Overhealed route decorator. URI struct now understands query part.

lib/src/request.rs

@@ -4,7 +4,7 @@ use method::Method;
 
 pub use hyper::server::Request as HyperRequest;
 
-#[derive(Clone)]
+#[derive(Clone, Debug)]
 pub struct Request<'a> {
     params: Option<Vec<&'a str>>,
     pub method: Method,

lib/src/rocket.rs

@@ -93,12 +93,12 @@ impl Rocket {
             return handle_not_found(res);
         }
 
-        // Okay, we've got a route. Unwrap it, generate a request, and try to
+        // Okay, we've got a route. Unwrap it, generate a request, and dispatch.
-        // dispatch.
-        println!("\t=> {}", Magenta.paint("Dispatching request."));
         let route = route.unwrap();
         let params = route.get_params(uri);
         let request = Request::new(method, uri, Some(params), &buf);
+
+        println!("\t=> {}", Magenta.paint("Dispatching request."));
         let outcome = (route.handler)(request).respond(res);
 
         // TODO: keep trying lower ranked routes before dispatching a not found

lib/src/router/uri.rs

@@ -5,15 +5,26 @@ use std::fmt::{self, Write};
 
 #[derive(Debug, Clone, PartialEq, Eq)]
 pub struct URI<'a> {
+    uri: &'a str,
     path: &'a str,
+    query: Option<&'a str>,
     segment_count: Cell<Option<usize>>
 }
 
 impl<'a> URI<'a> {
-    pub fn new<T: AsRef<str> + ?Sized>(path: &'a T) -> URI<'a> {
+    pub fn new<T: AsRef<str> + ?Sized>(uri: &'a T) -> URI<'a> {
+        let uri = uri.as_ref();
+
+        let (path, query) = match uri.find('?') {
+            Some(index) => (&uri[..index], Some(&uri[index..])),
+            None => (uri, None)
+        };
+
         URI {
             segment_count: Cell::new(None),
-            path: path.as_ref(),
+            uri: uri,
+            path: path,
+            query: query,
         }
     }
 
@@ -30,14 +41,14 @@ impl<'a> URI<'a> {
     }
 
     pub fn as_str(&self) -> &'a str {
-        self.path
+        self.uri
     }
 }
 
 impl<'a> fmt::Display for URI<'a> {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         let mut last = '\0';
-        for c in self.path.chars() {
+        for c in self.uri.chars() {
             if !(c == '/' && last == '/') { f.write_char(c)?; }
             last = c;
         }
@@ -50,7 +61,7 @@ unsafe impl<'a> Sync for URI<'a> { /* It's safe! */ }
 
 #[derive(Debug, Clone, PartialEq, Eq)]
 pub struct URIBuf {
-    path: String,
+    uri: String,
     segment_count: Cell<Option<usize>>
 }
 
@@ -65,25 +76,25 @@ impl URIBuf {
     }
 
     pub fn segments(&self) -> Segments {
-        Segments(self.path.as_str())
+        self.as_uri_uncached().segments()
     }
 
     fn as_uri_uncached(&self) -> URI {
-        URI::new(self.path.as_str())
+        URI::new(self.uri.as_str())
     }
 
     pub fn as_uri(&self) -> URI {
-        let mut uri = URI::new(self.path.as_str());
+        let mut uri = URI::new(self.uri.as_str());
         uri.segment_count = self.segment_count.clone();
         uri
     }
 
     pub fn as_str(&self) -> &str {
-        self.path.as_str()
+        self.uri.as_str()
     }
 
     pub fn to_string(&self) -> String {
-        self.path.clone()
+        self.uri.clone()
     }
 }
 
@@ -96,19 +107,19 @@ impl fmt::Display for URIBuf {
 }
 
 impl From<String> for URIBuf {
-    fn from(path: String) -> URIBuf {
+    fn from(uri: String) -> URIBuf {
         URIBuf {
             segment_count: Cell::new(None),
-            path: path,
+            uri: uri,
         }
     }
 }
 
 impl<'a> From<&'a str> for URIBuf {
-    fn from(path: &'a str) -> URIBuf {
+    fn from(uri: &'a str) -> URIBuf {
         URIBuf {
             segment_count: Cell::new(None),
-            path: path.to_string(),
+            uri: uri.to_string(),
         }
     }
 }

macros/src/error_decorator.rs

@@ -17,17 +17,15 @@ struct Params {
 }
 
 fn get_error_params(ecx: &mut ExtCtxt, meta_item: &MetaItem) -> Params {
-    assert_meta_item_list(ecx, meta_item, "error");
+    // Ensure we've been supplied with a k = v meta item. Error out if not.
-
+    let params = meta_item.expect_list(ecx, "Bad use. Expected: #[error(...)]");
-    // Ensure we can unwrap the k = v params.
-    let params = meta_item.node.get_list_items().unwrap();
 
     // Now grab all of the required and optional parameters.
     let req: [&'static str; 1] = ["code"];
     let kv_pairs = get_key_values(ecx, meta_item.span, &req, &[], &*params);
 
     // Ensure we have a code, just to keep parsing and generating errors.
-    let code = kv_pairs.get("code").map_or(dummy_kvspan(404), |c| {
+    let code = kv_pairs.get("code").map_or(KVSpanned::dummy(404), |c| {
         let numeric_code = match c.node.parse() {
             Ok(n) => n,
             Err(_) => {

macros/src/route_decorator.rs

@@ -2,13 +2,10 @@ use super::{ROUTE_STRUCT_PREFIX, ROUTE_FN_PREFIX};
 use utils::*;
 
 use std::str::FromStr;
-use std::collections::HashSet;
+use std::collections::HashMap;
 
-use syntax::ext::quote::rt::ToTokens;
 use syntax::codemap::{Span, BytePos, /* DUMMY_SP, */ Spanned};
-use syntax::tokenstream::TokenTree;
+use syntax::ast::{Stmt, Item, Expr, ItemKind, MetaItem, MetaItemKind, FnDecl};
-use syntax::ast::{Ident, PatKind, Stmt};
-use syntax::ast::{Item, Expr, ItemKind, MetaItem, MetaItemKind, FnDecl, Ty};
 use syntax::ext::base::{Annotatable, ExtCtxt};
 use syntax::ptr::P;
 use syntax::print::pprust::{item_to_string, stmt_to_string};
@@ -54,12 +51,10 @@ pub fn get_fn_decl<'a>(ecx: &mut ExtCtxt, sp: Span, annotated: &'a Annotatable)
     (item, wrap_span(&*fn_decl, item.span))
 }
 
-fn get_route_params(ecx: &mut ExtCtxt, meta_item: &MetaItem) -> Params {
+// Parses the MetaItem derived from the route(...) macro.
-    // First, check that the macro was used in the #[route(a, b, ..)] form.
+fn parse_route(ecx: &mut ExtCtxt, meta_item: &MetaItem) -> Params {
-    assert_meta_item_list(ecx, meta_item, "error");
+    // Ensure we've been supplied with a k = v meta item. Error out if not.
-
+    let params = meta_item.expect_list(ecx, "Bad use. Expected: #[route(...)]");
-    // Ensure we can unwrap the k = v params.
-    let params = meta_item.node.get_list_items().unwrap();
     if params.len() < 1 {
         bad_method_err(ecx, meta_item.span, "HTTP method parameter is missing.");
         ecx.span_fatal(meta_item.span, "At least 2 arguments are required.");
@@ -89,7 +84,7 @@ fn get_route_params(ecx: &mut ExtCtxt, meta_item: &MetaItem) -> Params {
     let kv_pairs = get_key_values(ecx, meta_item.span, &req, &opt, kv_params);
 
     // Ensure we have a path, just to keep parsing and generating errors.
-    let path = kv_pairs.get("path").map_or(dummy_kvspan("/".to_string()), |s| {
+    let path = kv_pairs.get("path").map_or(KVSpanned::dummy("/".to_string()), |s| {
         s.clone().map(String::from)
     });
 
@@ -107,7 +102,7 @@ fn get_route_params(ecx: &mut ExtCtxt, meta_item: &MetaItem) -> Params {
                 .emit();
         }
 
-        if f.node.chars().filter(|c| *c == '<').count() != 1 {
+        if f.node.chars().filter(|c| *c == '<' || *c == '>').count() != 2 {
             ecx.span_err(f.p_span, "`form` must contain exactly one parameter");
         }
 
@@ -121,29 +116,11 @@ fn get_route_params(ecx: &mut ExtCtxt, meta_item: &MetaItem) -> Params {
     }
 }
 
-// Is there a better way to do this? I need something with ToTokens for the
-// quote_expr macro that builds the route struct. I tried using
-// str_to_ident("rocket::Method::Options"), but this seems to miss the context,
-// and you get an 'ident not found' on compile. I also tried using the path expr
-// builder from ASTBuilder: same thing.
-fn method_variant_to_expr(ecx: &ExtCtxt, method: Method) -> P<Expr> {
-    match method {
-        Method::Options => quote_expr!(ecx, rocket::Method::Options),
-        Method::Get => quote_expr!(ecx, rocket::Method::Get),
-        Method::Post => quote_expr!(ecx, rocket::Method::Post),
-        Method::Put => quote_expr!(ecx, rocket::Method::Put),
-        Method::Delete => quote_expr!(ecx, rocket::Method::Delete),
-        Method::Head => quote_expr!(ecx, rocket::Method::Head),
-        Method::Trace => quote_expr!(ecx, rocket::Method::Trace),
-        Method::Connect => quote_expr!(ecx, rocket::Method::Connect),
-        Method::Patch => quote_expr!(ecx, rocket::Method::Patch),
-    }
-}
 
 // TODO: Put something like this in the library. Maybe as an iterator?
-pub fn gen_params_hashset<'a>(ecx: &ExtCtxt, params: &Spanned<&'a str>)
+pub fn extract_params<'a>(ecx: &ExtCtxt, params: &Spanned<&'a str>)
-        -> HashSet<&'a str> {
+        -> Vec<Spanned<&'a str>> {
-    let mut seen = HashSet::new();
+    let mut output_params = vec![];
     let bad_match_err = "Parameter string is malformed.";
 
     let mut start = 0;
@@ -163,13 +140,7 @@ pub fn gen_params_hashset<'a>(ecx: &ExtCtxt, params: &Spanned<&'a str>)
 
                 if i > start + 1 {
                     let param_name = &params.node[(start + 1)..i];
-                    if seen.contains(param_name) {
+                    output_params.push(wrap_span(param_name, param_span))
-                        let msg = format!("\"{}\" appears more than once in \
-                            the parameter string.", param_name);
-                        ecx.span_err(param_span, msg.as_str());
-                    }
-
-                    seen.insert(param_name);
                 } else {
                     ecx.span_err(param_span, "Parameter names cannot be empty.");
                 }
@@ -180,95 +151,52 @@ pub fn gen_params_hashset<'a>(ecx: &ExtCtxt, params: &Spanned<&'a str>)
         }
     }
 
-    seen
+    output_params
 }
 
-#[derive(Debug)]
+pub fn extract_params_from_kv<'a>(ecx: &ExtCtxt, params: &'a KVSpanned<String>)
-struct SimpleArg {
+        -> Vec<Spanned<&'a str>> {
-    name: String,
-    ty: P<Ty>,
-    span: Span
-}
-
-pub fn gen_kv_string_hashset<'a>(ecx: &ExtCtxt, params: &'a KVSpanned<String>)
-        -> HashSet<&'a str> {
     let mut param_span = params.v_span;
     param_span.lo = params.v_span.lo + BytePos(1);
-    let params = Spanned {
+    extract_params(ecx, &Spanned {
         span: param_span,
         node: &*params.node
-    };
+    })
-
-    gen_params_hashset(ecx, &params)
 }
 
-impl SimpleArg {
+fn get_fn_params<'a, T: Iterator<Item=&'a Spanned<&'a str>>>(ecx: &ExtCtxt,
-    fn new<T: ToString>(name: T, ty: P<Ty>, sp: Span) -> SimpleArg {
+        declared_params: T, fn_decl: &Spanned<&FnDecl>) -> Vec<SimpleArg> {
-        SimpleArg { name: name.to_string(), ty: ty, span: sp }
-    }
-
-    fn as_str(&self) -> &str {
-        self.name.as_str()
-    }
-}
-
-impl ToTokens for SimpleArg {
-    fn to_tokens(&self, cx: &ExtCtxt) -> Vec<TokenTree> {
-        str_to_ident(self.as_str()).to_tokens(cx)
-    }
-}
-
-fn get_fn_params<'a>(ecx: &ExtCtxt, dec_span: Span, path: &'a KVSpanned<String>,
-        fn_decl: &Spanned<&FnDecl>, mut external: HashSet<&'a str>)
-            -> Vec<SimpleArg> {
     debug!("FUNCTION: {:?}", fn_decl);
-    let mut path_params = gen_kv_string_hashset(ecx, &path);
 
-    // Ensure that there are no collisions between path parameters and external
+    // First, check that all of the parameters are unique.
-    // params. If there are, get rid of one of them so we don't double error.
+    let mut seen: HashMap<&str, &Spanned<&str>> = HashMap::new();
-    let new_external = external.clone();
+    for item in declared_params {
-    for param in path_params.intersection(&new_external) {
+        if seen.contains_key(item.node) {
-        let msg = format!("'{}' appears as a parameter more than once.", param);
+            let msg = format!(
-        external.remove(param);
+                "\"{}\" was declared as a parameter more than once.", item.node);
-        ecx.span_err(dec_span, msg.as_str());
+            ecx.span_err(item.span, msg.as_str());
+        } else {
+            seen.insert(item.node, item);
+        }
     }
 
-    // Ensure every param in the function declaration is in `path`. Also add
+    // Ensure every param in the function declaration was declared by the user.
-    // each param name in the declaration to the result vector.
     let mut result = vec![];
     for arg in &fn_decl.node.inputs {
-        let ident: &Ident = match arg.pat.node {
+        let name = arg.pat.expect_ident(ecx, "Expected identifier.");
-            PatKind::Ident(_, ref ident, _) => &ident.node,
+        if seen.remove(&*name.to_string()).is_none() {
-            _ => {
+            let msg = format!("'{}' appears in the function declaration \
-                ecx.span_err(arg.pat.span, "Expected an identifier.");
+                but does not appear as a parameter in the attribute.", name);
-                return result
+            ecx.span_err(arg.pat.span, msg.as_str());
-            }
-        };
-
-        let name = ident.to_string();
-        if !path_params.remove(name.as_str()) && !external.remove(name.as_str()) {
-            let msg1 = format!("'{}' appears in the function declaration...", name);
-            let msg2 = format!("...but does not appear as a parameter \
-                         (e.g., <{}>).", name);
-            ecx.span_err(arg.pat.span, msg1.as_str());
-            ecx.span_err(dec_span, msg2.as_str());
         }
 
         result.push(SimpleArg::new(name, arg.ty.clone(), arg.pat.span));
     }
 
-    // Ensure every param in `path` and `exclude` is in the function declaration.
+    // Ensure every declared parameter is in the function declaration.
-    for item in path_params {
+    for item in seen.values() {
-            let msg = format!("'{}' appears in the path string...", item);
+        let msg = format!("'{}' was declared in the attribute...", item.node);
-            ecx.span_err(path.v_span, msg.as_str());
+        ecx.span_err(item.span, msg.as_str());
-            ecx.span_err(fn_decl.span, "...but does not appear in the function \
-                         declration.");
-    }
-
-    // FIXME: need the spans for the external params
-    for item in external {
-            let msg = format!("'{}' appears as a parameter...", item);
-            ecx.span_err(dec_span, msg.as_str());
         ecx.span_err(fn_decl.span, "...but does not appear in the function \
                      declaration.");
     }
@@ -277,40 +205,37 @@ fn get_fn_params<'a>(ecx: &ExtCtxt, dec_span: Span, path: &'a KVSpanned<String>,
 }
 
 fn get_form_stmt(ecx: &ExtCtxt, fn_args: &mut Vec<SimpleArg>,
-                 form_params: &HashSet<&str>) -> Option<Stmt> {
+                 form_params: &[Spanned<&str>]) -> Option<Stmt> {
     if form_params.len() < 1 {
         return None
     } else if form_params.len() > 1 {
         panic!("Allowed more than 1 form parameter!");
     }
 
-
+    let param_name = &form_params[0].node;
-    let param_ty;
+    let (param_ty, param_ident) = {
-    let param_ident;
-    let param_name = form_params.iter().next().unwrap();
-
-    {
         // Get the first item in the hashset, i.e., the form params variable name.
         let fn_arg = fn_args.iter().filter(|a| &&*a.name == param_name).next();
         if fn_arg.is_none() {
             // This happens when a form parameter doesn't appear in the function.
+            // We should have already caught this, so just return None.
             return None;
         }
 
-        param_ty = fn_arg.unwrap().ty.clone();
+        (fn_arg.unwrap().ty.clone(), str_to_ident(param_name))
-        param_ident = str_to_ident(param_name);
+    };
-    }
 
+    // Remove the paramter from the function arguments.
     debug!("Form parameter variable: {}: {:?}", param_name, param_ty);
     let fn_arg_index = fn_args.iter().position(|a| &&*a.name == param_name).unwrap();
     fn_args.remove(fn_arg_index);
+
+    // The actual code we'll be inserting.
     quote_stmt!(ecx,
-        // TODO: Actually get the form parameters to pass into from_form_string.
-        // Alternatively, pass in some already parsed thing.
         let $param_ident: $param_ty = {
             let form_string = std::str::from_utf8(_req.data);
             if form_string.is_err() {
-                return ::rocket::Response::not_found()
+                return ::rocket::Response::server_error();
             };
 
             match ::rocket::form::FromForm::from_form_string(form_string.unwrap()) {
@@ -324,30 +249,50 @@ fn get_form_stmt(ecx: &ExtCtxt, fn_args: &mut Vec<SimpleArg>,
     )
 }
 
+// Is there a better way to do this? I need something with ToTokens for the
+// quote_expr macro that builds the route struct. I tried using
+// str_to_ident("rocket::Method::Options"), but this seems to miss the context,
+// and you get an 'ident not found' on compile. I also tried using the path expr
+// builder from ASTBuilder: same thing.
+fn method_variant_to_expr(ecx: &ExtCtxt, method: Method) -> P<Expr> {
+    match method {
+        Method::Options => quote_expr!(ecx, ::rocket::Method::Options),
+        Method::Get => quote_expr!(ecx, ::rocket::Method::Get),
+        Method::Post => quote_expr!(ecx, ::rocket::Method::Post),
+        Method::Put => quote_expr!(ecx, ::rocket::Method::Put),
+        Method::Delete => quote_expr!(ecx, ::rocket::Method::Delete),
+        Method::Head => quote_expr!(ecx, ::rocket::Method::Head),
+        Method::Trace => quote_expr!(ecx, ::rocket::Method::Trace),
+        Method::Connect => quote_expr!(ecx, ::rocket::Method::Connect),
+        Method::Patch => quote_expr!(ecx, ::rocket::Method::Patch),
+    }
+}
+
 // FIXME: Compilation fails when parameters have the same name as the function!
 pub fn route_decorator(ecx: &mut ExtCtxt, sp: Span, meta_item: &MetaItem,
           annotated: &Annotatable, push: &mut FnMut(Annotatable)) {
+    // Get the encompassing item and function declaration for the annotated func.
     let (item, fn_decl) = get_fn_decl(ecx, sp, annotated);
-    let route_params = get_route_params(ecx, meta_item);
 
-    // TODO: move this elsewhere
+    // Parse and retrieve all of the parameters of the route.
-    let mut external_params = HashSet::new();
+    let route = parse_route(ecx, meta_item);
-    let mut form_param_hashset = HashSet::new();
-    if let Some(ref form) = route_params.form {
-        form_param_hashset = gen_kv_string_hashset(ecx, form);
-        external_params.extend(&form_param_hashset);
-    }
 
-    let mut fn_params = get_fn_params(ecx, sp, &route_params.path, &fn_decl,
+    // Get a list of the user declared parameters in `path` and `form`.
-                                      external_params.clone());
+    let path_params = extract_params_from_kv(ecx, &route.path);
+    let form_thing = route.form.unwrap_or_default(); // Default is empty string.
+    let form_params = extract_params_from_kv(ecx, &form_thing);
+
+    // Ensure the params match the function declaration and return the params.
+    let all_params = path_params.iter().chain(form_params.iter());
+    let mut fn_params = get_fn_params(ecx, all_params, &fn_decl);
 
     // Create a comma seperated list (token tree) of the function parameters
     // We pass this in to the user's function that we're wrapping.
     let fn_param_idents = token_separate(ecx, &fn_params, token::Comma);
 
     // Generate the statements that will attempt to parse forms during run-time.
-    // let form_span = route_params.form.map_or(DUMMY_SP, |f| f.span.clone());
+    // Calling this function also remove the form parameter from fn_params.
-    let form_stmt = get_form_stmt(ecx, &mut fn_params, &form_param_hashset);
+    let form_stmt = get_form_stmt(ecx, &mut fn_params, &form_params);
     form_stmt.as_ref().map(|s| debug!("Form stmt: {:?}", stmt_to_string(s)));
 
     // Generate the statements that will attempt to parse the paramaters during
@@ -384,8 +329,8 @@ pub fn route_decorator(ecx: &mut ExtCtxt, sp: Span, meta_item: &MetaItem,
     push(Annotatable::Item(route_fn_item));
 
     let struct_name = prepend_ident(ROUTE_STRUCT_PREFIX, &item.ident);
-    let path = route_params.path.node;
+    let path = &route.path.node;
-    let method = method_variant_to_expr(ecx, route_params.method.node);
+    let method = method_variant_to_expr(ecx, route.method.node);
     push(Annotatable::Item(quote_item!(ecx,
         #[allow(non_upper_case_globals)]
         pub static $struct_name: rocket::StaticRouteInfo = rocket::StaticRouteInfo {

macros/src/utils.rs

@@ -1,7 +1,7 @@
 use syntax::parse::{token};
 use syntax::parse::token::Token;
 use syntax::tokenstream::TokenTree;
-use syntax::ast::{Path, Ident, MetaItem, MetaItemKind, LitKind};
+use syntax::ast::{Path, Ident, MetaItem, MetaItemKind, LitKind, Ty, self};
 use syntax::ext::base::{ExtCtxt};
 use syntax::codemap::{Span, Spanned, BytePos, DUMMY_SP};
 use syntax::ext::quote::rt::ToTokens;
@@ -50,22 +50,30 @@ pub fn dummy_span<T>(t: T) -> Spanned<T> {
     }
 }
 
-#[inline]
+#[derive(Debug, Clone)]
-pub fn dummy_kvspan<T>(t: T) -> KVSpanned<T> {
+pub struct KVSpanned<T> {
+    pub k_span: Span, // Span for the key.
+    pub v_span: Span, // Span for the value.
+    pub p_span: Span, // Span for the full parameter.
+    pub node: T       // The value.
+}
+
+impl<T> KVSpanned<T> {
+    #[inline]
+    pub fn dummy(t: T) -> KVSpanned<T> {
         KVSpanned {
             k_span: DUMMY_SP,
             v_span: DUMMY_SP,
             p_span: DUMMY_SP,
             node: t,
         }
+    }
 }
 
-#[derive(Debug, Clone)]
+impl<T: Default> Default for KVSpanned<T> {
-pub struct KVSpanned<T> {
+    fn default() -> KVSpanned<T> {
-    pub k_span: Span,
+        KVSpanned::dummy(T::default())
-    pub v_span: Span,
+    }
-    pub p_span: Span,
-    pub node: T
 }
 
 impl<T: ToTokens> ToTokens for KVSpanned<T> {
@@ -147,27 +155,38 @@ pub fn token_separate<T: ToTokens>(ecx: &ExtCtxt, things: &[T],
     output
 }
 
-pub fn assert_meta_item_list(ecx: &ExtCtxt, meta_item: &MetaItem, s: &str) {
-    if !meta_item.node.is_list() {
-        let msg = format!("Incorrect use of macro. Expected: #[{}(...)]", s);
-        ecx.span_fatal(meta_item.span, msg.as_str());
-    }
-}
-
 pub trait MetaItemExt {
-    fn is_list(&self) -> bool;
+    fn expect_list<'a>(&'a self, ecx: &ExtCtxt, msg: &str) -> &'a Vec<P<MetaItem>>;
-    fn get_list_items(&self) -> Option<&Vec<P<MetaItem>>>;
+    fn expect_word<'a>(&'a self, ecx: &ExtCtxt, msg: &str) -> &'a str;
 }
 
-impl MetaItemExt for MetaItemKind {
+impl MetaItemExt for MetaItem {
-    fn is_list(&self) -> bool {
+    fn expect_list<'a>(&'a self, ecx: &ExtCtxt, msg: &str) -> &'a Vec<P<MetaItem>> {
-        self.get_list_items().is_some()
+        match self.node {
+            MetaItemKind::List(_, ref params) => params,
+            _ => ecx.span_fatal(self.span, msg)
+        }
     }
 
-    fn get_list_items(&self) -> Option<&Vec<P<MetaItem>>> {
+    fn expect_word<'a>(&'a self, ecx: &ExtCtxt, msg: &str) -> &'a str {
-        match *self {
+        match self.node {
-            MetaItemKind::List(_, ref params) => Some(params),
+            MetaItemKind::Word(ref s) => &*s,
-            _ => None
+            _ => ecx.span_fatal(self.span, msg)
+        }
+    }
+}
+
+pub trait PatExt {
+    fn expect_ident<'a>(&'a self, ecx: &ExtCtxt, msg: &str) -> &'a Ident;
+}
+
+impl PatExt for ast::Pat {
+    fn expect_ident<'a>(&'a self, ecx: &ExtCtxt, msg: &str) -> &'a Ident {
+        match self.node {
+            ast::PatKind::Ident(_, ref ident, _) => &ident.node,
+            _ => {
+                ecx.span_fatal(self.span, msg)
+            }
         }
     }
 }
@@ -198,16 +217,26 @@ pub fn prefix_paths(prefix: &str, paths: &mut Vec<Path>) {
     }
 }
 
-// pub fn find_value_for(key: &str, kv_params: &[P<MetaItem>]) -> Option<String> {
+#[derive(Debug)]
-//     for param in kv_params {
+pub struct SimpleArg {
-//         if let MetaItemKind::NameValue(ref name, ref value) = param.node {
+    pub name: String,
-//             if &**name == key {
+    pub ty: P<Ty>,
-//                 if let LitKind::Str(ref string, _) = value.node {
+    pub span: Span
-//                     return Some(String::from(&**string));
+}
-//                 }
+
-//             }
+impl SimpleArg {
-//         }
+    pub fn new<T: ToString>(name: T, ty: P<Ty>, sp: Span) -> SimpleArg {
-//     }
+        SimpleArg { name: name.to_string(), ty: ty, span: sp }
+    }
+
+    pub fn as_str(&self) -> &str {
+        self.name.as_str()
+    }
+}
+
+impl ToTokens for SimpleArg {
+    fn to_tokens(&self, cx: &ExtCtxt) -> Vec<TokenTree> {
+        token::str_to_ident(self.as_str()).to_tokens(cx)
+    }
+}
 
-//     None
-// }