NAME

       body - change the body for a class method/proc

SYNOPSIS

       itcl::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  separate  "interface"  and
       "implementation"  parts.   The  "interface" part is a class command with declarations for methods, procs,
       instance variables and common variables.  The "implementation" 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_RegisterC().  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.  itcl::class File {
           private variable fid ""
           constructor {name access} {
               set fid [open $name $access]
           }
           destructor {
               close $fid
           }

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

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

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

KEYWORDS

       class, object, procedure