myString$ = "This string gets saved with project"; // Notice it isn't proceeded by the variable type declaration

myDouble = 1234.56789; // Notice it isn't proceeded by the variable type declaration

// File name: make_proj_level_tree_var.c

#include <Origin.h>

#pragma labtalk(1)


/*
Function creates a new project-level Tree variable named after string parameter passed into function.
Returns 1 if the new Tree was created and added to the current project.
Returns 0 if there is already a project-level Tree variable with the desired name.
Returns -1 if strTreeName param isn't a valid variable name.
Returns -2 if the project-level Tree simply wasn't created (for another reason).
*/
int make_proj_level_tree_var(string strTreeName)
{
	// Make sure the string param isn't empty.
	// If empty, return -1.
	if (0 == strTreeName.GetLength())
	{
		return -1;
	}

	// Make sure desired name is a valid name for a variable.
	// If not, return -1.
	if (!is_good_C_identifier(strTreeName))
	{
		return -1;
	}

	// See if a project-level Tree with the desired name already exists.
	// If so, return 0.
	TreeNode trTest1;
	Project.GetTree(strTreeName, trTest1);
	if(trTest1.IsValid())
	{
		return 0;
	}

	// Create a new Tree with the desired name and make it project-level.
	Tree trNew;
	trNew.SetAttribute(STR_LABEL_ATTRIB, strTreeName);
	Project.AddTree(strTreeName, trNew);

	// Test again to see if the new Tree was created and added to project.
	// If not, return -2;
	TreeNode trTest2;
	Project.GetTree(strTreeName, trTest2);
	if(!trTest2.IsValid())
	{
		return -2;
	}

	// Finally return 1 indicating sucess.
	return 1;
}

// Compile the Origin C file
run.LoadOC("%YOriginC\make_proj_level_tree_var.c", 16);

// Now create the project-level Tree var
string strTreeName$ = "mytree";
int nRet = make_proj_level_tree_var(strTreeName$);
if (nRet < 0)
{
	// Some sort of error in creating the Tree variable. See function documentation.
}

mytree.test$ = "It Works";
mytree.test$ = ;