parser: refactor grammar to banish #[] etc.

Turns out we have an over-eager parser whcih recognizes
invalid notion such as #[...], #S[...] and others.
This is because the grammar nonterminal list is overloaded
with phrase structures. The syntax of a vector literal,
for instance, is '#' list, but a list can be '[' ...
and other expressions.

* parser.y (dwim, meta, compound): New non-terminal symbols.
Dwim derives the square bracketed "dwim" expressons that were
previously overloaded into list. Meta derives the @ exprs.
compound is what list used to be.
(list): Handle only (...) list expressions.
(o_elem, modifiers): Derives compound rather than list, thus
preserving existing behavior.
(i_expr, n_expr): Likewise.
All other uses references to the list nonterminal
stay, thereby trimming the grammar of dubious expressions.

0 files changed, 0 insertions, 0 deletions