linenoise: parenthesis-matching backward jump.

* linenoise/linenoise.c (LINENOISE_PAREN_DELAY): New
preprocessor symbol.
(scan_match_rev, scan_rev, usec_delay, paren_jump):
New static functions.
(edit): Handle closing parenthesis, bracket and brace
by inserting and calling paren_jump.

* txr.1: Documented.

1 files changed, 22 insertions, 0 deletions

diff --git a/txr.1 b/txr.1
index 9b7b2dbd..9a77cf9e 100644
--- a/txr.1
+++ b/txr.1
@@ -33677,6 +33677,28 @@ that is, when the
 .code -i
 option isn't present.
 
+.SS* Parenthesis Matching
+
+A feature of the listener is visual parenthesis matching in the form of a
+brief backward jump of the cursor.  This provides a hint to the programmer,
+helping to prevent avoid parenthesis balancing errors.
+
+When any of the three closing characters
+.codn ) ,
+.codn ]
+or
+.code }
+is inserted, the listener scans backward for the matching opening
+character. If the matching character is found, the cursor jumps to that
+character and then returns to the original position a brief moment later. If a
+new character is typed during the brief time delay, the delay is immediately
+canceled, so as not to hinder rapid typing.
+
+Note that the backward matching is unsophisticated; it doesn't observe the
+lexical conventions and syntax of the \*(TL programming language.  For
+instance, a closing parenthesis outside a string literal may match
+match an opening one inside a string literal.
+
 .SH* DEBUGGER
 \*(TX has a simple, crude, built-in debugger. The debugger is invoked by adding
 the