Ctrl+^ is no longer translated to a single caret in string building (refs #20)

* Ctrl+^ (30) and Caret+caret (^^) were both translated to a single caret.
  While there might be some reason to keep this behavior for double-caret,
  it is certainly pointless for Ctrl+^.
* That gives you an easy way to insert Ctrl+^ (code 30) into documents with <I>.
  Perviously, you either had to insert a double-caret, typing 4 carets in a row,
  or you had to use <EI> or 30I$.
* The special handling of double-caret could perhaps be abolished altogether,
  as we also have ^Q^ to escape plain carets.
  The double-caret syntax is very archaic from the time that there was no proper
  ^Q as far as I recall correctly.

3 files changed, 24 insertions, 7 deletions

diff --git a/TODO b/TODO
index 1ec8387..0487a65 100644
--- a/TODO
+++ b/TODO
@@ -509,8 +509,6 @@ Features:
  * ^^ in string building expanding to a single caret is not
    consistent. Perhaps we should allow only ^Q^ as a way to insert a
    single caret?
-   At the very least, Ctrl+^ should insert char 30 instead of a single
-   caret.
  * Support for non-ANSI single byte encodings is still incomplete.
    You can set them with EE and they will be correctly
    displayed (on Gtk at least), but there is no way
diff --git a/doc/sciteco.7.template b/doc/sciteco.7.template
index 8486203..52fa742 100644
--- a/doc/sciteco.7.template
+++ b/doc/sciteco.7.template
@@ -1653,7 +1653,9 @@ stages:
 .IP 1. 4
 Carets followed by characters are translated to control codes,
 so \(lq^a\(rq and \(lq^A\(rq are equivalent to CTRL+A (code 1).
-A double caret \(lq^^\(rq is translated to a single caret.
+\# FIXME: Should we change the double-caret behavior?
+A double caret \(lq^^\(rq is translated to a single caret,
+but Ctrl+caret (code 30) is not translated at all.
 This caret-handling is independent of the caret-handling in
 command names.
 .IP 2.
diff --git a/src/parser.c b/src/parser.c
index 45e31cf..e73c877 100644
--- a/src/parser.c
+++ b/src/parser.c
@@ -383,10 +383,20 @@ TECO_DECLARE_STATE(teco_state_stringbuilding_ctle_n);
 static teco_state_t *
 teco_state_stringbuilding_start_input(teco_machine_stringbuilding_t *ctx, gunichar chr, GError **error)
 {
-	if (chr == '^')
+	switch (chr) {
+	case '^':
 		return &teco_state_stringbuilding_ctl;
-	if (TECO_IS_CTL(chr))
-		return teco_state_stringbuilding_ctl_input(ctx, TECO_CTL_ECHO(chr), error);
+	case TECO_CTL_KEY('^'):
+		/*
+		 * Ctrl+^ is inserted verbatim as code 30.
+		 * Otherwise it would expand to a single caret
+		 * just like caret+caret (^^).
+		 */
+		break;
+	default:
+		if (TECO_IS_CTL(chr))
+			return teco_state_stringbuilding_ctl_input(ctx, TECO_CTL_ECHO(chr), error);
+	}
 
 	return teco_state_stringbuilding_escaped_input(ctx, chr, error);
 }
@@ -407,7 +417,14 @@ teco_state_stringbuilding_ctl_input(teco_machine_stringbuilding_t *ctx, gunichar
 	chr = teco_ascii_toupper(chr);
 
 	switch (chr) {
-	case '^': break;
+	case '^':
+		/*
+		 * Double-caret expands to a single caret.
+		 * Ctrl+^ (30) is handled separately and inserts code 30.
+		 * The special handling of the double-caret should perhaps
+		 * be abolished altogether.
+		 */
+		break;
 	case 'Q':
 	case 'R': return &teco_state_stringbuilding_escaped;
 	case 'V': return &teco_state_stringbuilding_lower;