Instead of using a custom parse function to process {}, treat it as a

set of statements and parse with yacc, then convert back to a string as
the last step. This means the rules are consistent inside and outside
{}, %if and friends work at the right time, and the final result isn't
littered with unnecessary newlines.

arguments.c

@@ -227,6 +227,11 @@ args_escape(const char *s)
 		return (escaped);
 	}
 
+	if (strchr(s, ' ') != NULL && strchr(s, '\'') == NULL) {
+		xasprintf(&escaped, "'%s'", s);
+		return (escaped);
+	}
+
 	flags = VIS_OCTAL|VIS_CSTYLE|VIS_TAB|VIS_NL;
 	if (s[strcspn(s, quoted)] != '\0')
 		flags |= VIS_DQ;

cmd-parse.y

@@ -43,7 +43,6 @@ struct cmd_parse_scope {
 };
 
 struct cmd_parse_command {
-	char				 *name;
 	u_int				  line;
 
 	int				  argc;
@@ -78,6 +77,7 @@ static char	*cmd_parse_get_error(const char *, u_int, const char *);
 static void	 cmd_parse_free_command(struct cmd_parse_command *);
 static struct cmd_parse_commands *cmd_parse_new_commands(void);
 static void	 cmd_parse_free_commands(struct cmd_parse_commands *);
+static char	*cmd_parse_commands_to_string(struct cmd_parse_commands *);
 static void	 cmd_parse_print_commands(struct cmd_parse_input *, u_int,
 		     struct cmd_list *);
 
@@ -111,7 +111,8 @@ static void	 cmd_parse_print_commands(struct cmd_parse_input *, u_int,
 %type <arguments> arguments
 %type <flag> if_open if_elif
 %type <elif> elif elif1
-%type <commands> statements statement commands condition condition1
+%type <commands> argument_statements statements statement
+%type <commands> commands condition condition1
 %type <command> command
 
 %%
@@ -359,7 +360,7 @@ commands	: command
 			struct cmd_parse_state	*ps = &parse_state;
 
 			$$ = cmd_parse_new_commands();
-			if ($1->name != NULL &&
+			if ($1->argc != 0 &&
 			    (ps->scope == NULL || ps->scope->flag))
 				TAILQ_INSERT_TAIL($$, $1, entry);
 			else
@@ -379,7 +380,7 @@ commands	: command
 		{
 			struct cmd_parse_state	*ps = &parse_state;
 
-			if ($3->name != NULL &&
+			if ($3->argc != 0 &&
 			    (ps->scope == NULL || ps->scope->flag)) {
 				$$ = $1;
 				TAILQ_INSERT_TAIL($$, $3, entry);
@@ -399,7 +400,6 @@ command		: assignment
 			struct cmd_parse_state	*ps = &parse_state;
 
 			$$ = xcalloc(1, sizeof *$$);
-			$$->name = NULL;
 			$$->line = ps->input->line;
 		}
 		| optional_assignment TOKEN
@@ -407,20 +407,21 @@ command		: assignment
 			struct cmd_parse_state	*ps = &parse_state;
 
 			$$ = xcalloc(1, sizeof *$$);
-			$$->name = $2;
 			$$->line = ps->input->line;
 
+			cmd_prepend_argv(&$$->argc, &$$->argv, $2);
+
 		}
 		| optional_assignment TOKEN arguments
 		{
 			struct cmd_parse_state	*ps = &parse_state;
 
 			$$ = xcalloc(1, sizeof *$$);
-			$$->name = $2;
 			$$->line = ps->input->line;
 
 			$$->argc = $3.argc;
 			$$->argv = $3.argv;
+			cmd_prepend_argv(&$$->argc, &$$->argv, $2);
 		}
 
 condition1	: if_open commands if_close
@@ -524,6 +525,20 @@ argument	: TOKEN
 		{
 			$$ = $1;
 		}
+		| '{' argument_statements
+		{
+			$$ = cmd_parse_commands_to_string($2);
+			cmd_parse_free_commands($2);
+		}
+
+argument_statements	: statement '}'
+			{
+				$$ = $1;
+			}
+			| statements '}'
+			{
+				$$ = $1;
+			}
 
 %%
 
@@ -558,7 +573,6 @@ cmd_parse_print_commands(struct cmd_parse_input *pi, u_int line,
 static void
 cmd_parse_free_command(struct cmd_parse_command *cmd)
 {
-	free(cmd->name);
 	cmd_free_argv(cmd->argc, cmd->argv);
 	free(cmd);
 }
@@ -585,6 +599,30 @@ cmd_parse_free_commands(struct cmd_parse_commands *cmds)
 	free(cmds);
 }
 
+static char *
+cmd_parse_commands_to_string(struct cmd_parse_commands *cmds)
+{
+	struct cmd_parse_command	 *cmd;
+	char				 *string = NULL, *s, *line;
+
+	TAILQ_FOREACH(cmd, cmds, entry) {
+		line = cmd_stringify_argv(cmd->argc, cmd->argv);
+		if (string == NULL)
+			s = line;
+		else {
+			xasprintf(&s, "%s ; %s", s, line);
+			free(line);
+		}
+
+		free(string);
+		string = s;
+	}
+	if (string == NULL)
+		string = xstrdup("");
+	log_debug("%s: %s", __func__, string);
+	return (string);
+}
+
 static struct cmd_parse_commands *
 cmd_parse_run_parser(char **cause)
 {
@@ -645,7 +683,7 @@ cmd_parse_build_commands(struct cmd_parse_commands *cmds,
 	int				 i;
 	struct cmd_list			*cmdlist = NULL, *result;
 	struct cmd			*add;
-	char				*alias, *cause, *s;
+	char				*name, *alias, *cause, *s;
 
 	/* Check for an empty list. */
 	if (TAILQ_EMPTY(cmds)) {
@@ -661,12 +699,14 @@ cmd_parse_build_commands(struct cmd_parse_commands *cmds,
 	 * command list.
 	 */
 	TAILQ_FOREACH_SAFE(cmd, cmds, entry, next) {
-		alias = cmd_get_alias(cmd->name);
+		name = cmd->argv[0];
+
+		alias = cmd_get_alias(name);
 		if (alias == NULL)
 			continue;
 
 		line = cmd->line;
-		log_debug("%s: %u %s = %s", __func__, line, cmd->name, alias);
+		log_debug("%s: %u %s = %s", __func__, line, name, alias);
 
 		pi->line = line;
 		cmds2 = cmd_parse_do_buffer(alias, strlen(alias), pi, &cause);
@@ -683,7 +723,7 @@ cmd_parse_build_commands(struct cmd_parse_commands *cmds,
 			cmd_parse_free_command(cmd);
 			continue;
 		}
-		for (i = 0; i < cmd->argc; i++)
+		for (i = 1; i < cmd->argc; i++)
 			cmd_append_argv(&cmd2->argc, &cmd2->argv, cmd->argv[i]);
 
 		after = cmd;
@@ -707,7 +747,8 @@ cmd_parse_build_commands(struct cmd_parse_commands *cmds,
 	 */
 	result = cmd_list_new();
 	TAILQ_FOREACH(cmd, cmds, entry) {
-		log_debug("%s: %u %s", __func__, cmd->line, cmd->name);
+		name = cmd->argv[0];
+		log_debug("%s: %u %s", __func__, cmd->line, name);
 		cmd_log_argv(cmd->argc, cmd->argv, __func__);
 
 		if (cmdlist == NULL ||
@@ -721,7 +762,6 @@ cmd_parse_build_commands(struct cmd_parse_commands *cmds,
 		}
 		line = cmd->line;
 
-		cmd_prepend_argv(&cmd->argc, &cmd->argv, cmd->name);
 		add = cmd_parse(cmd->argc, cmd->argv, pi->file, line, &cause);
 		if (add == NULL) {
 			cmd_list_free(result);
@@ -921,11 +961,10 @@ cmd_parse_from_arguments(int argc, char **argv, struct cmd_parse_input *pi)
 			    i);
 
 			cmd = xcalloc(1, sizeof *cmd);
-			cmd->name = xstrdup(new_argv[0]);
 			cmd->line = pi->line;
 
-			cmd->argc = new_argc - 1;
+			cmd->argc = new_argc;
-			cmd->argv = cmd_copy_argv(new_argc - 1, new_argv + 1);
+			cmd->argv = cmd_copy_argv(new_argc, new_argv);
 
 			TAILQ_INSERT_TAIL(cmds, cmd, entry);
 		}
@@ -941,11 +980,10 @@ cmd_parse_from_arguments(int argc, char **argv, struct cmd_parse_input *pi)
 			    last);
 
 			cmd = xcalloc(1, sizeof *cmd);
-			cmd->name = xstrdup(new_argv[0]);
 			cmd->line = pi->line;
 
-			cmd->argc = new_argc - 1;
+			cmd->argc = new_argc;
-			cmd->argv = cmd_copy_argv(new_argc - 1, new_argv + 1);
+			cmd->argv = cmd_copy_argv(new_argc, new_argv);
 
 			TAILQ_INSERT_TAIL(cmds, cmd, entry);
 		}
@@ -1123,11 +1161,11 @@ yylex(void)
 			return ('\n');
 		}
 
-		if (ch == ';') {
+		if (ch == ';' || ch == '{' || ch == '}') {
 			/*
-			 * A semicolon is itself.
+			 * A semicolon or { or } is itself.
 			 */
-			return (';');
+			return (ch);
 		}
 
 		if (ch == '#') {
@@ -1442,119 +1480,6 @@ yylex_token_tilde(char **buf, size_t *len)
 	return (1);
 }
 
-static int
-yylex_token_brace(char **buf, size_t *len)
-{
-	struct cmd_parse_state	*ps = &parse_state;
-	int 			 ch, lines = 0, nesting = 1, escape = 0;
-	int			 quote = '\0', token = 0;
-
-	/*
-	 * Extract a string up to the matching unquoted '}', including newlines
-	 * and handling nested braces.
-	 *
-	 * To detect the final and intermediate braces which affect the nesting
-	 * depth, we scan the input as if it was a tmux config file, and ignore
-	 * braces which would be considered quoted, escaped, or in a comment.
-	 *
-	 * We update the token state after every character because '#' begins a
-	 * comment only when it begins a token. For simplicity, we treat an
-	 * unquoted directive format as comment.
-	 *
-	 * The result is verbatim copy of the input excluding the final brace.
-	 */
-
-	for (ch = yylex_getc1(); ch != EOF; ch = yylex_getc1()) {
-		yylex_append1(buf, len, ch);
-		if (ch == '\n')
-			lines++;
-
-		/*
-		 * If the previous character was a backslash (escape is set),
-		 * escape anything if unquoted or in double quotes, otherwise
-		 * escape only '\n' and '\\'.
-		 */
-		if (escape &&
-		    (quote == '\0' ||
-		    quote == '"' ||
-		    ch == '\n' ||
-		    ch == '\\')) {
-			escape = 0;
-			if (ch != '\n')
-				token = 1;
-			continue;
-		}
-
-		/*
-		 * The character is not escaped. If it is a backslash, set the
-		 * escape flag.
-		 */
-		if (ch == '\\') {
-			escape = 1;
-			continue;
-		}
-		escape = 0;
-
-		/* A newline always resets to unquoted. */
-		if (ch == '\n') {
-			quote = token = 0;
-			continue;
-		}
-
-		if (quote) {
-			/*
-			 * Inside quotes or comment. Check if this is the
-			 * closing quote.
-			 */
-			if (ch == quote && quote != '#')
-				quote = 0;
-			token = 1;  /* token continues regardless */
-		} else {
-			/* Not inside quotes or comment. */
-			switch (ch) {
-			case '"':
-			case '\'':
-			case '#':
-				/* Beginning of quote or maybe comment. */
-				if (ch != '#' || !token)
-					quote = ch;
-				token = 1;
-				break;
-			case ' ':
-			case '\t':
-			case ';':
-				/* Delimiter - token resets. */
-				token = 0;
-				break;
-			case '{':
-				nesting++;
-				token = 0; /* new commands set - token resets */
-				break;
-			case '}':
-				nesting--;
-				token = 1;  /* same as after quotes */
-				if (nesting == 0) {
-					(*len)--; /* remove closing } */
-					ps->input->line += lines;
-					return (1);
-				}
-				break;
-			default:
-				token = 1;
-				break;
-			}
-		}
-	}
-
-	/*
-	 * Update line count after error as reporting the opening line is more
-	 * useful than EOF.
-	 */
-	yyerror("unterminated brace string");
-	ps->input->line += lines;
-	return (0);
-}
-
 static char *
 yylex_token(int ch)
 {
@@ -1580,7 +1505,8 @@ yylex_token(int ch)
 		}
 
 		/* Whitespace or ; ends a token unless inside quotes. */
-		if ((ch == ' ' || ch == '\t' || ch == ';') && state == NONE)
+		if ((ch == ' ' || ch == '\t' || ch == ';' || ch == '}') &&
+		    state == NONE)
 			break;
 
 		/*
@@ -1601,11 +1527,6 @@ yylex_token(int ch)
 				goto error;
 			goto skip;
 		}
-		if (ch == '{' && state == NONE) {
-			if (!yylex_token_brace(&buf, &len))
-				goto error;
-			goto skip;
-		}
 		if (ch == '}' && state == NONE)
 			goto error;  /* unmatched (matched ones were handled) */
 

cmd.c

@@ -357,25 +357,27 @@ cmd_free_argv(int argc, char **argv)
 char *
 cmd_stringify_argv(int argc, char **argv)
 {
-	char	*buf;
+	char	*buf = NULL, *s;
+	size_t	 len = 0;
 	int	 i;
-	size_t	 len;
 
 	if (argc == 0)
 		return (xstrdup(""));
 
-	len = 0;
-	buf = NULL;
-
 	for (i = 0; i < argc; i++) {
-		len += strlen(argv[i]) + 1;
+		s = args_escape(argv[i]);
+		log_debug("%s: %u %s = %s", __func__, i, argv[i], s);
+
+		len += strlen(s) + 1;
 		buf = xrealloc(buf, len);
 
 		if (i == 0)
 			*buf = '\0';
 		else
 			strlcat(buf, " ", len);
-		strlcat(buf, argv[i], len);
+		strlcat(buf, s, len);
+
+		free(s);
 	}
 	return (buf);
 }

tmux.1

@@ -552,17 +552,14 @@ is removed) and are not treated as having any special meaning - so for example
 variable.
 .El
 .Pp
-Braces are similar to single quotes in that the text inside is taken literally
+Braces are parsed as a configuration file (so conditions such as
-without any replacements but this also includes line continuation.
+.Ql %if
-Braces can span multiple lines in which case a literal newline is included in the
+are processed) and then converted into a string.
-string.
+They are designed to avoid the need for additional escaping when passing a
-They are designed to avoid the need for additional escaping when passing a group
+group of
-of
 .Nm
-or shell commands as an argument (for example to
+commands as an argument (for example to
-.Ic if-shell
+.Ic if-shell ) .
-or
-.Ic pipe-pane ) .
 These two examples produce an identical command - note that no escaping is
 needed when using {}:
 .Bd -literal -offset indent
@@ -570,7 +567,7 @@ if-shell true {
     display -p 'brace-dollar-foo: }$foo'
 }
 
-if-shell true "\en    display -p 'brace-dollar-foo: }\e$foo'\en"
+if-shell true "display -p 'brace-dollar-foo: }\e$foo'"
 .Ed
 .Pp
 Braces may be enclosed inside braces, for example: