no instance of constructor wxTextValidator matches instance - c++

I need to validate text within a wxTextControl as a float or an int (for starters). I will eventually need float > 0, float >= 0 etc etc. My idea was to create an enum defining all of my scenarios and create the val within a function. I'm having trouble getting started, as the declaration of the wxTextValidator throws an error.
enum class glValidate { glInt, glPosInt, gl0PosInt, glFloat, glPosFloat, gl0PosFloat, glString};
wxValidator GuiLib::CreateValidator(std::wstring* default_value, glValidate flag) {
wxArrayString numberArray;
numberArray.Add(wxT("0"));
numberArray.Add(wxT("1"));
numberArray.Add(wxT("2"));
numberArray.Add(wxT("3"));
numberArray.Add(wxT("4"));
numberArray.Add(wxT("5"));
numberArray.Add(wxT("6"));
numberArray.Add(wxT("7"));
numberArray.Add(wxT("8"));
numberArray.Add(wxT("9"));
wxTextValidator val(wxFILTER_NONE, default_value);
switch (flag) {
case glValidate::glInt:
numberArray.Add(wxT("-"));
val.SetStyle = wxFILTER_INCLUDE_LIST;
val.SetIncludes(numberArray);
break;
case glValidate::glPosInt:
val.SetStyle = wxFILTER_INCLUDE_LIST;
val.SetIncludes(numberArray);
break;
}
etc..
}
I recognize that even this simple scenario is busted because the glInt case would allow "123-456", but I think I can deal with that via an event handler once I get this part working. The problem is that I'm getting an error message stating
no instance of constructor "wxTextValidator::wxTextValidator" matches
the argument list

Did you try wxNumValidator< T > instead of your own?

I was fooled by Visual Studio. The problem with the above code is that default_value is wstring, when it needs to be wxString*. Visual Studio highlighted ```wxFILTER_NONE''', which lead me think the problem was there!
After rejigging to make fix the string param it works. Well it compiles - now I need to get the validation working as desired...

Related

C++ proto2 "expression is not assignable" error

I am trying to figure out how to assign a message field in protobuf2 in C++. Here is a small snippet of the code.
message Sub {
optional double x = 1 [[default = 46.0];
}
message Master {
optional Sub sub_message;
}
Now when I try to initialize a Master message, I got the following error:
Master msg;
msg.mutable_sub_message() = new Sub();
error: expression is not assignable
However, the following code works, and the sub_message is set to default values:
Master msg;
msg.set_sub_message(new Sub());
Can anyone kindly explain why mutable_sub_message() can not be used for assignment?
msg.mutable_sub_message() returns a pointer to the field, i.e. a Sub*. The idea is that you use that pointer to manipulate the field as you need.
Assigning a different pointer to it wouldn't change the value inside the class, it would at most change the temporary pointer that was returned, which doesn't make sense. I guess it could be made to work if mutable_sub_message returned something like a Sub*& (not even sure that syntax is right), but that's not how the library was written.
In a more practical note, calling mutable_sub_message will initialize the subfield, you don't need to do that explicitly. That means you'd usually set a nested field using
Master msg;
msg.mutable_sub_message()->set_x(4.0);
Also, it's always safe to call getters even if a field isn't set, in that case they will always return a default instance. In other words:
double use_field(const Master& msg) {
// This is always safe, and will return the default even if
// sub_message isn't set.
return msg.sub_message().x();
}

Lua checkudata type C++

I've been to the end of Google and back trying to solve this problem.
I have a few userdata objects that I push from C++ to Lua.
I have a function that should get the X value of either a 2D or 3D object.
When I try to get the userdata object, taking into consideration that it could be either a 2D element or 3D object, I need to be able to get the X for whichever the user chooses.
Here is what I tried:
int getX(lua_State* L)
{
Object3D* a = static_cast<Object3D*>(luaL_checkudata(L, 1, "Object3D"));
if (!a)
{
Object2D* b = static_cast<Object2D*>(luaL_checkudata(L, 1, "Object2D"));
if (b)
{
lua_pushnumber(L, b:getX());
}
else
{
lua_pushnil(L);
}
}
else
{
lua_pushnumber(L, a:getX());
}
return 1;
}
Unfortunately if the userdata type is not Object3D, it fails and exits on an lua error without continuing to try Object2D.
Therefore, it will only work in the above code if the object being passed is of type Object3D.
luaL_testudata
void *luaL_testudata (lua_State *L, int arg, const char *tname);
This function works like luaL_checkudata, except that, when the test fails, it returns NULL instead of raising an error.
The lua(L)_check* functions throw Lua errors on failure, the lua(L)_to* functions return NULL. For whatever reason, this one deviates from the naming convention and is named lua(L)_test* instead, which makes it a bit harder to find.
Your code is incomplete and doesn't compile as-is so I can't be bothered to check, but if I'm not mistaken, just replacing luaL_checkudata with luaL_testudata should make it work as intended.
Solved by using rawequal to see which class the registry matches.

variables alteration in c++

i got a ridiculous problem.
i have a class within inside an array member.i have a get method and a set method for the array.
the problem is that i call the set(to update) method to change the variables within the array and i see with the debugger that the variables do actually update.then when i call immediately the get method just after the set method i found the variables of the array been changed back to their ancient values.
here is the code approximately :
object.updatFunction();//sort of set method
//nothing in between
Type variable=object.getFunction();
added code:
void Cube::updtCornersNextToCentr()
{
int iHalfSide=m_SideSize/2;
int centerX(m_Center.x()),centerY(m_Center.y()),centerZ(m_Center.z());
m_CubeCornerVertices[0].setX(centerX-iHalfSide);
m_CubeCornerVertices[0].setY(centerY+iHalfSide);
m_CubeCornerVertices[0].setZ(centerZ-iHalfSide);
m_CubeCornerVertices[1].setX(centerX+iHalfSide);
m_CubeCornerVertices[1].setY(centerY+iHalfSide);
m_CubeCornerVertices[1].setZ(centerZ-iHalfSide);
//.......
m_CubeCornerVertices[7].setX(centerX+iHalfSide);
m_CubeCornerVertices[7].setY(centerY-iHalfSide);
m_CubeCornerVertices[7].setZ(centerZ+iHalfSide);
}
QVector3D * Cube::getCubeCornerVertices()const
{
static QVector3D temp[8];
for(int i=0;i<8;i++)
{
temp[i]=m_CubeCornerVertices[i];
}
return &temp[0];
}
The problem was really ridiculous, i didn’t want to let this post ambiguous.it’s a very beginner fault and it’s all about a missing « & » that caused me to update a copy.
Actually i did above simplify write the next code :
object.updatFunction();//sort of set method
//nothing in between
Type variable=object.getFunction();
And the more real code was something like:
m_WorldSpace->getCube().updtCornersNextToCentr()
//nothing in between
const QVector3D corners[8]=m_WorldSpace->getCube().getCubeCornerVertices();
all the problem was in the getCube() function which instead of being something like this :
Cube& WorldSpace::getCube()//here is the missing "&"
{
return m_Cube;
}
I wrote this
Cube WorldSpace::getCube()//this caused to get and update just a temporary copy
{
return m_Cube;
}
someone can say that i got multiple levels of getters which blinded me.
thank you.

Trying to figure out an alternative method for switch statements

I am currently trying to figure out an alternative method for switch statements as the program I have the switch statements are getting really long and confusing. Therefore I thought it would be a good idea to use array of pointers to functions. I am using c++ and qt. But when I try and implement, I am getting the following error.
cannot convert 'CheckPl::comA' from type 'void (CheckPl::)()' to type 'void (*)()'
It would be much appreciated if someone would help me out with this or at least point me to correct direction.
[...] alternative method for switch statements as the program I have the switch statements are getting really long and confusing.
Extract each case block into a separate function; This way, the switch changes from a 10km long function to a dispatch function:
void dispatch_function()
{
switch(x)
{
case 1: do_case_1(); break;
...
case n: do_case_n(); break;
}
}
Therefore I thought it would be a good idea to use array of pointers to functions.
It's not a good idea (especially, not in the way you went about it - you are solving the xy problem). In C++, when you have a requirement for multiple functions that are called in similar conditions, you have the requirements for an abstract interface.
Your resulting client code should look like this:
std::vector<handlers> handlers; // filled with handler instances, one for each case
for(const auto& h: handlers) // replaces switch
if(h.fits_case(x)) // replaces case statement
{
h.do_case(x); // replaces case block
break;
}
It follows that your handler classes should inherit from a base class like this:
class handler_base
{
virtual bool fits_case(int x) = 0;
virtual void do_case(int x) = 0;
}
This is easy to understand (in both implementation and client code), it is modular, testable (you can test each case separately) and extensible (if you need a new case you only add the case and add it to the vector); It also doesn't use any pointers.
A pointer to a member function has to be stored in a variable of the appropriate type. A pointer to a member function is not compatible with a pointer to a function.
void (CheckPl::*mptr)() = &CheckPl::comA;
A pointer to a member function requires an instance to an object for invocation.
CheckPl c;
CheckPl *cp = &c;
(c.*mptr)();
(cp->*mptr)();
The hardest thing to remember about the above syntax is that the extra set of parentheses is required.

Visual Studio Compiler is highlighting Static variables differently?

I'm programming in C++ and have a method which uses a static variable. The method isn't working as I think it should; upon investigation, I found that my static variable is being highlighted in red in two places and blue in other places. Below is the code:
int GameModeState::changeJob(int number)
{
static int job = 1; //red
if (number == 1)
{
job = (job+1); //First one is red, second one is blue
return job; //blue
} else {
return job; //blue
}
}
I'm calling this method with other methods, one shown for example:
int GameModeState::getJob()
{
int currentJob = (changeJob(2));
return currentJob;
}
I want a method like getJob() to simply return the current value of job, while another method, when calling changeJob(number) is changeJob(1), to increment job's value by one. (Hence the if/else statement in changeJob(number)).
Since the job variables are highlighted differently, I'm thinking the compiler is saying that it views the two separately somehow? I'm getting stuck with job being some even value.
EDIT I also have Awesomium... I believe that is the only addition to the compiler, but I'm not completely sure.
MOAR EDIT In another class, I have a method which should determine the current job's number and do something based on if the number is even or odd (since right now there are only two jobs)
void ZoneMovementState::_changeZone(const String& message, const Awesomium::JSValue& input, Awesomium::JSValue& output)
{
//Awesomium::JSValue::Object object = input.getObject();
//String zoneFilename = Convert::toString(object[L"zoneFilename"].toString());
// If the number from getJob is even, the player is currently a geologist
if (GameModeState::getJob()%2 == 0)
{
ZoneParser::getSingleton().load("../media/zones/geology_zone.xml", false);
} else {
ZoneParser::getSingleton().load("../media/zones/farm_zone.xml", false);
}
transitionHandler->go();
}
Ignore the two commented out lines; they deal with JS, which I'm not working on for now.
In the program, I can access the farm_zone until I increment job's value using the below method in GameModeState:
void GameModeState::_openNotebook(const String& message, const Awesomium::JSValue& input, Awesomium::JSValue& output)
{
mNotebookTransition->go();
static int currentJob = changeJob(1);
}
.... So I figured out my problem. While going through the code to show you guys, I realized that the static for currentJob was probably unneeded... once I removed it, my code works as it should now.
Thanks for the help guys!
Part of the problem here is you're using a static local for what very likely should just be a member variable. A static local maintains it's value across all calls to a function in all threads in a process. It's much more likely that you want it to persist for all calls to changeJob in a particular GameModeState instance (else why make it a member functon to begin with?).
To do this you'll need to define a member variable on GameModeState initialize it in the constructor and then access it in the method. For example
class GameModeState {
int job;
GameModeState() : job(1) {}
int changeJob(int number);
};
int GameModeState::changeJob(int number) {
if (number == 1) {
job = (job+1);
return job;
} else {
return job;
}
}
Note: I'm not entirely sure why you're seeing the color's your are seeing. Visual Studio by default won't color member variables a particular color in C++ so it's very likely another add-in you are using.
Nah, highlighting doesn't mean anything. That is, the editor doesn't call the compiler before deciding how/what/when to highlight. So that is not your problem. Sorry 'bout that :-)
You can prove this to yourself by going to Tools->Options->TextEditor and noticing that you can change the highlighting by choosing a different text-editing model.