fixup serialize_variant

1 files changed, 564 insertions, 0 deletions

diff --git a/src/rustc/syntax/ext/auto_serialize.rs b/src/rustc/syntax/ext/auto_serialize.rs
new file mode 100644
index 00000000000..5f1fa8cb379
--- /dev/null
+++ b/src/rustc/syntax/ext/auto_serialize.rs
@@ -0,0 +1,564 @@
+/*
+
+The compiler code necessary to implement the #[auto_serialize]
+extension.  The idea here is that type-defining items may be tagged
+with #[auto_serialize], which will cause us to generate a little
+companion module with the same name as the item.
+
+For example, a type like:
+
+    type node_id = uint;
+
+would generate a companion module like:
+
+    mod node_id {
+        use std;
+        import std::serialization::serializer;
+        import std::serialization::deserializer;
+        fn serialize<S: serializer>(s: S, v: node_id) {
+             s.emit_uint(v);
+        }
+        fn deserializer<D: deserializer>(d: D) -> node_id {
+             d.read_uint()
+        }
+    }
+
+Other interesting scenarios are whe the item has type parameters or
+references other non-built-in types.  A type definition like:
+
+    type spanned<T> = {node: T, span: span};
+
+would yield a helper module like:
+
+    mod spanned {
+        use std;
+        import std::serialization::serializer;
+        import std::serialization::deserializer;
+        fn serialize<S: serializer,T>(s: S, t: fn(T), v: spanned<T>) {
+             s.emit_rec(2u) {||
+                 s.emit_rec_field("node", 0u) {||
+                     t(s.node);
+                 };
+                 s.emit_rec_field("span", 1u) {||
+                     span::serialize(s, s.span);
+                 };
+             }
+        }
+        fn deserializer<D: deserializer>(d: D, t: fn() -> T) -> node_id {
+             d.read_rec(2u) {||
+                 {node: d.read_rec_field("node", 0u, t),
+                  span: d.read_rec_field("span", 1u) {||span::deserialize(d)}}
+             }
+        }
+    }
+
+In general, the code to serialize an instance `v` of a non-built-in
+type a::b::c<T0,...,Tn> looks like:
+
+    a::b::c::serialize(s, {|v| c_T0}, ..., {|v| c_Tn}, v)
+
+where `c_Ti` is the code to serialize an instance `v` of the type
+`Ti`.
+
+Similarly, the code to deserialize an instance of a non-built-in type
+`a::b::c<T0,...,Tn>` using the deserializer `d` looks like:
+
+    a::b::c::deserialize(d, {|| c_T0}, ..., {|| c_Tn})
+
+where `c_Ti` is the code to deserialize an instance of `Ti` using the
+deserializer `d`.
+
+TODO--Hygiene. Search for "__" strings.
+
+Misc notes:
+-----------
+
+I use move mode arguments for ast nodes that will get inserted as is
+into the tree.  This is intended to prevent us from inserting the same
+node twice.
+
+*/
+import base::*;
+import driver::session::session;
+import codemap::span;
+import std::map;
+
+export expand_auto_serialize;
+
+enum ser_cx = {
+    ext_cx: ext_ctxt,
+    tps: map::map<str, fn@(@ast::expr) -> [@ast::stmt]>
+};
+
+fn expand_auto_serialize(cx: ext_ctxt,
+                         span: span,
+                         _mitem: ast::meta_item,
+                         in_items: [@ast::item]) -> [@ast::item] {
+    vec::flat_map(in_items) {|in_item|
+        alt in_item.node {
+          ast::item_ty(ty, tps) {
+            [in_item, ty_module(cx, in_item.ident, copy ty, tps)]
+          }
+
+          ast::item_enum(variants, tps) {
+            [in_item, enum_module(cx, in_item.ident, variants, tps)]
+          }
+
+          _ {
+            cx.session().span_err(span, "#[auto_serialize] can only be \
+                                         applied to type and enum \
+                                         definitions");
+            [in_item]
+          }
+        }
+    }
+}
+
+impl helpers for ext_ctxt {
+    fn next_id() -> ast::node_id { self.session().next_node_id() }
+
+    fn path(span: span, strs: [str]) -> @ast::path {
+        @{node: {global: false,
+                 idents: strs + ["serialize"],
+                 types: []},
+          span: span}
+    }
+
+    fn ty_path(span: span, strs: [str]) -> @ast::ty {
+        @{node: ast::ty_path(self.path(span, strs), self.next_id()),
+          span: span}
+    }
+}
+
+impl helpers for ser_cx {
+    fn session() -> session { self.ext_cx.session() }
+    fn next_id() -> ast::node_id { self.ext_cx.next_id() }
+    fn path(span: span, strs: [str]) -> @ast::path {
+        self.ext_cx.path(span, strs)
+    }
+    fn ty_path(span: span, strs: [str]) -> @ast::ty {
+        self.ext_cx.ty_path(span, strs)
+    }
+
+    fn expr(span: span, node: ast::expr_) -> @ast::expr {
+        @{id: self.next_id(), node: node, span: span}
+    }
+
+    fn var_ref(span: span, name: str) -> @ast::expr {
+        self.expr(span, ast::expr_path(self.path(span, [name])))
+    }
+
+    fn blk(span: span, stmts: [@ast::stmt]) -> ast::blk {
+        {node: {view_items: [],
+                stmts: stmts,
+                expr: none,
+                id: self.next_id(),
+                rules: ast::default_blk},
+         span: span}
+    }
+
+    fn binder_pat(span: span, nm: str) -> @ast::pat {
+        let path = @{node: {global: false,
+                            idents: [nm],
+                            types: []},
+                     span: span};
+        @{id: self.next_id(),
+          node: ast::pat_ident(path, none),
+          span: span}
+    }
+
+    fn stmt(expr: @ast::expr) -> @ast::stmt {
+        @{node: ast::stmt_semi(expr, self.next_id()),
+          span: expr.span}
+    }
+
+    fn alt_stmt(arms: [ast::arm], span: span, -v: @ast::expr) -> @ast::stmt {
+        self.stmt(
+            self.expr(
+                span,
+                ast::expr_alt(v, arms, ast::alt_exhaustive)))
+    }
+
+    fn lit_str(span: span, s: str) -> @ast::expr {
+        self.expr(
+            span,
+            ast::expr_lit(
+                @{node: ast::lit_str(s),
+                  span: span}))
+    }
+
+    fn lit_uint(span: span, i: uint) -> @ast::expr {
+        self.expr(
+            span,
+            ast::expr_lit(
+                @{node: ast::lit_uint(i as u64, ast::ty_u),
+                  span: span}))
+    }
+
+    fn lambda(-blk: @ast::blk) -> @ast::expr {
+        let blk_e = cx.expr(blk.span, expr_block(blk));
+        #ast(expr){{|| $(blk_e) }}
+    }
+
+    fn clone(v: @ast::expr) -> @ast::expr {
+        let fld = fold::make_fold({
+            new_id: {|_id| self.next_id()}
+            with *fold::default_ast_fold()
+        });
+        fld.fold_expr(v)
+    }
+
+    fn clone_ty_param(v: ast::ty_param) -> ast::ty_param {
+        let fld = fold::make_fold({
+            new_id: {|_id| self.next_id()}
+            with *fold::default_ast_fold()
+        });
+        fold::fold_ty_param(v, fld)
+    }
+
+    fn at(span: span, expr: @ast::expr) -> @ast::expr {
+        fn repl_sp(old_span: span, repl_span: span, with_span: span) -> span {
+            if old_span == repl_span {
+                with_span
+            } else {
+                old_span
+            }
+        }
+
+        let fld = fold::make_fold({
+            new_span: repl_sp(_, ast_util::dummy_sp(), span)
+            with *fold::default_ast_fold()
+        });
+
+        fld.fold_expr(expr)
+    }
+}
+
+fn serialize_path(cx: ser_cx, path: @ast::path,
+                  -s: @ast::expr, -v: @ast::expr)
+    -> [@ast::stmt] {
+    let ext_cx = cx.ext_cx;
+
+    // We want to take a path like a::b::c<...> and generate a call
+    // like a::b::c::serialize(s, ...), as described above.
+
+    let callee =
+        cx.expr(
+            path.span,
+            ast::expr_path(
+                cx.path(path.span, path.node.idents + ["serialize"])));
+
+    let ty_args = vec::map(path.node.types) {|ty|
+        let sv = serialize_ty(cx, ty, s, #ast(expr){"__v"});
+        cx.at(ty.span, #ast(expr){"{|__v| $(sv)}"})
+    };
+
+    [cx.stmt(
+        cx.expr(
+            path.span,
+            ast::expr_call(callee, [s] + ty_args + [v], false)))]
+}
+
+fn serialize_variant(cx: ser_cx,
+                     tys: [@ast::ty],
+                     span: span,
+                     -s: @ast::expr,
+                     pfn: fn([@ast::pat]) -> ast::pat_,
+                     bodyfn: fn(-@ast::expr, @ast::blk) -> @ast::expr,
+                     argfn: fn(-@ast::expr, uint, @ast::blk) -> @ast::expr)
+    -> ast::arm {
+    let vnames = vec::init_fn(vec::len(tys)) {|i| #fmt["__v%u", i]};
+    let pats = vec::init_fn(vec::len(tys)) {|i|
+        cx.binder_pat(tys[i].span, vnames[i])
+    };
+    let pat: @ast::pat = @{id: cx.next_id(), node: pfn(pats), span: span};
+    let stmts = vec::init_fn(vec::len(tys)) {|i|
+        let v = cx.var_ref(span, vnames[i]);
+        let arg_blk =
+            cx.blk(
+                span,
+                serialize_ty(cx, tys[i], cx.clone(s), v));
+        cx.stmt(argfn(cx.clone(s), i, arg_blk))
+    };
+
+    let body_blk = cx.blk(span, vec::concat(stmts));
+    let body = cx.blk(span, [cx.stmt(bodyfn(s, body_blk))]);
+
+    {pats: [pat], guard: none, body: body}
+}
+
+fn serialize_ty(cx: ser_cx, ty: @ast::ty, -s: @ast::expr, -v: @ast::expr)
+    -> [@ast::stmt] {
+    let ext_cx = cx.ext_cx;
+
+    alt ty.node {
+      ast::ty_nil | ast::ty_bot {
+        []
+      }
+
+      ast::ty_box(mt) |
+      ast::ty_uniq(mt) |
+      ast::ty_ptr(mt) {
+        serialize_ty(cx, mt.ty, s, #ast(expr){"*$(v)"})
+      }
+
+      ast::ty_rec(flds) {
+        vec::flat_map(flds) {|fld|
+            let vf = cx.expr(
+                fld.span,
+                ast::expr_field(cx.clone(v), fld.node.ident, []));
+            serialize_ty(cx, fld.node.mt.ty, cx.clone(s), vf)
+        }
+      }
+
+      ast::ty_fn(_, _) {
+        cx.session().span_err(
+            ty.span, #fmt["Cannot serialize function types"]);
+        []
+      }
+
+      ast::ty_tup(tys) {
+        // Generate code like
+        //
+        // alt v {
+        //    (v1, v2, v3) {
+        //       .. serialize v1, v2, v3 ..
+        //    }
+        // };
+
+        let arms = [
+            serialize_variant(
+
+                cx, tys, ty.span, s,
+
+                // Generate pattern (v1, v2, v3)
+                {|pats| ast::pat_tup(pats)},
+
+                // Generate body s.emit_tup(3, {|| blk })
+                {|-s, -blk|
+                    let sz = cx.lit_uint(ty.span, vec::len(tys));
+                    let body = cx.lambda(blk);
+                    #ast[expr]{
+                        $(s).emit_tup($(sz), $(body))
+                    }
+                },
+
+                // Generate s.emit_tup_elt(i, {|| blk })
+                {|-s, i, -blk|
+                    let idx = cx.lit_uint(ty.span, i);
+                    let body = cx.lambda(blk);
+                    #ast[expr]{
+                        $(s).emit_tup_elt($(idx), $(body))
+                    }
+                })
+        ];
+        [cx.alt_stmt(arms, ty.span, v)]
+      }
+
+      ast::ty_path(path, _) {
+        if vec::len(path.node.idents) == 1u &&
+            vec::is_empty(path.node.types) {
+            let ident = path.node.idents[0];
+
+            alt cx.tps.find(ident) {
+              some(f) { f(v) }
+              none { serialize_path(cx, path, s, v) }
+            }
+        } else {
+            serialize_path(cx, path, s, v)
+        }
+      }
+
+      ast::ty_constr(ty, _) {
+        serialize_ty(cx, ty, s, v)
+      }
+
+      ast::ty_mac(_) {
+        cx.session().span_err(
+            ty.span, #fmt["Cannot serialize macro types"]);
+        []
+      }
+
+      ast::ty_infer {
+        cx.session().span_err(
+            ty.span, #fmt["Cannot serialize inferred types"]);
+        []
+      }
+
+      ast::ty_vec(mt) {
+        let ser_e =
+            cx.expr(
+                ty.span,
+                ast::expr_block(
+                    cx.blk(
+                        ty.span,
+                        serialize_ty(
+                            cx, mt.ty,
+                            cx.clone(s),
+                            cx.at(
+                                ty.span,
+                                #ast(expr){__e})))));
+
+        [cx.stmt(
+            cx.expr(
+                ty.span,
+                ast::expr_call(
+                    #ast(expr){$(s).emit_from_vec},
+                    [#ast(expr){{|__e| $(ser_e)}}],
+                    false)))]
+      }
+    }
+}
+
+fn mk_ser_fn(ext_cx: ext_ctxt, span: span,
+             -v_ty: @ast::ty, tps: [ast::ty_param],
+             f: fn(ser_cx, @ast::ty, -@ast::expr, -@ast::expr) -> [@ast::stmt])
+    -> @ast::item {
+
+    let cx = ser_cx({ext_cx: ext_cx, tps: map::new_str_hash()});
+
+    let tp_inputs =
+        vec::map(tps, {|tp|
+            {mode: ast::expl(ast::by_ref),
+             ty: cx.ty_path(span, [tp.ident]),
+             ident: "__s" + tp.ident,
+             id: cx.next_id()}});
+
+    let ser_inputs: [ast::arg] =
+        [{mode: ast::expl(ast::by_ref),
+          ty: cx.ty_path(span, ["__S"]),
+          ident: "__s",
+          id: cx.next_id()},
+         {mode: ast::expl(ast::by_ref),
+          ty: v_ty,
+          ident: "__v",
+          id: cx.next_id()}]
+        + tp_inputs;
+
+    vec::iter2(tps, ser_inputs) {|tp, arg|
+        let arg_ident = arg.ident;
+        cx.tps.insert(
+            tp.ident,
+            fn@(v: @ast::expr) -> [@ast::stmt] {
+                let f = cx.var_ref(span, arg_ident);
+                [cx.stmt(
+                    cx.expr(
+                        span,
+                        ast::expr_call(f, [v], false)))]
+            });
+    }
+
+    let ser_bnds = @[ast::bound_iface(cx.ty_path(span,
+                                                 ["__std", "serialization",
+                                                  "serializer"]))];
+
+    let ser_tps: [ast::ty_param] =
+        [{ident: "__S",
+          id: cx.next_id(),
+          bounds: ser_bnds}] +
+        vec::map(tps) {|tp| cx.clone_ty_param(tp) };
+
+    let ser_output: @ast::ty = @{node: ast::ty_nil,
+                                 span: span};
+
+    let ser_blk = cx.blk(span,
+                         f(cx, v_ty, #ast(expr){"__s"}, #ast(expr){"__v"}));
+
+    @{ident: "serialize",
+      attrs: [],
+      id: cx.next_id(),
+      node: ast::item_fn({inputs: ser_inputs,
+                          output: ser_output,
+                          purity: ast::impure_fn,
+                          cf: ast::return_val,
+                          constraints: []},
+                         ser_tps,
+                         ser_blk),
+      span: span}
+}
+
+fn ty_module(ext_cx: ext_ctxt, name: str, -ty: @ast::ty, tps: [ast::ty_param])
+    -> @ast::item {
+
+    let span = ty.span;
+    let ser_fn = mk_ser_fn(ext_cx, span, ty, tps, serialize_ty);
+
+    // Return a module containing the serialization and deserialization
+    // functions:
+    @{ident: name,
+      attrs: [],
+      id: ext_cx.session().next_node_id(),
+      node: ast::item_mod({view_items: [],
+                           items: [ser_fn]}),
+      span: span}
+}
+
+fn enum_module(ext_cx: ext_ctxt, name: str, span: span,
+               variants: [ast::variant], tps: [ast::ty_param])
+    -> @ast::item {
+
+    let span = ty.span;
+    let ty = ext_cx.ty_path(span, [name]);
+    let ser_fn = mk_ser_fn(ext_cx, span, ty, tps) {|cx, ty, s, v|
+        let arms = vec::init_fn(vec::len(variants)) {|vidx|
+            let variant = variants[vidx];
+
+            if vec::is_empty(variant.args) {
+                // degenerate case.
+                let pat = {id: cx.next_id(),
+                           node: ast::pat_ident(cx.path(variant.ident), none),
+                           Span: variant.span};
+                //#ast(expr){
+                //    $(s).emit_enum_variant(X, Y, SZ) {||
+                //    };
+                //}
+            }
+
+            let variant_tys = vec::map(variant.args) {|a| a.ty };
+
+            serialize_variant(
+                cx, variant_tys, variant.span, cx.clone(s),
+
+                // Generate pattern var(v1, v2, v3)
+                {|pats|
+                    let pat = {id: cx.next_id(),
+                               node: ast::pat_enum(cx.path(variant.ident)),
+                               span: variant.span};
+
+                    {id: cx.next_id(),
+                     node: expr_call(s, [v_name,
+                                         v_id,
+                                         sz,
+                                         f], false),
+                     span: variant.span}
+                },
+
+                // Generate body s.emit_enum_variant("foo", 0u, 3u, {|| blk })
+                {|-s, -blk|
+                    let v_name = cx.lit_str(variant.span, variant.ident);
+                    let v_id = cx.lit_uint(variant.span, vidx);
+                    let sz = cx.lit_uint(variant.span, vec::len(variant_tys));
+                    let body = cx.lambda(blk);
+                    #ast[expr]{
+                        $(s).emit_enum_variant($(v_name), $(v_id), $(sz), $(body))
+                    }
+                },
+
+                // Generate s.emit_enum_variant_arg(i, {|| blk })
+                {|-s, i, -blk|
+                    let idx = cx.lit_uint(i);
+                    let body = cx.lambda(blk);
+                    #ast[expr]{
+                        $(s).emit_enum_variant_arg($(idx), $(body))
+                    }
+                })
+        };
+    };
+
+    @{ident: name,
+      attrs: [],
+      id: ext_cx.session().next_node_id(),
+      node: ast::item_mod({view_items: [],
+                           items: [ser_fn]}),
+      span: span}
+}