Let irssi tab completion consider current word up to cursor instead of up to separator. Ugly hack.

patch

diff --git a/src/fe-common/core/completion.c b/src/fe-common/core/completion.c
index 46fd9db..0decb4f 100644
--- a/src/fe-common/core/completion.c
+++ b/src/fe-common/core/completion.c
@@ -80,6 +80,7 @@ static char *get_word_at(const char *str, int pos, char **startpos)
        while (start > str && !isseparator(start[-1])) start--;
        while (*end != '\0' && !isseparator(*end)) end++;
        while (*end != '\0' && isseparator_notspace(*end)) end++;
+        if (end > str+pos) end = str+pos;
 
        *startpos = (char *) start;
        return g_strndup(start, (int) (end-start));