Message from JavaScript discussions
August 2017
— So if you have <w{5}> how can you tell it derives the same string as /hello/ without passing in any data or otherwise running the regular expression builtins? You do simple comparison operators on the transition ranges between the nodes, very simple!
All ranges for the first one would be {0, 65535} whereas for the second one it would vary... {72, 72} and then {69, 69} etc... since the ranges of the second expression fit into the ranges of the first you can say "Yes, these two expressions can derive the same string". If you want a strict result that says "these two expressions derive the same EXACT strings, no more and no less", then you can do a direct strict equality comparison instead
— Ah.
— Thanks
— This is, again, for /hello/ except showing the code points:
-->(s1)-72->(s2)-69->(s3)-76->(s4)-76->(s5)-79->((s6))
and here's what
<w{5}> looks like:-->(s1)-0,65535->(s2)-0,65535->(s3)-0,65535->(s4)-0,65535->(s5)-0,65535->((s6))
— Not yet but I might
— For now I just made a simple DFA which can function just like a regex
— Parsing the regex to the DFA is another story... haha
— Deterministic finite automata are a form of tree automation, it's how CPU's work on a low level and also parsers
— A parser will use DFA/NFA to parse code one symbol at a time
— For my use case you can tell if two totally different regex can derive the same strings
— So like diffRegex(myRegex1, myRegex2); // true would be the desired result