Part 1: Expand Binding::val() into Binding::{into_*,as_*}.

This is simply for completeness: we should provide fundamental
conversion patterns even when they are mostly unused in our code base.

core/src/types.rs

@@ -8,6 +8,10 @@
 // CONDITIONS OF ANY KIND, either express or implied. See the License for the
 // specific language governing permissions and limitations under the License.
 
+use ::std::convert::{
+    AsRef,
+};
+
 use ::std::ffi::{
     CString,
 };
@@ -282,12 +286,47 @@ impl From<Vec<Binding>> for Binding {
 }
 
 impl Binding {
-    pub fn val(self) -> Option<TypedValue> {
+    pub fn into_scalar(self) -> Option<TypedValue> {
         match self {
             Binding::Scalar(v) => Some(v),
             _ => None,
         }
     }
+
+    pub fn into_vec(self) -> Option<ValueRc<Vec<Binding>>> {
+        match self {
+            Binding::Vec(v) => Some(v),
+            _ => None,
+        }
+    }
+
+    pub fn into_map(self) -> Option<ValueRc<StructuredMap>> {
+        match self {
+            Binding::Map(v) => Some(v),
+            _ => None,
+        }
+    }
+
+    pub fn as_scalar(&self) -> Option<&TypedValue> {
+        match self {
+            &Binding::Scalar(ref v) => Some(v),
+            _ => None,
+        }
+    }
+
+    pub fn as_vec(&self) -> Option<&Vec<Binding>> {
+        match self {
+            &Binding::Vec(ref v) => Some(v),
+            _ => None,
+        }
+    }
+
+    pub fn as_map(&self) -> Option<&StructuredMap> {
+        match self {
+            &Binding::Map(ref v) => Some(v),
+            _ => None,
+        }
+    }
 }
 
 /// A pull expression expands a binding into a structure. The returned structure
@@ -379,15 +418,15 @@ impl TypedValue {
     /// Construct a new `TypedValue::Keyword` instance by cloning the provided
     /// values and wrapping them in a new `ValueRc`. This is expensive, so this might
     /// be best limited to tests.
-    pub fn typed_ns_keyword(ns: &str, name: &str) -> TypedValue {
+    pub fn typed_ns_keyword<S: AsRef<str>, T: AsRef<str>>(ns: S, name: T) -> TypedValue {
-        Keyword::namespaced(ns, name).into()
+        Keyword::namespaced(ns.as_ref(), name.as_ref()).into()
     }
 
     /// Construct a new `TypedValue::String` instance by cloning the provided
     /// value and wrapping it in a new `ValueRc`. This is expensive, so this might
     /// be best limited to tests.
-    pub fn typed_string(s: &str) -> TypedValue {
+    pub fn typed_string<S: AsRef<str>>(s: S) -> TypedValue {
-        s.into()
+        s.as_ref().into()
     }
 
     pub fn current_instant() -> TypedValue {
@@ -736,6 +775,62 @@ impl Binding {
             _ => None,
         }
     }
+
+    pub fn as_entid(&self) -> Option<&Entid> {
+        match self {
+            &Binding::Scalar(TypedValue::Ref(ref v)) => Some(v),
+            _ => None,
+        }
+    }
+
+    pub fn as_kw(&self) -> Option<&ValueRc<Keyword>> {
+        match self {
+            &Binding::Scalar(TypedValue::Keyword(ref v)) => Some(v),
+            _ => None,
+        }
+    }
+
+    pub fn as_boolean(&self) -> Option<&bool> {
+        match self {
+            &Binding::Scalar(TypedValue::Boolean(ref v)) => Some(v),
+            _ => None,
+        }
+    }
+
+    pub fn as_long(&self) -> Option<&i64> {
+        match self {
+            &Binding::Scalar(TypedValue::Long(ref v)) => Some(v),
+            _ => None,
+        }
+    }
+
+    pub fn as_double(&self) -> Option<&f64> {
+        match self {
+            &Binding::Scalar(TypedValue::Double(ref v)) => Some(&v.0),
+            _ => None,
+        }
+    }
+
+    pub fn as_instant(&self) -> Option<&DateTime<Utc>> {
+        match self {
+            &Binding::Scalar(TypedValue::Instant(ref v)) => Some(v),
+            _ => None,
+        }
+    }
+
+    pub fn as_string(&self) -> Option<&ValueRc<String>> {
+        match self {
+            &Binding::Scalar(TypedValue::String(ref v)) => Some(v),
+            _ => None,
+        }
+    }
+
+    pub fn as_uuid(&self) -> Option<&Uuid> {
+        match self {
+            &Binding::Scalar(TypedValue::Uuid(ref v)) => Some(v),
+            _ => None,
+        }
+    }
 }
 
 #[test]

src/query.rs

@@ -234,7 +234,7 @@ pub fn lookup_value<'sqlite, 'schema, 'cache, E, A>
         fetch_values(sqlite, known, entid, attrid, true)
             .into_scalar_result()
             // Safe to unwrap: we never retrieve structure.
-            .map(|r| r.map(|v| v.val().unwrap()))
+            .map(|r| r.map(|v| v.into_scalar().unwrap()))
     }
 }
 
@@ -256,7 +256,7 @@ pub fn lookup_values<'sqlite, E, A>
         fetch_values(sqlite, known, entid, attrid, false)
             .into_coll_result()
             // Safe to unwrap: we never retrieve structure.
-            .map(|v| v.into_iter().map(|x| x.val().unwrap()).collect())
+            .map(|v| v.into_iter().map(|x| x.into_scalar().unwrap()).collect())
     }
 }
 

src/store.rs

@@ -609,7 +609,7 @@ mod tests {
                 let mut builder = in_progress.builder().describe_tempid(&name);
                 builder.add(kw!(:todo/uuid), TypedValue::Uuid(uuid)).expect("Expected added uuid");
                 changeset.insert(uuid_entid.clone());
-                builder.add(kw!(:todo/name), TypedValue::typed_string(&name)).expect("Expected added name");
+                builder.add(kw!(:todo/name), TypedValue::typed_string(name)).expect("Expected added name");
                 changeset.insert(name_entid.clone());
                 if i % 2 == 0 {
                     builder.add(kw!(:todo/completion_date), TypedValue::current_instant()).expect("Expected added date");
@@ -678,7 +678,7 @@ mod tests {
             for i in 0..3 {
                 let name = format!("label{}", i);
                 let mut builder = in_progress.builder().describe_tempid(&name);
-                builder.add(kw!(:label/name), TypedValue::typed_string(&name)).expect("Expected added name");
+                builder.add(kw!(:label/name), TypedValue::typed_string(name)).expect("Expected added name");
                 builder.add(kw!(:label/color), TypedValue::typed_string("blue")).expect("Expected added color");
                 let (ip, _) = builder.transact();
                 in_progress = ip;

src/vocabulary.rs

@@ -227,7 +227,7 @@ pub struct Definition {
 ///                     for row in results.into_iter() {
 ///                         let mut r = row.into_iter();
 ///                         let e = r.next().and_then(|e| e.into_known_entid()).expect("entity");
-///                         let obsolete = r.next().expect("value").val().expect("typed value");
+///                         let obsolete = r.next().expect("value").into_scalar().expect("typed value");
 ///                         builder.retract(e, link_title, obsolete)?;
 ///                     }
 ///                     ip.transact_builder(builder)?;

tests/pull.rs

@@ -86,7 +86,7 @@ fn test_simple_pull() {
                                       .expect("hoods")
                                       .into_iter()
                                       .map(|b| {
-                                          b.val().and_then(|tv| tv.into_entid()).expect("scalar")
+                                          b.into_scalar().and_then(|tv| tv.into_entid()).expect("scalar")
                                       })
                                       .collect();
 

tests/vocabulary.rs

@@ -350,7 +350,7 @@ fn av(row: Vec<Binding>) -> (KnownEntid, TypedValue) {
     let mut row = row.into_iter();
     match (row.next(), row.next()) {
         (Some(Binding::Scalar(TypedValue::Ref(a))), Some(v)) => {
-            (KnownEntid(a), v.val().unwrap())
+            (KnownEntid(a), v.into_scalar().unwrap())
         },
         _ => panic!("Incorrect query shape for 'av' helper."),
     }