refactored commandline key processing: rewritten Cmdline::process_edit_cmd() as State::process_edit_cmd() virtual methods

 * Cmdline::process_edit_cmd() was much too long and deeply nested.
   It used RTTI excessively to implement the state-specific behaviour.
   It became apparent that the behaviour is largely state-specific and could be
   modelled much more elegantly as virtual methods of State.
 * Basically, a state can now implement a method to customize its
   commandline behaviour.
   In the case that the state does not define custom behaviour for
   the key pressed, it can "chain" to the parent class' process_edit_cmd().
   This can be optimized to tail calls by the compiler.
 * The State::process_edit_cmd() implementations are still isolated in
   cmdline.cpp. This is not strictly necessary but allows us keep the
   already large compilations units like parser.cpp small.
   Also, the edit command processing has little to do with the rest of
   a state's functionality and is only used in interactive mode.
 * As a result, we have many small functions now which are much easier to
   maintain.
   This makes adding new and more complex context sensitive editing behaviour
   easier.
 * State-specific function key masking has been refactored by introducing
   State::get_fnmacro_mask().
 * This allowed us to remove the States::is_*() functions which have
   always been a crutch to support context-sensitive key handling.
 * RTTI is almost completely eradicated, except for exception handling
   and StdError(). Both remaining cases can probably be avoided in the
   future, allowing us to compile smaller binaries.

1 files changed, 436 insertions, 319 deletions

diff --git a/src/cmdline.cpp b/src/cmdline.cpp
index ffe44d6..55d63d7 100644
--- a/src/cmdline.cpp
+++ b/src/cmdline.cpp
@@ -231,7 +231,7 @@ Cmdline::keypress(gchar key)
 	 * characters as necessary into the command line.
 	 */
 	try {
-		process_edit_cmd(key);
+		States::current->process_edit_cmd(key);
 	} catch (Return) {
 		/*
 		 * Return from top-level macro, results
@@ -295,318 +295,10 @@ Cmdline::keypress(gchar key)
 }
 
 void
-Cmdline::process_edit_cmd(gchar key)
-{
-	switch (key) {
-	case '\n': /* insert EOL sequence */
-		interface.popup_clear();
-
-		if (Flags::ed & Flags::ED_AUTOEOL)
-			insert("\n");
-		else
-			insert(get_eol_seq(interface.ssm(SCI_GETEOLMODE)));
-		break;
-
-	case CTL_KEY('G'): /* toggle immediate editing modifier */
-		interface.popup_clear();
-
-		modifier_enabled = !modifier_enabled;
-		interface.msg(InterfaceCurrent::MSG_INFO,
-			      "Immediate editing modifier is now %s.",
-			      modifier_enabled ? "enabled" : "disabled");
-		break;
-
-	case CTL_KEY('H'): /* rubout/reinsert character */
-		interface.popup_clear();
-
-		if (modifier_enabled)
-			/* re-insert character */
-			insert();
-		else
-			/* rubout character */
-			rubout();
-		break;
-
-	case CTL_KEY('W'): /* rubout/reinsert word/command */
-		interface.popup_clear();
-
-		if (States::is_file()) {
-			/* File names, including directories */
-			if (modifier_enabled) {
-				/* reinsert one level of file name */
-				while (States::is_file() && rubout_len &&
-				       !G_IS_DIR_SEPARATOR(str[len]))
-					insert();
-
-				/* reinsert final directory separator */
-				if (States::is_file() && rubout_len &&
-				    G_IS_DIR_SEPARATOR(str[len]))
-					insert();
-			} else if (strings[0] && *strings[0]) {
-				/* rubout directory separator */
-				if (strings[0] && *strings[0] &&
-				    G_IS_DIR_SEPARATOR(str[len-1]))
-					rubout();
-
-				/* rubout one level of file name */
-				while (strings[0] && *strings[0] &&
-				       !G_IS_DIR_SEPARATOR(str[len-1]))
-					rubout();
-			} else {
-				/*
-				 * Rub out entire command instead of
-				 * rubbing out nothing.
-				 */
-				rubout_command();
-			}
-		} else if (States::is_string()) {
-			gchar wchars[interface.ssm(SCI_GETWORDCHARS)];
-			interface.ssm(SCI_GETWORDCHARS, 0, (sptr_t)wchars);
-
-			if (modifier_enabled) {
-				/* reinsert word chars */
-				while (States::is_string() && rubout_len &&
-				       strchr(wchars, str[len]))
-					insert();
-
-				/* reinsert non-word chars */
-				while (States::is_string() && rubout_len &&
-				       !strchr(wchars, str[len]))
-					insert();
-			} else if (strings[0] && *strings[0]) {
-				/* rubout non-word chars */
-				while (strings[0] && *strings[0] &&
-				       !strchr(wchars, str[len-1]))
-					rubout();
-
-				/* rubout word chars */
-				while (strings[0] && *strings[0] &&
-				       strchr(wchars, str[len-1]))
-					rubout();
-			} else {
-				/*
-				 * Rub out entire command instead of
-				 * rubbing out nothing.
-				 */
-				rubout_command();
-			}
-		} else if (modifier_enabled) {
-			/* reinsert command */
-			do
-				insert();
-			while (!States::is_start() && rubout_len);
-		} else {
-			/* rubout command */
-			rubout_command();
-		}
-		break;
-
-	case CTL_KEY('U'): /* rubout/reinsert string */
-		interface.popup_clear();
-
-		if (States::is_string()) {
-			if (modifier_enabled) {
-				/* reinsert string */
-				while (States::is_string() && rubout_len)
-					insert();
-			} else {
-				/* rubout string */
-				while (strings[0] && *strings[0])
-					rubout();
-			}
-		} else {
-			insert(key);
-		}
-		break;
-
-	case '\t': /* autocomplete symbol or file name */
-		if (modifier_enabled) {
-			/*
-			 * TODO: In insertion commands, we can autocomplete
-			 * the string at the buffer cursor.
-			 */
-			if (States::is_string()) {
-				/* autocomplete filename using string argument */
-				if (interface.popup_is_shown()) {
-					/* cycle through popup pages */
-					interface.popup_show();
-					break;
-				}
-
-				const gchar *filename = last_occurrence(strings[0]);
-				gchar *new_chars = filename_complete(filename);
-
-				if (new_chars)
-					insert(new_chars);
-				g_free(new_chars);
-
-				/* may be reset if there was a rubbed out command line */
-				modifier_enabled = true;
-			} else {
-				interface.popup_clear();
-				insert(key);
-			}
-		} else if (States::is_qreg()) {
-			if (interface.popup_is_shown()) {
-				/* cycle through popup pages */
-				interface.popup_show();
-				break;
-			}
-
-			QRegSpecMachine &machine = ((StateExpectQReg *)States::current)->machine;
-			gchar *new_chars = machine.auto_complete();
-
-			if (new_chars)
-				insert(new_chars);
-			g_free(new_chars);
-		} else if (States::is_string() &&
-		           ((StateExpectString *)States::current)->machine.qregspec_machine) {
-			if (interface.popup_is_shown()) {
-				/* cycle through popup pages */
-				interface.popup_show();
-				break;
-			}
-
-			QRegSpecMachine *machine =
-				((StateExpectString *)States::current)->machine.qregspec_machine;
-			gchar *new_chars = machine->auto_complete();
-
-			if (new_chars)
-				insert(new_chars);
-			g_free(new_chars);
-		} else if (States::is_insertion() && !interface.ssm(SCI_GETUSETABS)) {
-			interface.popup_clear();
-
-			/* insert soft tabs */
-			gint spaces = interface.ssm(SCI_GETTABWIDTH);
-
-			spaces -= interface.ssm(SCI_GETCOLUMN,
-			                        interface.ssm(SCI_GETCURRENTPOS)) % spaces;
-
-			while (spaces--)
-				insert(' ');
-		} else if (States::is_dir()) {
-			if (interface.popup_is_shown()) {
-				/* cycle through popup pages */
-				interface.popup_show();
-				break;
-			}
-
-			gchar *new_chars = filename_complete(strings[0], '\0',
-			                                     G_FILE_TEST_IS_DIR);
-
-			if (new_chars)
-				insert(new_chars);
-			g_free(new_chars);
-		} else if (States::is_file()) {
-			if (interface.popup_is_shown()) {
-				/* cycle through popup pages */
-				interface.popup_show();
-				break;
-			}
-
-			gchar complete = escape_char == '{' ? '\0' : escape_char;
-			gchar *new_chars = filename_complete(strings[0], complete);
-
-			if (new_chars)
-				insert(new_chars);
-			g_free(new_chars);
-		} else if (States::current == &States::executecommand) {
-			/*
-			 * In the EC command, <TAB> completes files just like ^T
-			 * TODO: Implement shell-command completion by iterating
-			 * executables in $PATH
-			 */
-			if (interface.popup_is_shown()) {
-				/* cycle through popup pages */
-				interface.popup_show();
-				break;
-			}
-
-			const gchar *filename = last_occurrence(strings[0]);
-			gchar *new_chars = filename_complete(filename);
-
-			if (new_chars)
-				insert(new_chars);
-			g_free(new_chars);
-		} else if (States::current == &States::scintilla_symbols) {
-			if (interface.popup_is_shown()) {
-				/* cycle through popup pages */
-				interface.popup_show();
-				break;
-			}
-
-			const gchar *symbol = last_occurrence(strings[0], ",");
-			SymbolList &list = symbol == strings[0]
-						? Symbols::scintilla
-						: Symbols::scilexer;
-			gchar *new_chars = symbol_complete(list, symbol, ',');
-
-			if (new_chars)
-				insert(new_chars);
-			g_free(new_chars);
-		} else if (States::current == &States::gotocmd) {
-			if (interface.popup_is_shown()) {
-				/* cycle through popup pages */
-				interface.popup_show();
-				break;
-			}
-
-			const gchar *label = last_occurrence(strings[0], ",");
-			gchar *new_chars = Goto::table->auto_complete(label);
-
-			if (new_chars)
-				insert(new_chars);
-			g_free(new_chars);
-		} else if (States::current == &States::gethelp) {
-			if (interface.popup_is_shown()) {
-				/* cycle through popup pages */
-				interface.popup_show();
-				break;
-			}
-
-			gchar complete = escape_char == '{' ? '\0' : escape_char;
-			gchar *new_chars = help_index.auto_complete(strings[0], complete);
-
-			if (new_chars)
-				insert(new_chars);
-			g_free(new_chars);
-		} else {
-			interface.popup_clear();
-			insert(key);
-		}
-		break;
-
-#ifdef SIGTSTP
-	case CTL_KEY('Z'):
-		/*
-		 * <CTL/Z> does not raise signal if handling of
-		 * special characters temporarily disabled in terminal
-		 * (Curses), or command-line is detached from
-		 * terminal (GTK+).
-		 * This does NOT change the state of the popup window.
-		 */
-		raise(SIGTSTP);
-		break;
-#endif
-
-	default:
-		interface.popup_clear();
-		insert(key);
-	}
-}
-
-void
 Cmdline::fnmacro(const gchar *name)
 {
-	enum {
-		FNMACRO_MASK_START =	(1 << 0),
-		FNMACRO_MASK_STRING =	(1 << 1)
-	};
-
 	gchar macro_name[1 + strlen(name) + 1];
 	QRegister *reg;
-	tecoInt mask;
 	gchar *macro;
 
 	if (!(Flags::ed & Flags::ED_FNKEYS))
@@ -621,17 +313,8 @@ Cmdline::fnmacro(const gchar *name)
 		/* macro undefined */
 		goto default_action;
 
-	mask = reg->get_integer();
-	if (States::is_start()) {
-		if (mask & FNMACRO_MASK_START)
-			return;
-	} else if (States::is_string()) {
-		if (mask & FNMACRO_MASK_STRING)
-			return;
-	} else if (mask & ~(tecoInt)(FNMACRO_MASK_START | FNMACRO_MASK_STRING)) {
-		/* all other bits refer to any other state */
+	if (reg->get_integer() & States::current->get_fnmacro_mask())
 		return;
-	}
 
 	macro = reg->get_string();
 	try {
@@ -854,6 +537,440 @@ symbol_complete(SymbolList &list, const gchar *symbol, gchar completed)
 }
 
 /*
+ * Commandline key processing.
+ *
+ * These are all the implementations of State::process_edit_cmd().
+ * It makes sense to use virtual methods for key processing, as it is
+ * largely state-dependant; but it defines interactive-mode-only
+ * behaviour which can be kept isolated from the rest of the states'
+ * implementation.
+ */
+
+void
+State::process_edit_cmd(gchar key)
+{
+	switch (key) {
+	case '\n': /* insert EOL sequence */
+		interface.popup_clear();
+
+		if (Flags::ed & Flags::ED_AUTOEOL)
+			cmdline.insert("\n");
+		else
+			cmdline.insert(get_eol_seq(interface.ssm(SCI_GETEOLMODE)));
+		return;
+
+	case CTL_KEY('G'): /* toggle immediate editing modifier */
+		interface.popup_clear();
+
+		modifier_enabled = !modifier_enabled;
+		interface.msg(InterfaceCurrent::MSG_INFO,
+			      "Immediate editing modifier is now %s.",
+			      modifier_enabled ? "enabled" : "disabled");
+		return;
+
+	case CTL_KEY('H'): /* rubout/reinsert character */
+		interface.popup_clear();
+
+		if (modifier_enabled)
+			/* re-insert character */
+			cmdline.insert();
+		else
+			/* rubout character */
+			cmdline.rubout();
+		return;
+
+	case CTL_KEY('W'): /* rubout/reinsert command */
+		interface.popup_clear();
+
+		if (modifier_enabled) {
+			/* reinsert command */
+			do
+				cmdline.insert();
+			while (States::current != &States::start && cmdline.rubout_len);
+		} else {
+			/* rubout command */
+			do
+				cmdline.rubout();
+			while (States::current != &States::start);
+		}
+		return;
+
+#ifdef SIGTSTP
+	case CTL_KEY('Z'):
+		/*
+		 * <CTL/Z> does not raise signal if handling of
+		 * special characters temporarily disabled in terminal
+		 * (Curses), or command-line is detached from
+		 * terminal (GTK+).
+		 * This does NOT change the state of the popup window.
+		 */
+		raise(SIGTSTP);
+		return;
+#endif
+	}
+
+	interface.popup_clear();
+	cmdline.insert(key);
+}
+
+void
+StateExpectString::process_edit_cmd(gchar key)
+{
+	switch (key) {
+	case CTL_KEY('W'): { /* rubout/reinsert word */
+		interface.popup_clear();
+
+		gchar wchars[interface.ssm(SCI_GETWORDCHARS)];
+		interface.ssm(SCI_GETWORDCHARS, 0, (sptr_t)wchars);
+
+		if (modifier_enabled) {
+			/* reinsert word chars */
+			while (States::current == this && cmdline.rubout_len &&
+			       strchr(wchars, cmdline.str[cmdline.len]))
+				cmdline.insert();
+
+			/* reinsert non-word chars */
+			while (States::current == this && cmdline.rubout_len &&
+			       !strchr(wchars, cmdline.str[cmdline.len]))
+				cmdline.insert();
+			return;
+		}
+
+		if (strings[0] && *strings[0]) {
+			/* rubout non-word chars */
+			while (strings[0] && *strings[0] &&
+			       !strchr(wchars, cmdline.str[cmdline.len-1]))
+				cmdline.rubout();
+
+			/* rubout word chars */
+			while (strings[0] && *strings[0] &&
+			       strchr(wchars, cmdline.str[cmdline.len-1]))
+				cmdline.rubout();
+			return;
+		}
+
+		/*
+		 * Otherwise, the entire command string will
+		 * be rubbed out.
+		 */
+		break;
+	}
+
+	case CTL_KEY('U'): /* rubout/reinsert string */
+		interface.popup_clear();
+
+		if (modifier_enabled) {
+			/* reinsert string */
+			while (States::current == this && cmdline.rubout_len)
+				cmdline.insert();
+		} else {
+			/* rubout string */
+			while (strings[0] && *strings[0])
+				cmdline.rubout();
+		}
+		return;
+
+	case '\t': /* autocomplete file name */
+		if (modifier_enabled) {
+			/*
+			 * TODO: In insertion commands, we can autocomplete
+			 * the string at the buffer cursor.
+			 */
+			/* autocomplete filename using string argument */
+			if (interface.popup_is_shown()) {
+				/* cycle through popup pages */
+				interface.popup_show();
+				return;
+			}
+
+			const gchar *filename = last_occurrence(strings[0]);
+			gchar *new_chars = filename_complete(filename);
+
+			if (new_chars)
+				cmdline.insert(new_chars);
+			g_free(new_chars);
+
+			/* may be reset if there was a rubbed out command line */
+			modifier_enabled = true;
+			return;
+		}
+
+		if (machine.qregspec_machine) {
+			if (interface.popup_is_shown()) {
+				/* cycle through popup pages */
+				interface.popup_show();
+				return;
+			}
+
+			gchar *new_chars = machine.qregspec_machine->auto_complete();
+
+			if (new_chars)
+				cmdline.insert(new_chars);
+			g_free(new_chars);
+			return;
+		}
+		break;
+	}
+
+	State::process_edit_cmd(key);
+}
+
+void
+StateInsert::process_edit_cmd(gchar key)
+{
+	gint spaces;
+
+	switch (key) {
+	case '\t': /* insert <TAB> indention */
+		if (modifier_enabled || interface.ssm(SCI_GETUSETABS))
+			break;
+
+		interface.popup_clear();
+
+		/* insert soft tabs */
+		spaces = interface.ssm(SCI_GETTABWIDTH);
+		spaces -= interface.ssm(SCI_GETCOLUMN,
+		                        interface.ssm(SCI_GETCURRENTPOS)) % spaces;
+
+		while (spaces--)
+			cmdline.insert(' ');
+		return;
+	}
+
+	StateExpectString::process_edit_cmd(key);
+}
+
+void
+StateExpectFile::process_edit_cmd(gchar key)
+{
+	gchar *new_chars;
+
+	switch (key) {
+	case CTL_KEY('W'): /* rubout/reinsert file names including directories */
+		interface.popup_clear();
+
+		if (modifier_enabled) {
+			/* reinsert one level of file name */
+			while (States::current == this && cmdline.rubout_len &&
+			       !G_IS_DIR_SEPARATOR(cmdline.str[cmdline.len]))
+				cmdline.insert();
+
+			/* reinsert final directory separator */
+			if (States::current == this && cmdline.rubout_len &&
+			    G_IS_DIR_SEPARATOR(cmdline.str[cmdline.len]))
+				cmdline.insert();
+			return;
+		}
+
+		if (strings[0] && *strings[0]) {
+			/* rubout directory separator */
+			if (strings[0] && *strings[0] &&
+			    G_IS_DIR_SEPARATOR(cmdline.str[cmdline.len-1]))
+				cmdline.rubout();
+
+			/* rubout one level of file name */
+			while (strings[0] && *strings[0] &&
+			       !G_IS_DIR_SEPARATOR(cmdline.str[cmdline.len-1]))
+				cmdline.rubout();
+			return;
+		}
+
+		/*
+		 * Rub out entire command instead of
+		 * rubbing out nothing.
+		 */
+		break;
+
+	case '\t': /* autocomplete file name */
+		if (modifier_enabled)
+			break;
+
+		if (interface.popup_is_shown()) {
+			/* cycle through popup pages */
+			interface.popup_show();
+			return;
+		}
+
+		new_chars = filename_complete(strings[0],
+		                              escape_char == '{' ? '\0' : escape_char);
+		if (new_chars)
+			cmdline.insert(new_chars);
+		g_free(new_chars);
+		return;
+	}
+
+	StateExpectString::process_edit_cmd(key);
+}
+
+void
+StateExpectDir::process_edit_cmd(gchar key)
+{
+	gchar *new_chars;
+
+	switch (key) {
+	case '\t': /* autocomplete directory */
+		if (modifier_enabled)
+			break;
+
+		if (interface.popup_is_shown()) {
+			/* cycle through popup pages */
+			interface.popup_show();
+			return;
+		}
+
+		new_chars = filename_complete(strings[0], '\0',
+		                              G_FILE_TEST_IS_DIR);
+		if (new_chars)
+			cmdline.insert(new_chars);
+		g_free(new_chars);
+		return;
+	}
+
+	StateExpectFile::process_edit_cmd(key);
+}
+
+void
+StateExpectQReg::process_edit_cmd(gchar key)
+{
+	gchar *new_chars;
+
+	switch (key) {
+	case '\t': /* autocomplete Q-Register name */
+		if (modifier_enabled)
+			break;
+
+		if (interface.popup_is_shown()) {
+			/* cycle through popup pages */
+			interface.popup_show();
+			return;
+		}
+
+		new_chars = machine.auto_complete();
+		if (new_chars)
+			cmdline.insert(new_chars);
+		g_free(new_chars);
+		return;
+	}
+
+	State::process_edit_cmd(key);
+}
+
+void
+StateExecuteCommand::process_edit_cmd(gchar key)
+{
+	gchar *new_chars;
+
+	switch (key) {
+	case '\t': /* autocomplete symbol or file name */
+		if (modifier_enabled)
+			break;
+
+		/*
+		 * In the EC command, <TAB> completes files just like ^T
+		 * TODO: Implement shell-command completion by iterating
+		 * executables in $PATH
+		 */
+		if (interface.popup_is_shown()) {
+			/* cycle through popup pages */
+			interface.popup_show();
+			return;
+		}
+
+		new_chars = filename_complete(last_occurrence(strings[0]));
+		if (new_chars)
+			cmdline.insert(new_chars);
+		g_free(new_chars);
+		return;
+	}
+
+	StateExpectString::process_edit_cmd(key);
+}
+
+void
+StateScintilla_symbols::process_edit_cmd(gchar key)
+{
+	switch (key) {
+	case '\t': { /* autocomplete Scintilla symbol */
+		if (modifier_enabled)
+			break;
+
+		if (interface.popup_is_shown()) {
+			/* cycle through popup pages */
+			interface.popup_show();
+			return;
+		}
+
+		const gchar *symbol = last_occurrence(strings[0], ",");
+		SymbolList &list = symbol == strings[0]
+					? Symbols::scintilla
+					: Symbols::scilexer;
+		gchar *new_chars = symbol_complete(list, symbol, ',');
+
+		if (new_chars)
+			cmdline.insert(new_chars);
+		g_free(new_chars);
+		return;
+	}
+	}
+
+	StateExpectString::process_edit_cmd(key);
+}
+
+void
+StateGotoCmd::process_edit_cmd(gchar key)
+{
+	switch (key) {
+	case '\t': { /* autocomplete goto label */
+		if (modifier_enabled)
+			break;
+
+		if (interface.popup_is_shown()) {
+			/* cycle through popup pages */
+			interface.popup_show();
+			return;
+		}
+
+		const gchar *label = last_occurrence(strings[0], ",");
+		gchar *new_chars = Goto::table->auto_complete(label);
+
+		if (new_chars)
+			cmdline.insert(new_chars);
+		g_free(new_chars);
+		return;
+	}
+	}
+
+	StateExpectString::process_edit_cmd(key);
+}
+
+void
+StateGetHelp::process_edit_cmd(gchar key)
+{
+	switch (key) {
+	case '\t': { /* autocomplete help term */
+		if (modifier_enabled)
+			break;
+
+		if (interface.popup_is_shown()) {
+			/* cycle through popup pages */
+			interface.popup_show();
+			return;
+		}
+
+		gchar complete = escape_char == '{' ? '\0' : escape_char;
+		gchar *new_chars = help_index.auto_complete(strings[0], complete);
+
+		if (new_chars)
+			cmdline.insert(new_chars);
+		g_free(new_chars);
+		return;
+	}
+	}
+
+	StateExpectString::process_edit_cmd(key);
+}
+
+/*
  * Command states
  */