linenoise: substring flag in completion callback.

A feature is hereby introduced into linenoise whereby
completion mode can be entered via Ctrl-X Tab also, not only
Tab.  This is distinguished with a flag in the completion
structure. The intent is that the callback can use this to
provide substring matches not only prefix matches.

* linenoise/linenoise.c (complete_line): Takes a new argument,
and stores it in the new substring member of
lino_completions_t.
(edit): If Tab is typed while in Ctrl-X extended mode,
then fall through to the regular switch, where the TAB
case now recognizes that it is in extended mode and passes
the mode flag to complete_line.

* linenoise/linenoise.h (lino_completions_t): New member,
substring.

1 files changed, 7 insertions, 4 deletions

diff --git a/linenoise/linenoise.c b/linenoise/linenoise.c
index 973acce5..a9c68720 100644
--- a/linenoise/linenoise.c
+++ b/linenoise/linenoise.c
@@ -455,13 +455,15 @@ static int compare_completions(const void *larg, const void *rarg)
  *
  * The state of the editing is encapsulated into the pointed lino_state
  * structure as described in the structure definition. */
-static int complete_line(lino_t *ls) {
-    lino_completions_t lc = { 0, NULL };
+static int complete_line(lino_t *ls, int substring) {
+    lino_completions_t lc = { 0, NULL, 0 };
     int nread;
     char c = 0;
     char save = ls->data[ls->dpos];
     lino_t *lt = lino_copy(ls);
 
+    lc.substring = substring;
+
     if (lt == 0)
         return -1;
 
@@ -1717,7 +1719,7 @@ static int edit(lino_t *l, const char *prompt)
             continue;
         }
 
-        if (extended) {
+        if (extended && c != TAB) {
             switch (c) {
             case CTL('E'):
                 extended = 0;
@@ -1837,8 +1839,9 @@ static int edit(lino_t *l, const char *prompt)
             if (l->completion_callback != NULL) {
                 record_undo(l);
                 clear_sel(l);
-                c = complete_line(l);
+                c = complete_line(l, extended);
             }
+            extended = 0;
             break;
         case CTL('R'):
             record_undo(l);