allow setting the "*" register as an alternative to nEB

this is more consistent with SciTECO's idea of abstract registers
and allows the currend buffer to be saved on the Q-Register stack.
This allows the idiom: [* ! ...change current buffer... ! ]*

3 files changed, 23 insertions, 13 deletions

diff --git a/src/qregisters.cpp b/src/qregisters.cpp
index 24ca904..846a5a4 100644
--- a/src/qregisters.cpp
+++ b/src/qregisters.cpp
@@ -229,16 +229,24 @@ QRegister::load(const gchar *filename)
 }
 
 tecoInt
-QRegisterBufferInfo::get_integer(void)
+QRegisterBufferInfo::set_integer(tecoInt v)
 {
-	tecoInt id = 1;
+	if (!ring.edit(v))
+		throw Error("Invalid buffer id %" TECO_INTEGER_FORMAT, v);
 
-	for (Buffer *buffer = ring.first();
-	     buffer != ring.current;
-	     buffer = buffer->next())
-		id++;
+	return v;
+}
 
-	return id;
+void
+QRegisterBufferInfo::undo_set_integer(void)
+{
+	current_doc_undo_edit();
+}
+
+tecoInt
+QRegisterBufferInfo::get_integer(void)
+{
+	return ring.get_id();
 }
 
 gchar *
diff --git a/src/qregisters.h b/src/qregisters.h
index cf2c644..9a7618b 100644
--- a/src/qregisters.h
+++ b/src/qregisters.h
@@ -146,12 +146,9 @@ class QRegisterBufferInfo : public QRegister {
 public:
 	QRegisterBufferInfo() : QRegister("*") {}
 
-	tecoInt
-	set_integer(tecoInt v)
-	{
-		return v;
-	}
-	void undo_set_integer(void) {}
+	/* setting "*" is equivalent to nEB */
+	tecoInt set_integer(tecoInt v);
+	void undo_set_integer(void);
 
 	tecoInt get_integer(void);
 
diff --git a/src/ring.h b/src/ring.h
index 5dc3a37..7aa4f27 100644
--- a/src/ring.h
+++ b/src/ring.h
@@ -187,6 +187,11 @@ public:
 	}
 
 	tecoInt get_id(Buffer *buffer);
+	inline tecoInt
+	get_id(void)
+	{
+		return get_id(current);
+	}
 
 	Buffer *find(const gchar *filename);
 	Buffer *find(tecoInt id);