From 0e4c956c1d3707f55fbdbb4eb606873cd399d087 Mon Sep 17 00:00:00 2001 From: Michael Stapelberg Date: Tue, 25 Dec 2012 14:15:06 +0100 Subject: [PATCH] i3-config-wizard: switch away from bison/flex to hand-written parser MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit This adds some code duplication which we might remove in a future refactoring or not. Depends on whether unifying the parsers actually makes the code better or not. I suspect it doesn’t :-). --- i3-config-wizard/cfgparse.l | 105 --------- i3-config-wizard/cfgparse.y | 208 ---------------- i3-config-wizard/i3-config-wizard.mk | 15 +- i3-config-wizard/main.c | 339 ++++++++++++++++++++++++++- parser-specs/config.spec | 4 +- 5 files changed, 343 insertions(+), 328 deletions(-) delete mode 100644 i3-config-wizard/cfgparse.l delete mode 100644 i3-config-wizard/cfgparse.y diff --git a/i3-config-wizard/cfgparse.l b/i3-config-wizard/cfgparse.l deleted file mode 100644 index 772b8470..00000000 --- a/i3-config-wizard/cfgparse.l +++ /dev/null @@ -1,105 +0,0 @@ -%option nounput -%option noinput -%option noyy_top_state -%option stack - -%{ -/* - * vim:ts=8:expandtab - * - */ -#include -#include -#include -#include -#include "cfgparse.tab.h" - -int yycolumn = 1; - -struct context { - int line_number; - char *line_copy; - - char *compact_error; - - /* These are the same as in YYLTYPE */ - int first_column; - int last_column; -}; - - -#define YY_DECL int yylex (struct context *context) - -#define YY_USER_ACTION { \ - context->first_column = yycolumn; \ - context->last_column = yycolumn+yyleng-1; \ - yycolumn += yyleng; \ -} - -%} - -EOL (\r?\n) - -%s BINDCODE_COND -%s BIND_AWS_COND -%s BIND_A2WS_COND -%x BUFFER_LINE - -%% - - { - /* This is called when a new line is lexed. We only want the - * first line to match to go into state BUFFER_LINE */ - if (context->line_number == 0) { - context->line_number = 1; - BEGIN(INITIAL); - yy_push_state(BUFFER_LINE); - } - } - -^[^\r\n]*/{EOL}? { - /* save whole line */ - context->line_copy = strdup(yytext); - - yyless(0); - yy_pop_state(); - yy_set_bol(true); - yycolumn = 1; -} - - -[^\n]+ { BEGIN(INITIAL); yylval.string = strdup(yytext); return STR; } -[0-9]+ { yylval.number = atoi(yytext); return NUMBER; } -bind { BEGIN(BINDCODE_COND); return TOKBINDCODE; } -bindcode { BEGIN(BINDCODE_COND); return TOKBINDCODE; } -Mod1 { yylval.number = (1 << 3); return MODIFIER; } -Mod2 { yylval.number = (1 << 4); return MODIFIER; } -Mod3 { yylval.number = (1 << 5); return MODIFIER; } -Mod4 { yylval.number = (1 << 6); return MODIFIER; } -Mod5 { yylval.number = (1 << 7); return MODIFIER; } -Mode_switch { yylval.number = (1 << 8); return MODIFIER; } -$mod { yylval.number = (1 << 9); return TOKMODVAR; } -control { return TOKCONTROL; } -ctrl { return TOKCONTROL; } -shift { return TOKSHIFT; } -{EOL} { - if (context->line_copy) { - free(context->line_copy); - context->line_copy = NULL; - } - context->line_number++; - BEGIN(INITIAL); - yy_push_state(BUFFER_LINE); - } -[ \t]+ { BEGIN(BIND_AWS_COND); return WHITESPACE; } -[ \t]+ { BEGIN(BIND_A2WS_COND); return WHITESPACE; } -[ \t]+ { return WHITESPACE; } -. { return (int)yytext[0]; } - -<> { - while (yy_start_stack_ptr > 0) - yy_pop_state(); - yyterminate(); -} - -%% diff --git a/i3-config-wizard/cfgparse.y b/i3-config-wizard/cfgparse.y deleted file mode 100644 index 17c3953c..00000000 --- a/i3-config-wizard/cfgparse.y +++ /dev/null @@ -1,208 +0,0 @@ -%{ -/* - * vim:ts=4:sw=4:expandtab - * - */ -#include -#include -#include -#include -#include -#include -#include -#include - -#include -#include - -#include "libi3.h" - -extern Display *dpy; - -struct context { - int line_number; - char *line_copy; - - char *compact_error; - - /* These are the same as in YYLTYPE */ - int first_column; - int last_column; - - char *result; -}; - -typedef struct yy_buffer_state *YY_BUFFER_STATE; -extern int yylex(struct context *context); -extern int yyparse(void); -extern FILE *yyin; -YY_BUFFER_STATE yy_scan_string(const char *); - -static struct context *context; -static xcb_connection_t *conn; -static xcb_key_symbols_t *keysyms; - -/* We don’t need yydebug for now, as we got decent error messages using - * yyerror(). Should you ever want to extend the parser, it might be handy - * to just comment it in again, so it stays here. */ -//int yydebug = 1; - -void yyerror(const char *error_message) { - fprintf(stderr, "\n"); - fprintf(stderr, "CONFIG: %s\n", error_message); - fprintf(stderr, "CONFIG: line %d:\n", - context->line_number); - fprintf(stderr, "CONFIG: %s\n", context->line_copy); - fprintf(stderr, "CONFIG: "); - for (int c = 1; c <= context->last_column; c++) - if (c >= context->first_column) - fprintf(stderr, "^"); - else fprintf(stderr, " "); - fprintf(stderr, "\n"); - fprintf(stderr, "\n"); -} - -int yywrap() { - return 1; -} - -char *rewrite_binding(const char *bindingline) { - char *result = NULL; - - conn = xcb_connect(NULL, NULL); - if (conn == NULL || xcb_connection_has_error(conn)) { - fprintf(stderr, "Cannot open display\n"); - exit(1); - } - keysyms = xcb_key_symbols_alloc(conn); - - context = calloc(sizeof(struct context), 1); - - yy_scan_string(bindingline); - - if (yyparse() != 0) { - fprintf(stderr, "Could not parse configfile\n"); - exit(1); - } - - result = context->result; - - if (context->line_copy) - free(context->line_copy); - free(context); - xcb_key_symbols_free(keysyms); - xcb_disconnect(conn); - - return result; -} - -/* XXX: does not work for combinations of modifiers yet */ -static char *modifier_to_string(int modifiers) { - //printf("should convert %d to string\n", modifiers); - if (modifiers == (1 << 3)) - return strdup("$mod+"); - else if (modifiers == ((1 << 3) | (1 << 0))) - return strdup("$mod+Shift+"); - else if (modifiers == (1 << 9)) - return strdup("$mod+"); - else if (modifiers == ((1 << 9) | (1 << 0))) - return strdup("$mod+Shift+"); - else if (modifiers == (1 << 0)) - return strdup("Shift+"); - else return strdup(""); -} - -/* - * Returns true if sym is bound to any key except for 'except_keycode' on the - * first four layers (normal, shift, mode_switch, mode_switch + shift). - * - */ -static bool keysym_used_on_other_key(KeySym sym, xcb_keycode_t except_keycode) { - xcb_keycode_t i, - min_keycode = xcb_get_setup(conn)->min_keycode, - max_keycode = xcb_get_setup(conn)->max_keycode; - - for (i = min_keycode; i && i <= max_keycode; i++) { - if (i == except_keycode) - continue; - for (int level = 0; level < 4; level++) { - if (xcb_key_symbols_get_keysym(keysyms, i, level) != sym) - continue; - return true; - } - } - return false; -} - -%} - -%error-verbose -%lex-param { struct context *context } - -%union { - int number; - char *string; -} - -%token NUMBER "" -%token STR "" -%token TOKBINDCODE -%token TOKMODVAR "$mod" -%token MODIFIER "" -%token TOKCONTROL "control" -%token TOKSHIFT "shift" -%token WHITESPACE "" - -%% - -lines: /* empty */ - | lines WHITESPACE bindcode - | lines error - | lines bindcode - ; - -bindcode: - TOKBINDCODE WHITESPACE binding_modifiers NUMBER WHITESPACE STR - { - //printf("\tFound keycode binding mod%d with key %d and command %s\n", $3, $4, $6); - int level = 0; - if (($3 & (1 << 0))) { - /* When shift is included, we really need to use the second-level - * symbol (upper-case). The lower-case symbol could be on a - * different key than the upper-case one (unlikely for letters, but - * more likely for special characters). */ - level = 1; - - /* Try to use the keysym on the first level (lower-case). In case - * this doesn’t make it ambiguous (think of a keyboard layout - * having '1' on two different keys, but '!' only on keycode 10), - * we’ll stick with the keysym of the first level. - * - * This reduces a lot of confusion for users who switch keyboard - * layouts from qwerty to qwertz or other slight variations of - * qwerty (yes, that happens quite often). */ - KeySym sym = XkbKeycodeToKeysym(dpy, $4, 0, 0); - if (!keysym_used_on_other_key(sym, $4)) - level = 0; - } - KeySym sym = XkbKeycodeToKeysym(dpy, $4, 0, level); - char *str = XKeysymToString(sym); - char *modifiers = modifier_to_string($3); - sasprintf(&(context->result), "bindsym %s%s %s\n", modifiers, str, $6); - free(modifiers); - } - ; - -binding_modifiers: - /* NULL */ { $$ = 0; } - | binding_modifier - | binding_modifiers '+' binding_modifier { $$ = $1 | $3; } - | binding_modifiers '+' { $$ = $1; } - ; - -binding_modifier: - MODIFIER { $$ = $1; } - | TOKMODVAR { $$ = $1; } - | TOKCONTROL { $$ = (1 << 2); } - | TOKSHIFT { $$ = (1 << 0); } - ; diff --git a/i3-config-wizard/i3-config-wizard.mk b/i3-config-wizard/i3-config-wizard.mk index 3847786e..703c0ad6 100644 --- a/i3-config-wizard/i3-config-wizard.mk +++ b/i3-config-wizard/i3-config-wizard.mk @@ -2,27 +2,18 @@ ALL_TARGETS += i3-config-wizard/i3-config-wizard INSTALL_TARGETS += install-i3-config-wizard CLEAN_TARGETS += clean-i3-config-wizard -i3_config_wizard_SOURCES_GENERATED = i3-config-wizard/cfgparse.tab.c i3-config-wizard/cfgparse.yy.c -i3_config_wizard_SOURCES := $(filter-out $(i3_config_wizard_SOURCES_GENERATED),$(wildcard i3-config-wizard/*.c)) +i3_config_wizard_SOURCES := $(wildcard i3-config-wizard/*.c) i3_config_wizard_HEADERS := $(wildcard i3-config-wizard/*.h) i3_config_wizard_CFLAGS = $(XCB_CFLAGS) $(XCB_KBD_CFLAGS) $(X11_CFLAGS) $(PANGO_CFLAGS) i3_config_wizard_LIBS = $(XCB_LIBS) $(XCB_KBD_LIBS) $(X11_LIBS) $(PANGO_LIBS) -i3_config_wizard_OBJECTS := $(i3_config_wizard_SOURCES_GENERATED:.c=.o) $(i3_config_wizard_SOURCES:.c=.o) +i3_config_wizard_OBJECTS := $(i3_config_wizard_SOURCES:.c=.o) -i3-config-wizard/%.o: i3-config-wizard/%.c $(i3_config_wizard_HEADERS) +i3-config-wizard/%.o: i3-config-wizard/%.c $(i3_config_wizard_HEADERS) i3-config-parser.stamp echo "[i3-config-wizard] CC $<" $(CC) $(I3_CPPFLAGS) $(XCB_CPPFLAGS) $(CPPFLAGS) $(i3_config_wizard_CFLAGS) $(I3_CFLAGS) $(CFLAGS) -c -o $@ $< -i3-config-wizard/cfgparse.yy.c: i3-config-wizard/cfgparse.l i3-config-wizard/cfgparse.tab.o $(i3_config_wizard_HEADERS) - echo "[i3-config-wizard] LEX $<" - $(FLEX) -i -o $@ $< - -i3-config-wizard/cfgparse.tab.c: i3-config-wizard/cfgparse.y $(i3_config_wizard_HEADERS) - echo "[i3-config-wizard] YACC $<" - $(BISON) --debug --verbose -b $(basename $< .y) -d $< - i3-config-wizard/i3-config-wizard: libi3.a $(i3_config_wizard_OBJECTS) echo "[i3-config-wizard] Link i3-config-wizard" $(CC) $(I3_LDFLAGS) $(LDFLAGS) -o $@ $(filter-out libi3.a,$^) $(LIBS) $(i3_config_wizard_LIBS) diff --git a/i3-config-wizard/main.c b/i3-config-wizard/main.c index 1eb738f6..54c8e024 100644 --- a/i3-config-wizard/main.c +++ b/i3-config-wizard/main.c @@ -36,6 +36,7 @@ #include #include #include +#include #include #include @@ -44,6 +45,7 @@ #include #include +#include /* We need SYSCONFDIR for the path to the keycode config template, so raise an * error if it’s not defined for whatever reason */ @@ -68,6 +70,7 @@ enum { MOD_Mod1, MOD_Mod4 } modifier = MOD_Mod4; static char *config_path; static uint32_t xcb_numlock_mask; xcb_connection_t *conn; +static xcb_key_symbols_t *keysyms; xcb_screen_t *root_screen; static xcb_get_modifier_mapping_reply_t *modmap_reply; static i3Font font; @@ -80,9 +83,342 @@ static xcb_key_symbols_t *symbols; xcb_window_t root; Display *dpy; -char *rewrite_binding(const char *bindingline); static void finish(); +#include "GENERATED_config_enums.h" + +typedef struct token { + char *name; + char *identifier; + /* This might be __CALL */ + cmdp_state next_state; + union { + uint16_t call_identifier; + } extra; +} cmdp_token; + +typedef struct tokenptr { + cmdp_token *array; + int n; +} cmdp_token_ptr; + + +#include "GENERATED_config_tokens.h" + +static cmdp_state state; +/* A list which contains the states that lead to the current state, e.g. + * INITIAL, WORKSPACE_LAYOUT. + * When jumping back to INITIAL, statelist_idx will simply be set to 1 + * (likewise for other states, e.g. MODE or BAR). + * This list is used to process the nearest error token. */ +static cmdp_state statelist[10] = { INITIAL }; +/* NB: statelist_idx points to where the next entry will be inserted */ +static int statelist_idx = 1; + +struct stack_entry { + /* Just a pointer, not dynamically allocated. */ + const char *identifier; + enum { + STACK_STR = 0, + STACK_LONG = 1, + } type; + union { + char *str; + long num; + } val; +}; + +/* 10 entries should be enough for everybody. */ +static struct stack_entry stack[10]; + +/* + * Pushes a string (identified by 'identifier') on the stack. We simply use a + * single array, since the number of entries we have to store is very small. + * + */ +static void push_string(const char *identifier, const char *str) { + for (int c = 0; c < 10; c++) { + if (stack[c].identifier != NULL && + strcmp(stack[c].identifier, identifier) != 0) + continue; + if (stack[c].identifier == NULL) { + /* Found a free slot, let’s store it here. */ + stack[c].identifier = identifier; + stack[c].val.str = sstrdup(str); + stack[c].type = STACK_STR; + } else { + /* Append the value. */ + char *prev = stack[c].val.str; + sasprintf(&(stack[c].val.str), "%s,%s", prev, str); + free(prev); + } + return; + } + + /* When we arrive here, the stack is full. This should not happen and + * means there’s either a bug in this parser or the specification + * contains a command with more than 10 identified tokens. */ + fprintf(stderr, "BUG: commands_parser stack full. This means either a bug " + "in the code, or a new command which contains more than " + "10 identified tokens.\n"); + exit(1); +} + +static void push_long(const char *identifier, long num) { + for (int c = 0; c < 10; c++) { + if (stack[c].identifier != NULL) + continue; + /* Found a free slot, let’s store it here. */ + stack[c].identifier = identifier; + stack[c].val.num = num; + stack[c].type = STACK_LONG; + return; + } + + /* When we arrive here, the stack is full. This should not happen and + * means there’s either a bug in this parser or the specification + * contains a command with more than 10 identified tokens. */ + fprintf(stderr, "BUG: commands_parser stack full. This means either a bug " + "in the code, or a new command which contains more than " + "10 identified tokens.\n"); + exit(1); + +} + +static const char *get_string(const char *identifier) { + for (int c = 0; c < 10; c++) { + if (stack[c].identifier == NULL) + break; + if (strcmp(identifier, stack[c].identifier) == 0) + return stack[c].val.str; + } + return NULL; +} + + +static void clear_stack(void) { + for (int c = 0; c < 10; c++) { + if (stack[c].type == STACK_STR && stack[c].val.str != NULL) + free(stack[c].val.str); + stack[c].identifier = NULL; + stack[c].val.str = NULL; + stack[c].val.num = 0; + } +} + +/* + * Returns true if sym is bound to any key except for 'except_keycode' on the + * first four layers (normal, shift, mode_switch, mode_switch + shift). + * + */ +static bool keysym_used_on_other_key(KeySym sym, xcb_keycode_t except_keycode) { + xcb_keycode_t i, + min_keycode = xcb_get_setup(conn)->min_keycode, + max_keycode = xcb_get_setup(conn)->max_keycode; + + for (i = min_keycode; i && i <= max_keycode; i++) { + if (i == except_keycode) + continue; + for (int level = 0; level < 4; level++) { + if (xcb_key_symbols_get_keysym(keysyms, i, level) != sym) + continue; + return true; + } + } + return false; +} + + +static char *next_state(const cmdp_token *token) { + cmdp_state _next_state = token->next_state; + + if (token->next_state == __CALL) { + const char *modifiers = get_string("modifiers"); + int keycode = atoi(get_string("key")); + int level = 0; + if (modifiers != NULL && + strstr(modifiers, "Shift") != NULL) { + /* When shift is included, we really need to use the second-level + * symbol (upper-case). The lower-case symbol could be on a + * different key than the upper-case one (unlikely for letters, but + * more likely for special characters). */ + level = 1; + + /* Try to use the keysym on the first level (lower-case). In case + * this doesn’t make it ambiguous (think of a keyboard layout + * having '1' on two different keys, but '!' only on keycode 10), + * we’ll stick with the keysym of the first level. + * + * This reduces a lot of confusion for users who switch keyboard + * layouts from qwerty to qwertz or other slight variations of + * qwerty (yes, that happens quite often). */ + KeySym sym = XkbKeycodeToKeysym(dpy, keycode, 0, 0); + if (!keysym_used_on_other_key(sym, keycode)) + level = 0; + } + KeySym sym = XkbKeycodeToKeysym(dpy, keycode, 0, level); + char *str = XKeysymToString(sym); + const char *release = get_string("release"); + char *res; + char *modrep = (modifiers == NULL ? sstrdup("") : sstrdup(modifiers)); + char *comma; + while ((comma = strchr(modrep, ',')) != NULL) { + *comma = '+'; + } + sasprintf(&res, "bindsym %s%s%s %s%s\n", (modifiers == NULL ? "" : modrep), (modifiers == NULL ? "" : "+"), str, (release == NULL ? "" : release), get_string("command")); + clear_stack(); + return res; + } + + state = _next_state; + + /* See if we are jumping back to a state in which we were in previously + * (statelist contains INITIAL) and just move statelist_idx accordingly. */ + for (int i = 0; i < statelist_idx; i++) { + if (statelist[i] != _next_state) + continue; + statelist_idx = i+1; + return NULL; + } + + /* Otherwise, the state is new and we add it to the list */ + statelist[statelist_idx++] = _next_state; + return NULL; +} + + +static char *rewrite_binding(const char *input) { + state = INITIAL; + statelist_idx = 1; + + const char *walk = input; + const size_t len = strlen(input); + int c; + const cmdp_token *token; + char *result = NULL; + + /* The "<=" operator is intentional: We also handle the terminating 0-byte + * explicitly by looking for an 'end' token. */ + while ((walk - input) <= len) { + /* Skip whitespace before every token, newlines are relevant since they + * separate configuration directives. */ + while ((*walk == ' ' || *walk == '\t') && *walk != '\0') + walk++; + + //printf("remaining input: %s\n", walk); + + cmdp_token_ptr *ptr = &(tokens[state]); + for (c = 0; c < ptr->n; c++) { + token = &(ptr->array[c]); + + /* A literal. */ + if (token->name[0] == '\'') { + if (strncasecmp(walk, token->name + 1, strlen(token->name) - 1) == 0) { + if (token->identifier != NULL) + push_string(token->identifier, token->name + 1); + walk += strlen(token->name) - 1; + if ((result = next_state(token)) != NULL) + return result; + break; + } + continue; + } + + if (strcmp(token->name, "number") == 0) { + /* Handle numbers. We only accept decimal numbers for now. */ + char *end = NULL; + errno = 0; + long int num = strtol(walk, &end, 10); + if ((errno == ERANGE && (num == LONG_MIN || num == LONG_MAX)) || + (errno != 0 && num == 0)) + continue; + + /* No valid numbers found */ + if (end == walk) + continue; + + if (token->identifier != NULL) + push_long(token->identifier, num); + + /* Set walk to the first non-number character */ + walk = end; + if ((result = next_state(token)) != NULL) + return result; + break; + } + + if (strcmp(token->name, "string") == 0 || + strcmp(token->name, "word") == 0) { + const char *beginning = walk; + /* Handle quoted strings (or words). */ + if (*walk == '"') { + beginning++; + walk++; + while (*walk != '\0' && (*walk != '"' || *(walk-1) == '\\')) + walk++; + } else { + if (token->name[0] == 's') { + while (*walk != '\0' && *walk != '\r' && *walk != '\n') + walk++; + } else { + /* For a word, the delimiters are white space (' ' or + * '\t'), closing square bracket (]), comma (,) and + * semicolon (;). */ + while (*walk != ' ' && *walk != '\t' && + *walk != ']' && *walk != ',' && + *walk != ';' && *walk != '\r' && + *walk != '\n' && *walk != '\0') + walk++; + } + } + if (walk != beginning) { + char *str = scalloc(walk-beginning + 1); + /* We copy manually to handle escaping of characters. */ + int inpos, outpos; + for (inpos = 0, outpos = 0; + inpos < (walk-beginning); + inpos++, outpos++) { + /* We only handle escaped double quotes to not break + * backwards compatibility with people using \w in + * regular expressions etc. */ + if (beginning[inpos] == '\\' && beginning[inpos+1] == '"') + inpos++; + str[outpos] = beginning[inpos]; + } + if (token->identifier) + push_string(token->identifier, str); + free(str); + /* If we are at the end of a quoted string, skip the ending + * double quote. */ + if (*walk == '"') + walk++; + if ((result = next_state(token)) != NULL) + return result; + break; + } + } + + if (strcmp(token->name, "end") == 0) { + //printf("checking for end: *%s*\n", walk); + if (*walk == '\0' || *walk == '\n' || *walk == '\r') { + if ((result = next_state(token)) != NULL) + return result; + /* To make sure we start with an appropriate matching + * datastructure for commands which do *not* specify any + * criteria, we re-initialize the criteria system after + * every command. */ + // TODO: make this testable + walk++; + break; + } + } + } + } + + return NULL; +} + + /* * Having verboselog() and errorlog() is necessary when using libi3. * @@ -466,6 +802,7 @@ int main(int argc, char *argv[]) { xcb_connection_has_error(conn)) errx(1, "Cannot open display\n"); + keysyms = xcb_key_symbols_alloc(conn); xcb_get_modifier_mapping_cookie_t modmap_cookie; modmap_cookie = xcb_get_modifier_mapping(conn); symbols = xcb_key_symbols_alloc(conn); diff --git a/parser-specs/config.spec b/parser-specs/config.spec index 7a31a5d8..427d9fc4 100644 --- a/parser-specs/config.spec +++ b/parser-specs/config.spec @@ -272,7 +272,7 @@ state FONT: state BINDING: release = '--release' -> - modifiers = 'Mod1', 'Mod2', 'Mod3', 'Mod4', 'Mod5', 'Shift', 'Control', 'Ctrl', 'Mode_switch' + modifiers = 'Mod1', 'Mod2', 'Mod3', 'Mod4', 'Mod5', 'Shift', 'Control', 'Ctrl', 'Mode_switch', '$mod' -> '+' -> @@ -317,7 +317,7 @@ state MODE_IGNORE_LINE: state MODE_BINDING: release = '--release' -> - modifiers = 'Mod1', 'Mod2', 'Mod3', 'Mod4', 'Mod5', 'Shift', 'Control', 'Ctrl', 'Mode_switch' + modifiers = 'Mod1', 'Mod2', 'Mod3', 'Mod4', 'Mod5', 'Shift', 'Control', 'Ctrl', 'Mode_switch', '$mod' -> '+' ->