Tcl Source Code

'\" Note:  do not modify the .SH NAME line immediately below!
.SH NAME
oo::copy \- create copies of objects and classes
.SH SYNOPSIS
.nf
package require TclOO

\fBoo::copy\fI sourceObject \fR?\fItargetObject\fR? ?\fItargetNamespace\fR?
.fi
.BE
.SH DESCRIPTION
.PP
The \fBoo::copy\fR command creates a copy of an object or class. It takes the
name of the object or class to be copied, \fIsourceObject\fR, and optionally
the name of the object or class to create, \fItargetObject\fR, which will be
resolved relative to the current namespace if not an absolute qualified name
and
.VS TIP473
\fItargetNamespace\fR which is the name of the namespace where the object is
going to be created in.
If either \fItargetObject\fR or \fItargetNamespace\fR is omitted or is given
as the empty string, a new name is chosen. Names, unless specified, are
chosen with the same algorithm used by the \fBnew\fR method of
\fBoo::class\fR.
.VE TIP473
The copied object will be of the same class as the source object, and will have 
all its per-object methods copied. If it is a class, it will also have all the 
class methods in the class copied, but it will not have any of its instances 
copied.
.PP
.VS
After the \fItargetObject\fR has been created and all definitions of its
configuration (e.g., methods, filters, mixins) copied, the \fB<cloned>\fR
method of \fItargetObject\fR will be invoked, to allow for customization of
the created object such as installing related variable traces. The only
argument given will be \fIsourceObject\fR. The default implementation of this

    ClientData clientData,
    Tcl_Interp *interp,
    int objc,
    Tcl_Obj *const *objv)
{
    Tcl_Object oPtr, o2Ptr;

    if (objc < 2 || objc > 4) {
	Tcl_WrongNumArgs(interp, 1, objv,
			 "sourceName ?targetName? ?targetNamespace?");
	return TCL_ERROR;
    }

    oPtr = Tcl_GetObjectFromObj(interp, objv[1]);
    if (oPtr == NULL) {
	return TCL_ERROR;
    }

    /*
     * Create a cloned object of the correct class. Note that constructors are
     * not called. Also note that we must resolve the object name ourselves
     * because we do not want to create the object in the current namespace,
     * but rather in the context of the namespace of the caller of the overall
     * [oo::define] command.
     */

    if (objc == 2) {
	o2Ptr = Tcl_CopyObjectInstance(interp, oPtr, NULL, NULL);
    } else {
	const char *name, *namespaceName;
	Tcl_DString buffer;

	name = TclGetString(objv[2]);
	Tcl_DStringInit(&buffer);
	if (name[0] == '\0') {
	    name = NULL;
	} else if (name[0]!=':' || name[1]!=':') {
	    Interp *iPtr = (Interp *) interp;

	    if (iPtr->varFramePtr != NULL) {
		Tcl_DStringAppend(&buffer,
			iPtr->varFramePtr->nsPtr->fullName, -1);
	    }
	    TclDStringAppendLiteral(&buffer, "::");
	    Tcl_DStringAppend(&buffer, name, -1);
	    name = Tcl_DStringValue(&buffer);
	}

	/*
	 * Choose a unique namespace name if the user didn't supply one.
	 */

	namespaceName = NULL;
	if (objc == 4) {
	    namespaceName = TclGetString(objv[3]);

	    if (namespaceName[0] == '\0') {
		namespaceName = NULL;
	    } else if (Tcl_FindNamespace(interp, namespaceName, NULL,
		    0) != NULL) {
		Tcl_SetObjResult(interp, Tcl_ObjPrintf(
			"%s refers to an existing namespace", namespaceName));
		return TCL_ERROR;
	    }
	}

	o2Ptr = Tcl_CopyObjectInstance(interp, oPtr, name, namespaceName);
	Tcl_DStringFree(&buffer);
    }

    if (o2Ptr == NULL) {
	return TCL_ERROR;
    }

    $obj1 eval {
	set var grill
    }
    lappend result [$obj1 get] [$obj2 get]
} -cleanup {
    FooClass destroy
} -result {foo bar grill bar}
test oo-15.11 {OO: object cloning} -returnCodes error -body {
    oo::copy
} -result {wrong # args: should be "oo::copy sourceName ?targetName? ?targetNamespace?"}
test oo-15.12 {OO: object cloning with target NS} -setup {
    oo::class create Super
    oo::class create Cls {superclass Super}
} -body {
    namespace eval ::existing {}
    oo::copy Cls {} ::existing
} -returnCodes error -cleanup {
    Super destroy
    catch {namespace delete ::existing}
} -result {::existing refers to an existing namespace}
test oo-15.13 {OO: object cloning with target NS} -setup {
    oo::class create Super
    oo::class create Cls {superclass Super}
} -body {
    list [namespace exist ::dupens] [oo::copy Cls Cls2 ::dupens] [namespace exist ::dupens]
} -cleanup {
    Super destroy
} -result {0 ::Cls2 1}
test oo-15.14 {OO: object cloning with target NS} -setup {
    oo::class create Cls {export eval}
    set result {}
} -body {
    Cls create obj
    obj eval {
	proc test-15.14 {} {}
    }
    lappend result [info commands ::dupens::t*]
    oo::copy obj obj2 ::dupens
    lappend result [info commands ::dupens::t*]
} -cleanup {
    Cls destroy
} -result {{} ::dupens::test-15.14}

test oo-16.1 {OO: object introspection} -body {
    info object
} -returnCodes 1 -result "wrong \# args: should be \"info object subcommand ?arg ...?\""
test oo-16.1.1 {OO: object introspection} -body {
    catch {info object} m o
    dict get $o -errorinfo