lookup tables

[Skaperen]

i don't require contiguous bytes. but since all the items are < 256, then bytes are usable and they can be contiguous. a contiguous lookup would be faster than, for example, a list of ints, which was in earlier code prototypes. the bytes type does look good in Python3. but in Python2, bytes == str. in some places i split the code based on Python2 vs. Python3, while i try to make most of the code work in both Python2 and Python3. my goal for my UTF-8 code and my Escape Sequence code is to make everything work in 2.7 and 3.x as much as i can.

one thing i am putting some thought into is whether someone might want to get UTF-8 results back in a byte type but had to give Unicode data in a type that supports the full range of Unicode code points (a list of ints in both versions, str in Python3, unicode in Python2). originally i was going to return the same type as given. going from UTF-8 to Unicode is easier to see. even if the UTF-8 is given as bytes, the Unicode result probably can't be, so i will need to return something bigger. going the other way has a different issue. if the Unicode is given as some large type (which the caller usually must do), is that the type they want UTF-8 in? or do they want it in a byte type. so i'm thinking of adding support for a returntype= option to let the caller specify.