diff --git a/tor-netdoc/src/parse.rs b/tor-netdoc/src/parse.rs
index 204b85208..80542287b 100644
--- a/tor-netdoc/src/parse.rs
+++ b/tor-netdoc/src/parse.rs
@@ -149,38 +149,6 @@ impl<'a, T: Keyword> Section<'a, T> {
     }
 }
 
-/// Check whether a single Item matches a TokenFmt rule, with respect
-/// to its number of arguments.
-///
-/// TODO: Move this to rules?
-fn item_matches_fmt_args<'a, T: Keyword>(t: T, fmt: &TokenFmt<T>, item: &Item<'a>) -> Result<()> {
-    let n_args = item.n_args();
-    if let Some(max) = fmt.max_args {
-        if n_args > max {
-            return Err(Error::TooManyArguments(t.to_str(), item.pos()));
-        }
-    }
-    if let Some(min) = fmt.min_args {
-        if n_args < min {
-            return Err(Error::TooFewArguments(t.to_str(), item.pos()));
-        }
-    }
-
-    Ok(())
-}
-
-/// Check whether a single Item matches a TokenFmt rule, with respect
-/// to its object's presence and type.
-///
-/// TODO: Move this to rules?
-fn item_matches_fmt_obj<'a, T: Keyword>(t: T, fmt: &TokenFmt<T>, item: &Item<'a>) -> Result<()> {
-    match (&fmt.obj, item.has_obj()) {
-        (ObjKind::NoObj, true) => Err(Error::UnexpectedObject(t.to_str(), item.pos())),
-        (ObjKind::RequireObj, false) => Err(Error::MissingObject(t.to_str(), item.pos())),
-        (_, _) => Ok(()),
-    }
-}
-
 impl<T: Keyword> SectionRules<T> {
     /// Create a new SectionRules with no rules.
     ///
@@ -265,8 +233,7 @@ impl<T: Keyword> SectionRules<T> {
                     // The number is right. Check each individual item.
                     for item in t.as_slice() {
                         let tok = T::from_idx(idx).unwrap();
-                        item_matches_fmt_args(tok, rule, item)?;
-                        item_matches_fmt_obj(tok, rule, item)?;
+                        rule.check_item(tok, item)?
                     }
                 }
             }
diff --git a/tor-netdoc/src/rules.rs b/tor-netdoc/src/rules.rs
index f16f78f5b..ea89a210a 100644
--- a/tor-netdoc/src/rules.rs
+++ b/tor-netdoc/src/rules.rs
@@ -1,3 +1,5 @@
+use crate::tokenize::Item;
+use crate::{Error, Result};
 use std::hash::Hash;
 
 pub trait Keyword: Hash + Eq + PartialEq + Copy + Clone {
@@ -24,11 +26,49 @@ pub enum ObjKind {
 #[derive(Clone)]
 pub struct TokenFmt<T: Keyword> {
     pub kwd: T,
-    pub min_args: Option<usize>,
-    pub max_args: Option<usize>,
+    min_args: Option<usize>,
+    max_args: Option<usize>,
     pub required: bool,
     pub may_repeat: bool,
-    pub obj: ObjKind,
+    obj: ObjKind,
+}
+
+impl<T: Keyword> TokenFmt<T> {
+    /// Check whether a single Item matches this TokenFmt rule, with respect
+    /// to its number of arguments.
+    fn item_matches_args<'a>(&self, t: T, item: &Item<'a>) -> Result<()> {
+        let n_args = item.n_args();
+        if let Some(max) = self.max_args {
+            if n_args > max {
+                return Err(Error::TooManyArguments(t.to_str(), item.pos()));
+            }
+        }
+        if let Some(min) = self.min_args {
+            if n_args < min {
+                return Err(Error::TooFewArguments(t.to_str(), item.pos()));
+            }
+        }
+        Ok(())
+    }
+
+    /// Check whether a single Item matches a TokenFmt rule, with respect
+    /// to its object's presence and type.
+    ///
+    /// TODO: Move this to rules?
+    fn item_matches_obj<'a>(&self, t: T, item: &Item<'a>) -> Result<()> {
+        match (&self.obj, item.has_obj()) {
+            (ObjKind::NoObj, true) => Err(Error::UnexpectedObject(t.to_str(), item.pos())),
+            (ObjKind::RequireObj, false) => Err(Error::MissingObject(t.to_str(), item.pos())),
+            (_, _) => Ok(()),
+        }
+    }
+
+    /// Check whether a single item has the right number of arguments
+    /// and object.
+    pub fn check_item<'a>(&self, t: T, item: &Item<'a>) -> Result<()> {
+        self.item_matches_args(t, item)?;
+        self.item_matches_obj(t, item)
+    }
 }
 
 pub struct TokenFmtBuilder<T: Keyword>(TokenFmt<T>);