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Merge pull request #208 from wieczyk/issue203_enable_constructing_lr1_states_via_envvar

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Enabling lane-table-algorithm via environment variable
This commit is contained in:
Niko Matsakis 2017-03-29 07:50:57 -06:00 committed by GitHub
commit 6f12cfe41b
1 changed files with 22 additions and 10 deletions
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32
lalrpop/src/lr1/build/mod.rs
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@ -8,29 +8,41 @@ use lr1::first;
use lr1::lane_table::*;
use lr1::lookahead::*;
use std::rc::Rc;
use std::env;
use tls::Tls;
#[cfg(test)]
mod test;
fn build_lr1_states_legacy<'grammar>(grammar: &'grammar Grammar, start: NonterminalString) -> LR1Result<'grammar>
{
let eof = TokenSet::eof();
let mut lr1: LR<'grammar, TokenSet> = LR::new(grammar, start, eof);
lr1.set_permit_early_stop(true);
lr1.build_states()
}
type ConstructionFunction<'grammar> = fn(&'grammar Grammar, NonterminalString) -> LR1Result<'grammar> ;
pub fn build_lr1_states<'grammar>(grammar: &'grammar Grammar,
start: NonterminalString)
-> LR1Result<'grammar>
{
// this is just here to squash dead code warnings while work on
// lane-table proceeds
if false {
let _ = build_lane_table_states(grammar, start);
}
let (method_name, method_fn) = match env::var("LALRPOP_LANE_TABLE") {
Ok(ref s) if s == "enabled" => {
("lane", build_lane_table_states as ConstructionFunction)
}
_ => {
("legacy", build_lr1_states_legacy as ConstructionFunction)
}
};
profile! {
&Tls::session(),
"LR(1) state construction",
format!("LR(1) state construction ({})", method_name),
{
let eof = TokenSet::eof();
let mut lr1: LR<'grammar, TokenSet> = LR::new(grammar, start, eof);
lr1.set_permit_early_stop(true);
lr1.build_states()
method_fn(grammar, start)
}
}
}