ntdls / cmathparser

A fairly robust mathematics parsing engine for C++ projects.

• 👋 Hi, I'm @NTDLS (AKA Josh Patterson).
• 👀 I'm interested in C / C++ / C# and the Sea (mainly the Atlantic as I live in Charleston SC).
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• My website is: http://networkdls.com/

cmathparser's Issues

Nested powers

Yo, this thing is awesome, just doing some messing around with it now, this could very well be user error, but I found that "sin(pow(10,2))" gives me this error, but it works the other way round ("pow(sin(10))" for example), wondering if I'm just missing something or if something wacky is going on with powers in other functions!
Either way this is amazing, looking forward to messing around more with it!
(Edit, I did find a workaround by parsing the string for pow and solving that as a seperate expression!)

Compiler Error C2440

When trying to compile the code I am receiving Compiler Error C2440 at:

CMathParser/CMathParser.cpp

Line 720 in ae5b5fe

sOp = "!";

CMathParser/CMathParser.cpp

Lines 737 to 748 in ae5b5fe

	if (pSubExp->Text[iOpPos] == '*') {
	sOp = "*";
	}
	else if (pSubExp->Text[iOpPos] == '/') {
	sOp = "/";
	}
	else if (pSubExp->Text[iOpPos] == '%') {
	sOp = "%";
	}
	else if (pSubExp->Text[iOpPos] == '~') {
	sOp = "~";
	}

CMathParser/CMathParser.cpp

Lines 771 to 776 in ae5b5fe

	if (pSubExp->Text[iOpPos] == '-') {
	sOp = "-";
	}
	else if (pSubExp->Text[iOpPos] == '+') {
	sOp = "+";
	}

error C2440: '=': cannot convert from 'const char [2]' to 'char *'

I am using Visual Studio C++20 but I get the same error switching from 20 to 17 or 14 so I am not sure how you are compiling this without any issues. If you have any workarounds for this I will gladly try them out, I just thought I would create this issue incase it's the compiler I am using or maybe some other issue.

Variable support

This looks super interesting for a OSS project I'm working on (and it looks like nice, clean code). However I need to support variables. Basically I'll have a number of these expressions and some will use expressions or literals to define variables and yet other expressions will use these variables, etc. etc.
Have you thought about supporting that? If not, where would be the best place to inject variable detection and handling in this code?

Segmentation fault when using multiple variables in the expression

Hi,

I'm testing the library using expressions containing more than one variable.

These expression for example are causing segmentation fault:

X+X
X+Y
X*X
... and so on

The reason is the following code:

	//Get variable value...
	if (this->pVariableSetProc!=NULL){
		if(!this->pVariableSetProc(this, sVarName, &dVarValue))
		{
			return this->SetError(ResultInvalidToken, "Variable not defined: %s.", sVarName);
		}
	} else {
		return this->SetError(ResultInvalidToken, "Variable not defined: %s.", sVarName);
	}

	char sVarValue[64];
	//Convert double to string (must be a faster way, but this is just super safe and doesn't create infinite repeating patterns).
	//TODO: Fixed percision of 8 on variables seems inflexible.
	int iVarValLength = sprintf_s(sVarValue, sizeof(sVarValue), "%.8f", dVarValue);

	if (iSourceSz + iVarValLength >= pExp->Allocated)
	{
		pExp->Allocated = (iSourceSz + iVarValLength) + 1;
		pExp->Text = (char*)realloc(pExp->Text, sizeof(char) * pExp->Allocated);
		if (!pExp->Text)
		{
			return this->SetError(ResultMemoryAllocationError, "Memory allocation error.");
		}
	}

Have you tried to use more than one variable in the expression?