Module isla_lib::zencode

This module implements the name mangling scheme used by Sail

It allows all ASCII strings to be represented using just the characters allowed in C identifers. The way it works is all characters that are not allowed in C identifiers are encoded as zX where X is some C allowed character. The letter z is encoded as zz. Additionally a ‘z’ prefix is placed at the start of the string. This prefix allows us to undo multiple rounds of encoding, which can happen when Sail does multiple rounds of monomorphisation. This works as we can decode until either the string has no z prefix or zz, in which case we can do one more decode step and the first letter of the original string was z.

We could adapt this to support unicode by having something like zu<codepoint> for each unicode character, but as Sail does not allow unicode identifiers this is not supported at the moment.

The inspiration for this name-mangling scheme is GHC, see: https://gitlab.haskell.org/ghc/ghc/-/wikis/commentary/compiler/symbol-names

Functions

decode
encode