From 45829580113f577a9ce2460dcdbf39700442b9c5 Mon Sep 17 00:00:00 2001
From: Devin Yeung <devin.cg.yeung.dev@outlook.com>
Date: Sat, 18 Nov 2023 22:47:43 +0800
Subject: [PATCH] refactor: factor out `epsilon()`

---
 src/utils/first/builder.rs | 8 +-------
 src/utils/mod.rs           | 6 ++++++
 2 files changed, 7 insertions(+), 7 deletions(-)

diff --git a/src/utils/first/builder.rs b/src/utils/first/builder.rs
index 4d007fc..8a12ef8 100644
--- a/src/utils/first/builder.rs
+++ b/src/utils/first/builder.rs
@@ -1,15 +1,9 @@
 use crate::utils::first::First;
-use crate::utils::symbols;
+use crate::utils::{epsilon, symbols};
 use bnf::{Grammar, Production, Term};
-use once_cell::sync::OnceCell;
 use std::cell::RefCell;
 use std::collections::{HashMap, HashSet};
 
-pub fn epsilon() -> &'static Term {
-    static EPSILON: OnceCell<Term> = OnceCell::new();
-    EPSILON.get_or_init(|| Term::Terminal(String::from("ε")))
-}
-
 pub struct FirstBuilder<'grammar> {
     pub(crate) grammar: &'grammar Grammar,
     pub(crate) first: RefCell<HashMap<&'grammar Term, HashSet<&'grammar Term>>>,
diff --git a/src/utils/mod.rs b/src/utils/mod.rs
index 47fc680..72d192e 100644
--- a/src/utils/mod.rs
+++ b/src/utils/mod.rs
@@ -1,4 +1,5 @@
 use bnf::{Grammar, Term};
+use once_cell::sync::OnceCell;
 use std::collections::HashSet;
 
 pub mod builder;
@@ -13,3 +14,8 @@ pub fn symbols(grammar: &Grammar) -> HashSet<&Term> {
         .flat_map(|expr| expr.terms_iter())
         .collect::<HashSet<_>>()
 }
+
+pub fn epsilon() -> &'static Term {
+    static EPSILON: OnceCell<Term> = OnceCell::new();
+    EPSILON.get_or_init(|| Term::Terminal(String::from("ε")))
+}