On Mon, Aug 23, 2010 at 8:07 AM, Richard O'Keefe
But what _is_ "the core functionality". The Single Unix Specification can be browsed on-line. There is no part of it labelled "core"; it's all required or it isn't AWK. There are weird little gotchas like File "foo" = '{ prin' File "bar" = 't 2 }' awk -f foo -f bar is legal and is required to act the same as awk '{ print 2 }' mawk fails this, and I don't blame it, and I don't really _care_. Is that "core"? Who knows?
I say that that behaviour is not part of the language but of the runtime.
Whatever the "core functionality" might be, YOU will have to define what that "core" is. There's no standard, or even common, sublanguage.
One approach to find the core of a language is to find which parts can be implemented in terms of other parts. If part B can be expressed in terms of part A then B doesn't belong in the core.