DM Reference

DM Ref

call proc

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Format

  • call(ProcRef)(Arguments)
  • call(Object,ProcName)(Arguments)
  • call(LibName,FuncName)(Arguments) (use call_ext() instead)

Args

  • ProcRef: path of proc (/proc/MyProc)
  • Object: source of proc or verb
  • ProcName: name of proc or verb (“MyProc”)
  • LibName: name of external library (“test.DLL”)
  • FuncName: name of function in external library (“func”)

Returns

The return value of the proc being called.

This instruction exists in order to call procs dynamically, since the proc reference or name may be an expression rather than a hard-coded value. This may serve the same purpose as a “function pointer” in C programs.

The following examples do not demonstrate why you would want to do this, but the syntax is illustrated. The first one calls a specific procedure by using a path reference to that procedure.

/proc/MyProc(Arg)
   usr << "MyProc([Arg])"
mob
   var
      MyProc = /proc/MyProc
   verb
      call_myproc()
         call(MyProc)("Hello, world!")

The next example calls an object procedure (or verb) by name, rather than by path.

mob
   proc
      Proc1(Arg)
         usr << "Proc1([Arg])"
      Proc2(Arg)
         usr << "Proc2([Arg])"
   verb
      call_proc(Proc in list("Proc1","Proc2"))
         call(src,Proc)("Hello, world!")

Note

In prior versions, call() was also used to access third-party libraries (.DLL files on Windows, .SO files on Unix), but this has been moved to call_ext() for clarity.

See also

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