Updated [catch] docs to cover new TIP 90 features.

1 files changed, 57 insertions, 11 deletions

diff --git a/doc/catch.n b/doc/catch.n
index 01d0628..4d83c5d 100644
--- a/doc/catch.n
+++ b/doc/catch.n
@@ -1,37 +1,83 @@
 '\"
 '\" Copyright (c) 1993-1994 The Regents of the University of California.
 '\" Copyright (c) 1994-1996 Sun Microsystems, Inc.
+'\" Contributions from Don Porter, NIST, 2003.  (not subject to US copyright)
 '\"
 '\" See the file "license.terms" for information on usage and redistribution
 '\" of this file, and for a DISCLAIMER OF ALL WARRANTIES.
 '\" 
-'\" RCS: @(#) $Id: catch.n,v 1.5 2000/09/07 14:27:46 poenitz Exp $
+'\" RCS: @(#) $Id: catch.n,v 1.6 2003/08/31 21:39:23 dgp Exp $
 '\" 
 .so man.macros
-.TH catch n "8.0" Tcl "Tcl Built-In Commands"
+.TH catch n "8.5" Tcl "Tcl Built-In Commands"
 .BS
 '\" Note:  do not modify the .SH NAME line immediately below!
 .SH NAME
 catch \- Evaluate script and trap exceptional returns
 .SH SYNOPSIS
-\fBcatch\fI script \fR?\fIvarName\fR?
+\fBcatch\fI script \fR?\fIresultVarName\fR? ?\fIoptionsVarName\fR?
 .BE
 
 .SH DESCRIPTION
 .PP
 The \fBcatch\fR command may be used to prevent errors from aborting command
-interpretation.  \fBCatch\fR calls the Tcl interpreter recursively to
+interpretation.  The \fBcatch\fR command calls the Tcl interpreter recursively to
 execute \fIscript\fR, and always returns without raising an error,
 regardless of any errors that might occur while executing \fIscript\fR.
 .PP
 If \fIscript\fR raises an error, \fBcatch\fR will return a non-zero integer
-value corresponding to one of the exceptional return codes (see tcl.h
-for the definitions of code values).  If the \fIvarName\fR argument is
-given, then the variable it names is set to the error message from
-interpreting \fIscript\fR.
+value corresponding to the exceptional return code returned by evaluation
+of \fIscript\fR.  Tcl defines the normal return code from script
+evalation to be zero (0), or TCL_OK.  Tcl also defines four exceptional
+return codes: 1 (TCL_ERROR), 2 (TCL_RETURN), 3 (TCL_BREAK),
+and 4 (TCL_CONTINUE).  Errors during evaluation of a script are indicated
+by a return code of TCL_ERROR.  The other exceptional return codes are
+returned by the \fBreturn\fR, \fBbreak\fR, and \fBcontinue\fR commands
+and in other special situations as documented.  Tcl packages can define
+new commands that return other integer values as return codes as well,
+and scripts that make use of the \fBreturn -code\fR command can also
+have return codes other than the five defined by Tcl.
 .PP
-If \fIscript\fR does not raise an error, \fBcatch\fR will return 0
-(TCL_OK) and set the variable to the value returned from \fIscript\fR.
+If the \fIresultVarName\fR argument is given, then the variable it names is
+set to the result of the script evaluation.  When the return code from
+the script is TCL_ERROR, the value stored in \fIresultVarName\fR is an error
+message.  When the return code from the script is TCL_OK, the value
+stored in \fIresultVarName\fR is the value returned from \fIscript\fR.
+.VS 8.5
+.PP
+If the \fIoptionsVarName\fR argument is given, then the variable it
+names is set to a dictionary of return options returned by evaluation
+of \fIscript\fR.  Tcl specifies two entries that are always 
+defined in the dictionary: \fB-code\fR and \fB-level\fR.  When
+the return code from evaluation of \fIscript\fR is not TCL_RETURN,
+the value of the \fB-level\fR entry will be 0, and the value
+of the \fB-code\fR entry will be the same as the return code.
+Only when the return code is TCL_RETURN will the values of
+the \fB\level\fR and \fB-code\fR entries be something else, as
+further described in the documentation for the \fBreturn\fR command.
+.PP
+When the return code from evaluation of \fIscript\fR is TCL_ERROR,
+three additional entries are defined in the dictionary of return options
+stored in \fIoptionsVarName\fR: \fB-errorinfo\fR, \fB-errorcode\fR, 
+and \fB-errorline\fR.  The value of the \fB-errorinfo\fR entry
+is a formatted stack trace containing more information about
+the context in which the error happened.  The formatted stack
+trace is meant to be read by a person.  The value of
+the \fB-errorcode\fR entry is additional information about the
+error stored as a list.  The \fB-errorcode\fR value is meant to
+be further processed by programs, and may not be particularly
+readable by people.  The value of the \fB-errorline\fR entry
+is an integer indicating which line of \fIscript\fR was being
+evaluated when the error occurred.  The values of the \fB-errorinfo\fR
+and \fB-errorcode\fR entries of the most recent error are also
+available as values of the global variables \fB::errorInfo\fR
+and \fB::errorCode\fR respectively.
+.PP
+Tcl packages may provide commands that set other entries in the
+dictionary of return options, and the \fBreturn\fR command may be
+used by scripts to set return options in addition to those defined
+above.
+.VE 8.5
 .PP
 Note that \fBcatch\fR catches all exceptions, including those
 generated by \fBbreak\fR and \fBcontinue\fR as well as errors.  The
@@ -63,7 +109,7 @@ proc foo {} {
 .CE
 
 .SH "SEE ALSO" 
-error(n), break(n), continue(n)
+break(n), continue(n), dict(n), error(n), return(n), tclvars(n)
 
 .SH KEYWORDS
 catch, error