enhance M-. parsing

[adavies42]

afaict M-. currently inserts the last word of the last command as defined only by splitting on spaces

it would be nice to have at least a little of the improvement readline provides for this action, e.g. that it should also split on redirect instructions -- if i do

... >file
cat <M-.>

then in bash the second command is cat file, but in ksh, it's cat >file, which is actively harmful, since it wipes file

however, exactly what to change here should be considered carefully, as readline's version is so "enhanced" that it sometimes returns something that i can't figure out the source of

[McDutchie]

Took me a minute to figure out the context. This is about ESC . aka ESC _ in emacs.

Any changes here would also affect the _ command in vi, as they use the same hist_word function to find words.

[McDutchie]

It is probably best to use the same word boundary characters as those introduced for history expansion in 0a71a8a.

Try this patch:

diff --git a/src/cmd/ksh93/edit/history.c b/src/cmd/ksh93/edit/history.c
index 94cf50536..5f0228e6e 100644
--- a/src/cmd/ksh93/edit/history.c
+++ b/src/cmd/ksh93/edit/history.c
@@ -1015,7 +1015,7 @@ char *hist_word(char *string,int size,int word)
 	hist_copy(string,size,(int)hp->histind-1,-1);
 	for(quoted=0;c = *cp;cp++)
 	{
-		is_space = isspace(c) && !quoted;
+		is_space = !quoted && (isspace(c) || strchr("|&;()`<>",c));
 		if(is_space && flag)
 		{
 			*cp = 0;