Type hack

Author: sgrif

src/connection/cursor.rs

@@ -4,13 +4,13 @@ use types::{NativeSqlType, FromSqlRow};
 
 use std::marker::PhantomData;
 
-pub struct Cursor<ST, T> {
+pub struct Cursor<ST, T, Hack = ()> {
     current_row: usize,
     db_result: DbResult,
-    _marker: PhantomData<(ST, T)>,
+    _marker: PhantomData<(ST, T, Hack)>,
 }
 
-impl<ST, T> Cursor<ST, T> {
+impl<ST, T, Hack> Cursor<ST, T, Hack> {
     pub fn new(db_result: DbResult) -> Self {
         Cursor {
             current_row: 0,
@@ -20,9 +20,9 @@ impl<ST, T> Cursor<ST, T> {
     }
 }
 
-impl<ST, T> Iterator for Cursor<ST, T> where
+impl<ST, T, Hack> Iterator for Cursor<ST, T, Hack> where
     ST: NativeSqlType,
-    T: Queriable<ST>,
+    T: Queriable<ST, Hack>,
 {
     type Item = T;
 

src/connection/mod.rs

@@ -47,17 +47,17 @@ impl Connection {
         self.query_all(source).map(|mut e| e.nth(0))
     }
 
-    pub fn query_all<T, U>(&self, source: &T) -> Result<Cursor<T::SqlType, U>> where
+    pub fn query_all<T, U, Hack>(&self, source: &T) -> Result<Cursor<T::SqlType, U, Hack>> where
         T: QuerySource,
-        U: Queriable<T::SqlType>,
+        U: Queriable<T::SqlType, Hack>,
     {
         let sql = self.prepare_query(source);
         self.query_sql(&sql)
     }
 
-    pub fn query_sql<T, U>(&self, query: &str) -> Result<Cursor<T, U>> where
+    pub fn query_sql<T, U, Hack>(&self, query: &str) -> Result<Cursor<T, U, Hack>> where
         T: NativeSqlType,
-        U: Queriable<T>,
+        U: Queriable<T, Hack>,
     {
         let result = try!(self.execute_inner(query));
         Ok(Cursor::new(result))

src/macros.rs

@@ -180,9 +180,10 @@ macro_rules! joinable_inner {
     }
 }
 
+#[macro_export]
 macro_rules! belongs_to {
     ($parent:ty, $parent_table:ident, $child:ty, $child_table:ident) => {
-        impl $crate::Queriable<($child_table::SqlType, $parent_table::SqlType)>
+        impl $crate::Queriable<($child_table::SqlType, $parent_table::SqlType), $parent>
         for ($child, $parent) {
             type Row = (
                 <$child as $crate::Queriable<$child_table::SqlType>>::Row,

src/query_source/mod.rs

@@ -8,7 +8,7 @@ use self::select::SelectSqlQuerySource;
 
 pub use self::joins::JoinTo;
 
-pub trait Queriable<ST: NativeSqlType> {
+pub trait Queriable<ST: NativeSqlType, Hack = ()> {
     type Row: FromSqlRow<ST>;
 
     fn build(row: Self::Row) -> Self;

tests/types.rs

@@ -119,7 +119,7 @@ fn pg_array_containing_null() {
 
 fn query_single_value<T: NativeSqlType, U: Queriable<T>>(sql: &str) -> U {
     let connection = connection();
-    let mut cursor = connection.query_sql::<T, U>(sql)
+    let mut cursor = connection.query_sql::<T, U, _>(sql)
         .unwrap();
     cursor.nth(0).unwrap()
 }