3 files changed, 49 insertions, 5 deletions
diff --git a/grammar/src/abnf/mod.rs b/grammar/src/abnf/mod.rs
index b53dcc1..2e2d0f2 100644
--- a/grammar/src/abnf/mod.rs
+++ b/grammar/src/abnf/mod.rs
@@ -2439,9 +2439,9 @@ impl std::str::FromStr for Grammar {
                 break;
             }
 
-            if appending_p && nonterminals_map.get(&rule_name).is_none() {
+            if appending_p && !nonterminals_map.contains_key(&rule_name) {
                 return Err(Error::AppendToNothing(current_skipped_index));
-            } else if !appending_p && nonterminals_map.get(&rule_name).is_some() {
+            } else if !appending_p && nonterminals_map.contains_key(&rule_name) {
                 return Err(Error::CreateAgain(current_skipped_index));
             }
 
@@ -2473,13 +2473,13 @@ impl std::str::FromStr for Grammar {
             for data in rule_data {
                 match data {
                     IntermediateConstruct::Terminal(name) => {
-                        if terminals_map.get(&name).is_none() {
+                        if !terminals_map.contains_key(&name) {
                             terminals_map.insert(name.clone(), terminals_vec.len());
                             terminals_vec.push(name);
                         }
                     }
                     IntermediateConstruct::Nonterminal(name) => {
-                        if nonterminals_map.get(&name).is_none() {
+                        if !nonterminals_map.contains_key(&name) {
                             return Err(Error::UnknownNonterminal(name));
                         }
                     }
diff --git a/grammar/src/lib.rs b/grammar/src/lib.rs
index 64f4cdb..79c19e0 100644
--- a/grammar/src/lib.rs
+++ b/grammar/src/lib.rs
@@ -68,6 +68,13 @@ impl Nonterminal {
     pub fn name(&self) -> &str {
         &self.0
     }
+
+    /// A public constructor for the purposes of easy grammar
+    /// constructions.
+    #[inline]
+    pub fn new(name: String) -> Self {
+        Self(name)
+    }
 }
 
 /// The type of a terminal or a non-terminal.
@@ -82,6 +89,16 @@ pub enum TNT {
     Non(usize),
 }
 
+impl TNT {
+    /// Retrieve the index of this enum.
+    pub fn value(&self) -> usize {
+        match self {
+            Self::Ter(index) => *index,
+            Self::Non(index) => *index,
+        }
+    }
+}
+
 impl Display for TNT {
     fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
         match self {
@@ -881,6 +898,33 @@ impl Grammar {
             )
             .unwrap())
     }
+
+    /// Print the names of terminals and non-terminals into a given
+    /// file.
+    pub fn print_tnt(&self, file_name: &str) -> Result<(), String> {
+        let mut fs = std::fs::OpenOptions::new()
+            .write(true)
+            .create(true)
+            .truncate(true)
+            .open(file_name)
+            .map_err(|e| format!("{e}"))?;
+
+        use std::io::Write;
+
+        for (n, ter) in (0..(self.ter_num())).map(TNT::Ter).enumerate() {
+            let name = self.name_of_tnt(ter).unwrap();
+
+            writeln!(&mut fs, "{n}-th terminal: {name}").map_err(|e| format!("{e}"))?;
+        }
+
+        for (n, non) in (0..(self.non_num())).map(TNT::Non).enumerate() {
+            let name = self.name_of_tnt(non).unwrap();
+
+            writeln!(&mut fs, "{n}-th non-terminal: {name}").map_err(|e| format!("{e}"))?;
+        }
+
+        Ok(())
+    }
 }
 
 pub mod first_set;
diff --git a/grammar/src/test_grammar_helper.rs b/grammar/src/test_grammar_helper.rs
index 9d86865..8c9c2ed 100644
--- a/grammar/src/test_grammar_helper.rs
+++ b/grammar/src/test_grammar_helper.rs
@@ -18,7 +18,7 @@ pub fn new_closure_regex(
 }
 
 /// A function to scan the inputs.
-fn scan_tnt(
+pub fn scan_tnt(
     parser: &DefaultRegParser<TNT>,
     input: &str,
 ) -> Result<Option<(usize, RegexType<TNT>, ParseDirection)>, ParseError> {