For some reason one might need to know the type name of a Tcl object. The type name is stored in Tcl_Obj's `typePtr->name`. Below is the small C extension ''typeof'' to get the type name. 

[DKF]: Be aware that Tcl makes ''no'' guarantee about the type of any value; basing any semantic decision on this information is ''strongly'' discouraged, which is why Tcl does not provide this operation itself.
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/*
 * typeof
 * BSD License
 */
#include <tcl.h>

#ifdef WIN32
#ifdef typeof_EXPORTS
#define typeof_EXPORT __declspec(dllexport)
#else
#define typeof_EXPORT __declspec(dllimport)
#endif
#else
#define typeof_EXPORT 
#endif

static int Typeof_Cmd(ClientData clientData, Tcl_Interp *interp, int argc, Tcl_Obj *const argv[]) {
	if (argc != 2) {
		Tcl_WrongNumArgs(interp, 1, argv, "object");
		return TCL_ERROR;
	}
	
	if (argv[1]->typePtr) {
		Tcl_SetObjResult(interp, Tcl_NewStringObj(argv[1]->typePtr->name, -1));
	} else {
		Tcl_SetObjResult(interp, Tcl_NewStringObj("", -1));
	}
	return TCL_OK;
}

int typeof_EXPORT Typeof_Init(Tcl_Interp *interp) {
	/*
	 * This may work with 8.0, but we are using strictly stubs here,
	 * which requires 8.1.
	 */
	if (Tcl_InitStubs(interp, "8.1", 0) == NULL
			|| Tcl_PkgProvide(interp, "typeof", "0.1.1") != TCL_OK) {
		return TCL_ERROR;
	}

	Tcl_CreateObjCommand(interp, "typeof", Typeof_Cmd, NULL, NULL);
	return TCL_OK;
}
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'''Usage:'''
 typeof object

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%| Extensions |%
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