_overrides.get(k, name_to_code.get(k))
+        for k, v in different_trailer_functionals.items() if v in 'ABCDHFPQRSZ'}
+    text = f'functional_key_number_to_name_map = {serialize_dict(code_to_name)}'
+    text += f'\ncsi_number_to_functional_number_map = {serialize_dict(csi_map)}'
+    text += f'\nletter_trailer_to_csi_number_map = {letter_trailer_codes!r}'
+    text += f'\ntilde_trailers = {tilde_trailers!r}'
+    patch_file('kitty/key_encoding.py', 'csi mapping', text, start_marker='# ', end_marker='')
 
 
 def generate_legacy_text_key_maps() -> None:
@@ -236,7 +262,7 @@ def generate_legacy_text_key_maps() -> None:
 
     def simple(c: str) -> None:
         shifted = shift_map.get(c, c)
-        ctrled = chr(ord(c) & 0b111111)
+        ctrled = chr(ctrl_mapping.get(c, ord(c)))
         for m in range(16):
             if m == 0:
                 tests.append(f'{tp}ae(enc(ord({c!r})), {c!r})')
@@ -257,11 +283,41 @@ def generate_legacy_text_key_maps() -> None:
     patch_file('kitty_tests/keys.py', 'legacy letter tests', '\n'.join(tests), start_marker='# ', end_marker='')
 
 
+def chunks(lst: List, n: int) -> Any:
+    """Yield successive n-sized chunks from lst."""
+    for i in range(0, len(lst), n):
+        yield lst[i:i + n]
+
+
+def generate_ctrl_mapping() -> None:
+    lines = [
+        '.. csv-table:: Emitted bytes when :kbd:`ctrl` is held down and a key is pressed',
+        '   :header: "Key", "Byte", "Key", "Byte", "Key", "Byte"',
+        ''
+    ]
+    items = []
+    mi = []
+    for k in sorted(ctrl_mapping):
+        items.append(k)
+        val = str(ctrl_mapping[k])
+        items.append(val)
+        if k in "\\'":
+            k = '\\' + k
+        mi.append(f"        case '{k}': return {val};")
+
+    for line_items in chunks(items, 6):
+        lines.append('   ' + ', '.join(f'"{x}"' for x in line_items))
+    lines.append('')
+    patch_file('docs/keyboard-protocol.rst', 'ctrl mapping', '\n'.join(lines), start_marker='.. ', end_marker='')
+    patch_file('kitty/key_encoding.c', 'ctrl mapping', '\n'.join(mi))
+
+
 def main() -> None:
     generate_glfw_header()
     generate_xkb_mapping()
     generate_functional_table()
     generate_legacy_text_key_maps()
+    generate_ctrl_mapping()
 
 
 if __name__ == '__main__':