1 files changed, 72 insertions, 0 deletions
diff --git a/askama_derive/src/lib.rs b/askama_derive/src/lib.rs
new file mode 100644
index 0000000..d923e19
--- /dev/null
+++ b/askama_derive/src/lib.rs
@@ -0,0 +1,72 @@
+#![feature(proc_macro, proc_macro_lib)]
+
+#[macro_use]
+extern crate nom;
+extern crate proc_macro;
+#[macro_use]
+extern crate quote;
+extern crate syn;
+
+mod generator;
+mod parser;
+
+use proc_macro::TokenStream;
+use std::fs::File;
+use std::io::Read;
+use std::path::{Path, PathBuf};
+
+fn get_path_from_attrs(attrs: &Vec<syn::Attribute>) -> String {
+    for attr in attrs {
+        if attr.name() == "template" {
+            match attr.value {
+                syn::MetaItem::List(_, ref inner) => {
+                    match inner[0] {
+                        syn::NestedMetaItem::MetaItem(ref item) => {
+                            match item {
+                                &syn::MetaItem::NameValue(ref key, ref val) => {
+                                    assert_eq!(key.as_ref(), "path");
+                                    match val {
+                                        &syn::Lit::Str(ref s, _) => { return s.clone(); },
+                                        _ => panic!("template path must be a string"),
+                                    }
+                                },
+                                _ => panic!("template annotation must contain key/value pair"),
+                            }
+                        },
+                        _ => panic!("template annotation must contain item"),
+                    }
+                },
+                _ => panic!("template annotation must be of List type"),
+            }
+        }
+    }
+    panic!("template annotation not found");
+}
+
+fn get_template_source(tpl_file: &str) -> String {
+    let root = ::std::env::var("CARGO_MANIFEST_DIR").unwrap();
+    let mut path = PathBuf::from(root);
+    path.push("templates");
+    path.push(Path::new(tpl_file));
+    let mut f = File::open(path).unwrap();
+    let mut s = String::new();
+    f.read_to_string(&mut s).unwrap();
+    s
+}
+
+#[proc_macro_derive(Template, attributes(template))]
+pub fn derive_template(input: TokenStream) -> TokenStream {
+    let source = input.to_string();
+
+    let ast = syn::parse_macro_input(&source).unwrap();
+    let _ctx = match ast.body {
+        syn::Body::Struct(ref data) => data,
+        _ => panic!("#[derive(Template)] can only be used with structs"),
+    };
+
+    let name = &ast.ident;
+    let path = get_path_from_attrs(&ast.attrs);
+    let src = get_template_source(&path);
+    let tokens = parser::parse(&src);
+    generator::generate(name.as_ref(), &tokens).parse().unwrap()
+}