Add parsing and code generation for simple if blocks

askama/src/generator.rs

@@ -79,11 +79,24 @@ impl Generator {
         self.writeln(")).unwrap();");
     }
 
+    fn write_cond(&mut self, cond: &Expr, nodes: &Vec<Node>) {
+        self.write("if ");
+        self.visit_expr(cond);
+        self.writeln(" {");
+        self.indent();
+        self.handle(nodes);
+        self.dedent();
+        self.writeln("}");
+    }
+
     fn handle(&mut self, tokens: &Vec<Node>) {
         for n in tokens {
             match n {
                 &Node::Lit(val) => { self.write_lit(val); },
                 &Node::Expr(ref val) => { self.write_expr(&val); },
+                &Node::Cond(ref cond, ref nodes) => {
+                    self.write_cond(&cond, &nodes);
+                },
             }
         }
     }

askama/src/parser.rs

@@ -9,6 +9,7 @@ pub enum Expr<'a> {
 pub enum Node<'a> {
     Lit(&'a [u8]),
     Expr(Expr<'a>),
+    Cond(Expr<'a>, Vec<Node<'a>>),
 }
 
 fn take_content(i: &[u8]) -> IResult<&[u8], Node> {
@@ -58,7 +59,21 @@ named!(expr_node<Node>, map!(
     delimited!(tag_s!("{{"), ws!(expr_filtered), tag_s!("}}")),
     Node::Expr));
 
-named!(parse_template< Vec<Node> >, many1!(alt!(take_content | expr_node)));
+named!(block_if<Node>, do_parse!(
+    tag_s!("{%") >>
+    ws!(tag_s!("if")) >>
+    cond: ws!(expr_filtered) >>
+    ws!(tag_s!("%}")) >>
+    block: parse_template >>
+    ws!(tag_s!("{%")) >>
+    ws!(tag_s!("endif")) >>
+    tag_s!("%}") >>
+    (Node::Cond(cond, block))));
+
+named!(parse_template< Vec<Node> >, many1!(alt!(
+    take_content |
+    expr_node |
+    block_if)));
 
 pub fn parse<'a>(src: &'a str) -> Vec<Node> {
     match parse_template(src.as_bytes()) {