Add union helper macro and tests

README.md

@@ -127,8 +127,8 @@ as well.
     * [ ] Sending input objects and partial input objects in variables
     * [ ] Sending enums in variables
     * [ ] General input value type checking and validation
-* [ ] Improve helper macros
-    * [ ] `graphql_union!` helper completely missing
+* [X] Improve helper macros
+    * [X] `graphql_union!` helper completely missing
     * [X] `graphql_input_object!` helper completely missing
     * [X] Add support for deprecating things
     * [X] Custom enum values and descriptions

src/macros/mod.rs

@@ -5,5 +5,6 @@
 #[macro_use] mod args;
 #[macro_use] mod field;
 #[macro_use] mod input_object;
+#[macro_use] mod union;
 
 #[cfg(test)] mod tests;

src/macros/tests/mod.rs

@@ -5,3 +5,4 @@ mod args;
 mod field;
 mod object;
 mod interface;
+mod union;

src/macros/tests/union.rs

@@ -0,0 +1,219 @@
+use std::collections::HashMap;
+use std::marker::PhantomData;
+
+use ast::InputValue;
+use value::Value;
+use schema::model::RootNode;
+
+/*
+
+Syntax to validate:
+
+* Order of items: description, instance resolvers
+* Optional Generics/lifetimes
+* Custom name vs. default name
+* Optional commas between items
+* Optional trailing commas on instance resolvers
+
+ */
+
+struct Concrete;
+
+enum DefaultName { Concrete(Concrete) }
+
+enum WithLifetime<'a> { Int(PhantomData<&'a i64>) }
+enum WithGenerics<T> { Generic(T) }
+
+enum DescriptionFirst { Concrete(Concrete) }
+enum ResolversFirst { Concrete(Concrete) }
+
+enum CommasWithTrailing { Concrete(Concrete) }
+enum ResolversWithTrailingComma { Concrete(Concrete) }
+
+struct Root;
+
+graphql_object!(Concrete: () |&self| {
+    field simple() -> i64 { 123 }
+});
+
+graphql_union!(DefaultName: () |&self| {
+    instance_resolvers: |&_| {
+        Concrete => match *self { DefaultName::Concrete(ref c) => Some(c) }
+    }
+});
+
+graphql_union!(<'a> WithLifetime<'a>: () as "WithLifetime" |&self| {
+    instance_resolvers: |&_| {
+        Concrete => match *self { WithLifetime::Int(_) => Some(Concrete) }
+    }
+});
+
+graphql_union!(<T> WithGenerics<T>: () as "WithGenerics" |&self| {
+    instance_resolvers: |&_| {
+        Concrete => match *self { WithGenerics::Generic(_) => Some(Concrete) }
+    }
+});
+
+graphql_union!(DescriptionFirst: () |&self| {
+    description: "A description"
+    instance_resolvers: |&_| {
+        Concrete => match *self { DescriptionFirst::Concrete(ref c) => Some(c) }
+    }
+});
+
+graphql_union!(ResolversFirst: () |&self| {
+    instance_resolvers: |&_| {
+        Concrete => match *self { ResolversFirst::Concrete(ref c) => Some(c) }
+    }
+    description: "A description"
+});
+
+graphql_union!(CommasWithTrailing: () |&self| {
+    instance_resolvers: |&_| {
+        Concrete => match *self { CommasWithTrailing::Concrete(ref c) => Some(c) }
+    },
+    description: "A description",
+});
+
+graphql_union!(ResolversWithTrailingComma: () |&self| {
+    instance_resolvers: |&_| {
+        Concrete => match *self { ResolversWithTrailingComma::Concrete(ref c) => Some(c) },
+    }
+    description: "A description"
+});
+
+graphql_object!(<'a> Root: () as "Root" |&self| {
+    field default_name() -> DefaultName { DefaultName::Concrete(Concrete) }
+    field with_lifetime() -> WithLifetime<'a> { WithLifetime::Int(PhantomData) }
+    field with_generics() -> WithGenerics<i64> { WithGenerics::Generic(123) }
+    field description_first() -> DescriptionFirst { DescriptionFirst::Concrete(Concrete) }
+    field resolvers_first() -> ResolversFirst { ResolversFirst::Concrete(Concrete) }
+    field commas_with_trailing() -> CommasWithTrailing { CommasWithTrailing::Concrete(Concrete) }
+    field resolvers_with_trailing_comma() -> ResolversWithTrailingComma {
+        ResolversWithTrailingComma::Concrete(Concrete)
+    }
+});
+
+
+fn run_type_info_query<F>(type_name: &str, f: F)
+    where F: Fn(&HashMap<String, Value>, &Vec<Value>) -> ()
+{
+    let doc = r#"
+    query ($typeName: String!) {
+        __type(name: $typeName) {
+            name
+            description
+            possibleTypes {
+                name
+            }
+        }
+    }
+    "#;
+    let schema = RootNode::new(Root {}, ());
+    let vars = vec![
+        ("typeName".to_owned(), InputValue::string(type_name)),
+    ].into_iter().collect();
+
+    let (result, errs) = ::execute(doc, None, &schema, &vars, &())
+        .expect("Execution failed");
+
+    assert_eq!(errs, []);
+
+    println!("Result: {:?}", result);
+
+    let type_info = result
+        .as_object_value().expect("Result is not an object")
+        .get("__type").expect("__type field missing")
+        .as_object_value().expect("__type field not an object value");
+
+    let possible_types = type_info
+        .get("possibleTypes").expect("possibleTypes field missing")
+        .as_list_value().expect("possibleTypes field not a list value");
+
+    f(type_info, possible_types);
+}
+
+
+#[test]
+fn introspect_default_name() {
+    run_type_info_query("DefaultName", |union, possible_types| {
+        assert_eq!(union.get("name"), Some(&Value::string("DefaultName")));
+        assert_eq!(union.get("description"), Some(&Value::null()));
+
+        assert!(possible_types.contains(&Value::object(vec![
+            ("name", Value::string("Concrete")),
+        ].into_iter().collect())));
+    });
+}
+
+#[test]
+fn introspect_with_lifetime() {
+    run_type_info_query("WithLifetime", |union, possible_types| {
+        assert_eq!(union.get("name"), Some(&Value::string("WithLifetime")));
+        assert_eq!(union.get("description"), Some(&Value::null()));
+
+        assert!(possible_types.contains(&Value::object(vec![
+            ("name", Value::string("Concrete")),
+        ].into_iter().collect())));
+    });
+}
+
+#[test]
+fn introspect_with_generics() {
+    run_type_info_query("WithGenerics", |union, possible_types| {
+        assert_eq!(union.get("name"), Some(&Value::string("WithGenerics")));
+        assert_eq!(union.get("description"), Some(&Value::null()));
+
+        assert!(possible_types.contains(&Value::object(vec![
+            ("name", Value::string("Concrete")),
+        ].into_iter().collect())));
+    });
+}
+
+#[test]
+fn introspect_description_first() {
+    run_type_info_query("DescriptionFirst", |union, possible_types| {
+        assert_eq!(union.get("name"), Some(&Value::string("DescriptionFirst")));
+        assert_eq!(union.get("description"), Some(&Value::string("A description")));
+
+        assert!(possible_types.contains(&Value::object(vec![
+            ("name", Value::string("Concrete")),
+        ].into_iter().collect())));
+    });
+}
+
+#[test]
+fn introspect_resolvers_first() {
+    run_type_info_query("ResolversFirst", |union, possible_types| {
+        assert_eq!(union.get("name"), Some(&Value::string("ResolversFirst")));
+        assert_eq!(union.get("description"), Some(&Value::string("A description")));
+
+        assert!(possible_types.contains(&Value::object(vec![
+            ("name", Value::string("Concrete")),
+        ].into_iter().collect())));
+    });
+}
+
+#[test]
+fn introspect_commas_with_trailing() {
+    run_type_info_query("CommasWithTrailing", |union, possible_types| {
+        assert_eq!(union.get("name"), Some(&Value::string("CommasWithTrailing")));
+        assert_eq!(union.get("description"), Some(&Value::string("A description")));
+
+        assert!(possible_types.contains(&Value::object(vec![
+            ("name", Value::string("Concrete")),
+        ].into_iter().collect())));
+    });
+}
+
+#[test]
+fn introspect_resolvers_with_trailing_comma() {
+    run_type_info_query("ResolversWithTrailingComma", |union, possible_types| {
+        assert_eq!(union.get("name"), Some(&Value::string("ResolversWithTrailingComma")));
+        assert_eq!(union.get("description"), Some(&Value::string("A description")));
+
+        assert!(possible_types.contains(&Value::object(vec![
+            ("name", Value::string("Concrete")),
+        ].into_iter().collect())));
+    });
+}

src/macros/union.rs

@@ -0,0 +1,160 @@
+#[macro_export]
+macro_rules! graphql_union {
+    ( @as_item, $i:item) => { $i };
+    ( @as_expr, $e:expr) => { $e };
+    ( @as_path, $p:path) => { $p };
+    ( @as_type, $t:ty) => { $t };
+
+    // description: <description>
+    (
+        @ gather_meta,
+        ($reg:expr, $acc:expr, $descr:expr),
+        description : $value:tt $( $rest:tt )*
+    ) => {
+        $descr = Some(graphql_interface!(@as_expr, $value));
+
+        graphql_union!(@ gather_meta, ($reg, $acc, $descr), $( $rest )*)
+    };
+
+    // Gathering meta for instance resolvers
+    // instance_resolvers: | <ctxtvar> | [...]
+    (
+        @ gather_meta,
+        ($reg:expr, $acc:expr, $descr:expr),
+        instance_resolvers: | $ctxtvar:pat | { $( $srctype:ty => $resolver:expr ),* $(,)* } $( $rest:tt )*
+    ) => {
+        $acc = vec![
+            $(
+                $reg.get_type::<$srctype>()
+            ),*
+        ];
+
+        graphql_union!(@ gather_meta, ($reg, $acc, $descr), $( $rest )*)
+    };
+
+    // To generate the "concrete type name" resolver, syntax case:
+    // instance_resolvers: | <ctxtvar> | [...]
+    (
+        @ concrete_type_name,
+        ($outname:tt, $ctxtarg:ident, $ctxttype:ty),
+        instance_resolvers: | $ctxtvar:pat | { $( $srctype:path => $resolver:expr ),* $(,)* } $( $rest:tt )*
+    ) => {
+        let $ctxtvar = &$ctxtarg;
+
+        $(
+            if let Some(_) = $resolver {
+                return (<$srctype as $crate::GraphQLType<$ctxttype>>::name()).unwrap().to_owned();
+            }
+        )*
+
+            panic!("Concrete type not handled by instance resolvers on {}", $outname);
+    };
+
+    // To generate the "resolve into type" resolver, syntax case:
+    // instance_resolvers: | <ctxtvar> | [...]
+    (
+        @ resolve_into_type,
+        ($outname:tt, $typenamearg:ident, $execarg:ident, $ctxttype:ty),
+        instance_resolvers: | $ctxtvar:pat | { $( $srctype:path => $resolver:expr ),* $(,)* } $( $rest:tt )*
+    ) => {
+        let $ctxtvar = &$execarg.context();
+
+        $(
+            if $typenamearg == (<$srctype as $crate::GraphQLType<$ctxttype>>::name()).unwrap().to_owned() {
+                return $execarg.resolve(&$resolver);
+            }
+        )*
+
+            panic!("Concrete type not handled by instance resolvers on {}", $outname);
+    };
+
+    // eat commas
+    ( @ $mfn:ident, $args:tt, , $($rest:tt)* ) => {
+        graphql_union!(@ $mfn, $args, $($rest)*);
+    };
+
+    // eat one tt
+    ( @ $mfn:ident, $args:tt, $item:tt $($rest:tt)* ) => {
+        graphql_union!(@ $mfn, $args, $($rest)*);
+    };
+
+    // end case
+    ( @ $mfn:ident, $args:tt, ) => {};
+
+    (
+        ( $($lifetime:tt),* ) $name:ty : $ctxt:ty as $outname:tt | &$mainself:ident | {
+            $( $items:tt )*
+        }
+    ) => {
+        graphql_union!(@as_item, impl<$($lifetime)*> $crate::GraphQLType<$ctxt> for $name {
+            fn name() -> Option<&'static str> {
+                Some($outname)
+            }
+
+            #[allow(unused_assignments)]
+            #[allow(unused_mut)]
+            fn meta(registry: &mut $crate::Registry<$ctxt>) -> $crate::meta::MetaType {
+                let mut types;
+                let mut description = None;
+                graphql_union!(@ gather_meta, (registry, types, description), $($items)*);
+                let mut mt = registry.build_union_type::<$name>()(&types);
+
+                if let Some(description) = description {
+                    mt = mt.description(description);
+                }
+
+                mt.into_meta()
+            }
+
+            fn concrete_type_name(&$mainself, context: &$ctxt) -> String {
+                graphql_union!(
+                    @ concrete_type_name,
+                    ($outname, context, $ctxt),
+                    $($items)*);
+            }
+
+            fn resolve_into_type(
+                &$mainself,
+                type_name: &str,
+                _: Option<Vec<$crate::Selection>>,
+                executor: &mut $crate::Executor<$ctxt>,
+            ) -> $crate::ExecutionResult {
+                graphql_union!(
+                    @ resolve_into_type,
+                    ($outname, type_name, executor, $ctxt),
+                    $($items)*);
+            }
+        });
+
+        impl<$($lifetime)*> $crate::IntoFieldResult<$name> for $name {
+            fn into(self) -> $crate::FieldResult<$name> {
+                Ok(self)
+            }
+        }
+    };
+
+    (
+        <$($lifetime:tt),*> $name:ty : $ctxt:ty as $outname:tt | &$mainself:ident | {
+            $( $items:tt )*
+        }
+    ) => {
+        graphql_union!(
+            ($($lifetime),*) $name : $ctxt as $outname | &$mainself | { $( $items )* });
+    };
+
+    (
+        $name:ty : $ctxt:ty as $outname:tt | &$mainself:ident | {
+            $( $items:tt )*
+        }
+    ) => {
+        graphql_union!(() $name : $ctxt as $outname | &$mainself | { $( $items )* });
+    };
+
+    (
+        $name:ty : $ctxt:ty | &$mainself:ident | {
+            $( $items:tt )*
+        }
+    ) => {
+        graphql_union!(() $name : $ctxt as (stringify!($name)) | &$mainself | { $( $items )* });
+    };
+}