syntax: add support for #[deriving(Decodable)]

src/libsyntax/ext/build.rs

@@ -279,10 +279,10 @@ pub fn mk_lambda_(cx: @ext_ctxt,
     mk_expr(cx, span, ast::expr_fn_block(fn_decl, blk))
 }
 pub fn mk_lambda(cx: @ext_ctxt,
-                       span: span,
-                       fn_decl: ast::fn_decl,
-                       expr: @ast::expr)
-                    -> @ast::expr {
+                 span: span,
+                 fn_decl: ast::fn_decl,
+                 expr: @ast::expr)
+              -> @ast::expr {
     let blk = mk_simple_block(cx, span, expr);
     mk_lambda_(cx, span, fn_decl, blk)
 }
@@ -294,6 +294,13 @@ pub fn mk_lambda_stmts(cx: @ext_ctxt,
     let blk = mk_block(cx, span, ~[], stmts, None);
     mk_lambda(cx, span, fn_decl, blk)
 }
+pub fn mk_lambda_no_args(cx: @ext_ctxt,
+                         span: span,
+                         expr: @ast::expr)
+                      -> @ast::expr {
+    let fn_decl = mk_fn_decl(~[], mk_ty_infer(cx, span));
+    mk_lambda(cx, span, fn_decl, expr)
+}
 pub fn mk_copy(cx: @ext_ctxt, sp: span, e: @ast::expr) -> @ast::expr {
     mk_expr(cx, sp, ast::expr_copy(e))
 }
@@ -303,11 +310,20 @@ pub fn mk_managed(cx: @ext_ctxt, sp: span, e: @ast::expr) -> @ast::expr {
 pub fn mk_pat(cx: @ext_ctxt, span: span, +pat: ast::pat_) -> @ast::pat {
     @ast::pat { id: cx.next_id(), node: pat, span: span }
 }
+pub fn mk_pat_wild(cx: @ext_ctxt, span: span) -> @ast::pat {
+    mk_pat(cx, span, ast::pat_wild)
+}
+pub fn mk_pat_lit(cx: @ext_ctxt,
+                  span: span,
+                  expr: @ast::expr) -> @ast::pat {
+    mk_pat(cx, span, ast::pat_lit(expr))
+}
 pub fn mk_pat_ident(cx: @ext_ctxt,
                     span: span,
                     ident: ast::ident) -> @ast::pat {
     mk_pat_ident_with_binding_mode(cx, span, ident, ast::bind_by_copy)
 }
+
 pub fn mk_pat_ident_with_binding_mode(cx: @ext_ctxt,
                                       span: span,
                                       ident: ast::ident,
@@ -435,8 +451,38 @@ pub fn mk_ty_param(cx: @ext_ctxt,
 }
 pub fn mk_lifetime(cx: @ext_ctxt,
                    span: span,
-                   ident: ast::ident) -> ast::Lifetime
-{
+                   ident: ast::ident)
+                -> ast::Lifetime {
     ast::Lifetime { id: cx.next_id(), span: span, ident: ident }
 }
-
+pub fn mk_arm(cx: @ext_ctxt,
+              span: span,
+              pats: ~[@ast::pat],
+              expr: @ast::expr)
+           -> ast::arm {
+    ast::arm {
+        pats: pats,
+        guard: None,
+        body: mk_simple_block(cx, span, expr)
+    }
+}
+pub fn mk_unreachable(cx: @ext_ctxt, span: span) -> @ast::expr {
+    let loc = cx.codemap().lookup_char_pos(span.lo);
+    mk_call_global(
+        cx,
+        span,
+        ~[
+            cx.ident_of(~"core"),
+            cx.ident_of(~"sys"),
+            cx.ident_of(~"begin_unwind"),
+        ],
+        ~[
+            mk_uniq_str(cx, span, ~"internal error: entered unreachable code"),
+            mk_uniq_str(cx, span, loc.file.name),
+            mk_uint(cx, span, loc.line),
+        ]
+    )
+}
+pub fn mk_unreachable_arm(cx: @ext_ctxt, span: span) -> ast::arm {
+    mk_arm(cx, span, ~[mk_pat_wild(cx, span)], mk_unreachable(cx, span))
+}