Document [info errostack] faithfully.

FossilOrigin-Name: 997462044d4f903d617d02efdade5c4a521802ff

1 files changed, 14 insertions, 4 deletions

diff --git a/doc/info.n b/doc/info.n
index 63ce180..3bfb713 100644
--- a/doc/info.n
+++ b/doc/info.n
@@ -8,7 +8,7 @@
 '\" See the file "license.terms" for information on usage and redistribution
 '\" of this file, and for a DISCLAIMER OF ALL WARRANTIES.
 '\" 
-'\" RCS: @(#) $Id: info.n,v 1.38 2010/04/07 09:51:31 dkf Exp $
+'\" RCS: @(#) $Id: info.n,v 1.39 2010/10/17 20:16:55 ferrieux Exp $
 '\" 
 .so man.macros
 .TH info n 8.4 Tcl "Tcl Built-In Commands"
@@ -96,9 +96,19 @@ into variable \fIvarname\fR.
 .TP
 \fBinfo errorstack \fR?\fIinterp\fR?
 .VS 8.6
-Returns a list of lists made of the function names and arguments at each level
-from the call stack of the last error in the given \fIinterp\fR, or in the
-current one if not specified.  This information is also present in the
+Returns, in a form that is programmatically easy to parse, the function names
+and arguments at each level from the call stack of the last error in the given
+\fIinterp\fR, or in the current one if not specified.
+
+This form is an
+even-sized list alternating tokens and parameters. Tokens are currently either
+\fBCALL\fR or \fBUP\fR, but other values may be introduced in the
+future. \fBCALL\fR indicates a procedure call, and its parameter is the
+corresponding [info level 0]; \fBUP\fR indicates a shift in variable frames
+generated by uplevel or similar, and applies to the previous CALL item. Its
+parameter is the level offset.
+
+This information is also present in the
 \fB\-errorstack\fR entry of the options dictionary returned by 3-argument
 \fBcatch\fR; \fBinfo errorstack\fR is a convenient way of retrieving it for
 uncaught errors at toplevel in an interactive tclsh.