added support for TECO stack tracing

 * when an error is thrown, stack frames are collected on clean up, up to
   the toplevel macro
 * the toplevel macro decides how to display the error
 * now errors in interactive and batch mode are displayed differently
   * in batch mode, a backtrace is displayed as a sequence of messages
 * Execute::file() forwards errors correctly
   * the correct error in the file is displayed in interactive mode
   * necessary to build the stack trace

6 files changed, 171 insertions, 37 deletions

diff --git a/src/cmdline.cpp b/src/cmdline.cpp
index c6dcf2a..641b062 100644
--- a/src/cmdline.cpp
+++ b/src/cmdline.cpp
@@ -97,7 +97,10 @@ cmdline_keypress(gchar key)
 			cmdline_pos = repl_pos = r.pos;
 			macro_pc = r.pos-1;
 			continue;
-		} catch (...) {
+		} catch (State::Error &error) {
+			error.add_frame(new State::Error::ToplevelFrame());
+			error.display_short();
+
 			if (old_cmdline) {
 				undo.pop(repl_pos);
 
diff --git a/src/main.cpp b/src/main.cpp
index ca3a37d..d0dfd84 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -254,26 +254,33 @@ main(int argc, char **argv)
 	/*
 	 * Execute macro or mung file
 	 */
-	if (eval_macro) {
-		try {
-			Execute::macro(eval_macro, false);
-		} catch (...) {
-			exit(EXIT_FAILURE);
+	try {
+		if (eval_macro) {
+			try {
+				Execute::macro(eval_macro, false);
+			} catch (State::Error &error) {
+				error.add_frame(new State::Error::ToplevelFrame());
+				throw; /* forward */
+			}
+			exit(EXIT_SUCCESS);
 		}
-		exit(EXIT_SUCCESS);
-	}
 
-	if (g_file_test(mung_file, G_FILE_TEST_IS_REGULAR)) {
-		if (!Execute::file(mung_file, false))
-			exit(EXIT_FAILURE);
+		if (g_file_test(mung_file, G_FILE_TEST_IS_REGULAR)) {
+			Execute::file(mung_file, false);
 
-		/* FIXME: make quit immediate in batch/macro mode (non-UNDO)? */
-		if (quit_requested) {
-			/* FIXME */
-			exit(EXIT_SUCCESS);
+			/* FIXME: make quit immediate in batch/macro mode (non-UNDO)? */
+			if (quit_requested) {
+				/* FIXME */
+				exit(EXIT_SUCCESS);
+			}
 		}
+		g_free(mung_file);
+	} catch (State::Error &error) {
+		error.display_full();
+		exit(EXIT_FAILURE);
+	} catch (...) {
+		exit(EXIT_FAILURE);
 	}
-	g_free(mung_file);
 
 	/*
 	 * If munged file didn't quit, switch into interactive mode
diff --git a/src/parser.cpp b/src/parser.cpp
index 4572f02..016b8bd 100644
--- a/src/parser.cpp
+++ b/src/parser.cpp
@@ -82,10 +82,15 @@ Execute::step(const gchar *macro, gint stop_pos)
 			 States::current, mode);
 #endif
 
-		if (interface.is_interrupted())
-			throw State::Error("Interrupted");
-
-		State::input(macro[macro_pc]);
+		try {
+			if (interface.is_interrupted())
+				throw State::Error("Interrupted");
+
+			State::input(macro[macro_pc]);
+		} catch (State::Error &error) {
+			error.pos = macro_pc;
+			throw; /* forward */
+		}
 		macro_pc++;
 	}
 }
@@ -147,26 +152,34 @@ Execute::macro(const gchar *macro, bool locals)
 	States::current = parent_state;
 }
 
-bool
+void
 Execute::file(const gchar *filename, bool locals)
+	     throw (State::Error, ReplaceCmdline)
 {
-	gchar *macro_str, *p = NULL;
+	gchar *macro_str, *p;
 
 	if (!g_file_get_contents(filename, &macro_str, NULL, NULL))
-		return false;
+		throw State::Error("Error reading file \"%s\"", filename);
 	/* only when executing files, ignore Hash-Bang line */
 	if (*macro_str == '#')
-		p = MAX(strchr(macro_str, '\r'), strchr(macro_str, '\n'));
+		p = MAX(strchr(macro_str, '\r'), strchr(macro_str, '\n'))+1;
+	else
+		p = macro_str;
 
 	try {
-		macro(p ? p+1 : macro_str, locals);
+		macro(p, locals);
+	} catch (State::Error &error) {
+		error.pos += p - macro_str;
+		error.add_frame(new State::Error::FileFrame(filename));
+
+		g_free(macro_str);
+		throw; /* forward */
 	} catch (...) {
 		g_free(macro_str);
-		return false;
+		throw; /* forward */
 	}
 
 	g_free(macro_str);
-	return true;
 }
 
 ReplaceCmdline::ReplaceCmdline()
@@ -178,15 +191,45 @@ ReplaceCmdline::ReplaceCmdline()
 	pos++;
 }
 
-State::Error::Error(const gchar *fmt, ...)
+State::Error::Error(const gchar *fmt, ...) : frames(NULL), pos(0)
 {
 	va_list ap;
 
 	va_start(ap, fmt);
-	interface.vmsg(Interface::MSG_ERROR, fmt, ap);
+	description = g_strdup_vprintf(fmt, ap);
 	va_end(ap);
 }
 
+void
+State::Error::display_short(void)
+{
+	interface.msg(Interface::MSG_ERROR,
+		      "%s (at %d)", description, pos);
+}
+
+void
+State::Error::display_full(void)
+{
+	gint nr = 0;
+
+	interface.msg(Interface::MSG_ERROR, "%s", description);
+
+	frames = g_slist_reverse(frames);
+	for (GSList *cur = frames; cur; cur = g_slist_next(cur)) {
+		Frame *frame = (Frame *)cur->data;
+
+		frame->display(nr++);
+	}
+}
+
+State::Error::~Error()
+{
+	g_free(description);
+	for (GSList *cur = frames; cur; cur = g_slist_next(cur))
+		delete (Frame *)cur->data;
+	g_slist_free(frames);
+}
+
 State::State()
 {
 	for (guint i = 0; i < G_N_ELEMENTS(transitions); i++)
@@ -366,7 +409,7 @@ StringBuildingMachine::~StringBuildingMachine()
 }
 
 State *
-StateExpectString::custom(gchar chr) throw (Error)
+StateExpectString::custom(gchar chr) throw (Error, ReplaceCmdline)
 {
 	gchar *insert;
 
diff --git a/src/parser.h b/src/parser.h
index b96e8d4..8aa7ef5 100644
--- a/src/parser.h
+++ b/src/parser.h
@@ -39,8 +39,84 @@ public:
 class State {
 public:
 	class Error {
+		gchar *description;
+		GSList *frames;
+
 	public:
+		gint pos;
+
+		class Frame {
+		public:
+			gint pos;
+			virtual ~Frame() {}
+
+			virtual void display(gint nr) = 0;
+		};
+
+		class QRegFrame : public Frame {
+			gchar *name;
+
+		public:
+			QRegFrame(const gchar *_name)
+				 : name(g_strdup(_name)) {}
+
+			~QRegFrame()
+			{
+				g_free(name);
+			}
+
+			void
+			display(gint nr)
+			{
+				interface.msg(Interface::MSG_INFO,
+					      "#%d in Q-Register \"%s\" at %d",
+					      nr, name, pos);
+			}
+		};
+
+		class FileFrame : public Frame {
+			gchar *name;
+
+		public:
+			FileFrame(const gchar *_name)
+				 : name(g_strdup(_name)) {}
+
+			~FileFrame()
+			{
+				g_free(name);
+			}
+
+			void
+			display(gint nr)
+			{
+				interface.msg(Interface::MSG_INFO,
+					      "#%d in file \"%s\" at %d",
+					      nr, name, pos);
+			}
+		};
+
+		class ToplevelFrame : public Frame {
+		public:
+			void
+			display(gint nr)
+			{
+				interface.msg(Interface::MSG_INFO,
+					      "#%d in toplevel macro at %d", nr, pos);
+			}
+		};
+
 		Error(const gchar *fmt, ...) G_GNUC_PRINTF(2, 3);
+		~Error();
+
+		inline void
+		add_frame(Frame *frame)
+		{
+			frame->pos = pos;
+			frames = g_slist_prepend(frames, frame);
+		}
+
+		void display_short(void);
+		void display_full(void);
 	};
 
 	class SyntaxError : public Error {
@@ -193,12 +269,12 @@ public:
 			   string_building(_building), last(_last) {}
 
 private:
-	State *custom(gchar chr) throw (Error);
+	State *custom(gchar chr) throw (Error, ReplaceCmdline);
 
 protected:
 	virtual void initial(void) throw (Error) {}
 	virtual void process(const gchar *str, gint new_chars) throw (Error) {}
-	virtual State *done(const gchar *str) throw (Error) = 0;
+	virtual State *done(const gchar *str) throw (Error, ReplaceCmdline) = 0;
 };
 
 class StateExpectFile : public StateExpectString {
@@ -334,7 +410,8 @@ namespace Execute {
 		 throw (State::Error, ReplaceCmdline);
 	void macro(const gchar *macro, bool locals = true)
 		  throw (State::Error, ReplaceCmdline);
-	bool file(const gchar *filename, bool locals = true);
+	void file(const gchar *filename, bool locals = true)
+		 throw (State::Error, ReplaceCmdline);
 }
 
 #endif
diff --git a/src/qregisters.cpp b/src/qregisters.cpp
index 02a779a..a0dc5f5 100644
--- a/src/qregisters.cpp
+++ b/src/qregisters.cpp
@@ -185,6 +185,11 @@ QRegister::execute(bool locals) throw (State::Error, ReplaceCmdline)
 
 	try {
 		Execute::macro(str, locals);
+	} catch (State::Error &error) {
+		error.add_frame(new State::Error::QRegFrame(name));
+
+		g_free(str);
+		throw; /* forward */
 	} catch (...) {
 		g_free(str);
 		throw; /* forward */
@@ -698,13 +703,12 @@ StateMacro::got_register(QRegister &reg) throw (Error, ReplaceCmdline)
  * If <file> could not be read, the command yields an error.
  */
 State *
-StateMacroFile::done(const gchar *str) throw (Error)
+StateMacroFile::done(const gchar *str) throw (Error, ReplaceCmdline)
 {
 	BEGIN_EXEC(&States::start);
 
 	/* don't create new local Q-Registers if colon modifier is given */
-	if (!Execute::file(str, !eval_colon()))
-		throw Error("Cannot execute macro from file \"%s\"", str);
+	Execute::file(str, !eval_colon());
 
 	return &States::start;
 }
diff --git a/src/qregisters.h b/src/qregisters.h
index 840e442..4b1ad3d 100644
--- a/src/qregisters.h
+++ b/src/qregisters.h
@@ -383,7 +383,7 @@ private:
 
 class StateMacroFile : public StateExpectFile {
 private:
-	State *done(const gchar *str) throw (Error);
+	State *done(const gchar *str) throw (Error, ReplaceCmdline);
 };
 
 class StateCopyToQReg : public StateExpectQReg {