To summarize a phone call today, the more intelligent defaults we add to
differently named rule keywords the more comfortable I am with having
different names. So, here's what we have so far (posted both as an FYI
and to confirm that we have the coherent solution I think we have):
rule:
- Has :ratchet and :skip turned on by default
- May only be used inside a grammar
- Takes default modifiers (a.k.a. traits) from the grammar in which it
is defined
- Is inherited by subclasses of a grammar
- The default modifiers can be turned off by :!ratchet and :!skip both
for individual rules and for an entire grammar (I'd like to see some
syntax for this)
regex:
- Has no modifiers turned on by default
- May be used inside and outside a grammar
- Inside a grammar, it is not inherited by subclasses of the grammar
- Inside a grammar, it does not take default modifiers from the grammar
- Individual regexen can turn on the :ratchet or :skip modifiers
token:
- Has :ratchet turned on by default
- Is inherited by subclasses of a grammar
- Does not take default modifiers from the grammar
- Individual token rules can turn off the :ratchet modifier with
:!ratchet, and can turn on :skip
- (I'd still like to see more for token, perhaps some optimizations that
are possible when you're certain you have a terminal, like "cannot call
subrules")
skip:
- We keep :words as shorthand for :skip(/<ws>/)
- And :skip is shorthand for :skip(/<skip>/)
- To change skipping behavior: a) override <skip> in your grammar, b)
set :skip(/.../) on an individual rule, or c) set 'is skip(/.../)' on a
grammar
- <ws> is optional whitespace, following skippy behavior (and it always
behaves the same no matter what the current :skip pattern is)
- <sp> is a single character of obligatory whitespace
Allison
--
"E pur si muove!"
-- apocryphally attributed to Galileo Galilei
