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OpenDarwin 7.2.1 - man page for proc (opendarwin section n)

proc(n) 			      Tcl Built-In Commands				  proc(n)

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NAME
       proc - Create a Tcl procedure

SYNOPSIS
       proc name args body
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DESCRIPTION
       The proc command creates a new Tcl procedure named name, replacing any existing command or
       procedure there may have been by that name.  Whenever the new command is invoked, the con-
       tents  of  body	will  be  executed by the Tcl interpreter.  Normally, name is unqualified
       (does not include the names of any containing namespaces), and the new procedure  is  cre-
       ated  in  the current namespace.  If name includes any namespace qualifiers, the procedure
       is created in the specified namespace.  Args specifies the formal arguments to the  proce-
       dure.   It  consists of a list, possibly empty, each of whose elements specifies one argu-
       ment.  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.

       When name 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 com-
       mand 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  argu-
       ments.  There is one special case to permit procedures with variable numbers of arguments.
       If the last formal argument has the name args, 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 args are combined into a list  (as
       if  the list command had been used); this combined value is assigned to the local variable
       args.

       When body 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 global command or the upvar command.  Namespace vari-
       ables can only be accessed by invoking the variable command or the upvar command.

       The proc command returns an empty string.  When a procedure is  invoked,  the  procedure's
       return value is the value specified in a return command.  If the procedure doesn't execute
       an explicit return, 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 proce-
       dure-as-a-whole will return that same error.

SEE ALSO
       info(n), unknown(n)

KEYWORDS
       argument, procedure

Tcl											  proc(n)


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