Hello ,
I would like to add single quotes, square brackets, newline... to the left and right of my string.
It seems to me that I have several choices...
Tcl_ObjPrintf("%s", x) , Tcl_AppendObjToObj(...).

Can you advise me one ? or another ?

Thanks

Nicolas

On Monday, May 9, 2022 at 10:17:34 AM UTC+2, Nicolas Robert wrote:
> I would like to add single quotes, square brackets, newline... to the left and right of my string.
> It seems to me that I have several choices...
> Tcl_ObjPrintf("%s", x) , Tcl_AppendObjToObj(...).
>
> Can you advise me one ? or another ?

StringCatCmd uses Tcl_AppendObjToObj. That should be a reasonable choice.

Le lundi 9 mai 2022 à 13:32:16 UTC+2, heinrichmartin a écrit :
> On Monday, May 9, 2022 at 10:17:34 AM UTC+2, Nicolas Robert wrote:
> > I would like to add single quotes, square brackets, newline... to the left and right of my string.
> > It seems to me that I have several choices...
> > Tcl_ObjPrintf("%s", x) , Tcl_AppendObjToObj(...).
> >
> > Can you advise me one ? or another ?
> StringCatCmd uses Tcl_AppendObjToObj. That should be a reasonable choice.
Hi,
when I work with strings, I use the Tcl_DString API

++

Le lundi 9 mai 2022 à 16:19:22 UTC+2, Nicolas a écrit :
> Le lundi 9 mai 2022 à 13:32:16 UTC+2, heinrichmartin a écrit :
> > On Monday, May 9, 2022 at 10:17:34 AM UTC+2, Nicolas Robert wrote:
> > > I would like to add single quotes, square brackets, newline... to the left and right of my string.
> > > It seems to me that I have several choices...
> > > Tcl_ObjPrintf("%s", x) , Tcl_AppendObjToObj(...).
> > >
> > > Can you advise me one ? or another ?
> > StringCatCmd uses Tcl_AppendObjToObj. That should be a reasonable choice.
> Hi,
> when I work with strings, I use the Tcl_DString API
>
> ++

Thank you both for your answers.
I finally chose this function : Tcl_AppendObjToObj(...)
I have a problem, I have two objects to add to a list one on the left and one on the right.
Tcl_Obj* newlist = Tcl_NewObj();
Tcl_AppendObjToObj(newlist, Tcl_NewStringObj("'", 1));
Tcl_AppendObjToObj(newlist, listObj);
Tcl_AppendObjToObj(newlist, Tcl_NewStringObj("'", 1));

puts "newlist : [newlist]"
newlist : '{a 30 c 40}'

How I can remove my curly braces from my 'listObj' ?
To obtain this result : newlist : 'a 30 c 40'
Nicolas

On Tuesday, May 10, 2022 at 8:45:21 PM UTC+2, Nicolas Robert wrote:
> Le lundi 9 mai 2022 à 16:19:22 UTC+2, Nicolas a écrit :
> > Le lundi 9 mai 2022 à 13:32:16 UTC+2, heinrichmartin a écrit :
> > > On Monday, May 9, 2022 at 10:17:34 AM UTC+2, Nicolas Robert wrote:
> > > > I would like to add single quotes, square brackets, newline... to the left and right of my string.
> > > > It seems to me that I have several choices...
> > > > Tcl_ObjPrintf("%s", x) , Tcl_AppendObjToObj(...).
> > > >
> > > > Can you advise me one ? or another ?
> > > StringCatCmd uses Tcl_AppendObjToObj. That should be a reasonable choice.
> > Hi,
> > when I work with strings, I use the Tcl_DString API
> >
> > ++
> Thank you both for your answers.
> I finally chose this function : Tcl_AppendObjToObj(...)
> I have a problem, I have two objects to add to a list one on the left and one on the right.
> Tcl_Obj* newlist = Tcl_NewObj();
> Tcl_AppendObjToObj(newlist, Tcl_NewStringObj("'", 1));
> Tcl_AppendObjToObj(newlist, listObj);
> Tcl_AppendObjToObj(newlist, Tcl_NewStringObj("'", 1));

I am used to the script level, but
* You could init newlist with the left string already or
* reuse the single quote object left and right.
* If I get https://www.tcl-lang.org/man/tcl8.6/TclLib/StringObj.htm right, then Tcl_AppendObjToObj(Tcl_NewStringObj()) could be simplified to Tcl_AppendToObj().
* I have no experience with refCount, i.e. no idea whether this code is leaking objects. (My guess is that all your Tcl_New*Obj have refCount 0, but they should go through refCount 1, because only _dropping_ to zero would free them ...)

> puts "newlist : [newlist]"

You seem not to share all code. How do you create listObj above?
If newlist is the implementation of a proc, then look into https://www.tcl-lang.org/man/tcl8.6/TclLib/SetResult.htm.

> newlist : '{a 30 c 40}'

listObj already holds these braces; appending quotes is _not_ the issue.

> How I can remove my curly braces from my 'listObj' ?
> To obtain this result : newlist : 'a 30 c 40'

Besides looking elsewhere in your code (as stated above), maybe you should reconsider why you are mixing C and script level Tcl code. I cannot guess the real-world use case here.

On Tuesday, May 10, 2022 at 11:45:21 AM UTC-7, Nicolas Robert wrote:
> Le lundi 9 mai 2022 à 16:19:22 UTC+2, Nicolas a écrit :
> > Le lundi 9 mai 2022 à 13:32:16 UTC+2, heinrichmartin a écrit :
> > > On Monday, May 9, 2022 at 10:17:34 AM UTC+2, Nicolas Robert wrote:
> > > > I would like to add single quotes, square brackets, newline... to the left and right of my string.
> > > > It seems to me that I have several choices...
> > > > Tcl_ObjPrintf("%s", x) , Tcl_AppendObjToObj(...).
> > > >
> > > > Can you advise me one ? or another ?
> > > StringCatCmd uses Tcl_AppendObjToObj. That should be a reasonable choice.
> > Hi,
> > when I work with strings, I use the Tcl_DString API
> >
> > ++
> Thank you both for your answers.
> I finally chose this function : Tcl_AppendObjToObj(...)
> I have a problem, I have two objects to add to a list one on the left and one on the right.
> Tcl_Obj* newlist = Tcl_NewObj();
> Tcl_AppendObjToObj(newlist, Tcl_NewStringObj("'", 1));
> Tcl_AppendObjToObj(newlist, listObj);
> Tcl_AppendObjToObj(newlist, Tcl_NewStringObj("'", 1));
>
> puts "newlist : [newlist]"
> newlist : '{a 30 c 40}'
>
> How I can remove my curly braces from my 'listObj' ?
> To obtain this result : newlist : 'a 30 c 40'

Tcl_Obj* newlist = Tcl_NewObj();
Tcl_Obj** elemv;
Tcl_Obj *blank = Tcl_NewStringObj(" ",1);
int elemc, i;
Tcl_AppendObjToObj(newlist, Tcl_NewStringObj("'", 1));
Tcl_ListObjGetElements(interp, listObj, &elemc, &elemv);
/* Tcl_AppendObjToObj(newlist, listObj); */
/* essentially [join $list " "] */
for(i=0; i<elemc; i++) {
if (i>0) Tcl_AppendObjToObj(newlist, blank);
Tcl_AppendObjToObj(newlist, elemv[i]);
} Tcl_AppendObjToObj(newlist, Tcl_NewStringObj("'", 1));

So the next question is why? Because the value contained in listObj is a collection of Obj's in the form of a list. Tcl, when asked, will create a string representation of the collection so that the individual values are retained and the string as a whole can be used as if it were a scalar value. In essence this is what your example code is asking it to do when calling Tcl_AppendObjToObj(newlist, listObj);

A Tcl_Obj value is not just simply a string. It is any form of value that also has a string representation that retains its constituent values so that it can be decomposed later when needed.

This would be a good time to go back to the Tcl 12 rules and review them. https://www.tcl-lang.org/man/tcl8.6/TclCmd/Tcl.htm

-Brian

Le mardi 10 mai 2022 à 23:10:36 UTC+2, heinrichmartin a écrit :
> On Tuesday, May 10, 2022 at 8:45:21 PM UTC+2, Nicolas Robert wrote:
> > Le lundi 9 mai 2022 à 16:19:22 UTC+2, Nicolas a écrit :
> > > Le lundi 9 mai 2022 à 13:32:16 UTC+2, heinrichmartin a écrit :
> > > > On Monday, May 9, 2022 at 10:17:34 AM UTC+2, Nicolas Robert wrote:
> > > > > I would like to add single quotes, square brackets, newline... to the left and right of my string.
> > > > > It seems to me that I have several choices...
> > > > > Tcl_ObjPrintf("%s", x) , Tcl_AppendObjToObj(...).
> > > > >
> > > > > Can you advise me one ? or another ?
> > > > StringCatCmd uses Tcl_AppendObjToObj. That should be a reasonable choice.
> > > Hi,
> > > when I work with strings, I use the Tcl_DString API
> > >
> > > ++
> > Thank you both for your answers.
> > I finally chose this function : Tcl_AppendObjToObj(...)
> > I have a problem, I have two objects to add to a list one on the left and one on the right.
> > Tcl_Obj* newlist = Tcl_NewObj();
> > Tcl_AppendObjToObj(newlist, Tcl_NewStringObj("'", 1));
> > Tcl_AppendObjToObj(newlist, listObj);
> > Tcl_AppendObjToObj(newlist, Tcl_NewStringObj("'", 1));
> I am used to the script level, but
> * You could init newlist with the left string already or
> * reuse the single quote object left and right.
> * If I get https://www.tcl-lang.org/man/tcl8.6/TclLib/StringObj.htm right, then Tcl_AppendObjToObj(Tcl_NewStringObj()) could be simplified to Tcl_AppendToObj().
> * I have no experience with refCount, i.e. no idea whether this code is leaking objects. (My guess is that all your Tcl_New*Obj have refCount 0, but they should go through refCount 1, because only _dropping_ to zero would free them ...)
>
> > puts "newlist : [newlist]"
>
> You seem not to share all code. How do you create listObj above?
> If newlist is the implementation of a proc, then look into https://www.tcl-lang.org/man/tcl8.6/TclLib/SetResult.htm.
> > newlist : '{a 30 c 40}'
> listObj already holds these braces; appending quotes is _not_ the issue.
> > How I can remove my curly braces from my 'listObj' ?
> > To obtain this result : newlist : 'a 30 c 40'
> Besides looking elsewhere in your code (as stated above), maybe you should reconsider why you are mixing C and script level Tcl code. I cannot guess the real-world use case here.

You are right , without code you can't see my problem.
I’ll try to follow your advice...

I can’t reproduce my problem with this simple code :
critcl::cproc newlist {Tcl_Interp* interp} ok {

Tcl_Obj *listObj = Tcl_NewListObj (0,NULL);

Tcl_ListObjAppendElement (interp, listObj, Tcl_NewStringObj("a", 1));
Tcl_ListObjAppendElement (interp, listObj, Tcl_NewIntObj(30));
Tcl_ListObjAppendElement (interp, listObj, Tcl_NewStringObj("c", 1));
Tcl_ListObjAppendElement (interp, listObj, Tcl_NewIntObj(40));

Tcl_Obj* newlist = Tcl_NewObj();
Tcl_AppendObjToObj(newlist, Tcl_NewStringObj("'", 1));
Tcl_AppendObjToObj(newlist, listObj);
Tcl_AppendObjToObj(newlist, Tcl_NewStringObj("'", 1));

Tcl_SetObjResult(interp, newlist);

return TCL_OK;
}

puts [newlist] ; # 'a 30 c 40'

I'll continue

Le mercredi 11 mai 2022 à 00:00:22 UTC+2, Nicolas Robert a écrit :
> Le mardi 10 mai 2022 à 23:10:36 UTC+2, heinrichmartin a écrit :
> > On Tuesday, May 10, 2022 at 8:45:21 PM UTC+2, Nicolas Robert wrote:
> > > Le lundi 9 mai 2022 à 16:19:22 UTC+2, Nicolas a écrit :
> > > > Le lundi 9 mai 2022 à 13:32:16 UTC+2, heinrichmartin a écrit :
> > > > > On Monday, May 9, 2022 at 10:17:34 AM UTC+2, Nicolas Robert wrote:
> > > > > > I would like to add single quotes, square brackets, newline... to the left and right of my string.
> > > > > > It seems to me that I have several choices...
> > > > > > Tcl_ObjPrintf("%s", x) , Tcl_AppendObjToObj(...).
> > > > > >
> > > > > > Can you advise me one ? or another ?
> > > > > StringCatCmd uses Tcl_AppendObjToObj. That should be a reasonable choice.
> > > > Hi,
> > > > when I work with strings, I use the Tcl_DString API
> > > >
> > > > ++
> > > Thank you both for your answers.
> > > I finally chose this function : Tcl_AppendObjToObj(...)
> > > I have a problem, I have two objects to add to a list one on the left and one on the right.
> > > Tcl_Obj* newlist = Tcl_NewObj();
> > > Tcl_AppendObjToObj(newlist, Tcl_NewStringObj("'", 1));
> > > Tcl_AppendObjToObj(newlist, listObj);
> > > Tcl_AppendObjToObj(newlist, Tcl_NewStringObj("'", 1));
> > I am used to the script level, but
> > * You could init newlist with the left string already or
> > * reuse the single quote object left and right.
> > * If I get https://www.tcl-lang.org/man/tcl8.6/TclLib/StringObj.htm right, then Tcl_AppendObjToObj(Tcl_NewStringObj()) could be simplified to Tcl_AppendToObj().
> > * I have no experience with refCount, i.e. no idea whether this code is leaking objects. (My guess is that all your Tcl_New*Obj have refCount 0, but they should go through refCount 1, because only _dropping_ to zero would free them ...)
> >
> > > puts "newlist : [newlist]"
> >
> > You seem not to share all code. How do you create listObj above?
> > If newlist is the implementation of a proc, then look into https://www.tcl-lang.org/man/tcl8.6/TclLib/SetResult.htm.
> > > newlist : '{a 30 c 40}'
> > listObj already holds these braces; appending quotes is _not_ the issue..
> > > How I can remove my curly braces from my 'listObj' ?
> > > To obtain this result : newlist : 'a 30 c 40'
> > Besides looking elsewhere in your code (as stated above), maybe you should reconsider why you are mixing C and script level Tcl code. I cannot guess the real-world use case here.
> You are right , without code you can't see my problem.
> I’ll try to follow your advice...
>
> I can’t reproduce my problem with this simple code :
> critcl::cproc newlist {Tcl_Interp* interp} ok {
>
> Tcl_Obj *listObj = Tcl_NewListObj (0,NULL);
>
> Tcl_ListObjAppendElement (interp, listObj, Tcl_NewStringObj("a", 1));
> Tcl_ListObjAppendElement (interp, listObj, Tcl_NewIntObj(30));
> Tcl_ListObjAppendElement (interp, listObj, Tcl_NewStringObj("c", 1));
> Tcl_ListObjAppendElement (interp, listObj, Tcl_NewIntObj(40));
> Tcl_Obj* newlist = Tcl_NewObj();
> Tcl_AppendObjToObj(newlist, Tcl_NewStringObj("'", 1));
> Tcl_AppendObjToObj(newlist, listObj);
> Tcl_AppendObjToObj(newlist, Tcl_NewStringObj("'", 1));
> Tcl_SetObjResult(interp, newlist);
>
> return TCL_OK;
> }
>
> puts [newlist] ; # 'a 30 c 40'
>
> I'll continue

I finally found , my problem was that my input list was not of this form {a 30 c 40} but like this {{a 30 c 40}}.
problem solved with Tcl_ListObjIndex(...)

Nicolas

* Nicolas Robert <nicolasrobert.19000@gmail.com>
| I finally found , my problem was that my input list was not of this
| form {a 30 c 40} but like this {{a 30 c 40}}. problem solved with
| Tcl_ListObjIndex(...)

Note that if any of the list elements themselves are (sub-)lists or
have spaces or other special chars in the value, the "{}" might come
back again.

% set list [list a 30 b 40]
a 30 b 40
% lappend list c "10 20"
a 30 b 40 c {10 20}

Note the last element.

% lappend list d \{
a 30 b 40 c {10 20} d \{

Again...

If it is *really* important that there is no {} (or \ for the same
reason) in the printed string, you would need to check for that and take
appropriate action if there is.

R'

Le mercredi 11 mai 2022 à 19:25:45 UTC+2, Ralf Fassel a écrit :
> * Nicolas Robert <nicolasro...@gmail.com>
> | I finally found , my problem was that my input list was not of this
> | form {a 30 c 40} but like this {{a 30 c 40}}. problem solved with
> | Tcl_ListObjIndex(...)
> Note that if any of the list elements themselves are (sub-)lists or
> have spaces or other special chars in the value, the "{}" might come
> back again.
>
> % set list [list a 30 b 40]
> a 30 b 40
> % lappend list c "10 20"
> a 30 b 40 c {10 20}
>
> Note the last element.
>
> % lappend list d \{
> a 30 b 40 c {10 20} d \{
>
> Again...
>
> If it is *really* important that there is no {} (or \ for the same
> reason) in the printed string, you would need to check for that and take
> appropriate action if there is.
>
> R'

I would be surprised if I had this kind of case, since I work with structured lists. (huddle list).
If that were the case, I don’t think I can find a solution, as my knowledge of the C language is limited...

Nicolas

Le mercredi 11 mai 2022 à 19:57:42 UTC+2, Nicolas Robert a écrit :
> Le mercredi 11 mai 2022 à 19:25:45 UTC+2, Ralf Fassel a écrit :
> > * Nicolas Robert
> > | I finally found , my problem was that my input list was not of this
> > | form {a 30 c 40} but like this {{a 30 c 40}}. problem solved with
> > | Tcl_ListObjIndex(...)
> > Note that if any of the list elements themselves are (sub-)lists or
> > have spaces or other special chars in the value, the "{}" might come
> > back again.
> >
> > % set list [list a 30 b 40]
> > a 30 b 40
> > % lappend list c "10 20"
> > a 30 b 40 c {10 20}
> >
> > Note the last element.
> >
> > % lappend list d \{
> > a 30 b 40 c {10 20} d \{
> >
> > Again...
> >
> > If it is *really* important that there is no {} (or \ for the same
> > reason) in the printed string, you would need to check for that and take
> > appropriate action if there is.
> >
> > R'
> I would be surprised if I had this kind of case, since I work with structured lists. (huddle list).
> If that were the case, I don’t think I can find a solution, as my knowledge of the C language is limited...
>
> Nicolas

Hello ,
I have 2 questions
I need this result : > s {Hello World}

I encountered problems when my string contained spaces as in the above result ,
to avoid this, I added my string obj in a list.

Tcl_Obj* defaultTag = Tcl_NewObj();

Tcl_AppendObjToObj(defaultTag, Tcl_NewStringObj("s ", 2));
if (Tcl_DStringLength(srcObj) == 0) {
Tcl_AppendObjToObj(defaultTag, Tcl_NewStringObj("{}", 2));
} else {
Tcl_Obj *listStringObj = Tcl_NewListObj (0,NULL);
Tcl_ListObjAppendElement(interp, listStringObj, srcObj);
Tcl_AppendObjToObj(defaultTag, listStringObj);
}

Is that a correct solution? Or I’ll do it another way

2nd question :
'srcObj' can be empty... Checking its length is a correct solution ?

Nicolas

On Wednesday, May 25, 2022 at 9:03:33 AM UTC-7, Nicolas Robert wrote:
> Le mercredi 11 mai 2022 à 19:57:42 UTC+2, Nicolas Robert a écrit :
> > Le mercredi 11 mai 2022 à 19:25:45 UTC+2, Ralf Fassel a écrit :
> > > * Nicolas Robert
> > > | I finally found , my problem was that my input list was not of this
> > > | form {a 30 c 40} but like this {{a 30 c 40}}. problem solved with
> > > | Tcl_ListObjIndex(...)
> > > Note that if any of the list elements themselves are (sub-)lists or
> > > have spaces or other special chars in the value, the "{}" might come
> > > back again.
> > >
> > > % set list [list a 30 b 40]
> > > a 30 b 40
> > > % lappend list c "10 20"
> > > a 30 b 40 c {10 20}
> > >
> > > Note the last element.
> > >
> > > % lappend list d \{
> > > a 30 b 40 c {10 20} d \{
> > >
> > > Again...
> > >
> > > If it is *really* important that there is no {} (or \ for the same
> > > reason) in the printed string, you would need to check for that and take
> > > appropriate action if there is.
> > >
> > > R'
> > I would be surprised if I had this kind of case, since I work with structured lists. (huddle list).
> > If that were the case, I don’t think I can find a solution, as my knowledge of the C language is limited...
> >
> > Nicolas
> Hello ,
> I have 2 questions
> I need this result : > s {Hello World}
>
> I encountered problems when my string contained spaces as in the above result ,
> to avoid this, I added my string obj in a list.
>
> Tcl_Obj* defaultTag = Tcl_NewObj();
>
> Tcl_AppendObjToObj(defaultTag, Tcl_NewStringObj("s ", 2));
> if (Tcl_DStringLength(srcObj) == 0) {
> Tcl_AppendObjToObj(defaultTag, Tcl_NewStringObj("{}", 2));
> } else {
> Tcl_Obj *listStringObj = Tcl_NewListObj (0,NULL);
> Tcl_ListObjAppendElement(interp, listStringObj, srcObj);
> Tcl_AppendObjToObj(defaultTag, listStringObj);
> }
>
> Is that a correct solution? Or I’ll do it another way

No, this is not the correct solution. The mistake made here is that the code is trying to guess the correct string form of a list. This is re-inventing the code that already exists in Tcl to correctly manage a list.
Just don't do this and let Tcl do it for you.

Assuming that "defaultTag" is intended to be a list, then only List operations should be used to modify this Tcl_Obj value.

Tcl_Obj* defaultTag = Tcl_NewObj();
Tcl_Obj* s = Tcl_NewStringObj("s", 1);

Tcl_ListObjAppendElement(interp, defaultTag, s);
Tcl_ListObjAppendElement(interp, defaultTag, srcObj);

Work smarter, not harder.

>
> 2nd question :
> 'srcObj' can be empty... Checking its length is a correct solution ?

Answered above.

-Brian

Le mercredi 25 mai 2022 à 18:17:27 UTC+2, briang a écrit :
> On Wednesday, May 25, 2022 at 9:03:33 AM UTC-7, Nicolas Robert wrote:
> > Le mercredi 11 mai 2022 à 19:57:42 UTC+2, Nicolas Robert a écrit :
> > > Le mercredi 11 mai 2022 à 19:25:45 UTC+2, Ralf Fassel a écrit :
> > > > * Nicolas Robert
> > > > | I finally found , my problem was that my input list was not of this
> > > > | form {a 30 c 40} but like this {{a 30 c 40}}. problem solved with
> > > > | Tcl_ListObjIndex(...)
> > > > Note that if any of the list elements themselves are (sub-)lists or
> > > > have spaces or other special chars in the value, the "{}" might come
> > > > back again.
> > > >
> > > > % set list [list a 30 b 40]
> > > > a 30 b 40
> > > > % lappend list c "10 20"
> > > > a 30 b 40 c {10 20}
> > > >
> > > > Note the last element.
> > > >
> > > > % lappend list d \{
> > > > a 30 b 40 c {10 20} d \{
> > > >
> > > > Again...
> > > >
> > > > If it is *really* important that there is no {} (or \ for the same
> > > > reason) in the printed string, you would need to check for that and take
> > > > appropriate action if there is.
> > > >
> > > > R'
> > > I would be surprised if I had this kind of case, since I work with structured lists. (huddle list).
> > > If that were the case, I don’t think I can find a solution, as my knowledge of the C language is limited...
> > >
> > > Nicolas
> > Hello ,
> > I have 2 questions
> > I need this result : > s {Hello World}
> >
> > I encountered problems when my string contained spaces as in the above result ,
> > to avoid this, I added my string obj in a list.
> >
> > Tcl_Obj* defaultTag = Tcl_NewObj();
> >
> > Tcl_AppendObjToObj(defaultTag, Tcl_NewStringObj("s ", 2));
> > if (Tcl_DStringLength(srcObj) == 0) {
> > Tcl_AppendObjToObj(defaultTag, Tcl_NewStringObj("{}", 2));
> > } else {
> > Tcl_Obj *listStringObj = Tcl_NewListObj (0,NULL);
> > Tcl_ListObjAppendElement(interp, listStringObj, srcObj);
> > Tcl_AppendObjToObj(defaultTag, listStringObj);
> > }
> >
> > Is that a correct solution? Or I’ll do it another way
> No, this is not the correct solution. The mistake made here is that the code is trying to guess the correct string form of a list. This is re-inventing the code that already exists in Tcl to correctly manage a list.
> Just don't do this and let Tcl do it for you.
>
> Assuming that "defaultTag" is intended to be a list, then only List operations should be used to modify this Tcl_Obj value.
>
> Tcl_Obj* defaultTag = Tcl_NewObj();
> Tcl_Obj* s = Tcl_NewStringObj("s", 1);
>
> Tcl_ListObjAppendElement(interp, defaultTag, s);
> Tcl_ListObjAppendElement(interp, defaultTag, srcObj);
>
> Work smarter, not harder.
> >
> > 2nd question :
> > 'srcObj' can be empty... Checking its length is a correct solution ?
> Answered above.
>
> -Brian

Thanks for the advice, it’s much cleaner.

Nicolas

Am 26.05.2022 um 10:16 schrieb Nicolas Robert:
> Le mercredi 25 mai 2022 à 18:17:27 UTC+2, briang a écrit :
>> On Wednesday, May 25, 2022 at 9:03:33 AM UTC-7, Nicolas Robert wrote:
>>> Le mercredi 11 mai 2022 à 19:57:42 UTC+2, Nicolas Robert a écrit :
>>>> Le mercredi 11 mai 2022 à 19:25:45 UTC+2, Ralf Fassel a écrit :
>>>>> * Nicolas Robert
>>>>> | I finally found , my problem was that my input list was not of this
>>>>> | form {a 30 c 40} but like this {{a 30 c 40}}. problem solved with
>>>>> | Tcl_ListObjIndex(...)
>>>>> Note that if any of the list elements themselves are (sub-)lists or
>>>>> have spaces or other special chars in the value, the "{}" might come
>>>>> back again.
>>>>>
>>>>> % set list [list a 30 b 40]
>>>>> a 30 b 40
>>>>> % lappend list c "10 20"
>>>>> a 30 b 40 c {10 20}
>>>>>
>>>>> Note the last element.
>>>>>
>>>>> % lappend list d \{
>>>>> a 30 b 40 c {10 20} d \{
>>>>>
>>>>> Again...
>>>>>
>>>>> If it is *really* important that there is no {} (or \ for the same
>>>>> reason) in the printed string, you would need to check for that and take
>>>>> appropriate action if there is.
>>>>>
>>>>> R'
>>>> I would be surprised if I had this kind of case, since I work with structured lists. (huddle list).
>>>> If that were the case, I don’t think I can find a solution, as my knowledge of the C language is limited...
>>>>
>>>> Nicolas
>>> Hello ,
>>> I have 2 questions
>>> I need this result : > s {Hello World}
>>>
>>> I encountered problems when my string contained spaces as in the above result ,
>>> to avoid this, I added my string obj in a list.
>>>
>>> Tcl_Obj* defaultTag = Tcl_NewObj();
>>>
>>> Tcl_AppendObjToObj(defaultTag, Tcl_NewStringObj("s ", 2));
>>> if (Tcl_DStringLength(srcObj) == 0) {
>>> Tcl_AppendObjToObj(defaultTag, Tcl_NewStringObj("{}", 2));
>>> } else {
>>> Tcl_Obj *listStringObj = Tcl_NewListObj (0,NULL);
>>> Tcl_ListObjAppendElement(interp, listStringObj, srcObj);
>>> Tcl_AppendObjToObj(defaultTag, listStringObj);
>>> }
>>>
>>> Is that a correct solution? Or I’ll do it another way
>> No, this is not the correct solution. The mistake made here is that the code is trying to guess the correct string form of a list. This is re-inventing the code that already exists in Tcl to correctly manage a list.
>> Just don't do this and let Tcl do it for you.
>>
>> Assuming that "defaultTag" is intended to be a list, then only List operations should be used to modify this Tcl_Obj value.
>>
>> Tcl_Obj* defaultTag = Tcl_NewObj();
>> Tcl_Obj* s = Tcl_NewStringObj("s", 1);
>>
>> Tcl_ListObjAppendElement(interp, defaultTag, s);
>> Tcl_ListObjAppendElement(interp, defaultTag, srcObj);
>>
>> Work smarter, not harder.
>>>
>>> 2nd question :
>>> 'srcObj' can be empty... Checking its length is a correct solution ?
>> Answered above.
>>
>> -Brian
>
> Thanks for the advice, it’s much cleaner.
>
> Nicolas

I personally find it good practice to check eventual returned errors
from Tcl_ListObjAppendElement.
This is hypotetical in this case, as there may not be any error.
The typical error would be, that "defaultTag" is not a list. This may
not happen here.

Sorry, just noise,
Harald