Initial implementation of custom Renderable trait.

src/bin.rs

@@ -3,6 +3,7 @@ extern crate nom;
 use renderer::compile_template;
 use renderer::CompiledTemplate;
 use renderer::DustRenderer;
+use renderer::Renderable;
 use std::env;
 use std::fs;
 use std::io::{self, Read};
@@ -65,3 +66,9 @@ fn read_context_from_stdin() -> serde_json::map::Map<String, serde_json::Value>
         _ => panic!("Expected context to be an object"),
     }
 }
+
+impl Renderable for serde_json::Value {
+    fn render(&self) -> String {
+        self.to_string()
+    }
+}

src/renderer/mod.rs

@@ -1,8 +1,10 @@
 //! This module contains a renderer for a rust implementation of LinkedIn Dust
 
 mod errors;
+mod renderable;
 mod renderer;
 
+pub use renderable::Renderable;
 pub use renderer::compile_template;
 pub use renderer::CompiledTemplate;
 pub use renderer::DustRenderer;

src/renderer/renderable.rs

@@ -0,0 +1,3 @@
+pub trait Renderable {
+    fn render(&self) -> String;
+}

src/renderer/renderer.rs

@@ -4,6 +4,7 @@ use crate::parser::Template;
 use crate::parser::TemplateElement;
 use crate::renderer::errors::CompileError;
 use crate::renderer::errors::RenderError;
+use crate::renderer::renderable::Renderable;
 use std::collections::HashMap;
 use std::ops::Index;
 
@@ -46,7 +47,7 @@ impl<'a> DustRenderer<'a> {
     pub fn render<C>(&self, name: &str, context: &C) -> Result<String, RenderError>
     where
         C: Index<&'a str>,
-        <C as std::ops::Index<&'a str>>::Output: std::string::ToString,
+        <C as std::ops::Index<&'a str>>::Output: Renderable,
     {
         let main_template = match self.templates.get(name) {
             Some(tmpl) => tmpl,
@@ -62,7 +63,7 @@ impl<'a> DustRenderer<'a> {
     fn render_template<C>(&self, template: &Template, context: &C) -> Result<String, RenderError>
     where
         C: Index<&'a str>,
-        <C as std::ops::Index<&'a str>>::Output: std::string::ToString,
+        <C as std::ops::Index<&'a str>>::Output: Renderable,
     {
         let mut output = String::new();
         for elem in &template.contents.elements {
@@ -79,13 +80,13 @@ impl<'a> DustRenderer<'a> {
     fn render_tag<C>(&self, tag: &DustTag, context: &C) -> Result<String, RenderError>
     where
         C: Index<&'a str>,
-        <C as std::ops::Index<&'a str>>::Output: std::string::ToString,
+        <C as std::ops::Index<&'a str>>::Output: Renderable,
     {
         match tag {
             DustTag::DTComment(comment) => (),
             DustTag::DTReference(reference) => {
                 let val = context.index("name");
-                return Ok(val.to_string());
+                return Ok(val.render());
             }
             _ => (), // TODO: Implement the rest
         }