handle/handleize filter doesn't return a Liquid-consistent value

[deanebarker]

The example on this page of the Liquid doc claims this --

{{ '100% M & Ms!!!' | handle }}

-- should output this:

100-m-ms

In Fluid v2.2.8, it does not. It outputs:

100% m & ms!!!

The Fluid implementation seems to be missing:

1. Removal of punctuation
2. Replacement of spaces with dashes

[deanebarker]

I'm happy to write a PR for this, for the record, but I don't understand the regex magic that's happening in there. If I write this, I'm just gonna iterate the characters via a Select or something.

[hishamco]

Please submit a PR, then we can review it

Thanks

[deanebarker]

Okay, this is not the PR or the actual function, but this is my logic. Before I go any further, let me know if this is fine.

(It's over-commented for clarity.)

string Handle(string input)
{
	const char SPACE = ' ';
	const char DASH = '-';
	
	var validChars = new List<char>();
	foreach(var character in input)
	{	
		// Only allow letters, numbers, spaces, or dashes
		if(!Char.IsLetterOrDigit(character) && character != SPACE && character != DASH)
		{
			continue;
		}
		
		// Don't allow consecutive spaces
		if(character == SPACE && validChars.LastOrDefault() == SPACE)
		{
			continue;
		}
		
		// Convert any whitespace (tabs, newlines, whatever) to a single space
		if(Char.IsWhiteSpace(character))
		{
			validChars.Add(SPACE);
			continue;
		}
		
		// Allow the character
		validChars.Add(character);
	}
	
	var newString = new String(validChars.ToArray());
	newString = newString.Trim(); // Clean whitespace
	newString = newString.Replace(SPACE, DASH); // Spaces become dashs
	newString = newString.ToLower(); // Everthing is lower-case
	
	return newString;
}

[deanebarker]

I fuzzed it and found a bug, which I corrected above (Last() needed to be LastOrDefault())

Incidentally, on my desktop machine I ran it on 10,000 random 30-character strings and it took 5ms total.

[hishamco]

Just a quick not StringBuilder is a better option for string manipulation, If you don't plan to create a PR, I will create a unit test first that fails, then I can start the PR

[deanebarker]

I did that at first. I can't check the last character with a StringBuilder, can I?

[deanebarker]

Here, I re-wrote it with a StringBuilder.

string Handle(string input)
{
	const char SPACE = ' ';
	const char DASH = '-';
	
	var validChars = new StringBuilder();
	var lastCharacter = '\0';
	foreach(var character in input)
	{	
		// Only allow letters, numbers, spaces, or dashes
		if(!Char.IsLetterOrDigit(character) && character != SPACE && character != DASH)
		{
			continue;
		}
		
		// Don't allow consecutive spaces
		if(character == SPACE && lastCharacter == SPACE)
		{
			continue;
		}
		
		// Convert any whitespace (tabs, newlines, whatever) to a single space
		if(Char.IsWhiteSpace(character))
		{
			lastCharacter = character;
			validChars.Append(SPACE);
			continue;
		}
		
		// Allow the character
		validChars.Append(character);
		lastCharacter = character;
	}
	
	var newString = validChars.ToString();
	newString = newString.Trim(); // Clean whitespace
	newString = newString.Replace(SPACE, DASH); // Spaces become dashs
	newString = newString.ToLower(); // Everthing is lower-case
	
	return newString;
}