Add Rust macro support at templates

4 files changed, 46 insertions, 2 deletions

diff --git a/askama_derive/src/generator.rs b/askama_derive/src/generator.rs
index 33fbe4c..41e1647 100644
--- a/askama_derive/src/generator.rs
+++ b/askama_derive/src/generator.rs
@@ -644,10 +644,20 @@ impl<'a> Generator<'a> {
             Expr::Group(ref inner) => self.visit_group(buf, inner),
             Expr::MethodCall(ref obj, method, ref args) => {
                 self.visit_method_call(buf, obj, method, args)
-            }
+            },
+            Expr::RustMacro(name, ref args) => self.visit_rust_macro(buf, name, args),
         }
     }
 
+    fn visit_rust_macro(&mut self, buf: &mut Buffer, name: &str, args: &[Expr]) -> DisplayWrap {
+        buf.write(name);
+        buf.write("!(");
+        self._visit_args(buf, args);
+        buf.write(")");
+
+        DisplayWrap::Unwrapped
+    }
+
     fn visit_match_variant(&mut self, buf: &mut Buffer, param: &MatchVariant) -> DisplayWrap {
         let mut expr_buf = Buffer::new(0);
         let wrapped = match *param {
diff --git a/askama_derive/src/parser.rs b/askama_derive/src/parser.rs
index 1c5e28e..742a7a2 100644
--- a/askama_derive/src/parser.rs
+++ b/askama_derive/src/parser.rs
@@ -21,6 +21,7 @@ pub enum Expr<'a> {
     Range(&'a str, Option<Box<Expr<'a>>>, Option<Box<Expr<'a>>>),
     Group(Box<Expr<'a>>),
     MethodCall(Box<Expr<'a>>, &'a str, Vec<Expr<'a>>),
+    RustMacro(&'a str, Vec<Expr<'a>>),
 }
 
 #[derive(Debug)]
@@ -427,6 +428,14 @@ named!(expr_unary<Input, Expr>, do_parse!(
     })
 ));
 
+named!(rust_macro<Input, Expr>, do_parse!(
+    mname: identifier >>
+    tag!("!") >>
+    args: arguments >>
+    (Expr::RustMacro(mname, args))
+));
+
+
 macro_rules! expr_prec_layer {
     ( $name:ident, $inner:ident, $( $op:expr ),* ) => {
         named!($name<Input, Expr>, do_parse!(
@@ -463,6 +472,7 @@ named!(range_right<Input, Expr>, do_parse!(
 
 named!(expr_any<Input, Expr>, alt!(
     range_right |
+    rust_macro |
     do_parse!(
         left: expr_or >>
         rest: range_right >> (match rest {
@@ -776,6 +786,7 @@ mod tests {
             }
         }
     }
+
     #[test]
     fn test_ws_splitter() {
         check_ws_split("", &("", "", ""));
@@ -784,6 +795,7 @@ mod tests {
         check_ws_split("b\n", &("", "b", "\n"));
         check_ws_split(" \t\r\n", &(" \t\r\n", "", ""));
     }
+
     #[test]
     #[should_panic]
     fn test_invalid_block() {
@@ -805,5 +817,4 @@ mod tests {
 
         super::parse("{~ strvar|e ~}", &syntax);
     }
-
 }
diff --git a/testing/templates/rust-macros.html b/testing/templates/rust-macros.html
new file mode 100644
index 0000000..dc0b3de
--- /dev/null
+++ b/testing/templates/rust-macros.html
@@ -0,0 +1 @@
+Hello, {{ hello!(name) }}!
diff --git a/testing/tests/rust_macro.rs b/testing/tests/rust_macro.rs
new file mode 100644
index 0000000..c6e97ce
--- /dev/null
+++ b/testing/tests/rust_macro.rs
@@ -0,0 +1,22 @@
+#[macro_use]
+extern crate askama;
+
+use askama::Template;
+
+macro_rules! hello {
+    ($name:expr) => {
+        "world"
+    }
+}
+
+#[derive(Template)]
+#[template(path = "rust-macros.html")]
+struct RustMacrosTemplate<'a> {
+    name: &'a str,
+}
+
+#[test]
+fn main() {
+    let template = RustMacrosTemplate { name: "foo" };
+    assert_eq!("Hello, world!", template.render().unwrap());
+}