Implement support for format filter

2 files changed, 10 insertions, 1 deletions

diff --git a/askama/src/filters.rs b/askama/src/filters.rs
index 17d25c5..a9fe248 100644
--- a/askama/src/filters.rs
+++ b/askama/src/filters.rs
@@ -43,6 +43,10 @@ pub fn e(s: &fmt::Display) -> String {
     escape(s)
 }
 
+/// This is actually unused; format filter calls are forwarded directly to
+/// the format!() macro in the code generator (see `visit_filter()`).
+pub fn format() { }
+
 #[cfg(test)]
 mod tests {
     use super::*;
diff --git a/askama/src/generator.rs b/askama/src/generator.rs
index 911b860..40b6523 100644
--- a/askama/src/generator.rs
+++ b/askama/src/generator.rs
@@ -125,7 +125,12 @@ impl<'a> Generator<'a> {
     }
 
     fn visit_filter(&mut self, name: &str, args: &[Expr]) {
-        self.write(&format!("askama::filters::{}(&", name));
+        if name == "format" {
+            self.write("format!(");
+        } else {
+            self.write(&format!("askama::filters::{}(&", name));
+        }
+
         for (i, arg) in args.iter().enumerate() {
             if i > 0 {
                 self.write(", &");