diff options
Diffstat (limited to 'tcl/doc/proc.n')
| -rw-r--r-- | tcl/doc/proc.n | 74 |
1 files changed, 74 insertions, 0 deletions
diff --git a/tcl/doc/proc.n b/tcl/doc/proc.n new file mode 100644 index 00000000000..f7b3ac22e79 --- /dev/null +++ b/tcl/doc/proc.n @@ -0,0 +1,74 @@ +'\" +'\" 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: @(#) $Id$ +'\" +.so man.macros +.TH proc n "" Tcl "Tcl Built-In Commands" +.BS +'\" Note: do not modify the .SH NAME line immediately below! +.SH NAME +proc \- Create a Tcl procedure +.SH SYNOPSIS +\fBproc \fIname args body\fR +.BE + +.SH DESCRIPTION +.PP +The \fBproc\fR command creates a new Tcl procedure named +\fIname\fR, replacing +any existing command or procedure there may have been by that name. +Whenever the new command is invoked, the contents of \fIbody\fR will +be executed by the Tcl interpreter. +Normally, \fIname\fR is unqualified +(does not include the names of any containing namespaces), +and the new procedure is created in the current namespace. +If \fIname\fR includes any namespace qualifiers, +the procedure is created in the specified namespace. +\fIArgs\fR specifies the formal arguments to the +procedure. It consists of a list, possibly empty, each of whose +elements specifies +one argument. Each argument specifier is also a list with either +one or two fields. If there is only a single field in the specifier +then it is the name of the argument; if there are two fields, then +the first is the argument name and the second is its default value. +.PP +When \fIname\fR is invoked a local variable +will be created for each of the formal arguments to the procedure; its +value will be the value of corresponding argument in the invoking command +or the argument's default value. +Arguments with default values need not be +specified in a procedure invocation. However, there must be enough +actual arguments for all the +formal arguments that don't have defaults, and there must not be any extra +actual arguments. There is one special case to permit procedures with +variable numbers of arguments. If the last formal argument has the name +\fBargs\fR, then a call to the procedure may contain more actual arguments +than the procedure has formals. In this case, all of the actual arguments +starting at the one that would be assigned to \fBargs\fR are combined into +a list (as if the \fBlist\fR command had been used); this combined value +is assigned to the local variable \fBargs\fR. +.PP +When \fIbody\fR is being executed, variable names normally refer to +local variables, which are created automatically when referenced and +deleted when the procedure returns. One local variable is automatically +created for each of the procedure's arguments. +Global variables can only be accessed by invoking +the \fBglobal\fR command or the \fBupvar\fR command. +Namespace variables can only be accessed by invoking +the \fBvariable\fR command or the \fBupvar\fR command. +.PP +The \fBproc\fR command returns an empty string. When a procedure is +invoked, the procedure's return value is the value specified in a +\fBreturn\fR command. If the procedure doesn't execute an explicit +\fBreturn\fR, then its return value is the value of the last command +executed in the procedure's body. +If an error occurs while executing the procedure +body, then the procedure-as-a-whole will return that same error. + +.SH KEYWORDS +argument, procedure |