added <FG> command and special Q-Register "$" to set and get the current working directory

 * FG stands for "Folder Go"
 * FG behaves similar to a Unix shell `cd`.
   Without arguments, it changes to the $HOME directory.
 * The $HOME directory was previously only used by $SCITECOCONFIG on Unix.
   Now it is documented on its own, since the HOME directory should also
   be configurable on Windows - e.g. to adapt SciTECO to a MinGW or Cygwin
   installation.
   HOME is initialized just like the other environment variables.
   This also means that now, the $HOME Q-Register is always defined
   and can be used by platform-agnostic macros.
 * FG uses a new kind of tab-completion: for directories only.
   It would be annoying to complete the FG command after every
   directory, so this tab-completion does not close the command
   automatically. Theoretically, it would be possible to close
   the command after completing a directory with no subdirectories,
   but this is not supported currently.
 * Filename arguments are no longer completed with " " if {} escaping
   is in place as this brings no benefit. Instead no completion character
   is inserted for this escape mode.
 * "$" was mapped to the current directory to support an elegant way to
   insert/get the current directory.
   Also this allows the idiom "[$ FG...new_dir...$ ]$" for changing
   the current directory temporarily.
 * The Q-Register stack was extended to support restoring the string
   part of special Q-Registers (that overwrite the default functionality)
   when using the "[$" and "]$" commands.
 * fixed minor typos (american spelling)

1 files changed, 28 insertions, 3 deletions

diff --git a/src/qregisters.h b/src/qregisters.h
index b2d856d..1ef0564 100644
--- a/src/qregisters.h
+++ b/src/qregisters.h
@@ -119,10 +119,16 @@ public:
 	virtual gsize get_string_size(void);
 	virtual gint get_character(gint position);
 
+	virtual void
+	exchange_string(QRegisterData &reg)
+	{
+		string.exchange(reg.string);
+	}
+	virtual void undo_exchange_string(QRegisterData &reg);
+
 	/*
-	 * The QRegisterStack must currently access the
-	 * integer and string fields directly to exchange
-	 * data efficiently.
+	 * The QRegisterStack must currently still access the
+	 * string fields directly to exchange data efficiently.
 	 */
 	friend class QRegisterStack;
 };
@@ -183,6 +189,25 @@ public:
 	void edit(void);
 };
 
+class QRegisterWorkingDir : public QRegister {
+public:
+	QRegisterWorkingDir() : QRegister("$") {}
+
+	void set_string(const gchar *str, gsize len);
+	void undo_set_string(void);
+	void append_string(const gchar *str, gsize len) {}
+	void undo_append_string(void) {}
+
+	gchar *get_string(void);
+	gsize get_string_size(void);
+	gint get_character(gint pos);
+
+	void edit(void);
+
+	void exchange_string(QRegisterData &reg);
+	void undo_exchange_string(QRegisterData &reg);
+};
+
 class QRegisterTable : private RBTree {
 	class UndoTokenRemove : public UndoTokenWithSize<UndoTokenRemove> {
 		QRegisterTable *table;