implemented the <^A> command for printing arbitrary strings

* Greatly improved usability as a scripting language.
* The command is in DEC TECO, but in contrast to DEC TECO, we also
  support string building constructs in ^A.
* Required some refactoring: As we want it to write everything verbatim
  to stdout, the per-interface method is now teco_interface_msg_literal()
  and it has to deal with unprintable characters.
  When displaying in the UI, we use teco_curses_format_str() and TecoGtkLabel
  functions/widgets to deal with possible control codes.
* Numbers printed with `=` have to be written with a trailing linefeed,
  which would also be visible as a reverse "LF" in the UI.
  Not sure whether this is acceptable - the alternative would be to strip
  the strings before displaying them.
* Messages written to stdout are also auto-flushed at the moment.
  In the future we might want to put flushing under control of the language.
  Perhaps :^A could inhibit the flushing.

1 files changed, 6 insertions, 18 deletions

diff --git a/src/interface-gtk/interface.c b/src/interface-gtk/interface.c
index 973225e..544ff22 100644
--- a/src/interface-gtk/interface.c
+++ b/src/interface-gtk/interface.c
@@ -19,7 +19,6 @@
 #include "config.h"
 #endif
 
-#include <stdarg.h>
 #include <string.h>
 #include <signal.h>
 
@@ -193,7 +192,7 @@ teco_interface_init(void)
 	 */
 	teco_interface.info_bar_widget = gtk_header_bar_new();
 	gtk_widget_set_name(teco_interface.info_bar_widget, "sciteco-info-bar");
-	teco_interface.info_name_widget = teco_gtk_label_new(NULL, 0);
+	teco_interface.info_name_widget = teco_gtk_label_new("", 0);
 	gtk_widget_set_valign(teco_interface.info_name_widget, GTK_ALIGN_CENTER);
 	/* eases writing portable fallback.css that avoids CSS element names */
 	gtk_style_context_add_class(gtk_widget_get_style_context(teco_interface.info_name_widget),
@@ -279,8 +278,7 @@ teco_interface_init(void)
 	gtk_widget_set_name(teco_interface.message_bar_widget, "sciteco-message-bar");
 	GtkWidget *message_bar_content =
 			gtk_info_bar_get_content_area(GTK_INFO_BAR(teco_interface.message_bar_widget));
-	/* NOTE: Messages are always pre-canonicalized */
-	teco_interface.message_widget = gtk_label_new(NULL);
+	teco_interface.message_widget = teco_gtk_label_new(NULL, 0);
 	/* eases writing portable fallback.css that avoids CSS element names */
 	gtk_style_context_add_class(gtk_widget_get_style_context(teco_interface.message_widget),
 	                            "label");
@@ -391,7 +389,7 @@ teco_interface_get_options(void)
 void teco_interface_init_color(guint color, guint32 rgb) {}
 
 void
-teco_interface_vmsg(teco_msg_t type, const gchar *fmt, va_list ap)
+teco_interface_msg_literal(teco_msg_t type, const gchar *str, gsize len)
 {
 	/*
 	 * The message types are chosen such that there is a CSS class
@@ -407,21 +405,11 @@ teco_interface_vmsg(teco_msg_t type, const gchar *fmt, va_list ap)
 
 	g_assert(type < G_N_ELEMENTS(type2gtk));
 
-	gchar buf[256];
-
-	/*
-	 * stdio_vmsg() leaves `ap` undefined and we are expected
-	 * to do the same and behave like vprintf().
-	 */
-	va_list aq;
-	va_copy(aq, ap);
-	teco_interface_stdio_vmsg(type, fmt, ap);
-	g_vsnprintf(buf, sizeof(buf), fmt, aq);
-	va_end(aq);
+	teco_interface_stdio_msg(type, str, len);
 
 	gtk_info_bar_set_message_type(GTK_INFO_BAR(teco_interface.message_bar_widget),
 				      type2gtk[type]);
-	gtk_label_set_text(GTK_LABEL(teco_interface.message_widget), buf);
+	teco_gtk_label_set_text(TECO_GTK_LABEL(teco_interface.message_widget), str, len);
 
 	if (type == TECO_MSG_ERROR)
 		gtk_widget_error_bell(teco_interface.window);
@@ -432,7 +420,7 @@ teco_interface_msg_clear(void)
 {
 	gtk_info_bar_set_message_type(GTK_INFO_BAR(teco_interface.message_bar_widget),
 				      GTK_MESSAGE_QUESTION);
-	gtk_label_set_text(GTK_LABEL(teco_interface.message_widget), "");
+	teco_gtk_label_set_text(TECO_GTK_LABEL(teco_interface.message_widget), "", 0);
 }
 
 void