Pre: add Variable::from_valid_name, TypedValue::{typed_string,typed_ns_keyword}.

core/src/lib.rs

@@ -93,6 +93,20 @@ impl TypedValue {
             &TypedValue::Keyword(_) => ValueType::Keyword,
         }
     }
+
+    /// Construct a new `TypedValue::Keyword` instance by cloning the provided
+    /// values. This is expensive, so this might
+    /// be best limited to tests.
+    pub fn typed_ns_keyword(ns: &str, name: &str) -> TypedValue {
+        TypedValue::Keyword(NamespacedKeyword::new(ns, name))
+    }
+
+    /// Construct a new `TypedValue::String` instance by cloning the provided
+    /// value. This is expensive, so this might
+    /// be best limited to tests.
+    pub fn typed_string(s: &str) -> TypedValue {
+        TypedValue::String(s.to_string())
+    }
 }
 
 // Put this here rather than in `db` simply because it's widely needed.
@@ -141,9 +155,9 @@ impl SQLValueType for ValueType {
 fn test_typed_value() {
     assert!(TypedValue::Boolean(false).is_congruent_with(None));
     assert!(TypedValue::Boolean(false).is_congruent_with(ValueType::Boolean));
-    assert!(!TypedValue::String("foo".to_string()).is_congruent_with(ValueType::Boolean));
-    assert!(TypedValue::String("foo".to_string()).is_congruent_with(ValueType::String));
-    assert!(TypedValue::String("foo".to_string()).is_congruent_with(None));
+    assert!(!TypedValue::typed_string("foo").is_congruent_with(ValueType::Boolean));
+    assert!(TypedValue::typed_string("foo").is_congruent_with(ValueType::String));
+    assert!(TypedValue::typed_string("foo").is_congruent_with(None));
 }
 
 /// Bit flags used in `flags0` column in temporary tables created during search,

query/src/lib.rs

@@ -44,6 +44,27 @@ pub type SrcVarName = String;          // Do not include the required syntactic
 #[derive(Clone, PartialEq, Eq, PartialOrd, Ord)]
 pub struct Variable(pub PlainSymbol);
 
+impl Variable {
+    pub fn as_str(&self) -> &str {
+        (self.0).0.as_str()
+    }
+
+    pub fn to_string(&self) -> String {
+        (self.0).0.clone()
+    }
+
+    pub fn name(&self) -> PlainSymbol {
+        self.0.clone()
+    }
+
+    /// Return a new `Variable`, assuming that the provided string is a valid name.
+    pub fn from_valid_name(name: &str) -> Variable {
+        let s = PlainSymbol::new(name);
+        assert!(s.is_var_symbol());
+        Variable(s)
+    }
+}
+
 pub trait FromValue<T> {
     fn from_value(v: &edn::Value) -> Option<T>;
 }