/// <summary>
/// Read variable
/// </summary>
public static bool TryProceedSimpleVariable(List <BaseFormulaNode> nodes, ReadOnlySpan <char> formula, ref int index)
{
// Read unary minus
var localIndex = UnaryMinusReader.ReadUnaryMinus(nodes, formula, index, out var isNegativeLocal);
var numberBuilder = new IndexWatcher();
for (int i = localIndex; i < formula.Length; i++)
{
var ch = formula[i];
var isLastChar = i + 1 == formula.Length;
if (ch.IsSimpleVariable())
{
numberBuilder.Remember(i);
if (isLastChar && TryAddSimpleVariable(nodes, formula, numberBuilder, isNegativeLocal))
{
index = i;
return(true);
}
}
else if (TryAddSimpleVariable(nodes, formula, numberBuilder, isNegativeLocal))
{
index = i - 1;
return(true);
}
else
{
break;
}
}
return(false);
}
/// <summary>
/// Read word
/// </summary>
public static bool TryProceedWord(List <BaseFormulaNode> nodes, ReadOnlySpan <char> formula, ref int index)
{
// Read unary minus
var localIndex = UnaryMinusReader.ReadUnaryMinus(nodes, formula, index, out _);
// Check out of range
if (localIndex >= formula.Length)
{
return(false);
}
// Read word
if (!_quotes.Contains(formula[localIndex]))
{
return(false);
}
// Skip start char
localIndex++;
var variableBuilder = new IndexWatcher();
for (int i = localIndex; i < formula.Length; i++)
{
var ch = formula[i];
if (_quotes.Contains(ch))
{
var wordSpan = formula.Slice(variableBuilder.StartIndex.GetValueOrDefault(), variableBuilder.Length);
var word = wordSpan.ToString();
var varNode = new WordNode(word);
nodes.Add(varNode);
index = i;
return(true);
}
variableBuilder.Remember(i);
}
return(false);
}
/// <summary>
/// Read variable
/// </summary>
public static bool TryProceedBorderedVariable(List <BaseFormulaNode> nodes, ReadOnlySpan <char> formula, ref int index)
{
// Read unary minus
var localIndex = UnaryMinusReader.ReadUnaryMinus(nodes, formula, index, out var isNegativeLocal);
// Check out of range
if (localIndex >= formula.Length)
{
return(false);
}
// Read variable
if (formula[localIndex] != START_CHAR)
{
return(false);
}
// Skip start char
localIndex++;
var variableBuilder = new IndexWatcher();
for (int i = localIndex; i < formula.Length; i++)
{
var ch = formula[i];
if (ch == END_CHAR)
{
var variableSpan = formula.Slice(variableBuilder.StartIndex.GetValueOrDefault(), variableBuilder.Length);
var variableName = variableSpan.ToString();
AddFormulaNode(nodes, variableName, isNegativeLocal);
index = i;
return(true);
}
variableBuilder.Remember(i);
}
return(false);
}
private static bool TryAddSimpleVariable(List <BaseFormulaNode> nodes, ReadOnlySpan <char> formula, IndexWatcher nodeBuilder, bool isNegative)
{
if (nodeBuilder.InProcess)
{
var variableSpan = formula.Slice(nodeBuilder.StartIndex.GetValueOrDefault(), nodeBuilder.Length);
var variableName = variableSpan.ToString();
AddFormulaNode(nodes, variableName, isNegative);
return(true);
}
return(false);
}
private static bool TryAddNumber(List <BaseFormulaNode> nodes, ReadOnlySpan <char> formula, IndexWatcher nodeBuilder, bool isNegative)
{
if (nodeBuilder.InProcess)
{
var valueSpan = formula.Slice(nodeBuilder.StartIndex.GetValueOrDefault(), nodeBuilder.Length);
var value = GetDouble(valueSpan);
if (isNegative)
{
value *= -1;
}
var valNode = new NumberNode(value);
nodes.Add(valNode);
return(true);
}
return(false);
}
