repaired comments where SOMEthing went utterly wrong (cf. 2b04504fcb69)
Pure: The Pure Isabelle System
This directory contains the ML source files for Pure Isabelle, which
is the basis for all object-logics. The Isabelle/Pure image may be
compiled in batch mode like this:
isabelle make Pure
Developers may want to produce a RAW image that merely consists of the
ML compiler with the compatibility setup of ML-Systems/ preloaded:
isabelle make RAW
Now the Pure session may be compiled interactively as follows:
isabelle tty -l RAW
use "ROOT.ML";