Tcl Source Code

'\"
'\" Copyright (c) 1993-1997 Bell Labs Innovations for Lucent Technologies
'\" Copyright (c) 1997 Sun Microsystems, Inc.
'\"
'\" See the file "license.terms" for information on usage and redistribution
'\" of this file, and for a DISCLAIMER OF ALL WARRANTIES.
'\" 
'\" RCS: @(#) $Id: namespace.n,v 1.1.2.2 1999/04/09 18:42:02 surles Exp $
'\" 
.so man.macros
.TH namespace n 8.0 Tcl "Tcl Built-In Commands"
.BS
'\" Note:  do not modify the .SH NAME line immediately below!
.SH NAME
namespace \- create and manipulate contexts for commands and variables

Tcl has always had one such collection,
which we refer to as the \fIglobal namespace\fR.
The global namespace holds all global variables and commands.
The \fBnamespace eval\fR command lets you create new namespaces.
For example,
.CS
\fBnamespace eval Counter {
    namespace export bump
    variable num 0

    proc bump {} {
        variable num
        incr num
    }
}\fR
.CE
creates a new namespace containing the variable \fBnum\fR and
the procedure \fBbump\fR.
The commands and variables in this namespace are separate from
other commands and variables in the same program.
If there is a command named \fBbump\fR in the global namespace,
for example, it will be different from the command \fBbump\fR
in the \fBCounter\fR namespace.
.PP
Namespace variables resemble global variables in Tcl.
They exist outside of the procedures in a namespace
but can be accessed in a procedure via the \fBvariable\fR command,
as shown in the example above.
.PP
Namespaces are dynamic.
You can add and delete commands and variables at any time,
so you can build up the contents of a
namespace over time using a series of \fBnamespace eval\fR commands.
For example, the following series of commands has the same effect
as the namespace definition shown above:
.CS
\fBnamespace eval Counter {
    variable num 0
    proc bump {} {
        variable num
        return [incr num]
    }
}
namespace eval Counter {
    proc test {args} {
        return $args

.PP
If you want to access commands and variables from another namespace,
you must use some extra syntax.
Names must be qualified by the namespace that contains them.
From the global namespace,
we might access the \fBCounter\fR procedures like this:
.CS
\fBCounter::bump 5
Counter::Reset\fR
.CE
We could access the current count like this:
.CS
\fBputs "count = $Counter::num"\fR
.CE
When one namespace contains another, you may need more than one
qualifier to reach its elements.
If we had a namespace \fBFoo\fR that contained the namespace \fBCounter\fR,
you could invoke its \fBbump\fR procedure
from the global namespace like this:
.CS
\fBFoo::Counter::bump 3\fR
.CE
.PP
You can also use qualified names when you create and rename commands.
For example, you could add a procedure to the \fBFoo\fR
namespace like this:
.CS
\fBproc Foo::Test {args} {return $args}\fR

.CE
the command is automatically removed from all namespaces that import it.

.SH "EXPORTING COMMANDS"
You can export commands from a namespace like this:
.CS
\fBnamespace eval Counter {
    namespace export bump reset
    variable Num 0
    variable Max 100

    proc bump {{by 1}} {
        variable Num
        incr Num $by
        Check
        return $Num
    }
    proc reset {} {
        variable Num
        set Num 0
    }
    proc Check {} {
        variable Num
        variable Max
        if {$Num > $Max} {
            error "too high!"
        }
    }
}\fR
.CE
The procedures \fBbump\fR and \fBreset\fR are exported,
so they are included when you import from the \fBCounter\fR namespace,
like this:
.CS
\fBnamespace import Counter::*\fR
.CE
However, the \fBCheck\fR procedure is not exported,
so it is ignored by the import operation.
.PP
The \fBnamespace import\fR command only imports commands
that were declared as exported by their namespace.
The \fBnamespace export\fR command specifies what commands
may be imported by other namespaces.
If a \fBnamespace import\fR command specifies a command

'\"
'\" Copyright (c) 1993 The Regents of the University of California.
'\" Copyright (c) 1994-1996 Sun Microsystems, Inc.
'\"
'\" See the file "license.terms" for information on usage and redistribution
'\" of this file, and for a DISCLAIMER OF ALL WARRANTIES.
'\" 
'\" RCS: @(#) $Id: puts.n,v 1.1.2.2 1999/04/09 18:42:02 surles Exp $
'\" 
.so man.macros
.TH puts n 7.5 Tcl "Tcl Built-In Commands"
.BS
'\" Note:  do not modify the .SH NAME line immediately below!
.SH NAME
puts \- Write to a channel

.PP
Newline characters in the output are translated by \fBputs\fR to
platform-specific end-of-line sequences according to the current
value of the \fB\-translation\fR option for the channel (for example,
on PCs newlines are normally replaced with carriage-return-linefeed
sequences;  on Macintoshes newlines are normally replaced with
carriage-returns).
See the \fBfconfigure\fR manual entry for a discussion on ways in
which \fBfconfigure\fR will alter output.
.PP
Tcl buffers output internally, so characters written with \fBputs\fR
may not appear immediately on the output file or device;  Tcl will
normally delay output until the buffer is full or the channel is
closed.
You can force output to appear immediately with the \fBflush\fR
command.

'\"
'\" Copyright (c) 1993 The Regents of the University of California.
'\" Copyright (c) 1994-1996 Sun Microsystems, Inc.
'\"
'\" See the file "license.terms" for information on usage and redistribution
'\" of this file, and for a DISCLAIMER OF ALL WARRANTIES.
'\" 
'\" RCS: @(#) $Id: read.n,v 1.1.2.2 1999/04/09 18:42:03 surles Exp $
'\" 
.so man.macros
.TH read n 7.5 Tcl "Tcl Built-In Commands"
.BS
'\" Note:  do not modify the .SH NAME line immediately below!
.SH NAME
read \- Read from a channel

for more input.
The \fB\-nonewline\fR switch is ignored if the command returns
before reaching the end of the file.
.PP
\fBRead\fR translates end-of-line sequences in the input into
newline characters according to the \fB\-translation\fR option
for the channel.
See the \fBfconfigure\fR manual entry for a discussion on ways in
which \fBfconfigure\fR will alter input.

.SH "SEE ALSO"
eof(n), fblocked(n), fconfigure(n)

.SH KEYWORDS
blocking, channel, end of line, end of file, nonblocking, read, translation

'\"
'\" Copyright (c) 1998 Sun Microsystems, Inc.
'\"
'\" See the file "license.terms" for information on usage and redistribution
'\" of this file, and for a DISCLAIMER OF ALL WARRANTIES.
'\" 
'\" RCS: @(#) $Id: regexp.n,v 1.1.2.6 1999/04/09 18:42:03 surles Exp $
'\" 
.so man.macros
.TH regexp n 8.1 Tcl "Tcl Built-In Commands"
.BS
'\" Note:  do not modify the .SH NAME line immediately below!
.SH NAME
regexp \- Match a regular expression against a string

\fInon-greedy\fR quantifiers,
which match the same possibilities,
but prefer the smallest number rather than the largest number
of matches (see MATCHING)
.RE
.PP
The forms using
\fB{\fR and \fB}\fR
are known as \fIbound\fRs.
The numbers
\fIm\fR and \fIn\fR are unsigned decimal integers
with permissible values from 0 to 255 inclusive.
.PP
An atom is one of:
.RS 2