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RedHat 9 (Linux i386) - man page for body (redhat section n)

body(n) 				    [incr Tcl]					  body(n)

NAME
       body - change the body for a class method/proc

SYNOPSIS
       body className::function args body

DESCRIPTION
       The  body  command is used outside of an [incr Tcl] class definition to define or redefine
       the body of a class method or proc.  This facility allows a class definition to have sepa-
       rate "interface" and "implementation" parts.  The "interface" part is a class command with
       declarations for methods, procs, instance variables and common variables.  The  "implemen-
       tation" part is a series of body and configbody commands.  If the "implementation" part is
       kept in a separate file, it can be sourced again and again as bugs are fixed,  to  support
       interactive  development.   When using the "tcl" mode in the emacs editor, the "interface"
       and "implementation" parts can be kept in the same file; as  bugs  are  fixed,  individual
       bodies can be highlighted and sent to the test application.

       The name "className::function" identifies the method/proc being changed.

       If  an  args list was specified when the function was defined in the class definition, the
       args list for the body command must match in meaning.  Variable names can change, but  the
       argument  lists	must  have  the  same  required arguments and the same default values for
       optional arguments.  The special args argument acts as a wildcard  when	included  in  the
       args  list  in the class definition; it will match zero or more arguments of any type when
       the body is redefined.

       If the body string starts with "@", it is treated as the symbolic name for a C  procedure.
       The  args  list	has  little  meaning for the C procedure, except to document the expected
       usage.  (The C procedure is not guaranteed to use arguments in this manner.)  If body does
       not  start with "@", it is treated as a Tcl command script.  When the function is invoked,
       command line arguments are matched against the args list, and local variables are  created
       to represent each argument.  This is the usual behavior for a Tcl-style proc.

       Symbolic  names for C procedures are established by registering procedures via Itcl_Regis-
       terC().	This is usually done in  the  Tcl_AppInit()  procedure,  which	is  automatically
       called  when  the  interpreter  starts  up.   In  the  following  example,  the	procedure
       My_FooCmd() is registered with the symbolic name "foo".	This procedure can be  referenced
       in the body command as "@foo".  int Tcl_AppInit(interp)
	   Tcl_Interp *interp;	   /* Interpreter for application. */ {
	   if (Itcl_Init(interp) == TCL_ERROR) {
	       return TCL_ERROR;
	   }

	   if (Itcl_RegisterC(interp, "foo", My_FooCmd) != TCL_OK) {
	       return TCL_ERROR;
	   } }

EXAMPLE
       In  the	following example, a "File" class is defined to represent open files.  The method
       bodies are included below the class definition via the body command.  Note that the bodies
       of  the	constructor/destructor	must be included in the class definition, but they can be
       redefined via the body command as well.	class File {
	   private variable fid ""
	   constructor {name access} {
	       set fid [open $name $access]
	   }
	   destructor {
	       close $fid
	   }

	   method get {}
	   method put {line}
	   method eof {} }

       body File::get {} {
	   return [gets $fid] } body File::put {line} {
	   puts $fid $line } body File::eof {} {
	   return [::eof $fid] }

       # # See the File class in action: # File x /etc/passwd "r" while {![x eof]} {
	   puts "=> [x get]" } delete object x

KEYWORDS
       class, object, procedure

itcl					       3.0					  body(n)


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