#complexity O(n)
let strlen-nullterm =
	λ str : &[Char~Ascii~machine::Word]
	      ~ &<NullTerminatedSeq machine::Word>
		  ~ machine::Address
		  ~ machine::Word
	-> ℤ
	 ~ ℤ_2^64
	 ~ machine::UInt64
	 ~ machine::Word
{
	let mut len = 0;
	while ( @str ) {
		! len (i+ len 1);
		! str (i+ str 1);
	}
	len;
};

#complexity O(1)
let strlen-lenprefix =
	λ str : &[Char~Ascii~machine::Word]
	      ~ &<LenPrefixArray machine::Word>
		  ~ &{
			     len : ℤ_2^64
				     ~ machine::UInt64
					 ~ machine::Word,
				 data : [machine::Word]
		     }
		  ~ machine::Address
		  ~ machine::Word
	-> ℤ
	 ~ ℤ_2^64
	 ~ machine::UInt64
	 ~ machine::Word
{
	str.len
};