functiontable.cpp

a basic interpreter free basic

#include "StdAfx.h"
#include "FunctionTable.h"

CFunctionTable::CFunctionTable(void)
{
	this->m_FunctionTable = new functionlist_t();

	// Array of builtin functions
	struct builtins_t {
		string Name;
		float (*coderef)(float Value);
	} Builtin_Functions[] = {
		"SIN", &CBuiltins::SIN,
		"COS", &CBuiltins::COS,
		"TAN", &CBuiltins::TAN,
		"ATN", &CBuiltins::ATN,
		"EXP", &CBuiltins::EXP,
		"ABS", &CBuiltins::ABS,
		"LOG", &CBuiltins::LOG,
		"SQR", &CBuiltins::SQR,
		"RND", &CBuiltins::RND,
		"INT", &CBuiltins::INT,
		"", NULL
	};

	// Loop through the array of built in functions and bind them
	int i = 0;
	do
	{
		struct builtins_t Builtin = Builtin_Functions[i];
		CFunction *Func = new CFunction(Builtin.Name, Builtin.coderef);
		this->Add(Func);
		i++;
	} while(Builtin_Functions[i].Name != "");

	// Seed the random number generator
	srand((unsigned int)time(NULL));
}

CFunctionTable::~CFunctionTable(void)
{
	functionlist_t::iterator functionIterator = this->m_FunctionTable->begin();
	while(functionIterator != this->m_FunctionTable->end())
	{
		delete(*functionIterator);
		functionIterator++;
	}

	delete this->m_FunctionTable;
}

// Add a function to the function table
void CFunctionTable::Add(CFunction * Function)
{
	// First, make sure there are no existing functions
	// with this name
	CFunction *thisFunction = this->Find(Function->GetName());
	if(thisFunction != NULL)
	{
		// If there is an existing function, redefine it
		// (Does not work on builtin functions)
		if(thisFunction->GetBuiltin() == true)
		{
			throw ILLEGAL_INSTRUCTION;
		}

		thisFunction->SetExpression(Function->GetExpression());
		return;
	}

	// Otherwise, then push the symbol onto the list
	this->m_FunctionTable->push_back(Function);
}

// Find a function by name
CFunction * CFunctionTable::Find(string Name)
{
	// Iterate over the function table, find the function that
	// matches and return
	functionlist_t::iterator func = this->m_FunctionTable->begin();

	while(func != this->m_FunctionTable->end())
	{
		CFunction *thisFunction = *func;
		if(thisFunction->GetName() == Name)
		{
			return thisFunction;
		}

		func++;
	}

	return NULL;
}