Spintax C# ... How can I handle this?

Question

Spintax allows you to spin various words and sentences such as:

{Hello|Hi} {World|People}! {C{#|++|}|Java} is an {awesome|amazing} language.

The text between the braces would be selected at random to form different sentences.

I am able to possibly come up with a solution myself, but the problem I would have is the nesting. Sometimes the nesting can be very deep. What would be a possible solution to handling the nesting?

I can't gather the logic needed.

Answer 1

Don't worry about the nesting, just do it iteratively as follows:

1. Find the first sequence in the string that has {...} with no other braces inside. For your case, that's {Hello|Hi}. If there are no more of that pattern, go to step 3.

2. Grab all the possibilities out of there and choose a random one, replacing the brace section with its value. Then go back to step 1.

3. There's your modified string.

Let's say you have a slightly faulty random number generator that always returns zero. Your string modification history would then be:

a/ {Hello|Hi} {World|People}! {C{#|++|}|Java} is an {awesome|amazing} language.
b/ Hello {World|People}! {C{#|++|}|Java} is an {awesome|amazing} language.
c/ Hello World! {C{#|++|}|Java} is an {awesome|amazing} language.
d/ Hello World! {C#|Java} is an {awesome|amazing} language.
e/ Hello World! C# is an {awesome|amazing} language.
f/ Hello World! C# is an awesome language.

Note particularly the transition from (c) to (d). Because we're looking for the first brace section that doesn't have braces inside it, we do the {#|++|} before the {C{#|++|}|Java}.

All you need to add now is the possibility that you may have {, } or | within your actual text - these will need to be escaped somehow to protect them from your modification engine.

---

Here's a little C# program which shows this in action. It's probably not that impressively written, given my relative inexperience with the language, but it illustrates the process.

using System;
using System.Text.RegularExpressions;

namespace ConsoleApplication1
{
    class Program
    {
        static string spintax(Random rnd, string str) {
            // Loop over string until all patterns exhausted.
            string pattern = "{[^{}]*}";
            Match m = Regex.Match(str, pattern);
            while (m.Success) {
                // Get random choice and replace pattern match.
                string seg = str.Substring(m.Index + 1, m.Length - 2);
                string[] choices = seg.Split('|');
                str = str.Substring(0, m.Index) + choices[rnd.Next(choices.Length)] + str.Substring(m.Index + m.Length);
                m = Regex.Match(str, pattern);
            }

            // Return the modified string.
            return str;
        }

        static void Main(string[] args) {
            Random rnd = new Random();
            string str = "{Hello|Hi} {World|People}! {C{#|++|}|Java} is an {awesome|amazing} language.";
            Console.WriteLine(spintax(rnd, str));
            Console.ReadLine();
        }
    }
}

The output is, in one example run

Hello World! C# is an awesome language.

Answer 2

I'd be inclined to create a recursive method to handle the parsing. Write a method that takes a string, scans for first level braces, and makes the random selections from the enclosed options. The method would then call itself with the selected option string before inserting it into the final result.