fluencelabs/lalrpop
1
0
Fork 0
mirror of https://github.com/fluencelabs/lalrpop synced 2025-03-16 17:00:53 +00:00
Code Issues Projects Releases Wiki Activity

Collect the states when failure occurs in LR(1) construction

Browse Source
This commit is contained in:
Niko Matsakis 2016-02-01 13:59:59 -05:00
parent e6b057f551
commit e45d27bc3d
3 changed files with 22 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
lalrpop/src/lr1/core/mod.rs
View File

@ -88,6 +88,8 @@ impl<'session, 'grammar> LR1<'session, 'grammar> {
let prev = this_state.tokens.insert(item.lookahead, action);
if let Some(conflict) = prev {
return Err(TableConstructionError {
states: Some(states),
index: index,
items: items.clone(),
lookahead: item.lookahead,
production: item.production,

7
lalrpop/src/lr1/la0/mod.rs
View File

@ -93,7 +93,7 @@ pub fn collapse_to_lalr_states<'grammar>(lr_states: &[State<'grammar>])
Entry::Occupied(slot) => {
let old_action = *slot.get();
if old_action != lalr1_action {
return Err(conflict(&lalr1_state.items, lookahead,
return Err(conflict(lalr1_index, &lalr1_state.items, lookahead,
old_action, lalr1_action));
}
}
@ -130,7 +130,8 @@ pub fn collapse_to_lalr_states<'grammar>(lr_states: &[State<'grammar>])
.collect())
}
fn conflict<'grammar>(items: &[Item<'grammar>],
fn conflict<'grammar>(index: StateIndex,
items: &[Item<'grammar>],
lookahead: Lookahead,
action1: Action<'grammar>,
action2: Action<'grammar>)
@ -145,6 +146,8 @@ fn conflict<'grammar>(items: &[Item<'grammar>],
};
TableConstructionError {
states: None,
index: index,
items: Items { vec: Rc::new(items.to_vec()) },
lookahead: lookahead,
production: production,

15
lalrpop/src/lr1/mod.rs
View File

@ -55,6 +55,21 @@ struct Item<'grammar> {
#[derive(Debug)]
pub struct TableConstructionError<'grammar> {
// completed states: note that these may reference states that
// were never processed, so you can't follow outgoing edges with
// impunity.
//
// This is optional because, in the current LALR(1) code, we don't
// have a notion of "complete" states to supply. Really we should
// special case the error reporting there. Or, better yet, make
// the LR(1) -> LALR(1) compression infallible, by just detecting
// when it's going to work. (Or, the other way, only use the full
// LR(1) when needed.)
states: Option<Vec<State<'grammar>>>,
// state index where we encountered a failure
index: StateIndex,
// when in this state:
items: Items<'grammar>,