cleaned up usage of the escape control character: introduced CTL_KEY_ESC and CTL_KEY_ESC_STR

 * the reason for the CTL_KEY() macro is to get the control character
   resulting from a CTRL+Key press -- at least this is how SciTECO
   presents these key presses.
   It is also a macro and may be resolved to a constant expression,
   so it can be used in switch-case statements.
   Sometimes it is clearer to use standard C escape sequences (like '\t').
 * CTL_KEY('[') for escape is hard to read, so I always used '\x1B' which
   is even more cryptic.

6 files changed, 27 insertions, 14 deletions

diff --git a/src/cmdline.cpp b/src/cmdline.cpp
index a995d55..888a70c 100644
--- a/src/cmdline.cpp
+++ b/src/cmdline.cpp
@@ -102,7 +102,7 @@ copy(void) const
 void
 Cmdline::replace(void)
 {
-	QRegister *cmdline_reg = QRegisters::globals["\x1B"];
+	QRegister *cmdline_reg = QRegisters::globals[CTL_KEY_ESC_STR];
 	/* use heap object to avoid copy constructors etc. */
 	Cmdline *new_cmdline = new Cmdline();
 
@@ -426,11 +426,11 @@ Cmdline::process_edit_cmd(gchar key)
 		}
 		break;
 
-	case '\x1B': /* terminate command line */
+	case CTL_KEY_ESC: /* terminate command line */
 		interface.popup_clear();
 
 		if (States::current == &States::start &&
-		    str && str[len-1] == '\x1B') {
+		    str && str[len-1] == CTL_KEY_ESC) {
 			if (Goto::skip_label) {
 				interface.msg(InterfaceCurrent::MSG_ERROR,
 					      "Label \"%s\" not found",
diff --git a/src/interface-curses.cpp b/src/interface-curses.cpp
index dd08e8f..e05643b 100644
--- a/src/interface-curses.cpp
+++ b/src/interface-curses.cpp
@@ -257,7 +257,7 @@ InterfaceCurses::format_chr(chtype *&target, gchar chr, attr_t attr)
 	 * View::set_representations()
 	 */
 	switch (chr) {
-	case '\x1B': /* escape */
+	case CTL_KEY_ESC:
 		*target++ = '$' | attr | A_REVERSE;
 		break;
 	case '\r':
diff --git a/src/interface-gtk.cpp b/src/interface-gtk.cpp
index e7f6927..8375dd8 100644
--- a/src/interface-gtk.cpp
+++ b/src/interface-gtk.cpp
@@ -196,7 +196,7 @@ InterfaceGtk::cmdline_insert_chr(gint &pos, gchar chr)
 	 * View::set_representations()
 	 */
 	switch (chr) {
-	case '\x1B': /* escape */
+	case CTL_KEY_ESC:
 		strcpy(buffer, "$");
 		break;
 	case '\r':
@@ -308,7 +308,7 @@ handle_key_press(bool is_shift, bool is_ctl, guint keyval)
 {
 	switch (keyval) {
 	case GDK_Escape:
-		cmdline.keypress('\x1B');
+		cmdline.keypress(CTL_KEY_ESC);
 		break;
 	case GDK_BackSpace:
 		cmdline.keypress('\b');
diff --git a/src/main.cpp b/src/main.cpp
index ea192db..ed054d7 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -338,7 +338,7 @@ main(int argc, char **argv)
 	 * If munged file didn't quit, switch into interactive mode
 	 */
 	/* commandline replacement string register */
-	QRegisters::globals.insert("\x1B");
+	QRegisters::globals.insert(CTL_KEY_ESC_STR);
 
 	Goto::table = &cmdline_goto_table;
 	undo.enabled = true;
diff --git a/src/parser.cpp b/src/parser.cpp
index ce77aaf..1514e24 100644
--- a/src/parser.cpp
+++ b/src/parser.cpp
@@ -77,7 +77,7 @@ static bool skip_else = false;
 static gint nest_level = 0;
 
 gchar *strings[2] = {NULL, NULL};
-gchar escape_char = '\x1B';
+gchar escape_char = CTL_KEY_ESC;
 
 /**
  * Handles all expected exceptions, converting them to
@@ -440,7 +440,7 @@ StateExpectString::custom(gchar chr)
 			undo.push_var(Modifiers::at) = false;
 
 		switch (escape_char) {
-		case '\x1B':
+		case CTL_KEY_ESC:
 		case '{':
 			undo.push_var(escape_char) = g_ascii_toupper(chr);
 			return this;
@@ -466,7 +466,7 @@ StateExpectString::custom(gchar chr)
 
 		undo.push_str(strings[0]) = NULL;
 		if (last)
-			undo.push_var(escape_char) = '\x1B';
+			undo.push_var(escape_char) = CTL_KEY_ESC;
 		nesting = 1;
 
 		if (string_building)
@@ -1024,7 +1024,7 @@ StateStart::custom(gchar chr)
 				    "interactive mode");
 
 		current_doc_undo_edit();
-		QRegisters::globals.edit("\x1B");
+		QRegisters::globals.edit(CTL_KEY_ESC_STR);
 
 		interface.ssm(SCI_BEGINUNDOACTION);
 		interface.ssm(SCI_CLEARALL);
@@ -1041,7 +1041,7 @@ StateStart::custom(gchar chr)
 		if (!undo.enabled)
 			throw Error("Command-line editing only possible in "
 				    "interactive mode");
-		if (QRegisters::current != QRegisters::globals["\x1B"])
+		if (QRegisters::current != QRegisters::globals[CTL_KEY_ESC_STR])
 			throw Error("Command-line replacement only allowed when "
 				    "editing the replacement register");
 
diff --git a/src/sciteco.h b/src/sciteco.h
index 53131dc..c4395c1 100644
--- a/src/sciteco.h
+++ b/src/sciteco.h
@@ -49,15 +49,28 @@ namespace Flags {
 
 extern sig_atomic_t sigint_occurred;
 
-/*
- * for sentinels: NULL might not be defined as a
+/**
+ * For sentinels: NULL might not be defined as a
  * pointer type (LLVM/CLang)
  */
 #define NIL		((void *)0)
 
+/** true if C is a control character */
 #define IS_CTL(C)	((C) < ' ')
+/** ASCII character to echo control character C */
 #define CTL_ECHO(C)	((C) | 0x40)
+/**
+ * Control character of ASCII C, i.e.
+ * control character corresponding to CTRL+<C> keypress.
+ */
 #define CTL_KEY(C)	((C) & ~0x40)
+/**
+ * Control character of the escape key.
+ * Equivalent to CTL_KEY('[')
+ */
+#define CTL_KEY_ESC	27
+/** String containing the escape character */
+#define CTL_KEY_ESC_STR	"\x1B"
 
 #define SUCCESS		(-1)
 #define FAILURE		(0)