Tcl Source Code

2012-03-08  Donal K. Fellows  <[email protected]>

	* doc/info.n: Various minor fixes (prompted by Andreas Kupries
	detecting a spelling mistake).

2012-03-07  Andreas Kupries  <[email protected]>

	* library/http/http.tcl: [Bug 3498327]: Generate upper-case
	* library/http/pkgIndex.tcl: hexadecimal output for compliance
	* tests/http.test: with RFC 3986. Bumped version to 2.8.4.
	* unix/Makefile.in:
	* win/Makefile.in:

'\"
'\" Copyright (c) 1993 The Regents of the University of California.
'\" Copyright (c) 1994-1997 Sun Microsystems, Inc.
'\" Copyright (c) 1993-1997 Bell Labs Innovations for Lucent Technologies
'\" Copyright (c) 1998-2000 Ajuba Solutions
'\" Copyright (c) 2007-2012 Donal K. Fellows
'\"
'\" See the file "license.terms" for information on usage and redistribution
'\" of this file, and for a DISCLAIMER OF ALL WARRANTIES.
'\" 
.so man.macros
.TH info n 8.4 Tcl "Tcl Built-In Commands"
.BS

This command is typically used in line-oriented input environments
to allow users to type in commands that span multiple lines;  if the
command is not complete, the script can delay evaluating it until additional
lines have been typed to complete the command.
.TP
\fBinfo coroutine\fR
.VS 8.6
Returns the name of the currently executing \fBcoroutine\fR, or the empty
string if either no coroutine is currently executing, or the current coroutine
has been deleted (but has not yet returned or yielded since deletion).
.VE 8.6
.TP
\fBinfo default \fIprocname arg varname\fR
.
\fIProcname\fR must be the name of a Tcl command procedure and \fIarg\fR
must be the name of an argument to that procedure.  If \fIarg\fR
does not have a default value then the command returns \fB0\fR.
Otherwise it returns \fB1\fR and places the default value of \fIarg\fR
into variable \fIvarname\fR.
.TP
\fBinfo errorstack \fR?\fIinterp\fR?
.VS 8.6
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.
.RS
.PP
This form is an even-sized list alternating tokens and parameters. Tokens are
currently either \fBCALL\fR, \fBUP\fR, or \fBINNER\fR, but other values may be
introduced in the future. \fBCALL\fR indicates a procedure call, and its
parameter is the corresponding \fBinfo level\fR \fB0\fR. \fBUP\fR indicates a
shift in variable frames generated by \fBuplevel\fR or similar, and applies to
the previous \fBCALL\fR item. Its parameter is the level offset. \fBINNER\fR
identifies the
.QW "inner context" ,
which is the innermost atomic command or bytecode instruction that raised the
error, along with its arguments when available. While \fBCALL\fR and \fBUP\fR
allow to follow complex call paths, \fBINNER\fR homes in on the offending
operation in the innermost procedure call, even going to sub-expression
granularity.
.PP
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 top-level in an
interactive \fBtclsh\fR.
.RE
.VE 8.6
.TP
\fBinfo exists \fIvarName\fR
.
Returns \fB1\fR if the variable named \fIvarName\fR exists in the
current context (either as a global or local variable) and has been
defined by being given a value, returns \fB0\fR otherwise.

.TP
\fBeval\fR\0\0\0\0\0\0\0\0
.
means that the command is executed by \fBeval\fR or \fBuplevel\fR.
.TP
\fBprecompiled\fR\0\0\0\0\0\0\0\0
.
means that the command is found in a pre-compiled script (loadable by
the package \fBtbcload\fR), and no further information will be
available.
.RE
.TP
\fBline\fR
.
This entry provides the number of the line the command is at inside of
the script it is a part of. This information is not present for type
\fBprecompiled\fR. For type \fBsource\fR this information is counted
relative to the beginning of the file, whereas for the last two types
the line is counted relative to the start of the script.
.TP
\fBfile\fR
.
This entry is present only for type \fBsource\fR. It provides the
normalized path of the file the command is in.
.TP
\fBcmd\fR
.
This entry provides the string representation of the command. This is
usually the unsubstituted form, however for commands which are a
canonically-constructed list (e.g., as produced by the \fBlist\fR command)
executed by \fBeval\fR it is the substituted form as they have no other
string representation. Care is taken that the canonicality property of
the latter is not spoiled.
.TP
\fBproc\fR
.
This entry is present only if the command is found in the body of a
regular Tcl procedure. It then provides the name of that procedure.
.TP

A thing of note is that for procedures statically defined in files the
locations of commands in their bodies will be reported with type
\fBsource\fR and absolute line numbers, and not as type
\fBproc\fR. The same is true for procedures nested in statically
defined procedures, and literal eval scripts in files or statically
defined procedures.
.PP
In contrast, procedure definitions and \fBeval\fR within a dynamically
\fBeval\fRuated environment count line numbers relative to the start of
their script, even if they would be able to count relative to the
start of the outer dynamic script. That type of number usually makes
more sense.
.PP
A different way of describing this behaviour is that file based
locations are tracked as deeply as possible, and where this is not
possible the lines are counted based on the smallest possible
\fBeval\fR or procedure body, as that scope is usually easier to find
than any dynamic outer scope.
.PP
The syntactic form \fB{*}\fR is handled like \fBeval\fR. I.e. if it
is given a literal list argument the system tracks the line number
within the list words as well, and otherwise all line numbers are
counted relative to the start of each word (smallest scope)
.RE
.TP
\fBinfo functions \fR?\fIpattern\fR?
.
If \fIpattern\fR is not specified, returns a list of all the math
functions currently defined.

.TP
\fBinfo object vars\fI object\fR ?\fIpattern\fR?
.VS 8.6
This subcommand returns a list of all variables in the private namespace of
the object named \fIobject\fR. If the optional \fIpattern\fR argument is
given, it is a filter (in the syntax of a \fBstring match\fR glob pattern)
that constrains the list of variables returned. Note that this is different
from the list returned by \fBinfo object variables\fR; that can include
variables that are currently unset, whereas this can include variables that
are not automatically included by any of \fIobject\fR's methods (or those of
its class, superclasses or mixins).
.VE 8.6
.SH EXAMPLES
.PP
This command prints out a procedure suitable for saving in a Tcl

            return [\fBinfo class definition\fR $locus $name]
        }
    }
    error "no definition for $method"
}
.CE
.PP
This is an alternate way of looking up the definition; it is implemented by
manually scanning the list of methods up the inheritance tree. This code
assumes that only single inheritance is in use, and that there is no complex
use of mixed-in classes (in such cases, using \fBinfo object call\fR as above
is the simplest way of doing this by far):
.PP
.CS
proc getDef {obj method} {
    if {$method in [\fBinfo object methods\fR $obj]} {
        # Assume no forwards
        return [\fBinfo object definition\fR $obj $method]
    }
    set cls [\fBinfo object class\fR $obj]
    while {$method ni [\fBinfo class methods\fR $cls]} {
        # Assume the simple case
        set cls [lindex [\fBinfo class superclass\fR $cls] 0]
        if {$cls eq ""} {
            error "no definition for $method"
        }
    }
    # Assume no forwards
    return [\fBinfo class definition\fR $cls $method]
}
.CE