From ac0e5ea0ef22fbb7e0e2337a801584481b230a7b Mon Sep 17 00:00:00 2001
From: Paul Stansifer <paul.stansifer@gmail.com>
Date: Wed, 10 Aug 2011 13:21:51 -0700
Subject: [PATCH] Implement an untyped version of the AST, with a coversion
 back to the typed AST..

---
 src/comp/middle/typeck.rs      |   1 +
 src/comp/syntax/untyped_ast.rs | 816 +++++++++++++++++++++++++++++++++
 2 files changed, 817 insertions(+)
 create mode 100644 src/comp/syntax/untyped_ast.rs

diff --git a/src/comp/middle/typeck.rs b/src/comp/middle/typeck.rs
index 9a7d6fd1ef84..839e01a62f56 100644
--- a/src/comp/middle/typeck.rs
+++ b/src/comp/middle/typeck.rs
@@ -113,6 +113,7 @@ fn ty_param_kinds_and_ty_for_def(fcx: &@fn_ctxt, sp: &span, defn: &ast::def)
     let no_kinds: [ast::kind] = ~[];
     alt defn {
       ast::def_arg(id) {
+
         assert (fcx.locals.contains_key(id.node));
         let typ = ty::mk_var(fcx.ccx.tcx, lookup_local(fcx, sp, id.node));
         ret {kinds: no_kinds, ty: typ};
diff --git a/src/comp/syntax/untyped_ast.rs b/src/comp/syntax/untyped_ast.rs
new file mode 100644
index 000000000000..4ae7ef38f8d7
--- /dev/null
+++ b/src/comp/syntax/untyped_ast.rs
@@ -0,0 +1,816 @@
+import std::ivec;
+import std::ivec::map;
+import std::option;
+import std::option::some;
+import std::option::none;
+
+import ast::*;
+import codemap::span;
+import codemap::filename;
+
+tag ast_node {
+    branch(node_name, option::t[span], (@ast_node)[]);
+    i_seq((@ast_node)[]);
+    i_opt(option::t[@ast_node]);
+    l_bool(bool);
+    l_ident(ident);
+    l_fn_ident(fn_ident);
+    l_path(path); //doesn't have to be a leaf, but is effectively atomic
+    l_crate_num(crate_num);
+    l_node_id(node_id);
+    l_def_id(def_id);
+    l_ty_param(ty_param);
+    l_mutability(mutability);
+    l__auth(_auth); //singleton, but needed for uniformity
+    l_proto(proto);
+    l_binop(binop);
+    // moving this to node_name would make the macro system able to abstract
+    // over @/@mutable, but that poses parsing problems.
+    l_unop(unop);
+    l_mode(mode); //same here
+    l_init_op(init_op);
+    l_inlineness(inlineness);
+    l_native_abi(native_abi);
+    l_str(str);
+    l_char(char);
+    l_int(int);
+    l_uint(uint);
+    l_spawn_dom;
+    l_check_mode;
+    l_seq_kind;
+    l_ty_mach;
+    l_purity;
+    l_controlflow;
+    l_attr_style;
+
+    // these could be avoided, at the cost of making #br_* more convoluted
+    l_optional_filename(option::t[filename]);
+    l_optional_string(option::t[str]);
+    l_seq_ident(ident[]);
+    l_seq_ty_param(ty_param[]);
+
+}
+
+
+tag node_name {
+    n_crate_cfg;
+    n_crate;
+
+    //crate_directive:
+    n_cdir_src_mod;
+    n_cdir_dir_mod;
+    n_cdir_view_item;
+    n_cdir_syntax;
+    n_cdir_auth;
+
+    //meta_item:
+    n_meta_word;
+    n_meta_list;
+    n_meta_name_value;
+
+    n_blk;
+
+    //pat: (be sure to add node_id)
+    n_pat_wild;
+    n_pat_bind;
+    n_pat_lit;
+    n_pat_tag;
+    n_pat_rec;
+    n_pat_box;
+
+    n_field_pat;
+    //stmt:
+    n_stmt_decl;
+    n_stmt_expr;
+    n_stmt_crate_directive;
+
+    n_initializer;
+    n_local;
+
+    //decl:
+    n_decl_local;
+    n_decl_item;
+
+    n_arm;
+    //n_elt; //not used
+    n_field;
+    //expr: (be sure to add node_id)
+    n_expr_vec;
+    n_expr_rec;
+    n_expr_call;
+    n_expr_self_method;
+    n_expr_bind;
+    n_expr_spawn;
+    n_expr_binary;
+    n_expr_unary;
+    n_expr_lit;
+    n_expr_cast;
+    n_expr_if;
+    n_expr_ternary;
+    n_expr_while;
+    n_expr_for;
+    n_expr_for_each;
+    n_expr_do_while;
+    n_expr_alt;
+    n_expr_fn;
+    n_expr_block;
+    n_expr_move;
+    n_expr_assign;
+    n_expr_swap;
+    n_expr_assign_op;
+    n_expr_send;
+    n_expr_recv;
+    n_expr_field;
+    n_expr_index;
+    n_expr_path;
+    n_expr_fail;
+    n_expr_break;
+    n_expr_cont;
+    n_expr_ret;
+    n_expr_put;
+    n_expr_be;
+    n_expr_log;
+    n_expr_assert;
+    n_expr_check;
+    n_expr_if_check;
+    n_expr_port;
+    n_expr_chan;
+    n_expr_anon_obj;
+    n_expr_mac;
+
+    /*
+    n_mac_invoc; //must be expanded away
+    n_embed_type; //must be expanded away
+    n_embed_bloc; //must be expanded away
+    n_ellipsis; //must be expanded away
+    */
+
+    //lit:
+    n_lit_str;
+    n_lit_char;
+    n_lit_int;
+    n_lit_uint;
+    n_lit_mach_int;
+    n_lit_float;
+    n_lit_mach_float;
+    n_lit_nil;
+    n_lit_bool;
+
+    n_mt;
+    n_ty_field;
+    n_ty_arg;
+    n_ty_method;
+
+    //ty:
+    n_ty_nil;
+    //ty_bot; //"there is no syntax for this type"
+    n_ty_bool;
+    n_ty_int;
+    n_ty_uint;
+    n_ty_float;
+    n_ty_machine;
+    n_ty_char;
+    n_ty_str;
+    n_ty_istr;
+    n_ty_box;
+    n_ty_vec;
+    n_ty_ivec;
+    n_ty_ptr;
+    n_ty_task;
+    n_ty_port;
+    n_ty_chan;
+    n_ty_rec;
+    n_ty_fn;
+    n_ty_obj;
+    n_ty_path;
+    n_ty_type;
+    n_ty_constr;
+    //n_ty_mac; //should be expanded away
+
+    //carg_* and constr are a little funny, since they're type-parametric
+    //constr_arg:
+    n_carg_base;
+    n_carg_ident;
+    n_carg_lit;
+
+    n_constr;
+    //ack, there's a type and tag with the same name:
+    n_ty_constr_theactualconstraint;
+    n_arg;
+    n_fn_decl;
+    n__fn;
+    n_method;
+    n_obj_field;
+    n_anon_obj_field;
+    n__obj;
+    n_anon_obj;
+    n__mod;
+    n_native_mod;
+    n_variant_arg;
+    n_variant;
+
+    //view_item: (it might be necessary to restrict the generation of these)
+    n_view_item_use;
+    n_view_item_import;
+    n_view_item_import_glob;
+    n_view_item_export;
+
+    //n_obj_def_ids; //not used
+    n_attribute;
+
+    //special case; has ident, attrs, node_id, and span
+    n_item;
+    //item_:
+    n_item_const;
+    n_item_fn;
+    n_item_mod;
+    n_item_native_mod;
+    n_item_ty;
+    n_item_tag;
+    n_item_obj;
+    n_item_res;
+
+    //special case; has ident, attrs, node_id, and span
+    n_native_item;
+    //native_item_:
+    n_native_item_ty;
+    n_native_item_fn;
+}
+
+type ctx = {
+    ff: ff,
+    sess: driver::session::session, //maybe remove
+    next_id: fn() -> node_id
+};
+
+/** Type of failure function: to be invoked if typification fails.
+    It's hopefully a bug for this to be invoked without a span. */
+type ff = fn(sp: option::t[span], msg: str) -> !;
+
+fn dummy() {
+
+    // arguments explicitly structured here (instead of writing `args, ...`)
+    // to make error messages easier to deal with.
+    #macro[[#br_alt[val, ctx, [[tagname, n_tagname, [elt, ...]],
+                              more_tags, ...]],
+            #br_alt_gen[do_span, val, ctx, [[tagname, n_tagname, [elt, ...]],
+                                           more_tags, ...]]]];
+    #macro[[#br_alt_no_span[val, ctx,
+                            [[tagname, n_tagname, [elt, ...]],
+                             more_tags, ...]],
+            #br_alt_gen[do_not_span, val, ctx,
+                        [[tagname, n_tagname, [elt, ...]], more_tags, ...]]]];
+
+    // the silly `n_tagname` will be replacable with an invocation of
+    // #concat_idents after subtitution into arbitrary AST nodes works
+    #macro[[#br_alt_gen[possibly_span, val, ctx,
+                        [[tagname, n_tagname, [elt, ...]], more_tags, ...]],
+            alt val {
+              branch(n_tagname., sp, chldrn) {
+                #possibly_span[sp, #br_alt_core[ctx, sp, tagname,
+                                                chldrn, 0u, [elt, ...], []]]
+              }
+              //replace this explicit recursion with `...`, once it works
+              //over all kinds of AST nodes.
+              _ { #br_alt_gen[possibly_span, val, ctx, [more_tags, ...]] }
+            }
+           ],
+           [#br_alt_gen[possibly_span, val, ctx, []],
+            alt val {
+              branch(_, sp, _) {
+                ctx.ff(sp, "expected " + #ident_to_str[tagname])
+              }
+              _ { ctx.ff(none, "expected " + #ident_to_str[tagname]) }
+            }
+           ]];
+
+    // this wackiness is just because we need indices
+    #macro[[#br_alt_core[ctx, sp, ctor, kids, offset, [h, more_hs, ...],
+                         [accum, ...]],
+            #br_alt_core[ctx, sp, ctor, kids, offset+1u, [more_hs, ...],
+                         [accum, ...,
+                          #extract_elt[ctx, sp, kids, offset, h]]]],
+           [#br_alt_core[ctx, sp, ctor, kids, offset, [], [accum, ...]],
+            ctor(accum, ...)]];
+
+
+
+    #macro[[#br_rec[args, ...], #br_rec_gen[do_span, args, ...]]];
+    #macro[[#br_rec_no_span[args, ...], #br_rec_gen[do_not_span, args, ...]]];
+
+
+    #macro[[#br_rec_gen[possibly_span, val, ctx, tagname, n_tagname, fields],
+            alt val {
+              branch(n_tagname., sp, chldrn) {
+                #possibly_span[sp, #br_rec_core[ctx, sp, chldrn, fields]]
+              }
+              branch(_, sp, _) {
+                ctx.ff(sp, "expected " + #ident_to_str[tagname])
+              }
+              _ { ctx.ff(option::none, "expected " + #ident_to_str[tagname]) }
+            }]];
+
+    #macro[[#do_span[sp, node_val],
+            {node: node_val,
+             span: alt sp {
+               some(s) { s }
+               none. { ctx.ff(none, "needed a span"); }
+             }
+            }]];
+    #macro[[#do_not_span[sp, node_val], node_val]];
+
+
+    //this abomination can go away when `...` works properly over
+    //all kinds of AST nodes.
+    #macro[[#br_rec_core[ctx, sp, kids, [[f0, fh0]]],
+            {f0: #extract_elt[ctx, sp, kids, 0u, fh0]}],
+           [#br_rec_core[ctx, sp, kids, [[f0, fh0], [f1, fh1]]],
+            {f0: #extract_elt[ctx, sp, kids, 0u, fh0],
+             f1: #extract_elt[ctx, sp, kids, 1u, fh1]}],
+           [#br_rec_core[ctx, sp, kids, [[f0, fh0], [f1, fh1], [f2, fh2]]],
+            {f0: #extract_elt[ctx, sp, kids, 0u, fh0],
+             f1: #extract_elt[ctx, sp, kids, 1u, fh1],
+             f2: #extract_elt[ctx, sp, kids, 2u, fh2]}],
+           [#br_rec_core[ctx, sp, kids,
+                         [[f0, fh0], [f1, fh1], [f2, fh2], [f3, fh3]]],
+            {f0: #extract_elt[ctx, sp, kids, 0u, fh0],
+             f1: #extract_elt[ctx, sp, kids, 1u, fh1],
+             f2: #extract_elt[ctx, sp, kids, 2u, fh2],
+             f3: #extract_elt[ctx, sp, kids, 3u, fh3]}],
+           [#br_rec_core[ctx, sp, kids,
+                         [[f0, fh0], [f1, fh1], [f2, fh2], [f3, fh3],
+                          [f4, fh4]]],
+            {f0: #extract_elt[ctx, sp, kids, 0u, fh0],
+             f1: #extract_elt[ctx, sp, kids, 1u, fh1],
+             f2: #extract_elt[ctx, sp, kids, 2u, fh2],
+             f3: #extract_elt[ctx, sp, kids, 3u, fh3],
+             f4: #extract_elt[ctx, sp, kids, 4u, fh4]}],
+           [#br_rec_core[ctx, sp, kids,
+                         [[f0, fh0], [f1, fh1], [f2, fh2], [f3, fh3],
+                          [f4, fh4], [f5, fh5]]],
+            {f0: #extract_elt[ctx, sp, kids, 0u, fh0],
+             f1: #extract_elt[ctx, sp, kids, 1u, fh1],
+             f2: #extract_elt[ctx, sp, kids, 2u, fh2],
+             f3: #extract_elt[ctx, sp, kids, 3u, fh3],
+             f4: #extract_elt[ctx, sp, kids, 4u, fh4],
+             f5: #extract_elt[ctx, sp, kids, 5u, fh5]}]];
+
+    #macro[ //keywords would make these two nicer:
+        [#extract_elt[ctx, sp, elts, idx, []], ctx.next_id()],
+        [#extract_elt[ctx, cp, elts, idx, [[]]], sp],
+        [#extract_elt[ctx, sp, elts, idx, [leaf_destructure]],
+         alt *elts.(idx) {
+           leaf_destructure(x) { x }
+           _ {
+             ctx.ff(sp, #fmt["expected %s in position %u",
+                             #ident_to_str[leaf_destructure], idx])
+           }
+         }],
+        [#extract_elt[ctx, sp, elts, idx, extract_fn],
+         extract_fn(ctx, elts.(idx))]];
+}
+
+fn seq_cv[T](conversion: fn (&ctx, &@ast_node) -> T)
+    -> fn (&ctx, @ast_node) -> T[] {
+    ret lambda(ctx: &ctx, ut: @ast_node) -> T[] {
+        ret alt *ut {
+          i_seq(uts) { map(bind conversion(ctx, _), uts) }
+          branch(_, sp, _) {
+            ctx.ff(sp, "expected a sequence, found a branch");
+          }
+          _ { ctx.ff(none, "expected a sequence"); }
+        }
+    }
+}
+
+fn opt_cv[T](conversion: fn (&ctx, &@ast_node) -> T)
+    -> fn (&ctx, @ast_node) -> option::t[T] {
+    ret lambda(ctx: &ctx, ut: @ast_node) -> option::t[T] {
+        ret alt *ut {
+          i_opt(ut_maybe) { option::map(bind conversion(ctx, _), ut_maybe) }
+          branch(_, sp, _) {
+            ctx.ff(sp, "expected a sequence, found a branch");
+          }
+          _ { ctx.ff(none, "expected a sequence"); }
+        }
+    }
+}
+
+
+// expect leaf/branch fn × scalar/vec/option
+
+fn cv_crate(ctx: &ctx, ut: &@ast_node) -> @crate {
+    ret @#br_rec[*ut, ctx, crate, n_crate,
+                 [[directives, seq_cv(cv_crate_directive)],
+                  [module, cv__mod],
+                  [attrs, seq_cv(cv_attribute)],
+                  [config, cv_crate_cfg]]];
+}
+
+fn cv_crate_cfg(ctx: &ctx, ut: &@ast_node) -> crate_cfg {
+    ret alt *ut {
+      branch(n_crate_cfg., _, meta_items) {
+        ivec::map(bind cv_meta_item(ctx,_), meta_items)
+      }
+      branch(_, sp, _) { ctx.ff(sp,"Invalid crate_cfg") }
+    };
+}
+
+fn cv_crate_directive(ctx: &ctx, ut: &@ast_node) -> @crate_directive {
+    ret @#br_alt[*ut, ctx,
+                 [[cdir_src_mod, n_cdir_src_mod,
+                   [[l_ident], [l_optional_filename], seq_cv(cv_attribute)]],
+                  [cdir_dir_mod, n_cdir_dir_mod,
+                   [[l_ident], [l_optional_filename],
+                    seq_cv(cv_crate_directive),
+                    seq_cv(cv_attribute)]],
+                  [cdir_view_item, n_cdir_view_item, [cv_view_item]],
+                  [cdir_syntax, n_cdir_syntax,       [[l_path]]],
+                  [cdir_auth, n_cdir_auth,           [[l_path], [l__auth]]]]];
+}
+
+fn cv_meta_item(ctx: &ctx, ut: &@ast_node) -> @meta_item {
+    ret @#br_alt[*ut, ctx,
+                 [[meta_word, n_meta_word,             [[l_ident]]],
+                  [meta_list, n_meta_list,
+                   [[l_ident], seq_cv(cv_meta_item)]],
+                  [meta_name_value, n_meta_name_value, [[l_ident], cv_lit]]]];
+}
+
+fn cv_blk(ctx: &ctx, ut: &@ast_node) -> blk {
+    ret #br_rec[*ut, ctx, blk, n_blk,
+                [[stmts, seq_cv(cv_stmt)],
+                 [expr,  opt_cv(cv_stmt)],
+                 [id,    [l_node_id]]]];
+}
+
+fn cv_pat(ctx: &ctx, ut: &@ast_node) -> @pat {
+    ret @{id: ctx.next_id(),
+          node: #br_alt_no_span
+              [*ut, ctx,
+               [[pat_wild, n_pat_wild, []],
+                [pat_bind, n_pat_bind, [[l_ident]]],
+                [pat_tag, n_pat_tag,   [[l_ident], seq_cv(cv_pat)]],
+                [pat_rec, n_pat_rec,   [seq_cv(cv_field_pat),
+                                        [l_bool]]],
+                [pat_box, n_pat_box,   [cv_pat]]]],
+          span: alt *ut {
+            branch(_,some(sp),_) { sp }
+            none. { ctx.ff("pat needs a span"); }
+          }
+         }
+}
+
+fn cv_field_pat(ctx: &ctx, ut: &@ast_node) -> field_pat {
+    ret #br_rec[*ut, ctx, field_pat, n_field_pat,
+                [[ident, [l_ident]], [pat, cv_pat]]];
+}
+
+fn cv_stmt(ctx: &ctx, ut: &@ast_node) -> @stmt {
+    ret @#br_alt[*ut, ctx,
+                 [[stmt_decl, n_stmt_decl, [cv_decl, []]],
+                  [stmt_expr, n_stmt_expr, [cv_expr, []]],
+                  [stmt_crate_directive, n_stmt_crate_directive,
+                   [cv_crate_directive]]]];
+}
+
+fn cv_initializer(ctx: &ctx, ut: &@ast_node) -> initializer {
+    ret #br_rec[*ut, ctx, initializer, n_initializer,
+               [[op,   [l_init_op]],
+                [expr, cv_expr]]];
+}
+
+fn cv_local(ctx: &ctx, ut: &@ast_node) -> @local {
+    ret @#br_rec[*ut, ctx, local, n_local,
+                 [[ty,   opt_cv(cv_ty)],
+                  [pat,  cv_pat],
+                  [init, opt_cv(cv_initializer)],
+                  [id,   []]]]
+}
+
+fn cv_decl(ctx: &ctx, ut: &@ast_node) -> @decl {
+    ret @#br_alt[*ut, ctx,
+                 [[decl_local, n_decl_local, [cv_local]],
+                  [decl_item, n_decl_item, [cv_item]]]];
+}
+
+fn cv_arm(ctx: &ctx, ut: &@ast_node) -> arm {
+    ret #br_rec[*ut, ctx, arm, n_arm,
+                [[pats, seq_cv(cv_pat)],
+                 [body, cv_blk]]];
+}
+
+fn cv_field(ctx: &ctx, ut: &@ast_node) -> field {
+    ret #br_rec[*ut, ctx, field, n_field,
+                [[mut,   [l_mutability]],
+                 [ident, [l_ident]],
+                 [expr,  cv_expr]]];
+}
+
+fn cv_expr(ctx: &ctx, ut: &@ast_node) -> @expr {
+    ret @{id: ctx.next_id(),
+          node: #br_alt_no_span
+              [*ut, ctx,
+               [[expr_vec, n_expr_vec,
+                 [seq_cv(cv_expr), [l_mutability], [l_seq_kind]]],
+                [expr_rec, n_expr_rec,
+                 [seq_cv(cv_field), opt_cv(cv_expr)]],
+                [expr_call, n_expr_call,
+                 [cv_expr, seq_cv(cv_expr)]],
+                [expr_self_method, n_expr_self_method, [[l_ident]]],
+                [expr_bind, n_expr_bind,
+                 [cv_expr, seq_cv(opt_cv(cv_expr))]],
+                [expr_spawn, n_expr_spawn,
+                 [[l_spawn_dom], [l_optional_string], cv_expr,
+                  seq_cv(cv_expr)]],
+                [expr_binary, n_expr_binary, [[l_binop], cv_expr, cv_expr]],
+                [expr_unary, n_expr_unary, [[l_unop], cv_expr]],
+                [expr_lit, n_expr_lit, [cv_lit]],
+                [expr_cast, n_expr_cast, [cv_expr, cv_ty]],
+                [expr_if, n_expr_if, [cv_expr, cv_blk, opt_cv(cv_expr)]],
+                [expr_ternary, n_expr_ternary, [cv_expr, cv_expr, cv_expr]],
+                [expr_while, n_expr_while, [cv_expr, cv_blk]],
+                [expr_for, n_expr_for, [cv_local, cv_expr, cv_blk]],
+                [expr_for_each, n_expr_for_each, [cv_local, cv_expr, cv_blk]],
+                [expr_do_while, n_expr_do_while, [cv_blk, cv_expr]],
+                [expr_alt, n_expr_alt, [cv_expr, seq_cv(cv_arm)]],
+                [expr_fn, n_expr_fn, [cv__fn]],
+                [expr_block, n_expr_block, [cv_expr]],
+                [expr_move, n_expr_move, [cv_expr, cv_expr]],
+                [expr_assign, n_expr_assign, [cv_expr, cv_expr]],
+                [expr_swap, n_expr_swap, [cv_expr, cv_expr]],
+                [expr_assign_op, n_expr_assign_op,
+                 [[l_binop], cv_expr, cv_expr]],
+                [expr_send, n_expr_send, [cv_expr, cv_expr]],
+                [expr_recv, n_expr_recv, [cv_expr, cv_expr]],
+                [expr_field, n_expr_field, [cv_expr, [l_ident]]],
+                [expr_index, n_expr_index, [cv_expr, cv_expr]],
+                [expr_path, n_expr_path, [[l_path]]],
+                [expr_fail, n_expr_fail, [opt_cv(cv_expr)]],
+                [expr_break, n_expr_break, []],
+                [expr_cont, n_expr_cont, []],
+                [expr_ret, n_expr_ret, [opt_cv(cv_expr)]],
+                [expr_put, n_expr_put, [opt_cv(cv_expr)]],
+                [expr_be, n_expr_be, [cv_expr]],
+                [expr_log, n_expr_log, [cv_expr]],
+                [expr_assert, n_expr_assert, [cv_expr]],
+                [expr_check, n_expr_check, [cv_expr]],
+                [expr_if_check, n_expr_if_check,
+                 [cv_expr, cv_blk, opt_cv(cv_expr)]],
+                [expr_port, n_expr_port, [opt_cv(cv_ty)]],
+                [expr_chan, n_expr_chan, [cv_expr]],
+                [expr_anon_obj, n_expr_anon_obj, [cv_anon_obj]]]
+              ],
+          span: alt *ut {
+            branch(_,some(sp),_) { sp }
+            none. { ctx.ff("pat needs a span"); }
+          }
+         }
+}
+
+
+fn cv_lit(ctx: &ctx, ut: &@ast_node) -> @lit {
+    ret @#br_alt[*ut, ctx,
+                 [[lit_str, n_lit_str, [[l_str], [l_seq_kind]]],
+                  [lit_char, n_lit_char, [[l_char]]],
+                  [lit_int, n_lit_int, [[l_int]]],
+                  [lit_uint, n_lit_uint, [[l_uint]]],
+                  [lit_mach_int, n_lit_mach_int, [[l_ty_mach], [l_int]]],
+                  [lit_float, n_lit_float, [[l_str]]],
+                  [lit_mach_float, n_lit_mach_float, [[l_ty_mach], [l_str]]],
+                  [lit_nil, n_lit_nil, []],
+                  [lit_bool, n_lit_bool, [[l_bool]]]]];
+}
+
+fn cv_mt(ctx: &ctx, ut: &@ast_node) -> mt {
+    ret #br_rec_no_span[*ut, ctx, mt, n_mt,
+                        [[ty, cv_ty], [mut, [l_mutability]]]];
+}
+
+fn cv_ty_field(ctx: &ctx, ut: &@ast_node) -> ty_field {
+    ret #br_rec[*ut, ctx, ty_field, n_ty_field,
+                [[ident, [l_ident]], [mt, cv_mt]]];
+}
+
+fn cv_ty_arg(ctx: &ctx, ut: &@ast_node) -> ty_arg {
+    ret #br_rec[*ut, ctx, ty_arg, n_ty_arg,
+                [[mode, [l_mode]], [ty, cv_ty]]];
+}
+
+fn cv_ty_method(ctx: &ctx, ut: &@ast_node) -> ty_method {
+    ret #br_rec[*ut, ctx, ty_method, n_ty_method,
+                [[proto, [l_proto]],
+                 [ident, [l_ident]],
+                 [inputs, seq_cv(cv_ty_arg)],
+                 [output, cv_ty],
+                 [cf, [l_controlflow]],
+                 [constrs, seq_cv(cv_constr)]]];
+}
+
+fn cv_ty(ctx: &ctx, ut: &@ast_node) -> @ty {
+    ret @#br_alt[*ut, ctx,
+                 [[ty_nil, n_ty_nil, []],
+                  [ty_bool, n_ty_bool, []],
+                  [ty_int, n_ty_int, []],
+                  [ty_uint, n_ty_uint, []],
+                  [ty_float, n_ty_float, []],
+                  [ty_machine, n_ty_machine, [[l_ty_mach]]],
+                  [ty_char, n_ty_char, []],
+                  [ty_str, n_ty_str, []],
+                  [ty_istr, n_ty_istr, []],
+                  [ty_box, n_ty_box, [cv_mt]],
+                  [ty_vec, n_ty_vec, [cv_mt]],
+                  [ty_ivec, n_ty_ivec, [cv_mt]],
+                  [ty_ptr, n_ty_ptr, [cv_mt]],
+                  [ty_task, n_ty_task, []],
+                  [ty_port, n_ty_port, [cv_ty]],
+                  [ty_chan, n_ty_chan, [cv_ty]],
+                  [ty_rec, n_ty_rec, [seq_cv(cv_ty_field)]],
+                  [ty_fn, n_ty_fn,
+                   [[l_proto], seq_cv(cv_arg), cv_ty, [l_controlflow],
+                    seq_cv(cv_constr)]],
+                  [ty_obj, n_ty_obj, [seq_cv(cv_ty_method)]],
+                  [ty_path, n_ty_path, [[l_path], [] /*node_id*/]],
+                  [ty_type, n_ty_type, []],
+                  [ty_constr, n_ty_constr, [cv_ty, seq_cv(cv_constr)]]]]
+}
+
+/* these four are expanded from the type-parametric code in ast.rs */
+
+fn cv_carg_uint(ctx: &ctx, ut: &@ast_node) -> constr_arg_general_[uint] {
+    ret #br_alt[*ut, ctx,
+                [[carg_base, n_carg_base, []],
+                 [carg_ident, n_carg_ident, [[l_uint]]],
+                 [carg_lit, n_carg_lit, [cv_lit]]]];
+}
+fn cv_carg_path(ctx: &ctx, ut: &@ast_node) -> constr_arg_general_[path] {
+    ret #br_alt[*ut, ctx,
+                [[carg_base, n_carg_base, []],
+                 [carg_ident, n_carg_ident, [[l_path]]],
+                 [carg_lit, n_carg_lit, [cv_lit]]]];
+}
+
+fn cv_constr(ctx: &ctx, ut: &@ast_node) -> @constr {
+    ret @#br_rec[*ut, ctx, constr, n_constr,
+                 [[path, [l_path]],
+                  [args, cv_carg_uint],
+                  [id, [] /*node_id*/]]];
+}
+fn cv_typed_constr(ctx: &ctx, ut: &@ast_node) -> @ty_constr {
+    ret @#br_rec[*ut, ctx, ty_constr, n_ty_constr_theactualconstraint,
+                 [[path, [l_path]],
+                  [args, cv_carg_path],
+                  [id, [] /*node_id*/]]];
+}
+
+
+fn cv_arg(ctx: &ctx, ut: &@ast_node) -> arg {
+    ret #br_rec_no_span[*ut, ctx, arg, n_arg,
+                        [[mode, [l_mode]],
+                         [ty, cv_ty],
+                         [ident, [l_ident]],
+                         [id, [] /*node_id*/]]];
+}
+
+fn cv_fn_decl(ctx: &ctx, ut: &@ast_node) -> fn_decl {
+    ret #br_rec_no_span[*ut, ctx, fn_decl, n_fn_decl,
+                        [[inputs, seq_cv(cv_arg)],
+                         [output, cv_ty],
+                         [il, [l_inlineness]],
+                         [cf, [l_controlflow]],
+                         [constraints, seq_cv(cv_constr)]]];
+}
+
+fn cv__fn(ctx: &ctx, ut: &@ast_node) -> _fn {
+    ret #br_rec_no_span[*ut, ctx, _fn, n__fn,
+                        [[decl, cv_fn_decl],
+                         [proto, [l_proto]],
+                         [body, cv_blk]]];
+}
+
+fn cv_method(ctx: &ctx, ut: &@ast_node) -> @method {
+    ret @#br_rec[*ut, ctx, method, n_method,
+                 [[ident, [l_ident]],
+                  [meth, cv__fn],
+                  [id, [] /*node_id*/]]];
+}
+
+fn cv_obj_field(ctx: &ctx, ut: &@ast_node) -> obj_field {
+    ret #br_rec[*ut, ctx, obj_field, n_obj_field,
+                [[mut, [l_mutability]],
+                 [ty, cv_ty],
+                 [ident, [l_ident]],
+                 [id, [] /*node_id*/]]];
+}
+
+fn cv_anon_obj_field(ctx: &ctx, ut: &@ast_node) -> anon_obj_field {
+    ret #br_rec[*ut, ctx, anon_obj_field, n_anon_obj_field,
+                [[mut, [l_mutability]],
+                 [ty, cv_ty],
+                 [expr, cv_expr],
+                 [ident, [l_ident]],
+                 [id, [] /*node_id*/]]];
+}
+
+fn cv__obj(ctx: &ctx, ut: &@ast_node) ->  _obj {
+    ret #br_rec_no_span[*ut, ctx, _obj, n__obj,
+                        [[fields, seq_cv(cv_obj_field)],
+                         [methods, seq_cv(cv_method)]]];
+}
+
+fn cv_anon_obj(ctx: &ctx, ut: &@ast_node) ->  anon_obj {
+    ret #br_rec_no_span[*ut, ctx, anon_obj, n_anon_obj,
+                        [[fields, opt_cv(seq_cv(cv_anon_obj_field))],
+                         [methods, seq_cv(cv_method)],
+                         [inner_obj, opt_cv(cv_expr)]]];
+}
+
+fn cv__mod(ctx: &ctx, ut: &@ast_node) -> _mod {
+    ret #br_rec_no_span[*ut, ctx, _mod, n__mod,
+                        [[view_items, seq_cv(cv_view_item)],
+                         [items, seq_cv(cv_item)]]];
+}
+
+fn cv_native_mod(ctx: &ctx, ut: &@ast_node) -> native_mod {
+    ret #br_rec_no_span[*ut, ctx, native_mod, n_native_mod,
+                        [[native_name, [l_str]],
+                         [abi, [l_native_abi]],
+                         [view_items, seq_cv(cv_view_item)],
+                         [items, seq_cv(cv_item)]]];
+}
+
+fn cv_variant_arg(ctx: &ctx, ut: &@ast_node) -> variant_arg {
+    ret #br_rec_no_span[*ut, ctx, variant_arg, n_variant_arg,
+                        [[ty, cv_ty],
+                         [id, [] /*node_id*/]]];
+}
+
+fn cv_variant(ctx: &ctx, ut: &@ast_node) -> variant {
+    ret #br_rec[*ut, ctx, variant, n_variant,
+                [[name, [l_str]],
+                 [args, seq_cv(cv_variant_arg)],
+                 [id, [] /*node_id*/]]];
+}
+
+fn cv_view_item(ctx: &ctx, ut: &@ast_node) -> @view_item {
+    ret @#br_alt[*ut, ctx,
+                 [[view_item_use, n_view_item_use,
+                   [[l_ident], seq_cv(cv_meta_item), [] /*node_id*/]],
+                  [view_item_import, n_view_item_import,
+                   [[l_ident], [l_seq_ident], []]],
+                  [view_item_import_glob, n_view_item_import_glob,
+                   [[l_seq_ident], []]],
+                  [view_item_export, n_view_item_export,
+                   [[l_ident], []]]]];
+}
+
+fn cv_attribute(ctx: &ctx, ut: &@ast_node) -> attribute {
+    ret #br_rec[*ut, ctx, attribute, n_attribute,
+                [[style, [l_attr_style]],
+                 [value, cv_meta_item]]];
+}
+
+/* item and native_item have large enough wrappers that their underscored
+   components get separate handling */
+
+fn cv_item(ctx: &ctx, ut: &@ast_node) -> @item {
+    ret @#br_rec[*ut, ctx, item, n_item,
+                 [[ident, [l_ident]],
+                  [attrs, seq_cv(cv_attribute)],
+                  [id, [] /*node_id*/],
+                  [node, cv_item_],
+                  [span, [[]] /*span*/]]];
+}
+
+fn cv_item_(ctx: &ctx, ut: &@ast_node) -> item_ {
+    ret #br_alt_no_span[*ut, ctx,
+                        [[item_const, n_item_const, [cv_ty, cv_expr]],
+                         [item_fn, n_item_fn, [cv__fn, [l_seq_ty_param]]],
+                         [item_mod, n_item_mod, [cv__mod]],
+                         [item_native_mod, n_item_native_mod,
+                          [cv_native_mod]],
+                         [item_ty, n_item_ty, [cv_ty, [l_seq_ty_param]]],
+                         [item_tag, n_item_tag,
+                          [seq_cv(cv_variant), [l_seq_ty_param]]],
+                         [item_obj, n_item_obj,
+                          [cv__obj, [l_seq_ty_param], [] /*node_id*/]],
+                         [item_res, n_item_res,
+                          [cv__fn, [] /*node_id*/, [l_seq_ty_param],
+                           [] /*node_id*/]]]];
+}
+
+fn cv_native_item(ctx: &ctx, ut: &@ast_node) -> @native_item {
+    ret @#br_rec[*ut, ctx, native_item, n_native_item,
+                 [[ident, [l_ident]],
+                  [attrs, seq_cv(cv_attribute)],
+                  [node, cv_native_item_],
+                  [id, [] /*node_id*/],
+                  [span, [[]] /*span*/]]];
+}
+
+fn cv_native_item_(ctx: &ctx, ut: &@ast_node) -> native_item_ {
+    ret #br_alt[*ut, ctx,
+                [[native_item_ty, n_native_item_ty, []],
+                 [native_item_fn, n_native_item_fn,
+                  [[l_optional_string], cv_fn_decl, [l_seq_ty_param]]]]];
+}