/// <summary>
/// Parse a string with any number of interpolation tokens (%1, %2, ...).
/// '%' characters may be self-escaped (%%).
/// </summary>
/// <param name="message">Text containing interpolation tokens.</param>
/// <returns>Array of strings and numbers.</returns>
public static JsArray <Union <string, int> > tokenizeInterpolation(string message)
{
var tokens = new JsArray <Union <string, int> >();
var chars = new JsArray <char>(message.ToCharArray());
// End marker.
chars.Push('\0');
// Parse the message with a finite state machine.
// 0 - Base case.
// 1 - % found.
// 2 - Digit found.
var state = 0;
var buffer = new JsArray <char>();
var number = "";
for (var i = 0; i < chars.Length; i++)
{
var c = chars[i];
if (state == 0)
{
if (c == '%')
{
state = 1; // Start escape.
}
else
{
buffer.Push(c); // Regular char.
}
}
else if (state == 1)
{
if (c == '%')
{
buffer.Push(c); // Escaped %: %%
state = 0;
}
else if ('0' <= c && c <= '9')
{
state = 2;
number = c.ToString();
var text2 = new String(buffer.ToArray());
if (!String.IsNullOrEmpty(text2))
{
tokens.Push(text2);
}
buffer = new JsArray <char>();
}
else
{
buffer.Push('%', c); // Not an escape: %a
state = 0;
}
}
else if (state == 2)
{
if ('0' <= c && c <= '9')
{
number += c; // Multi-digit number.
}
else
{
tokens.Push(Int32.Parse(number));
i--; // Parse this char again.
state = 0;
}
}
}
var text = new String(buffer.ToArray());
if (!String.IsNullOrEmpty(text))
{
tokens.Push(text);
}
return(tokens);
}