summaryrefslogtreecommitdiff
path: root/grammar/src/lib.rs
diff options
context:
space:
mode:
Diffstat (limited to 'grammar/src/lib.rs')
-rw-r--r--grammar/src/lib.rs83
1 files changed, 79 insertions, 4 deletions
diff --git a/grammar/src/lib.rs b/grammar/src/lib.rs
index 297cb66..50a2b9b 100644
--- a/grammar/src/lib.rs
+++ b/grammar/src/lib.rs
@@ -320,11 +320,39 @@ impl Grammar {
self.accumulators.last().copied().unwrap_or(0)
}
+ /// Return an element of the accumulator.
+ #[inline]
+ pub fn nth_accumulator(&self, n: usize) -> Result<usize, Error> {
+ self.accumulators
+ .get(n)
+ .copied()
+ .ok_or_else(|| Error::IndexOutOfBounds(n, self.total()))
+ }
+
+ /// Return the index of the rules a rule position belongs to.
+ #[inline]
+ pub fn get_rule_num(&self, pos: usize) -> Result<usize, Error> {
+ let mut result = None;
+
+ for (index, accumulator) in self.accumulators.iter().copied().skip(1).enumerate() {
+ if accumulator > pos {
+ result = Some(index);
+ break;
+ }
+ }
+
+ if let Some(n) = result {
+ Ok(n)
+ } else {
+ Err(Error::IndexOutOfBounds(pos, self.total()))
+ }
+ }
+
/// Query if a position is the starting position of a
/// non-terminal. If it is, return the non-terminal, else return
/// `None` .
#[inline]
- pub fn is_nt_start_in_nfa_p(&self, pos: usize) -> Option<usize> {
+ pub fn get_nt_start_in_nfa(&self, pos: usize) -> Option<usize> {
for (index, accumulator) in self.accumulators.iter().copied().enumerate() {
let shifted_accumulator = accumulator << 1;
@@ -456,7 +484,7 @@ impl Grammar {
}
}
- Ok(self.expansion_map.get(&(pos1, pos2)).map(|v| &v[..]))
+ Ok(self.expansion_map.get(&(pos1, pos2)).map(|v| v.as_ref()))
}
// REVIEW: Do we have a better way to record expansion information
@@ -483,7 +511,11 @@ impl Grammar {
&mut self,
two_edges: TwoEdges<LabelType<TNT>>,
) -> LabelType<TNT> {
+ #[cfg(debug_assertions)]
let (first_source, first_target, first_label) = two_edges.first_edge();
+ #[cfg(not(debug_assertions))]
+ let (first_source, _, first_label) = two_edges.first_edge();
+
let (second_source, second_target, second_label) = two_edges.second_edge();
#[cfg(debug_assertions)]
@@ -501,11 +533,11 @@ impl Grammar {
// that is to say, the source of the second edge is the
// starting edge of a non-terminal.
- let mut left_p = first_label.get_left_p() || second_label.get_left_p();
+ let mut left_p = first_label.is_left_p() || second_label.is_left_p();
// Record left-linear expansion information.
- if let Some(second_nt) = self.is_nt_start_in_nfa_p(second_source) {
+ if let Some(second_nt) = self.get_nt_start_in_nfa(second_source) {
left_p = true;
if !self
@@ -554,12 +586,55 @@ impl Grammar {
.ok_or(Error::IndexOutOfBounds(non_terminal, self.non.len()))?
.iter())
}
+
+ /// Return a string describing a rule position.
+ pub fn rule_pos_to_string(&self, pos: usize) -> Result<String, Error> {
+ let rule_num = {
+ let mut result = None;
+
+ for (index, accumulator) in self.accumulators.iter().copied().skip(1).enumerate() {
+ if accumulator > pos {
+ result = Some(index);
+ break;
+ }
+ }
+
+ if let Some(n) = result {
+ n
+ } else {
+ return Err(Error::IndexOutOfBounds(pos, self.total()));
+ }
+ };
+
+ assert!(rule_num < self.rules.len());
+
+ let display_tnt = |tnt| self.name_of_tnt(tnt).unwrap_or_else(|e| format!("{e}"));
+
+ Ok(self
+ .rules
+ .get(rule_num)
+ .unwrap()
+ .regex
+ .to_string_with_dot(
+ display_tnt,
+ if rule_num == 0 {
+ pos
+ } else {
+ pos - self.accumulators.get(rule_num - 1).copied().unwrap()
+ },
+ )
+ .unwrap())
+ }
}
pub mod first_set;
pub mod left_closure;
+pub mod label;
+
+pub use label::{GrammarLabel, GrammarLabelType};
+
impl Display for Grammar {
fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
assert_eq!(self.non.len(), self.rules.len());