Previously, the way repeat rules were expanded, the auxiliary
rule always needed to be reduced, even if the repeating content
was empty. This caused problems in parse states where some items
contained the repeat rule and some did not. To make those cases
work, the repeat rule had to explicitly be marked as optional.
With this change, that is no longer necessary.
This reverts commit 5cd07648fd.
The separators construct is useful as an optimization. It turns out that
constructing a node for every chunk of whitespace in a document causes a
significant performance regression.
Conflicts:
src/compiler/build_tables/build_lex_table.cc
src/compiler/grammar.cc
src/runtime/parser.c
Now, grammars can handle whitespace by making it another ubiquitous
token, like comments.
For now, this has the side effect of whitespace being included in the
tree that precedes it. This was already an issue for other ubiquitous
tokens though, so it needs to be fixed anyway.
Now, the root node of a document is always a document node.
It will often have only one child node which corresponds to the grammar's
start symbol, but not always. Currently, it may have more than one child
if there are ubiquitous tokens such as comments at the beginning of the
document. In the future, it will also be possible be possible to have multiple
for the document to have multiple children if the document is partially parsed.
Generated parsers no longer export a parser constructor function.
They now export an opaque Language object which can be set on
Documents directly. This way, the logic for constructing parsers
lives entirely in the runtime. The Languages are just structs which
have no load-time dependency on the runtime
Now, instead of adding states to the lex table as they are needed
by the parse states, we iterate over the parse states after the fact
and set up their corresponding lex states. This has the nice side
effect that the lex states are in a more readable order.
