1
Fork 0
rust/src/libsyntax/ext/auto_encode.rs

1517 lines
42 KiB
Rust

// Copyright 2012 The Rust Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution and at
// http://rust-lang.org/COPYRIGHT.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.
/*!
The compiler code necessary to implement the #[auto_encode] and
#[auto_decode] extension. The idea here is that type-defining items may
be tagged with #[auto_encode] and #[auto_decode], which will cause
us to generate a little companion module with the same name as the item.
For example, a type like:
#[auto_encode]
#[auto_decode]
struct Node {id: uint}
would generate two implementations like:
impl<S:std::serialize::Encoder> Encodable<S> for Node {
fn encode(&self, s: &S) {
do s.emit_struct("Node", 1) {
s.emit_field("id", 0, || s.emit_uint(self.id))
}
}
}
impl<D:Decoder> Decodable for node_id {
fn decode(d: &D) -> Node {
do d.read_struct("Node", 1) {
Node {
id: d.read_field(~"x", 0, || decode(d))
}
}
}
}
Other interesting scenarios are whe the item has type parameters or
references other non-built-in types. A type definition like:
#[auto_encode]
#[auto_decode]
struct spanned<T> {node: T, span: span}
would yield functions like:
impl<
S: Encoder,
T: Encodable<S>
> spanned<T>: Encodable<S> {
fn encode<S:Encoder>(s: &S) {
do s.emit_rec {
s.emit_field("node", 0, || self.node.encode(s));
s.emit_field("span", 1, || self.span.encode(s));
}
}
}
impl<
D: Decoder,
T: Decodable<D>
> spanned<T>: Decodable<D> {
fn decode(d: &D) -> spanned<T> {
do d.read_rec {
{
node: d.read_field(~"node", 0, || decode(d)),
span: d.read_field(~"span", 1, || decode(d)),
}
}
}
}
FIXME (#2810)--Hygiene. Search for "__" strings. We also assume "std" is the
standard library.
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.
*/
use ast;
use ast_util;
use attr;
use codemap;
use codemap::span;
use ext::base::*;
use parse;
use opt_vec;
use opt_vec::OptVec;
use ext::build;
// Transitional reexports so qquote can find the paths it is looking for
mod syntax {
pub use ext;
pub use parse;
}
pub fn expand_auto_encode(
cx: @ext_ctxt,
span: span,
_mitem: @ast::meta_item,
in_items: ~[@ast::item]
) -> ~[@ast::item] {
fn is_auto_encode(a: &ast::attribute) -> bool {
*attr::get_attr_name(a) == ~"auto_encode"
}
fn filter_attrs(item: @ast::item) -> @ast::item {
@ast::item {
attrs: item.attrs.filtered(|a| !is_auto_encode(a)),
.. copy *item
}
}
do vec::flat_map(in_items) |item| {
if item.attrs.any(is_auto_encode) {
match item.node {
ast::item_struct(ref struct_def, ref generics) => {
let ser_impl = mk_struct_ser_impl(
cx,
item.span,
item.ident,
struct_def.fields,
generics
);
~[filter_attrs(*item), ser_impl]
},
ast::item_enum(ref enum_def, ref generics) => {
let ser_impl = mk_enum_ser_impl(
cx,
item.span,
item.ident,
copy *enum_def,
generics
);
~[filter_attrs(*item), ser_impl]
},
_ => {
cx.span_err(span, ~"#[auto_encode] can only be \
applied to structs, record types, \
and enum definitions");
~[*item]
}
}
} else {
~[*item]
}
}
}
pub fn expand_auto_decode(
cx: @ext_ctxt,
span: span,
_mitem: @ast::meta_item,
in_items: ~[@ast::item]
) -> ~[@ast::item] {
fn is_auto_decode(a: &ast::attribute) -> bool {
*attr::get_attr_name(a) == ~"auto_decode"
}
fn filter_attrs(item: @ast::item) -> @ast::item {
@ast::item {
attrs: item.attrs.filtered(|a| !is_auto_decode(a)),
.. copy *item
}
}
do vec::flat_map(in_items) |item| {
if item.attrs.any(is_auto_decode) {
match item.node {
ast::item_struct(ref struct_def, ref generics) => {
let deser_impl = mk_struct_deser_impl(
cx,
item.span,
item.ident,
struct_def.fields,
generics
);
~[filter_attrs(*item), deser_impl]
},
ast::item_enum(ref enum_def, ref generics) => {
let deser_impl = mk_enum_deser_impl(
cx,
item.span,
item.ident,
copy *enum_def,
generics
);
~[filter_attrs(*item), deser_impl]
},
_ => {
cx.span_err(span, ~"#[auto_decode] can only be \
applied to structs, record types, \
and enum definitions");
~[*item]
}
}
} else {
~[*item]
}
}
}
trait ExtCtxtMethods {
fn bind_path(&self,
span: span,
ident: ast::ident,
path: @ast::Path,
bounds: @OptVec<ast::TyParamBound>)
-> ast::TyParam;
fn expr(&self, span: span, node: ast::expr_) -> @ast::expr;
fn path(&self, span: span, strs: ~[ast::ident]) -> @ast::Path;
fn path_global(&self, span: span, strs: ~[ast::ident]) -> @ast::Path;
fn path_tps(&self, span: span, strs: ~[ast::ident], tps: ~[@ast::Ty])
-> @ast::Path;
fn path_tps_global(&self,
span: span,
strs: ~[ast::ident],
tps: ~[@ast::Ty])
-> @ast::Path;
fn ty_path(&self, span: span, strs: ~[ast::ident], tps: ~[@ast::Ty])
-> @ast::Ty;
fn binder_pat(&self, span: span, nm: ast::ident) -> @ast::pat;
fn stmt(&self, expr: @ast::expr) -> @ast::stmt;
fn lit_str(&self, span: span, s: @~str) -> @ast::expr;
fn lit_uint(&self, span: span, i: uint) -> @ast::expr;
fn lambda0(&self, blk: ast::blk) -> @ast::expr;
fn lambda1(&self, blk: ast::blk, ident: ast::ident) -> @ast::expr;
fn blk(&self, span: span, stmts: ~[@ast::stmt]) -> ast::blk;
fn expr_blk(&self, expr: @ast::expr) -> ast::blk;
fn expr_path(&self, span: span, strs: ~[ast::ident]) -> @ast::expr;
fn expr_path_global(&self, span: span, strs: ~[ast::ident]) -> @ast::expr;
fn expr_var(&self, span: span, var: ~str) -> @ast::expr;
fn expr_field(&self, span: span, expr: @ast::expr, ident: ast::ident)
-> @ast::expr;
fn expr_call(&self, span: span, expr: @ast::expr, args: ~[@ast::expr])
-> @ast::expr;
fn expr_method_call(&self,
span: span,
expr: @ast::expr,
ident: ast::ident,
args: ~[@ast::expr])
-> @ast::expr;
fn lambda_expr_0(&self, expr: @ast::expr) -> @ast::expr;
fn lambda_expr_1(&self, expr: @ast::expr, ident: ast::ident)
-> @ast::expr;
fn lambda_stmts_0(&self, span: span, stmts: ~[@ast::stmt]) -> @ast::expr;
fn lambda_stmts_1(&self,
span: span,
stmts: ~[@ast::stmt],
ident: ast::ident)
-> @ast::expr;
}
impl ExtCtxtMethods for @ext_ctxt {
fn bind_path(
&self,
_span: span,
ident: ast::ident,
path: @ast::Path,
bounds: @OptVec<ast::TyParamBound>
) -> ast::TyParam {
let bound = ast::TraitTyParamBound(@ast::trait_ref {
ref_id: self.next_id(),
path: path
});
ast::TyParam {
ident: ident,
id: self.next_id(),
bounds: @bounds.prepend(bound)
}
}
fn expr(&self, span: span, node: ast::expr_) -> @ast::expr {
@ast::expr {
id: self.next_id(),
callee_id: self.next_id(),
node: node,
span: span,
}
}
fn path(&self, span: span, strs: ~[ast::ident]) -> @ast::Path {
@ast::Path {
span: span,
global: false,
idents: strs,
rp: None,
types: ~[]
}
}
fn path_global(&self, span: span, strs: ~[ast::ident]) -> @ast::Path {
@ast::Path {
span: span,
global: true,
idents: strs,
rp: None,
types: ~[]
}
}
fn path_tps(
&self,
span: span,
strs: ~[ast::ident],
tps: ~[@ast::Ty]
) -> @ast::Path {
@ast::Path {
span: span,
global: false,
idents: strs,
rp: None,
types: tps
}
}
fn path_tps_global(
&self,
span: span,
strs: ~[ast::ident],
tps: ~[@ast::Ty]
) -> @ast::Path {
@ast::Path {
span: span,
global: true,
idents: strs,
rp: None,
types: tps
}
}
fn ty_path(
&self,
span: span,
strs: ~[ast::ident],
tps: ~[@ast::Ty]
) -> @ast::Ty {
@ast::Ty {
id: self.next_id(),
node: ast::ty_path(
self.path_tps(span, strs, tps),
self.next_id()),
span: span,
}
}
fn binder_pat(&self, span: span, nm: ast::ident) -> @ast::pat {
@ast::pat {
id: self.next_id(),
node: ast::pat_ident(
ast::bind_by_ref(ast::m_imm),
self.path(span, ~[nm]),
None),
span: span,
}
}
fn stmt(&self, expr: @ast::expr) -> @ast::stmt {
@codemap::spanned { node: ast::stmt_semi(expr, self.next_id()),
span: expr.span }
}
fn lit_str(&self, span: span, s: @~str) -> @ast::expr {
self.expr(
span,
ast::expr_vstore(
self.expr(
span,
ast::expr_lit(
@codemap::spanned { node: ast::lit_str(s),
span: span})),
ast::expr_vstore_uniq))
}
fn lit_uint(&self, span: span, i: uint) -> @ast::expr {
self.expr(
span,
ast::expr_lit(
@codemap::spanned { node: ast::lit_uint(i as u64, ast::ty_u),
span: span}))
}
fn lambda0(&self, blk: ast::blk) -> @ast::expr {
let ext_cx = *self;
let blk_e = self.expr(copy blk.span, ast::expr_block(copy blk));
quote_expr!( || $blk_e )
}
fn lambda1(&self, blk: ast::blk, ident: ast::ident) -> @ast::expr {
let ext_cx = *self;
let blk_e = self.expr(copy blk.span, ast::expr_block(copy blk));
quote_expr!( |$ident| $blk_e )
}
fn blk(&self, span: span, stmts: ~[@ast::stmt]) -> ast::blk {
codemap::spanned {
node: ast::blk_ {
view_items: ~[],
stmts: stmts,
expr: None,
id: self.next_id(),
rules: ast::default_blk,
},
span: span,
}
}
fn expr_blk(&self, expr: @ast::expr) -> ast::blk {
codemap::spanned {
node: ast::blk_ {
view_items: ~[],
stmts: ~[],
expr: Some(expr),
id: self.next_id(),
rules: ast::default_blk,
},
span: expr.span,
}
}
fn expr_path(&self, span: span, strs: ~[ast::ident]) -> @ast::expr {
self.expr(span, ast::expr_path(self.path(span, strs)))
}
fn expr_path_global(
&self,
span: span,
strs: ~[ast::ident]
) -> @ast::expr {
self.expr(span, ast::expr_path(self.path_global(span, strs)))
}
fn expr_var(&self, span: span, var: ~str) -> @ast::expr {
self.expr_path(span, ~[self.ident_of(var)])
}
fn expr_field(
&self,
span: span,
expr: @ast::expr,
ident: ast::ident
) -> @ast::expr {
self.expr(span, ast::expr_field(expr, ident, ~[]))
}
fn expr_call(
&self,
span: span,
expr: @ast::expr,
args: ~[@ast::expr]
) -> @ast::expr {
self.expr(span, ast::expr_call(expr, args, ast::NoSugar))
}
fn expr_method_call(
&self,
span: span,
expr: @ast::expr,
ident: ast::ident,
args: ~[@ast::expr]
) -> @ast::expr {
self.expr(span,
ast::expr_method_call(expr, ident, ~[], args, ast::NoSugar))
}
fn lambda_expr_0(&self, expr: @ast::expr) -> @ast::expr {
self.lambda0(self.expr_blk(expr))
}
fn lambda_expr_1(&self, expr: @ast::expr, ident: ast::ident)
-> @ast::expr {
self.lambda1(self.expr_blk(expr), ident)
}
fn lambda_stmts_0(&self, span: span, stmts: ~[@ast::stmt]) -> @ast::expr {
self.lambda0(self.blk(span, stmts))
}
fn lambda_stmts_1(&self,
span: span,
stmts: ~[@ast::stmt],
ident: ast::ident)
-> @ast::expr {
self.lambda1(self.blk(span, stmts), ident)
}
}
fn mk_impl(
cx: @ext_ctxt,
span: span,
ident: ast::ident,
ty_param: ast::TyParam,
path: @ast::Path,
generics: &ast::Generics,
f: &fn(@ast::Ty) -> @ast::method
) -> @ast::item {
/*!
*
* Given that we are deriving auto-encode a type `T<'a, ...,
* 'z, A, ..., Z>`, creates an impl like:
*
* impl<'a, ..., 'z, A:Tr, ..., Z:Tr> Tr for T<A, ..., Z> { ... }
*
* where Tr is either Serializable and Deserialize.
*
* FIXME(#5090): Remove code duplication between this and the code
* in deriving.rs
*/
// Copy the lifetimes
let impl_lifetimes = generics.lifetimes.map(|l| {
build::mk_lifetime(cx, l.span, l.ident)
});
// All the type parameters need to bound to the trait.
let mut impl_tps = opt_vec::with(ty_param);
for generics.ty_params.each |tp| {
let t_bound = ast::TraitTyParamBound(@ast::trait_ref {
path: path,
ref_id: cx.next_id(),
});
impl_tps.push(ast::TyParam {
ident: tp.ident,
id: cx.next_id(),
bounds: @tp.bounds.prepend(t_bound)
})
}
let opt_trait = Some(@ast::trait_ref {
path: path,
ref_id: cx.next_id(),
});
let ty = cx.ty_path(
span,
~[ident],
opt_vec::take_vec(generics.ty_params.map(
|tp| cx.ty_path(span, ~[tp.ident], ~[])))
);
let generics = ast::Generics {
lifetimes: impl_lifetimes,
ty_params: impl_tps
};
@ast::item {
// This is a new-style impl declaration.
// XXX: clownshoes
ident: parse::token::special_idents::clownshoes_extensions,
attrs: ~[],
id: cx.next_id(),
node: ast::item_impl(generics, opt_trait, ty, ~[f(ty)]),
vis: ast::public,
span: span,
}
}
fn mk_ser_impl(
cx: @ext_ctxt,
span: span,
ident: ast::ident,
generics: &ast::Generics,
body: @ast::expr
) -> @ast::item {
// Make a path to the std::serialize::Encodable typaram.
let ty_param = cx.bind_path(
span,
cx.ident_of(~"__S"),
cx.path_global(
span,
~[
cx.ident_of(~"std"),
cx.ident_of(~"serialize"),
cx.ident_of(~"Encoder"),
]
),
@opt_vec::Empty
);
// Make a path to the std::serialize::Encodable trait.
let path = cx.path_tps_global(
span,
~[
cx.ident_of(~"std"),
cx.ident_of(~"serialize"),
cx.ident_of(~"Encodable"),
],
~[cx.ty_path(span, ~[cx.ident_of(~"__S")], ~[])]
);
mk_impl(
cx,
span,
ident,
ty_param,
path,
generics,
|_ty| mk_ser_method(cx, span, cx.expr_blk(body))
)
}
fn mk_deser_impl(
cx: @ext_ctxt,
span: span,
ident: ast::ident,
generics: &ast::Generics,
body: @ast::expr
) -> @ast::item {
// Make a path to the std::serialize::Decodable typaram.
let ty_param = cx.bind_path(
span,
cx.ident_of(~"__D"),
cx.path_global(
span,
~[
cx.ident_of(~"std"),
cx.ident_of(~"serialize"),
cx.ident_of(~"Decoder"),
]
),
@opt_vec::Empty
);
// Make a path to the std::serialize::Decodable trait.
let path = cx.path_tps_global(
span,
~[
cx.ident_of(~"std"),
cx.ident_of(~"serialize"),
cx.ident_of(~"Decodable"),
],
~[cx.ty_path(span, ~[cx.ident_of(~"__D")], ~[])]
);
mk_impl(
cx,
span,
ident,
ty_param,
path,
generics,
|ty| mk_deser_method(cx, span, ty, cx.expr_blk(body))
)
}
fn mk_ser_method(
cx: @ext_ctxt,
span: span,
ser_body: ast::blk
) -> @ast::method {
let ty_s = @ast::Ty {
id: cx.next_id(),
node: ast::ty_rptr(
None,
ast::mt {
ty: cx.ty_path(span, ~[cx.ident_of(~"__S")], ~[]),
mutbl: ast::m_mutbl
}
),
span: span,
};
let ser_inputs = ~[ast::arg {
is_mutbl: false,
ty: ty_s,
pat: @ast::pat {
id: cx.next_id(),
node: ast::pat_ident(
ast::bind_by_copy,
ast_util::ident_to_path(span, cx.ident_of(~"__s")),
None),
span: span,
},
id: cx.next_id(),
}];
let ser_output = @ast::Ty {
id: cx.next_id(),
node: ast::ty_nil,
span: span,
};
let ser_decl = ast::fn_decl {
inputs: ser_inputs,
output: ser_output,
cf: ast::return_val,
};
@ast::method {
ident: cx.ident_of(~"encode"),
attrs: ~[],
generics: ast_util::empty_generics(),
self_ty: codemap::spanned {
node: ast::sty_region(None, ast::m_imm),
span: span
},
purity: ast::impure_fn,
decl: ser_decl,
body: ser_body,
id: cx.next_id(),
span: span,
self_id: cx.next_id(),
vis: ast::public,
}
}
fn mk_deser_method(
cx: @ext_ctxt,
span: span,
ty: @ast::Ty,
deser_body: ast::blk
) -> @ast::method {
let ty_d = @ast::Ty {
id: cx.next_id(),
node: ast::ty_rptr(
None,
ast::mt {
ty: cx.ty_path(span, ~[cx.ident_of(~"__D")], ~[]),
mutbl: ast::m_mutbl
}
),
span: span,
};
let deser_inputs = ~[
ast::arg {
is_mutbl: false,
ty: ty_d,
pat: @ast::pat {
id: cx.next_id(),
node: ast::pat_ident(ast::bind_by_copy,
ast_util::ident_to_path(span,
cx.ident_of(
~"__d")),
None),
span: span,
},
id: cx.next_id(),
}
];
let deser_decl = ast::fn_decl {
inputs: deser_inputs,
output: ty,
cf: ast::return_val,
};
@ast::method {
ident: cx.ident_of(~"decode"),
attrs: ~[],
generics: ast_util::empty_generics(),
self_ty: codemap::spanned { node: ast::sty_static, span: span },
purity: ast::impure_fn,
decl: deser_decl,
body: deser_body,
id: cx.next_id(),
span: span,
self_id: cx.next_id(),
vis: ast::public,
}
}
fn mk_struct_ser_impl(
cx: @ext_ctxt,
span: span,
ident: ast::ident,
fields: &[@ast::struct_field],
generics: &ast::Generics
) -> @ast::item {
let fields = do mk_struct_fields(fields).mapi |idx, field| {
// ast for `|__s| self.$(name).encode(__s)`
let expr_lambda = cx.lambda_expr_1(
cx.expr_method_call(
span,
cx.expr_field(
span,
cx.expr_var(span, ~"self"),
field.ident
),
cx.ident_of(~"encode"),
~[cx.expr_var(span, ~"__s")]
),
cx.ident_of(~"__s")
);
// ast for `__s.emit_struct_field($(name), $(idx), $(expr_lambda))`
cx.stmt(
cx.expr_method_call(
span,
cx.expr_var(span, ~"__s"),
cx.ident_of(~"emit_struct_field"),
~[
cx.lit_str(span, @cx.str_of(field.ident)),
cx.lit_uint(span, idx),
expr_lambda,
]
)
)
};
// ast for `__s.emit_struct($(name), |__s| $(fields))`
let ser_body = cx.expr_method_call(
span,
cx.expr_var(span, ~"__s"),
cx.ident_of(~"emit_struct"),
~[
cx.lit_str(span, @cx.str_of(ident)),
cx.lit_uint(span, vec::len(fields)),
cx.lambda_stmts_1(span, fields, cx.ident_of(~"__s")),
]
);
mk_ser_impl(cx, span, ident, generics, ser_body)
}
fn mk_struct_deser_impl(
cx: @ext_ctxt,
span: span,
ident: ast::ident,
fields: ~[@ast::struct_field],
generics: &ast::Generics
) -> @ast::item {
let fields = do mk_struct_fields(fields).mapi |idx, field| {
// ast for `|__d| std::serialize::decode(__d)`
let expr_lambda = cx.lambda1(
cx.expr_blk(
cx.expr_call(
span,
cx.expr_path_global(span, ~[
cx.ident_of(~"std"),
cx.ident_of(~"serialize"),
cx.ident_of(~"Decodable"),
cx.ident_of(~"decode"),
]),
~[cx.expr_var(span, ~"__d")]
)
),
cx.ident_of(~"__d")
);
// ast for `__d.read_struct_field($(name), $(idx), $(expr_lambda))`
let expr: @ast::expr = cx.expr_method_call(
span,
cx.expr_var(span, ~"__d"),
cx.ident_of(~"read_struct_field"),
~[
cx.lit_str(span, @cx.str_of(field.ident)),
cx.lit_uint(span, idx),
expr_lambda,
]
);
codemap::spanned {
node: ast::field_ {
mutbl: field.mutbl,
ident: field.ident,
expr: expr,
},
span: span,
}
};
// ast for `read_struct($(name), |__d| $(fields))`
let body = cx.expr_method_call(
span,
cx.expr_var(span, ~"__d"),
cx.ident_of(~"read_struct"),
~[
cx.lit_str(span, @cx.str_of(ident)),
cx.lit_uint(span, vec::len(fields)),
cx.lambda_expr_1(
cx.expr(
span,
ast::expr_struct(
cx.path(span, ~[ident]),
fields,
None
)
),
cx.ident_of(~"__d")
),
]
);
mk_deser_impl(cx, span, ident, generics, body)
}
// Records and structs don't have the same fields types, but they share enough
// that if we extract the right subfields out we can share the code
// generator code.
struct field {
span: span,
ident: ast::ident,
mutbl: ast::mutability,
}
fn mk_struct_fields(fields: &[@ast::struct_field]) -> ~[field] {
do fields.map |field| {
let (ident, mutbl) = match field.node.kind {
ast::named_field(ident, mutbl, _) => (ident, mutbl),
_ => fail!(~"[auto_encode] does not support \
unnamed fields")
};
field {
span: field.span,
ident: ident,
mutbl: match mutbl {
ast::struct_mutable => ast::m_mutbl,
ast::struct_immutable => ast::m_imm,
},
}
}
}
fn mk_enum_ser_impl(
cx: @ext_ctxt,
span: span,
ident: ast::ident,
enum_def: ast::enum_def,
generics: &ast::Generics
) -> @ast::item {
let body = mk_enum_ser_body(
cx,
span,
ident,
copy enum_def.variants
);
mk_ser_impl(cx, span, ident, generics, body)
}
fn mk_enum_deser_impl(
cx: @ext_ctxt,
span: span,
ident: ast::ident,
enum_def: ast::enum_def,
generics: &ast::Generics
) -> @ast::item {
let body = mk_enum_deser_body(
cx,
span,
ident,
enum_def.variants
);
mk_deser_impl(cx, span, ident, generics, body)
}
fn ser_variant(
cx: @ext_ctxt,
span: span,
v_name: ast::ident,
v_idx: uint,
args: ~[ast::variant_arg]
) -> ast::arm {
// Name the variant arguments.
let names = args.mapi(|i, _arg| cx.ident_of(fmt!("__v%u", i)));
// Bind the names to the variant argument type.
let pats = args.mapi(|i, arg| cx.binder_pat(arg.ty.span, names[i]));
let pat_node = if pats.is_empty() {
ast::pat_ident(
ast::bind_infer,
cx.path(span, ~[v_name]),
None
)
} else {
ast::pat_enum(
cx.path(span, ~[v_name]),
Some(pats)
)
};
let pat = @ast::pat {
id: cx.next_id(),
node: pat_node,
span: span,
};
let stmts = do args.mapi |a_idx, _arg| {
// ast for `__s.emit_enum_variant_arg`
let expr_emit = cx.expr_field(
span,
cx.expr_var(span, ~"__s"),
cx.ident_of(~"emit_enum_variant_arg")
);
// ast for `|__s| $(v).encode(__s)`
let expr_encode = cx.lambda_expr_1(
cx.expr_method_call(
span,
cx.expr_path(span, ~[names[a_idx]]),
cx.ident_of(~"encode"),
~[cx.expr_var(span, ~"__s")]
),
cx.ident_of(~"__s")
);
// ast for `$(expr_emit)($(a_idx), $(expr_encode))`
cx.stmt(
cx.expr_call(
span,
expr_emit,
~[cx.lit_uint(span, a_idx), expr_encode]
)
)
};
// ast for `__s.emit_enum_variant($(name), $(idx), $(sz), $(lambda))`
let body = cx.expr_method_call(
span,
cx.expr_var(span, ~"__s"),
cx.ident_of(~"emit_enum_variant"),
~[
cx.lit_str(span, @cx.str_of(v_name)),
cx.lit_uint(span, v_idx),
cx.lit_uint(span, stmts.len()),
cx.lambda_stmts_1(span, stmts, cx.ident_of(~"__s")),
]
);
ast::arm { pats: ~[pat], guard: None, body: cx.expr_blk(body) }
}
fn mk_enum_ser_body(
cx: @ext_ctxt,
span: span,
name: ast::ident,
variants: ~[ast::variant]
) -> @ast::expr {
let arms = do variants.mapi |v_idx, variant| {
match variant.node.kind {
ast::tuple_variant_kind(ref args) =>
ser_variant(
cx,
span,
variant.node.name,
v_idx,
/*bad*/ copy *args
),
ast::struct_variant_kind(*) =>
fail!(~"struct variants unimplemented"),
}
};
// ast for `match *self { $(arms) }`
let match_expr = cx.expr(
span,
ast::expr_match(
cx.expr(
span,
ast::expr_unary(ast::deref, cx.expr_var(span, ~"self"))
),
arms
)
);
// ast for `__s.emit_enum($(name), || $(match_expr))`
cx.expr_method_call(
span,
cx.expr_var(span, ~"__s"),
cx.ident_of(~"emit_enum"),
~[
cx.lit_str(span, @cx.str_of(name)),
cx.lambda_expr_1(match_expr, cx.ident_of(~"__s")),
]
)
}
fn mk_enum_deser_variant_nary(
cx: @ext_ctxt,
span: span,
name: ast::ident,
args: ~[ast::variant_arg]
) -> @ast::expr {
let args = do args.mapi |idx, _arg| {
// ast for `|__s| std::serialize::decode(__d)`
let expr_lambda = cx.lambda_expr_1(
cx.expr_call(
span,
cx.expr_path_global(span, ~[
cx.ident_of(~"std"),
cx.ident_of(~"serialize"),
cx.ident_of(~"Decodable"),
cx.ident_of(~"decode"),
]),
~[cx.expr_var(span, ~"__d")]
),
cx.ident_of(~"__d")
);
// ast for `__d.read_enum_variant_arg($(a_idx), $(expr_lambda))`
cx.expr_method_call(
span,
cx.expr_var(span, ~"__d"),
cx.ident_of(~"read_enum_variant_arg"),
~[cx.lit_uint(span, idx), expr_lambda]
)
};
// ast for `$(name)($(args))`
cx.expr_call(span, cx.expr_path(span, ~[name]), args)
}
fn mk_enum_deser_body(
ext_cx: @ext_ctxt,
span: span,
name: ast::ident,
variants: ~[ast::variant]
) -> @ast::expr {
let expr_arm_names = build::mk_base_vec_e(
ext_cx,
span,
do variants.map |variant| {
build::mk_base_str(
ext_cx,
span,
ext_cx.str_of(variant.node.name)
)
}
);
let mut arms = do variants.mapi |v_idx, variant| {
let body = match variant.node.kind {
ast::tuple_variant_kind(ref args) => {
if args.is_empty() {
// for a nullary variant v, do "v"
ext_cx.expr_path(span, ~[variant.node.name])
} else {
// for an n-ary variant v, do "v(a_1, ..., a_n)"
mk_enum_deser_variant_nary(
ext_cx,
span,
variant.node.name,
copy *args
)
}
},
ast::struct_variant_kind(*) =>
fail!(~"struct variants unimplemented"),
};
let pat = @ast::pat {
id: ext_cx.next_id(),
node: ast::pat_lit(ext_cx.lit_uint(span, v_idx)),
span: span,
};
ast::arm {
pats: ~[pat],
guard: None,
body: ext_cx.expr_blk(body),
}
};
let quoted_expr = copy quote_expr!(
::core::sys::FailWithCause::fail_with("explicit failure", "empty", 1);
).node;
let impossible_case = ast::arm {
pats: ~[@ast::pat {
id: ext_cx.next_id(),
node: ast::pat_wild,
span: span,
}],
guard: None,
// FIXME(#3198): proper error message
body: ext_cx.expr_blk(ext_cx.expr(span, quoted_expr)),
};
arms.push(impossible_case);
// ast for `|i| { match i { $(arms) } }`
let expr_lambda = ext_cx.expr(
span,
ast::expr_fn_block(
ast::fn_decl {
inputs: ~[
ast::arg {
is_mutbl: false,
ty: @ast::Ty {
id: ext_cx.next_id(),
node: ast::ty_infer,
span: span
},
pat: @ast::pat {
id: ext_cx.next_id(),
node: ast::pat_ident(
ast::bind_by_copy,
ast_util::ident_to_path(span,
ext_cx.ident_of(~"__d")),
None),
span: span,
},
id: ext_cx.next_id(),
},
ast::arg {
is_mutbl: false,
ty: @ast::Ty {
id: ext_cx.next_id(),
node: ast::ty_infer,
span: span
},
pat: @ast::pat {
id: ext_cx.next_id(),
node: ast::pat_ident(
ast::bind_by_copy,
ast_util::ident_to_path(span,
ext_cx.ident_of(~"i")),
None),
span: span,
},
id: ext_cx.next_id(),
}
],
output: @ast::Ty {
id: ext_cx.next_id(),
node: ast::ty_infer,
span: span,
},
cf: ast::return_val,
},
ext_cx.expr_blk(
ext_cx.expr(
span,
ast::expr_match(ext_cx.expr_var(span, ~"i"), arms)
)
)
)
);
// ast for `__d.read_enum_variant($expr_arm_names, $(expr_lambda))`
let expr_lambda = ext_cx.lambda_expr_1(
ext_cx.expr_method_call(
span,
ext_cx.expr_var(span, ~"__d"),
ext_cx.ident_of(~"read_enum_variant"),
~[expr_arm_names, expr_lambda]
),
ext_cx.ident_of(~"__d")
);
// ast for `__d.read_enum($(e_name), $(expr_lambda))`
ext_cx.expr_method_call(
span,
ext_cx.expr_var(span, ~"__d"),
ext_cx.ident_of(~"read_enum"),
~[
ext_cx.lit_str(span, @ext_cx.str_of(name)),
expr_lambda
]
)
}
#[cfg(test)]
mod test {
use core::option::{None, Some};
use std::serialize::Encodable;
use std::serialize::Encoder;
// just adding the ones I want to test, for now:
#[deriving(Eq)]
pub enum call {
CallToEmitEnum(~str),
CallToEmitEnumVariant(~str, uint, uint),
CallToEmitEnumVariantArg(uint),
CallToEmitUint(uint),
CallToEmitNil,
CallToEmitStruct(~str,uint),
CallToEmitField(~str,uint),
CallToEmitOption,
CallToEmitOptionNone,
CallToEmitOptionSome,
// all of the ones I was too lazy to handle:
CallToOther
}
// using `@mut` rather than changing the
// type of self in every method of every encoder everywhere.
pub struct TestEncoder {call_log : @mut ~[call]}
pub impl TestEncoder {
// these self's should be &mut self's, as well....
fn add_to_log (&self, c : call) {
self.call_log.push(copy c);
}
fn add_unknown_to_log (&self) {
self.add_to_log (CallToOther)
}
}
impl Encoder for TestEncoder {
fn emit_nil(&mut self) { self.add_to_log(CallToEmitNil) }
fn emit_uint(&mut self, v: uint) {
self.add_to_log(CallToEmitUint(v));
}
fn emit_u64(&mut self, _v: u64) { self.add_unknown_to_log(); }
fn emit_u32(&mut self, _v: u32) { self.add_unknown_to_log(); }
fn emit_u16(&mut self, _v: u16) { self.add_unknown_to_log(); }
fn emit_u8(&mut self, _v: u8) { self.add_unknown_to_log(); }
fn emit_int(&mut self, _v: int) { self.add_unknown_to_log(); }
fn emit_i64(&mut self, _v: i64) { self.add_unknown_to_log(); }
fn emit_i32(&mut self, _v: i32) { self.add_unknown_to_log(); }
fn emit_i16(&mut self, _v: i16) { self.add_unknown_to_log(); }
fn emit_i8(&mut self, _v: i8) { self.add_unknown_to_log(); }
fn emit_bool(&mut self, _v: bool) { self.add_unknown_to_log(); }
fn emit_f64(&mut self, _v: f64) { self.add_unknown_to_log(); }
fn emit_f32(&mut self, _v: f32) { self.add_unknown_to_log(); }
fn emit_float(&mut self, _v: float) { self.add_unknown_to_log(); }
fn emit_char(&mut self, _v: char) { self.add_unknown_to_log(); }
fn emit_str(&mut self, _v: &str) { self.add_unknown_to_log(); }
fn emit_enum(&mut self, name: &str, f: &fn(&mut TestEncoder)) {
self.add_to_log(CallToEmitEnum(name.to_str()));
f(self);
}
fn emit_enum_variant(&mut self,
name: &str,
id: uint,
cnt: uint,
f: &fn(&mut TestEncoder)) {
self.add_to_log(CallToEmitEnumVariant(name.to_str(), id, cnt));
f(self);
}
fn emit_enum_variant_arg(&mut self,
idx: uint,
f: &fn(&mut TestEncoder)) {
self.add_to_log(CallToEmitEnumVariantArg(idx));
f(self);
}
fn emit_enum_struct_variant(&mut self,
name: &str,
id: uint,
cnt: uint,
f: &fn(&mut TestEncoder)) {
self.emit_enum_variant(name, id, cnt, f)
}
fn emit_enum_struct_variant_field(&mut self,
_name: &str,
idx: uint,
f: &fn(&mut TestEncoder)) {
self.emit_enum_variant_arg(idx, f)
}
fn emit_struct(&mut self,
name: &str,
len: uint,
f: &fn(&mut TestEncoder)) {
self.add_to_log(CallToEmitStruct (name.to_str(),len));
f(self);
}
fn emit_struct_field(&mut self,
name: &str,
idx: uint,
f: &fn(&mut TestEncoder)) {
self.add_to_log(CallToEmitField (name.to_str(),idx));
f(self);
}
fn emit_tuple(&mut self, _len: uint, f: &fn(&mut TestEncoder)) {
self.add_unknown_to_log();
f(self);
}
fn emit_tuple_arg(&mut self, _idx: uint, f: &fn(&mut TestEncoder)) {
self.add_unknown_to_log();
f(self);
}
fn emit_tuple_struct(&mut self,
_name: &str,
_len: uint,
f: &fn(&mut TestEncoder)) {
self.add_unknown_to_log();
f(self);
}
fn emit_tuple_struct_arg(&mut self,
_idx: uint,
f: &fn(&mut TestEncoder)) {
self.add_unknown_to_log();
f(self);
}
fn emit_option(&mut self, f: &fn(&mut TestEncoder)) {
self.add_to_log(CallToEmitOption);
f(self);
}
fn emit_option_none(&mut self) {
self.add_to_log(CallToEmitOptionNone);
}
fn emit_option_some(&mut self, f: &fn(&mut TestEncoder)) {
self.add_to_log(CallToEmitOptionSome);
f(self);
}
fn emit_seq(&mut self, _len: uint, f: &fn(&mut TestEncoder)) {
self.add_unknown_to_log();
f(self);
}
fn emit_seq_elt(&mut self, _idx: uint, f: &fn(&mut TestEncoder)) {
self.add_unknown_to_log();
f(self);
}
fn emit_map(&mut self, _len: uint, f: &fn(&mut TestEncoder)) {
self.add_unknown_to_log();
f(self);
}
fn emit_map_elt_key(&mut self, _idx: uint, f: &fn(&mut TestEncoder)) {
self.add_unknown_to_log();
f(self);
}
fn emit_map_elt_val(&mut self, _idx: uint, f: &fn(&mut TestEncoder)) {
self.add_unknown_to_log();
f(self);
}
}
fn to_call_log<E:Encodable<TestEncoder>>(val: E) -> ~[call] {
let mut te = TestEncoder {
call_log: @mut ~[]
};
val.encode(&mut te);
copy *te.call_log
}
#[auto_encode]
enum Written {
Book(uint,uint),
Magazine(~str)
}
#[test]
fn test_encode_enum() {
assert_eq!(
to_call_log(Book(34,44)),
~[
CallToEmitEnum(~"Written"),
CallToEmitEnumVariant(~"Book",0,2),
CallToEmitEnumVariantArg(0),
CallToEmitUint(34),
CallToEmitEnumVariantArg(1),
CallToEmitUint(44),
]
);
}
pub struct BPos(uint);
#[auto_encode]
pub struct HasPos { pos : BPos }
#[test]
fn test_encode_newtype() {
assert_eq!(
to_call_log(HasPos { pos:BPos(48) }),
~[
CallToEmitStruct(~"HasPos",1),
CallToEmitField(~"pos",0),
CallToEmitUint(48),
]
);
}
#[test]
fn test_encode_option() {
let mut v = None;
assert_eq!(
to_call_log(v),
~[
CallToEmitOption,
CallToEmitOptionNone,
]
);
v = Some(54u);
assert_eq!(
to_call_log(v),
~[
CallToEmitOption,
CallToEmitOptionSome,
CallToEmitUint(54)
]
);
}
}