body(n)

💖 NAME 💖

Welcome to the body(n) manual page, bestie — this is the itcl::body situation from [incr Tcl]. itcl::body — change the body for a class method/proc. That's the whole assignment: swap the body of a class method or proc. 💅

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✨ SYNOPSIS ✨

itcl::body className::function args body

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🌸 DESCRIPTION 🌸

Okay so body is the command you use outside of an [incr Tcl] class definition to define or redefine the body of a class method or proc. It's giving separate "interface" and "implementation" parts for your class definition. 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. And when you're 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. iconic.

The name className::function identifies the method/proc being changed. That's your target, bestie.

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. periodt.

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. no cap.

Symbolic names for C procedures are established by registering procedures via Itcl_RegisterObjC(). 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_FooObjCmd() is registered with the symbolic name "foo". This procedure can be referenced in the body command as "@foo". Here's the code, bestie:

              int
              Tcl_AppInit(interp)
                  Tcl_Interp *interp;     /* Interpreter for application. */
              {
                  if (Itcl_Init(interp) == TCL_ERROR) {
                      return TCL_ERROR;
                  }

                  if (Itcl_RegisterObjC(interp, "foo", My_FooObjCmd) != TCL_OK) {
                      return TCL_ERROR;
                  }
              }

That registration moment is very slay. ✨

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🦋 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. Don't forget that part, bestie.

              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

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🌈 KEYWORDS 🌈

class, object, procedure — the keyword trio, periodt. 👑

And that's the footer vibe: this page comes from itcl version 3.0, the body(n) manual page — signing off with sparkles 💖✨🦋