Checking what you are running under¶

PortableTk provides a symbol "????". If this symbol is defined, your source is compiled with it.

New types of configuration options¶

PortableTk defines several new types of configuration options:

 TK_CONFIG_CALLBACK
 TK_CONFIG_LANGARG
 TK_CONFIG_SCALARVAR
 TK_CONFIG_HASHVAR
 TK_CONFIG_ARRAYVAR
 TK_CONFIG_IMAGE

You should use them instead of TK_CONFIG_STRING whenever appropriate. This allows your application to receive a direct representation of the corresponding resource instead of the string representation, if this is possible under given language.

???? It looks like "TK_CONFIG_IMAGE" and "TK_CONFIG_SCALARVAR" set variables of type "char*".

Language data¶

The following data types are defined:

"Tcl_Obj *"

is the main datatype of the language. This is a type that your C function gets pointers to for arguments when the corresponding Lang function is called. The corresponding config type is "TK_CONFIG_LANGARG".

This is also a type that keeps information about contents of Lang variable.

"Var"

Is a substitute for a "char *" that contains name of variable. In Lang it is an object that contains reference to another Lang variable.

"LangResultSave"

????

"LangCallback"

"LangCallback*" a substitute for a "char *" that contains command to call. The corresponding config type is "TK_CONFIG_CALLBACK".

"LangFreeProc"

It is the type that the "Lang_SplitList" sets. Before you call it, declare

    Args *args;
    LangFreeProc *freeProc = NULL;
    ...
    code = Lang_SplitList(interp, value,
        &argc, &args, &freeProc);
    

After you use the split values, call

    if (args != NULL && freeProc) (*freeProc)(argc,args);
    

It is not guaranteed that the "args" can survive deletion of "value".

Conversion¶

The following macros and functions are used for conversion between strings and the additional types:

 LangCallback * LangMakeCallback(Tcl_Obj *)
 Tcl_Obj * LangCallbackArg(LangCallback *)
 char * LangString(Tcl_Obj *)

After you use the result of LangCallbackArg(), you should free it with "freeProc" "LANG_DYNAMIC" (it is not guaranteed that any change of "Tcl_Obj *" will not be reflected in <LangCallback>, so you cannot do LangSet...() in between, and you should reset it to "NULL" if you want to do any further assignments to this "Tcl_Obj *").

The following function returns the "Tcl_Obj *" that is a reference to "Var":

 Tcl_Obj * LangVarArg(Var)

???? It is very anti-intuitive, I hope the name is changed.

 int LangCmpCallback(LangCallback *a,Tcl_Obj * b)

(currently only a stub), and, at last,

 LangCallback * LangCopyCallback(LangCallback *)

Callbacks¶

Above we have seen the new datatype "LangCallback" and the corresponding Config option "TK_CONFIG_CALLBACK". The following functions are provided for manipulation of "LangCallback"s:

 void LangFreeCallback(LangCallback *)
 int LangDoCallback(Tcl_Interp *,LangCallback *,
        int result,int argc, char *format,...)

The argument "format" of "LangDoCallback" should contain a string that is suitable for "sprintf" with optional arguments of "LangDoCallback". "result" should be false if result of callback is not needed.

 int LangMethodCall(Tcl_Interp *,Tcl_Obj *,char *method,
        int result,int argc,...)

????

Conceptually, "LangCallback*" is a substitute for ubiquitous "char *" in TCL. So you should use "LangFreeCallback" instead of "ckfree" or "free" if appropriate.

Setting variables¶

 void LangFreeArg (Tcl_Obj *, Tcl_FreeProc *freeProc)
 Tcl_Obj *  LangCopyArg (Tcl_Obj *);
 void Tcl_AppendArg (Tcl_Interp *interp, Tcl_Obj *)
 void LangSetString(Tcl_Obj * *, char *s)
 void LangSetDefault(Tcl_Obj * *, char *s)

These two are equivalent unless s is an empty string. In this case "LangSetDefault" behaves like "LangSetString" with "s==NULL", i.e., it sets the current value of the Lang variable to be false.

 void LangSetInt(Tcl_Obj * *,int)
 void LangSetDouble(Tcl_Obj * *,double)

The Lang functions separate uninitialized and initialized data comparing data with "NULL". So the declaration for an "Tcl_Obj *" should look like

 Tcl_Obj * arg = NULL;

if you want to use this "arg" with the above functions. After you are done, you should use "LangFreeArg" with "TCL_DYNAMIC" as "freeProc".

Language functions¶

Use

"int LangNull(Tcl_Obj *)"

to check that an object is false;

"int LangStringMatch(char *string, Tcl_Obj * match)"

????

"void LangExit(int)"

to make a proper shutdown;

"int LangEval(Tcl_Interp *interp, char *cmd, int global)"

to call Lang "eval";

"void Lang_SetErrorCode(Tcl_Interp *interp,char *code)"

"char *Lang_GetErrorCode(Tcl_Interp *interp)"

"char *Lang_GetErrorInfo(Tcl_Interp *interp)"

"void LangCloseHandler(Tcl_Interp *interp,Tcl_Obj * arg,FILE *f,Lang_FileCloseProc *proc)"

currently stubs only;

"int LangSaveVar(Tcl_Interp *,Tcl_Obj * arg,Var *varPtr,int type)"

to save the structure "arg" into Lang variable *varPtr;

"void LangFreeVar(Var var)"

to free the result;

"int LangEventCallback(Tcl_Interp *,LangCallback *,XEvent *,KeySym)"

????

"int LangEventHook(int flags)"

"void LangBadFile(int fd)"

"int LangCmpConfig(char *spec, char *arg, size_t length)"

unsupported????;

"void Tcl_AppendArg (Tcl_Interp *interp, Tcl_Obj *)"

Another useful construction is

 Tcl_Obj * variable = LangFindVar(interp, Tk_Window tkwin, char *name);

After using the above function, you should call

 LangFreeVar(Var variable);

???? Note discrepancy in types!

If you want to find the value of a variable (of type "Tcl_Obj *") given the variable name, use "Tcl_GetVar(interp, varName, flags)". If you are interested in the string value of this variable, use "LangString(Tcl_GetVar(...))".

To get a C array of "Tcl_Obj *" of length "n", use

    Tcl_Obj * *args = LangAllocVec(n);
    ...
    LangFreeVec(n,args);

You can set the values of the "Tcl_Obj *"s using "LangSet..." functions, and get string value using "LangString".

If you want to merge an array of "Tcl_Obj *"s into one "Tcl_Obj *" (that will be an array variable), use

    result = Tcl_Merge(listLength, list);

Translation of some TCL functions¶

We mark items that can be dealt with by "munge" by Autoconverted.

"Tcl_AppendResult"

does not take "(char*)NULL", but "NULL" as delimiter. Autoconverted.

"Tcl_CreateCommand", "Tcl_DeleteCommand"

"Tk_CreateWidget", "Tk_DeleteWidget", the second argument is the window itself, not the pathname. Autoconverted.

"sprintf(interp->result, "%d %d %d %d",...)"

"Tcl_IntResults(interp,4,0,...)". Autoconverted.

"interp->result = "1";"

"Tcl_SetResult(interp,"1", TCL_STATIC)". Autoconverted.

Reading "interp->result"

"Tcl_GetResult(interp)". Autoconverted.

"interp->result = Tk_PathName(textPtr->tkwin);"

"Tk_WidgetResult(interp,textPtr->tkwin)". Autoconverted.

Sequence "Tcl_PrintDouble, Tcl_PrintDouble, ..., Tcl_AppendResult"

Use a single command

 void Tcl_DoubleResults(Tcl_Interp *interp, int append,
        int argc,...);
    

"append" governs whether it is required to clear the result first.

A similar command for "int" arguments is "Tcl_IntResults".

"Tcl_SplitList"

Use "Lang_SplitList" (see the description above).

New types of events ????¶

PortableTk defines following new types of events:

 TK_EVENTTYPE_NONE
 TK_EVENTTYPE_STRING
 TK_EVENTTYPE_NUMBER
 TK_EVENTTYPE_WINDOW
 TK_EVENTTYPE_ATOM
 TK_EVENTTYPE_DISPLAY
 TK_EVENTTYPE_DATA

and a function

 char * Tk_EventInfo(int letter,
            Tk_Window tkwin, XEvent *eventPtr,
            KeySym keySym, int *numPtr, int *isNum, int *type,
            int num_size, char *numStorage)

"ListFactory"¶

Dynamic arrays in TCL are used for two different purposes: to construct strings, and to construct lists. These two usages will have separate interfaces in other languages (since list is a different type from a string), so you should use a different interface in your code.

The type for construction of dynamic lists is "ListFactory". The API below is a counterpart of the API for construction of dynamic lists in TCL:

 void ListFactoryInit(ListFactory *)
 void ListFactoryFinish(ListFactory *)
 void ListFactoryFree(ListFactory *)
 Tcl_Obj * * ListFactoryArg(ListFactory *)
 void ListFactoryAppend(ListFactory *, Tcl_Obj * *arg)
 void ListFactoryAppendCopy(ListFactory *, Tcl_Obj * *arg)
 ListFactory * ListFactoryNewLevel(ListFactory *)
 ListFactory * ListFactoryEndLevel(ListFactory *)
 void ListFactoryResult(Tcl_Interp *, ListFactory *)

The difference is that a call to "ListFactoryFinish" should precede the actual usage of the value of "ListFactory", and there are two different ways to append an "Tcl_Obj *" to a "ListFactory": ListFactoryAppendCopy() guarantees that the value of "arg" is copied to the list, but ListFactoryAppend() may append to the list a reference to the current value of "arg". If you are not going to change the value of "arg" after appending, the call to ListFactoryAppend may be quicker.

As in TCL, the call to ListFactoryFree() does not free the "ListFactory", only the objects it references.

The functions ListFactoryNewLevel() and ListFactoryEndLevel() return a pointer to a "ListFactory" to fill. The argument of ListFactoryEndLevel() cannot be used after a call to this function.

DStrings¶

Production of strings are still supported in portableTk.

Accessing "Tcl_Obj *"s¶

The following functions for getting a value of an "Tcl_Obj *" may be provided:

 double LangDouble(Tcl_Obj *)
 int LangInt(Tcl_Obj *)
 long LangLong(Tcl_Obj *)
 int LangIsList(Tcl_Obj * arg)

The function LangIsList() is supported only partially under TCL, since there is no data types. It checks whether there is a space inside the string "arg".

Assigning numbers to "Tcl_Obj *"s¶

While LangSetDouble() and LangSetInt() are supported ways to assign numbers to assign an integer value to a variable, for the sake of efficiency under TCL it is supposed that the destination of these commands was massaged before the call so it contains a long enough string to sprintf() the numbers inside it. If you are going to immediately use the resulting "Tcl_Obj *", the best way to do this is to declare a buffer in the beginning of a block by

   dArgBuffer;

and assign this buffer to the "Tcl_Obj *" by

   void LangSetDefaultBuffer(Tcl_Obj * *)

You can also create the buffer(s) manually and assign them using

   void LangSetBuffer(Tcl_Obj * *, char *)

This is the only choice if you need to assign numeric values to several "Tcl_Obj *"s simultaneously. The advantage of the first approach is that the above declarations can be made "nop"s in different languages.

Note that if you apply "LangSetDefaultBuffer" to an "Tcl_Obj *" that contains some value, you can create a leak if you do not free that "Tcl_Obj *" first. This is a non-problem in real languages, but can be a trouble in "TCL", unless you use only the above API.

Creating new "Tcl_Obj *"s¶

The API for creating a new "Tcl_Obj *" is

 void LangNewArg(Tcl_Obj * *, LangFreeProc *)

The API for creating a new "Tcl_Obj *" is absent. Just initialize "Tcl_Obj *" to be "NULL", and apply one of "LangSet..." methods.

After you use this "Tcl_Obj *", it should be freed thusly:

"LangFreeArg(arg, freeProc)".

Evaluating a list¶

Use

 int LangArgEval(Tcl_Interp *, Tcl_Obj * arg)

Here "arg" should be a list to evaluate, in particular, the first element should be a "LangCallback" massaged to be an "Tcl_Obj *". The arguments can be send to the subroutine by reference or by value in different languages.

Getting result as "Tcl_Obj *"¶

Use "Tcl_ArgResult". It is not guaranteed that result survives this operation, so the "Tcl_Obj *" you get should be the only mean to access the data from this moment on. After you use this "Tcl_Obj *", you should free it with "freeProc" "LANG_DYNAMIC" (you can do LangSet...() in between).