| // Copyright 2013-2014 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. |
| |
| //! Some code that abstracts away much of the boilerplate of writing |
| //! `derive` instances for traits. Among other things it manages getting |
| //! access to the fields of the 4 different sorts of structs and enum |
| //! variants, as well as creating the method and impl ast instances. |
| //! |
| //! Supported features (fairly exhaustive): |
| //! |
| //! - Methods taking any number of parameters of any type, and returning |
| //! any type, other than vectors, bottom and closures. |
| //! - Generating `impl`s for types with type parameters and lifetimes |
| //! (e.g. `Option<T>`), the parameters are automatically given the |
| //! current trait as a bound. (This includes separate type parameters |
| //! and lifetimes for methods.) |
| //! - Additional bounds on the type parameters (`TraitDef.additional_bounds`) |
| //! |
| //! The most important thing for implementers is the `Substructure` and |
| //! `SubstructureFields` objects. The latter groups 5 possibilities of the |
| //! arguments: |
| //! |
| //! - `Struct`, when `Self` is a struct (including tuple structs, e.g |
| //! `struct T(int, char)`). |
| //! - `EnumMatching`, when `Self` is an enum and all the arguments are the |
| //! same variant of the enum (e.g. `Some(1)`, `Some(3)` and `Some(4)`) |
| //! - `EnumNonMatchingCollapsed` when `Self` is an enum and the arguments |
| //! are not the same variant (e.g. `None`, `Some(1)` and `None`). |
| //! - `StaticEnum` and `StaticStruct` for static methods, where the type |
| //! being derived upon is either an enum or struct respectively. (Any |
| //! argument with type Self is just grouped among the non-self |
| //! arguments.) |
| //! |
| //! In the first two cases, the values from the corresponding fields in |
| //! all the arguments are grouped together. For `EnumNonMatchingCollapsed` |
| //! this isn't possible (different variants have different fields), so the |
| //! fields are inaccessible. (Previous versions of the deriving infrastructure |
| //! had a way to expand into code that could access them, at the cost of |
| //! generating exponential amounts of code; see issue #15375). There are no |
| //! fields with values in the static cases, so these are treated entirely |
| //! differently. |
| //! |
| //! The non-static cases have `Option<ident>` in several places associated |
| //! with field `expr`s. This represents the name of the field it is |
| //! associated with. It is only not `None` when the associated field has |
| //! an identifier in the source code. For example, the `x`s in the |
| //! following snippet |
| //! |
| //! ```rust |
| //! struct A { x : int } |
| //! |
| //! struct B(int); |
| //! |
| //! enum C { |
| //! C0(int), |
| //! C1 { x: int } |
| //! } |
| //! ``` |
| //! |
| //! The `int`s in `B` and `C0` don't have an identifier, so the |
| //! `Option<ident>`s would be `None` for them. |
| //! |
| //! In the static cases, the structure is summarised, either into the just |
| //! spans of the fields or a list of spans and the field idents (for tuple |
| //! structs and record structs, respectively), or a list of these, for |
| //! enums (one for each variant). For empty struct and empty enum |
| //! variants, it is represented as a count of 0. |
| //! |
| //! # "`cs`" functions |
| //! |
| //! The `cs_...` functions ("combine substructure) are designed to |
| //! make life easier by providing some pre-made recipes for common |
| //! tasks; mostly calling the function being derived on all the |
| //! arguments and then combining them back together in some way (or |
| //! letting the user chose that). They are not meant to be the only |
| //! way to handle the structures that this code creates. |
| //! |
| //! # Examples |
| //! |
| //! The following simplified `PartialEq` is used for in-code examples: |
| //! |
| //! ```rust |
| //! trait PartialEq { |
| //! fn eq(&self, other: &Self); |
| //! } |
| //! impl PartialEq for int { |
| //! fn eq(&self, other: &int) -> bool { |
| //! *self == *other |
| //! } |
| //! } |
| //! ``` |
| //! |
| //! Some examples of the values of `SubstructureFields` follow, using the |
| //! above `PartialEq`, `A`, `B` and `C`. |
| //! |
| //! ## Structs |
| //! |
| //! When generating the `expr` for the `A` impl, the `SubstructureFields` is |
| //! |
| //! ```{.text} |
| //! Struct(vec![FieldInfo { |
| //! span: <span of x> |
| //! name: Some(<ident of x>), |
| //! self_: <expr for &self.x>, |
| //! other: vec![<expr for &other.x] |
| //! }]) |
| //! ``` |
| //! |
| //! For the `B` impl, called with `B(a)` and `B(b)`, |
| //! |
| //! ```{.text} |
| //! Struct(vec![FieldInfo { |
| //! span: <span of `int`>, |
| //! name: None, |
| //! self_: <expr for &a> |
| //! other: vec![<expr for &b>] |
| //! }]) |
| //! ``` |
| //! |
| //! ## Enums |
| //! |
| //! When generating the `expr` for a call with `self == C0(a)` and `other |
| //! == C0(b)`, the SubstructureFields is |
| //! |
| //! ```{.text} |
| //! EnumMatching(0, <ast::Variant for C0>, |
| //! vec![FieldInfo { |
| //! span: <span of int> |
| //! name: None, |
| //! self_: <expr for &a>, |
| //! other: vec![<expr for &b>] |
| //! }]) |
| //! ``` |
| //! |
| //! For `C1 {x}` and `C1 {x}`, |
| //! |
| //! ```{.text} |
| //! EnumMatching(1, <ast::Variant for C1>, |
| //! vec![FieldInfo { |
| //! span: <span of x> |
| //! name: Some(<ident of x>), |
| //! self_: <expr for &self.x>, |
| //! other: vec![<expr for &other.x>] |
| //! }]) |
| //! ``` |
| //! |
| //! For `C0(a)` and `C1 {x}` , |
| //! |
| //! ```{.text} |
| //! EnumNonMatchingCollapsed( |
| //! vec![<ident of self>, <ident of __arg_1>], |
| //! &[<ast::Variant for C0>, <ast::Variant for C1>], |
| //! &[<ident for self index value>, <ident of __arg_1 index value>]) |
| //! ``` |
| //! |
| //! It is the same for when the arguments are flipped to `C1 {x}` and |
| //! `C0(a)`; the only difference is what the values of the identifiers |
| //! <ident for self index value> and <ident of __arg_1 index value> will |
| //! be in the generated code. |
| //! |
| //! `EnumNonMatchingCollapsed` deliberately provides far less information |
| //! than is generally available for a given pair of variants; see #15375 |
| //! for discussion. |
| //! |
| //! ## Static |
| //! |
| //! A static method on the types above would result in, |
| //! |
| //! ```{.text} |
| //! StaticStruct(<ast::StructDef of A>, Named(vec![(<ident of x>, <span of x>)])) |
| //! |
| //! StaticStruct(<ast::StructDef of B>, Unnamed(vec![<span of x>])) |
| //! |
| //! StaticEnum(<ast::EnumDef of C>, |
| //! vec![(<ident of C0>, <span of C0>, Unnamed(vec![<span of int>])), |
| //! (<ident of C1>, <span of C1>, Named(vec![(<ident of x>, <span of x>)]))]) |
| //! ``` |
| |
| pub use self::StaticFields::*; |
| pub use self::SubstructureFields::*; |
| use self::StructType::*; |
| |
| use std::cell::RefCell; |
| use std::vec; |
| |
| use abi::Abi; |
| use abi; |
| use ast; |
| use ast::{EnumDef, Expr, Ident, Generics, StructDef}; |
| use ast_util; |
| use attr; |
| use attr::AttrMetaMethods; |
| use ext::base::ExtCtxt; |
| use ext::build::AstBuilder; |
| use codemap::{self, DUMMY_SP}; |
| use codemap::Span; |
| use fold::MoveMap; |
| use owned_slice::OwnedSlice; |
| use parse::token::InternedString; |
| use parse::token::special_idents; |
| use ptr::P; |
| |
| use self::ty::{LifetimeBounds, Path, Ptr, PtrTy, Self, Ty}; |
| |
| pub mod ty; |
| |
| pub struct TraitDef<'a> { |
| /// The span for the current #[derive(Foo)] header. |
| pub span: Span, |
| |
| pub attributes: Vec<ast::Attribute>, |
| |
| /// Path of the trait, including any type parameters |
| pub path: Path<'a>, |
| |
| /// Additional bounds required of any type parameters of the type, |
| /// other than the current trait |
| pub additional_bounds: Vec<Ty<'a>>, |
| |
| /// Any extra lifetimes and/or bounds, e.g. `D: serialize::Decoder` |
| pub generics: LifetimeBounds<'a>, |
| |
| pub methods: Vec<MethodDef<'a>>, |
| } |
| |
| |
| pub struct MethodDef<'a> { |
| /// name of the method |
| pub name: &'a str, |
| /// List of generics, e.g. `R: rand::Rng` |
| pub generics: LifetimeBounds<'a>, |
| |
| /// Whether there is a self argument (outer Option) i.e. whether |
| /// this is a static function, and whether it is a pointer (inner |
| /// Option) |
| pub explicit_self: Option<Option<PtrTy<'a>>>, |
| |
| /// Arguments other than the self argument |
| pub args: Vec<Ty<'a>>, |
| |
| /// Return type |
| pub ret_ty: Ty<'a>, |
| |
| pub attributes: Vec<ast::Attribute>, |
| |
| pub combine_substructure: RefCell<CombineSubstructureFunc<'a>>, |
| } |
| |
| /// All the data about the data structure/method being derived upon. |
| pub struct Substructure<'a> { |
| /// ident of self |
| pub type_ident: Ident, |
| /// ident of the method |
| pub method_ident: Ident, |
| /// dereferenced access to any `Self` or `Ptr(Self, _)` arguments |
| pub self_args: &'a [P<Expr>], |
| /// verbatim access to any other arguments |
| pub nonself_args: &'a [P<Expr>], |
| pub fields: &'a SubstructureFields<'a> |
| } |
| |
| /// Summary of the relevant parts of a struct/enum field. |
| pub struct FieldInfo { |
| pub span: Span, |
| /// None for tuple structs/normal enum variants, Some for normal |
| /// structs/struct enum variants. |
| pub name: Option<Ident>, |
| /// The expression corresponding to this field of `self` |
| /// (specifically, a reference to it). |
| pub self_: P<Expr>, |
| /// The expressions corresponding to references to this field in |
| /// the other `Self` arguments. |
| pub other: Vec<P<Expr>>, |
| } |
| |
| /// Fields for a static method |
| pub enum StaticFields { |
| /// Tuple structs/enum variants like this. |
| Unnamed(Vec<Span>), |
| /// Normal structs/struct variants. |
| Named(Vec<(Ident, Span)>), |
| } |
| |
| /// A summary of the possible sets of fields. |
| pub enum SubstructureFields<'a> { |
| Struct(Vec<FieldInfo>), |
| /// Matching variants of the enum: variant index, ast::Variant, |
| /// fields: the field name is only non-`None` in the case of a struct |
| /// variant. |
| EnumMatching(uint, &'a ast::Variant, Vec<FieldInfo>), |
| |
| /// Non-matching variants of the enum, but with all state hidden from |
| /// the consequent code. The first component holds `Ident`s for all of |
| /// the `Self` arguments; the second component is a slice of all of the |
| /// variants for the enum itself, and the third component is a list of |
| /// `Ident`s bound to the variant index values for each of the actual |
| /// input `Self` arguments. |
| EnumNonMatchingCollapsed(Vec<Ident>, &'a [P<ast::Variant>], &'a [Ident]), |
| |
| /// A static method where `Self` is a struct. |
| StaticStruct(&'a ast::StructDef, StaticFields), |
| /// A static method where `Self` is an enum. |
| StaticEnum(&'a ast::EnumDef, Vec<(Ident, Span, StaticFields)>), |
| } |
| |
| |
| |
| /// Combine the values of all the fields together. The last argument is |
| /// all the fields of all the structures. |
| pub type CombineSubstructureFunc<'a> = |
| Box<FnMut(&mut ExtCtxt, Span, &Substructure) -> P<Expr> + 'a>; |
| |
| /// Deal with non-matching enum variants. The tuple is a list of |
| /// identifiers (one for each `Self` argument, which could be any of the |
| /// variants since they have been collapsed together) and the identifiers |
| /// holding the variant index value for each of the `Self` arguments. The |
| /// last argument is all the non-`Self` args of the method being derived. |
| pub type EnumNonMatchCollapsedFunc<'a> = |
| Box<FnMut(&mut ExtCtxt, Span, (&[Ident], &[Ident]), &[P<Expr>]) -> P<Expr> + 'a>; |
| |
| pub fn combine_substructure<'a>(f: CombineSubstructureFunc<'a>) |
| -> RefCell<CombineSubstructureFunc<'a>> { |
| RefCell::new(f) |
| } |
| |
| |
| impl<'a> TraitDef<'a> { |
| pub fn expand<F>(&self, |
| cx: &mut ExtCtxt, |
| mitem: &ast::MetaItem, |
| item: &ast::Item, |
| push: F) where |
| F: FnOnce(P<ast::Item>), |
| { |
| let newitem = match item.node { |
| ast::ItemStruct(ref struct_def, ref generics) => { |
| self.expand_struct_def(cx, |
| &**struct_def, |
| item.ident, |
| generics) |
| } |
| ast::ItemEnum(ref enum_def, ref generics) => { |
| self.expand_enum_def(cx, |
| enum_def, |
| item.ident, |
| generics) |
| } |
| _ => { |
| cx.span_err(mitem.span, "`derive` may only be applied to structs and enums"); |
| return; |
| } |
| }; |
| // Keep the lint attributes of the previous item to control how the |
| // generated implementations are linted |
| let mut attrs = newitem.attrs.clone(); |
| attrs.extend(item.attrs.iter().filter(|a| { |
| match a.name().get() { |
| "allow" | "warn" | "deny" | "forbid" => true, |
| _ => false, |
| } |
| }).map(|a| a.clone())); |
| push(P(ast::Item { |
| attrs: attrs, |
| ..(*newitem).clone() |
| })) |
| } |
| |
| /// Given that we are deriving a trait `Tr` for a type `T<'a, ..., |
| /// 'z, A, ..., Z>`, creates an impl like: |
| /// |
| /// ```ignore |
| /// impl<'a, ..., 'z, A:Tr B1 B2, ..., Z: Tr B1 B2> Tr for T<A, ..., Z> { ... } |
| /// ``` |
| /// |
| /// where B1, B2, ... are the bounds given by `bounds_paths`.' |
| fn create_derived_impl(&self, |
| cx: &mut ExtCtxt, |
| type_ident: Ident, |
| generics: &Generics, |
| methods: Vec<P<ast::Method>>) -> P<ast::Item> { |
| let trait_path = self.path.to_path(cx, self.span, type_ident, generics); |
| |
| let Generics { mut lifetimes, ty_params, mut where_clause } = |
| self.generics.to_generics(cx, self.span, type_ident, generics); |
| let mut ty_params = ty_params.into_vec(); |
| |
| // Copy the lifetimes |
| lifetimes.extend(generics.lifetimes.iter().map(|l| (*l).clone())); |
| |
| // Create the type parameters. |
| ty_params.extend(generics.ty_params.iter().map(|ty_param| { |
| // I don't think this can be moved out of the loop, since |
| // a TyParamBound requires an ast id |
| let mut bounds: Vec<_> = |
| // extra restrictions on the generics parameters to the type being derived upon |
| self.additional_bounds.iter().map(|p| { |
| cx.typarambound(p.to_path(cx, self.span, |
| type_ident, generics)) |
| }).collect(); |
| |
| // require the current trait |
| bounds.push(cx.typarambound(trait_path.clone())); |
| |
| // also add in any bounds from the declaration |
| for declared_bound in ty_param.bounds.iter() { |
| bounds.push((*declared_bound).clone()); |
| } |
| |
| cx.typaram(self.span, |
| ty_param.ident, |
| OwnedSlice::from_vec(bounds), |
| None) |
| })); |
| |
| // and similarly for where clauses |
| where_clause.predicates.extend(generics.where_clause.predicates.iter().map(|clause| { |
| match *clause { |
| ast::WherePredicate::BoundPredicate(ref wb) => { |
| ast::WherePredicate::BoundPredicate(ast::WhereBoundPredicate { |
| span: self.span, |
| bounded_ty: wb.bounded_ty.clone(), |
| bounds: OwnedSlice::from_vec(wb.bounds.iter().map(|b| b.clone()).collect()) |
| }) |
| } |
| ast::WherePredicate::RegionPredicate(ref rb) => { |
| ast::WherePredicate::RegionPredicate(ast::WhereRegionPredicate { |
| span: self.span, |
| lifetime: rb.lifetime, |
| bounds: rb.bounds.iter().map(|b| b.clone()).collect() |
| }) |
| } |
| ast::WherePredicate::EqPredicate(ref we) => { |
| ast::WherePredicate::EqPredicate(ast::WhereEqPredicate { |
| id: ast::DUMMY_NODE_ID, |
| span: self.span, |
| path: we.path.clone(), |
| ty: we.ty.clone() |
| }) |
| } |
| } |
| })); |
| |
| let trait_generics = Generics { |
| lifetimes: lifetimes, |
| ty_params: OwnedSlice::from_vec(ty_params), |
| where_clause: where_clause |
| }; |
| |
| // Create the reference to the trait. |
| let trait_ref = cx.trait_ref(trait_path); |
| |
| // Create the type parameters on the `self` path. |
| let self_ty_params = generics.ty_params.map(|ty_param| { |
| cx.ty_ident(self.span, ty_param.ident) |
| }); |
| |
| let self_lifetimes: Vec<ast::Lifetime> = |
| generics.lifetimes |
| .iter() |
| .map(|ld| ld.lifetime) |
| .collect(); |
| |
| // Create the type of `self`. |
| let self_type = cx.ty_path( |
| cx.path_all(self.span, false, vec!( type_ident ), self_lifetimes, |
| self_ty_params.into_vec(), Vec::new())); |
| |
| let attr = cx.attribute( |
| self.span, |
| cx.meta_word(self.span, |
| InternedString::new("automatically_derived"))); |
| // Just mark it now since we know that it'll end up used downstream |
| attr::mark_used(&attr); |
| let opt_trait_ref = Some(trait_ref); |
| let ident = ast_util::impl_pretty_name(&opt_trait_ref, &*self_type); |
| let mut a = vec![attr]; |
| a.extend(self.attributes.iter().map(|a| a.clone())); |
| cx.item( |
| self.span, |
| ident, |
| a, |
| ast::ItemImpl(ast::Unsafety::Normal, |
| ast::ImplPolarity::Positive, |
| trait_generics, |
| opt_trait_ref, |
| self_type, |
| methods.into_iter() |
| .map(|method| { |
| ast::MethodImplItem(method) |
| }).collect())) |
| } |
| |
| fn expand_struct_def(&self, |
| cx: &mut ExtCtxt, |
| struct_def: &StructDef, |
| type_ident: Ident, |
| generics: &Generics) -> P<ast::Item> { |
| let methods = self.methods.iter().map(|method_def| { |
| let (explicit_self, self_args, nonself_args, tys) = |
| method_def.split_self_nonself_args( |
| cx, self, type_ident, generics); |
| |
| let body = if method_def.is_static() { |
| method_def.expand_static_struct_method_body( |
| cx, |
| self, |
| struct_def, |
| type_ident, |
| &self_args[], |
| &nonself_args[]) |
| } else { |
| method_def.expand_struct_method_body(cx, |
| self, |
| struct_def, |
| type_ident, |
| &self_args[], |
| &nonself_args[]) |
| }; |
| |
| method_def.create_method(cx, |
| self, |
| type_ident, |
| generics, |
| abi::Rust, |
| explicit_self, |
| tys, |
| body) |
| }).collect(); |
| |
| self.create_derived_impl(cx, type_ident, generics, methods) |
| } |
| |
| fn expand_enum_def(&self, |
| cx: &mut ExtCtxt, |
| enum_def: &EnumDef, |
| type_ident: Ident, |
| generics: &Generics) -> P<ast::Item> { |
| let methods = self.methods.iter().map(|method_def| { |
| let (explicit_self, self_args, nonself_args, tys) = |
| method_def.split_self_nonself_args(cx, self, |
| type_ident, generics); |
| |
| let body = if method_def.is_static() { |
| method_def.expand_static_enum_method_body( |
| cx, |
| self, |
| enum_def, |
| type_ident, |
| &self_args[], |
| &nonself_args[]) |
| } else { |
| method_def.expand_enum_method_body(cx, |
| self, |
| enum_def, |
| type_ident, |
| self_args, |
| &nonself_args[]) |
| }; |
| |
| method_def.create_method(cx, |
| self, |
| type_ident, |
| generics, |
| abi::Rust, |
| explicit_self, |
| tys, |
| body) |
| }).collect(); |
| |
| self.create_derived_impl(cx, type_ident, generics, methods) |
| } |
| } |
| |
| fn variant_to_pat(cx: &mut ExtCtxt, sp: Span, enum_ident: ast::Ident, variant: &ast::Variant) |
| -> P<ast::Pat> { |
| let path = cx.path(sp, vec![enum_ident, variant.node.name]); |
| cx.pat(sp, match variant.node.kind { |
| ast::TupleVariantKind(..) => ast::PatEnum(path, None), |
| ast::StructVariantKind(..) => ast::PatStruct(path, Vec::new(), true), |
| }) |
| } |
| |
| impl<'a> MethodDef<'a> { |
| fn call_substructure_method(&self, |
| cx: &mut ExtCtxt, |
| trait_: &TraitDef, |
| type_ident: Ident, |
| self_args: &[P<Expr>], |
| nonself_args: &[P<Expr>], |
| fields: &SubstructureFields) |
| -> P<Expr> { |
| let substructure = Substructure { |
| type_ident: type_ident, |
| method_ident: cx.ident_of(self.name), |
| self_args: self_args, |
| nonself_args: nonself_args, |
| fields: fields |
| }; |
| let mut f = self.combine_substructure.borrow_mut(); |
| let f: &mut CombineSubstructureFunc = &mut *f; |
| f(cx, trait_.span, &substructure) |
| } |
| |
| fn get_ret_ty(&self, |
| cx: &mut ExtCtxt, |
| trait_: &TraitDef, |
| generics: &Generics, |
| type_ident: Ident) |
| -> P<ast::Ty> { |
| self.ret_ty.to_ty(cx, trait_.span, type_ident, generics) |
| } |
| |
| fn is_static(&self) -> bool { |
| self.explicit_self.is_none() |
| } |
| |
| fn split_self_nonself_args(&self, |
| cx: &mut ExtCtxt, |
| trait_: &TraitDef, |
| type_ident: Ident, |
| generics: &Generics) |
| -> (ast::ExplicitSelf, Vec<P<Expr>>, Vec<P<Expr>>, Vec<(Ident, P<ast::Ty>)>) { |
| |
| let mut self_args = Vec::new(); |
| let mut nonself_args = Vec::new(); |
| let mut arg_tys = Vec::new(); |
| let mut nonstatic = false; |
| |
| let ast_explicit_self = match self.explicit_self { |
| Some(ref self_ptr) => { |
| let (self_expr, explicit_self) = |
| ty::get_explicit_self(cx, trait_.span, self_ptr); |
| |
| self_args.push(self_expr); |
| nonstatic = true; |
| |
| explicit_self |
| } |
| None => codemap::respan(trait_.span, ast::SelfStatic), |
| }; |
| |
| for (i, ty) in self.args.iter().enumerate() { |
| let ast_ty = ty.to_ty(cx, trait_.span, type_ident, generics); |
| let ident = cx.ident_of(&format!("__arg_{}", i)[]); |
| arg_tys.push((ident, ast_ty)); |
| |
| let arg_expr = cx.expr_ident(trait_.span, ident); |
| |
| match *ty { |
| // for static methods, just treat any Self |
| // arguments as a normal arg |
| Self if nonstatic => { |
| self_args.push(arg_expr); |
| } |
| Ptr(box Self, _) if nonstatic => { |
| self_args.push(cx.expr_deref(trait_.span, arg_expr)) |
| } |
| _ => { |
| nonself_args.push(arg_expr); |
| } |
| } |
| } |
| |
| (ast_explicit_self, self_args, nonself_args, arg_tys) |
| } |
| |
| fn create_method(&self, |
| cx: &mut ExtCtxt, |
| trait_: &TraitDef, |
| type_ident: Ident, |
| generics: &Generics, |
| abi: Abi, |
| explicit_self: ast::ExplicitSelf, |
| arg_types: Vec<(Ident, P<ast::Ty>)> , |
| body: P<Expr>) -> P<ast::Method> { |
| // create the generics that aren't for Self |
| let fn_generics = self.generics.to_generics(cx, trait_.span, type_ident, generics); |
| |
| let self_arg = match explicit_self.node { |
| ast::SelfStatic => None, |
| // creating fresh self id |
| _ => Some(ast::Arg::new_self(trait_.span, ast::MutImmutable, special_idents::self_)) |
| }; |
| let args = { |
| let args = arg_types.into_iter().map(|(name, ty)| { |
| cx.arg(trait_.span, name, ty) |
| }); |
| self_arg.into_iter().chain(args).collect() |
| }; |
| |
| let ret_type = self.get_ret_ty(cx, trait_, generics, type_ident); |
| |
| let method_ident = cx.ident_of(self.name); |
| let fn_decl = cx.fn_decl(args, ret_type); |
| let body_block = cx.block_expr(body); |
| |
| // Create the method. |
| P(ast::Method { |
| attrs: self.attributes.clone(), |
| id: ast::DUMMY_NODE_ID, |
| span: trait_.span, |
| node: ast::MethDecl(method_ident, |
| fn_generics, |
| abi, |
| explicit_self, |
| ast::Unsafety::Normal, |
| fn_decl, |
| body_block, |
| ast::Inherited) |
| }) |
| } |
| |
| /// ``` |
| /// #[derive(PartialEq)] |
| /// struct A { x: int, y: int } |
| /// |
| /// // equivalent to: |
| /// impl PartialEq for A { |
| /// fn eq(&self, __arg_1: &A) -> bool { |
| /// match *self { |
| /// A {x: ref __self_0_0, y: ref __self_0_1} => { |
| /// match *__arg_1 { |
| /// A {x: ref __self_1_0, y: ref __self_1_1} => { |
| /// __self_0_0.eq(__self_1_0) && __self_0_1.eq(__self_1_1) |
| /// } |
| /// } |
| /// } |
| /// } |
| /// } |
| /// } |
| /// ``` |
| fn expand_struct_method_body(&self, |
| cx: &mut ExtCtxt, |
| trait_: &TraitDef, |
| struct_def: &StructDef, |
| type_ident: Ident, |
| self_args: &[P<Expr>], |
| nonself_args: &[P<Expr>]) |
| -> P<Expr> { |
| |
| let mut raw_fields = Vec::new(); // ~[[fields of self], |
| // [fields of next Self arg], [etc]] |
| let mut patterns = Vec::new(); |
| for i in range(0u, self_args.len()) { |
| let struct_path= cx.path(DUMMY_SP, vec!( type_ident )); |
| let (pat, ident_expr) = |
| trait_.create_struct_pattern(cx, |
| struct_path, |
| struct_def, |
| &format!("__self_{}", |
| i)[], |
| ast::MutImmutable); |
| patterns.push(pat); |
| raw_fields.push(ident_expr); |
| } |
| |
| // transpose raw_fields |
| let fields = if raw_fields.len() > 0 { |
| let mut raw_fields = raw_fields.into_iter().map(|v| v.into_iter()); |
| let first_field = raw_fields.next().unwrap(); |
| let mut other_fields: Vec<vec::IntoIter<(Span, Option<Ident>, P<Expr>)>> |
| = raw_fields.collect(); |
| first_field.map(|(span, opt_id, field)| { |
| FieldInfo { |
| span: span, |
| name: opt_id, |
| self_: field, |
| other: other_fields.iter_mut().map(|l| { |
| match l.next().unwrap() { |
| (_, _, ex) => ex |
| } |
| }).collect() |
| } |
| }).collect() |
| } else { |
| cx.span_bug(trait_.span, |
| "no self arguments to non-static method in generic \ |
| `derive`") |
| }; |
| |
| // body of the inner most destructuring match |
| let mut body = self.call_substructure_method( |
| cx, |
| trait_, |
| type_ident, |
| self_args, |
| nonself_args, |
| &Struct(fields)); |
| |
| // make a series of nested matches, to destructure the |
| // structs. This is actually right-to-left, but it shouldn't |
| // matter. |
| for (arg_expr, pat) in self_args.iter().zip(patterns.iter()) { |
| body = cx.expr_match(trait_.span, arg_expr.clone(), |
| vec!( cx.arm(trait_.span, vec!(pat.clone()), body) )) |
| } |
| body |
| } |
| |
| fn expand_static_struct_method_body(&self, |
| cx: &mut ExtCtxt, |
| trait_: &TraitDef, |
| struct_def: &StructDef, |
| type_ident: Ident, |
| self_args: &[P<Expr>], |
| nonself_args: &[P<Expr>]) |
| -> P<Expr> { |
| let summary = trait_.summarise_struct(cx, struct_def); |
| |
| self.call_substructure_method(cx, |
| trait_, |
| type_ident, |
| self_args, nonself_args, |
| &StaticStruct(struct_def, summary)) |
| } |
| |
| /// ``` |
| /// #[derive(PartialEq)] |
| /// enum A { |
| /// A1, |
| /// A2(int) |
| /// } |
| /// |
| /// // is equivalent to |
| /// |
| /// impl PartialEq for A { |
| /// fn eq(&self, __arg_1: &A) -> ::bool { |
| /// match (&*self, &*__arg_1) { |
| /// (&A1, &A1) => true, |
| /// (&A2(ref __self_0), |
| /// &A2(ref __arg_1_0)) => (*__self_0).eq(&(*__arg_1_0)), |
| /// _ => { |
| /// let __self_vi = match *self { A1(..) => 0u, A2(..) => 1u }; |
| /// let __arg_1_vi = match *__arg_1 { A1(..) => 0u, A2(..) => 1u }; |
| /// false |
| /// } |
| /// } |
| /// } |
| /// } |
| /// ``` |
| /// |
| /// (Of course `__self_vi` and `__arg_1_vi` are unused for |
| /// `PartialEq`, and those subcomputations will hopefully be removed |
| /// as their results are unused. The point of `__self_vi` and |
| /// `__arg_1_vi` is for `PartialOrd`; see #15503.) |
| fn expand_enum_method_body(&self, |
| cx: &mut ExtCtxt, |
| trait_: &TraitDef, |
| enum_def: &EnumDef, |
| type_ident: Ident, |
| self_args: Vec<P<Expr>>, |
| nonself_args: &[P<Expr>]) |
| -> P<Expr> { |
| self.build_enum_match_tuple( |
| cx, trait_, enum_def, type_ident, self_args, nonself_args) |
| } |
| |
| |
| /// Creates a match for a tuple of all `self_args`, where either all |
| /// variants match, or it falls into a catch-all for when one variant |
| /// does not match. |
| |
| /// There are N + 1 cases because is a case for each of the N |
| /// variants where all of the variants match, and one catch-all for |
| /// when one does not match. |
| |
| /// The catch-all handler is provided access the variant index values |
| /// for each of the self-args, carried in precomputed variables. (Nota |
| /// bene: the variant index values are not necessarily the |
| /// discriminant values. See issue #15523.) |
| |
| /// ```{.text} |
| /// match (this, that, ...) { |
| /// (Variant1, Variant1, Variant1) => ... // delegate Matching on Variant1 |
| /// (Variant2, Variant2, Variant2) => ... // delegate Matching on Variant2 |
| /// ... |
| /// _ => { |
| /// let __this_vi = match this { Variant1 => 0u, Variant2 => 1u, ... }; |
| /// let __that_vi = match that { Variant1 => 0u, Variant2 => 1u, ... }; |
| /// ... // catch-all remainder can inspect above variant index values. |
| /// } |
| /// } |
| /// ``` |
| fn build_enum_match_tuple( |
| &self, |
| cx: &mut ExtCtxt, |
| trait_: &TraitDef, |
| enum_def: &EnumDef, |
| type_ident: Ident, |
| self_args: Vec<P<Expr>>, |
| nonself_args: &[P<Expr>]) -> P<Expr> { |
| |
| let sp = trait_.span; |
| let variants = &enum_def.variants; |
| |
| let self_arg_names = self_args.iter().enumerate() |
| .map(|(arg_count, _self_arg)| { |
| if arg_count == 0 { |
| "__self".to_string() |
| } else { |
| format!("__arg_{}", arg_count) |
| } |
| }) |
| .collect::<Vec<String>>(); |
| |
| let self_arg_idents = self_arg_names.iter() |
| .map(|name|cx.ident_of(&name[])) |
| .collect::<Vec<ast::Ident>>(); |
| |
| // The `vi_idents` will be bound, solely in the catch-all, to |
| // a series of let statements mapping each self_arg to a uint |
| // corresponding to its variant index. |
| let vi_idents: Vec<ast::Ident> = self_arg_names.iter() |
| .map(|name| { let vi_suffix = format!("{}_vi", &name[]); |
| cx.ident_of(&vi_suffix[]) }) |
| .collect::<Vec<ast::Ident>>(); |
| |
| // Builds, via callback to call_substructure_method, the |
| // delegated expression that handles the catch-all case, |
| // using `__variants_tuple` to drive logic if necessary. |
| let catch_all_substructure = EnumNonMatchingCollapsed( |
| self_arg_idents, &variants[], &vi_idents[]); |
| |
| // These arms are of the form: |
| // (Variant1, Variant1, ...) => Body1 |
| // (Variant2, Variant2, ...) => Body2 |
| // ... |
| // where each tuple has length = self_args.len() |
| let mut match_arms: Vec<ast::Arm> = variants.iter().enumerate() |
| .map(|(index, variant)| { |
| let mk_self_pat = |&: cx: &mut ExtCtxt, self_arg_name: &str| { |
| let (p, idents) = trait_.create_enum_variant_pattern(cx, type_ident, |
| &**variant, |
| self_arg_name, |
| ast::MutImmutable); |
| (cx.pat(sp, ast::PatRegion(p, ast::MutImmutable)), idents) |
| }; |
| |
| // A single arm has form (&VariantK, &VariantK, ...) => BodyK |
| // (see "Final wrinkle" note below for why.) |
| let mut subpats = Vec::with_capacity(self_arg_names.len()); |
| let mut self_pats_idents = Vec::with_capacity(self_arg_names.len() - 1); |
| let first_self_pat_idents = { |
| let (p, idents) = mk_self_pat(cx, &self_arg_names[0][]); |
| subpats.push(p); |
| idents |
| }; |
| for self_arg_name in self_arg_names.tail().iter() { |
| let (p, idents) = mk_self_pat(cx, &self_arg_name[]); |
| subpats.push(p); |
| self_pats_idents.push(idents); |
| } |
| |
| // Here is the pat = `(&VariantK, &VariantK, ...)` |
| let single_pat = cx.pat_tuple(sp, subpats); |
| |
| // For the BodyK, we need to delegate to our caller, |
| // passing it an EnumMatching to indicate which case |
| // we are in. |
| |
| // All of the Self args have the same variant in these |
| // cases. So we transpose the info in self_pats_idents |
| // to gather the getter expressions together, in the |
| // form that EnumMatching expects. |
| |
| // The transposition is driven by walking across the |
| // arg fields of the variant for the first self pat. |
| let field_tuples = first_self_pat_idents.into_iter().enumerate() |
| // For each arg field of self, pull out its getter expr ... |
| .map(|(field_index, (sp, opt_ident, self_getter_expr))| { |
| // ... but FieldInfo also wants getter expr |
| // for matching other arguments of Self type; |
| // so walk across the *other* self_pats_idents |
| // and pull out getter for same field in each |
| // of them (using `field_index` tracked above). |
| // That is the heart of the transposition. |
| let others = self_pats_idents.iter().map(|fields| { |
| let (_, _opt_ident, ref other_getter_expr) = |
| fields[field_index]; |
| |
| // All Self args have same variant, so |
| // opt_idents are the same. (Assert |
| // here to make it self-evident that |
| // it is okay to ignore `_opt_ident`.) |
| assert!(opt_ident == _opt_ident); |
| |
| other_getter_expr.clone() |
| }).collect::<Vec<P<Expr>>>(); |
| |
| FieldInfo { span: sp, |
| name: opt_ident, |
| self_: self_getter_expr, |
| other: others, |
| } |
| }).collect::<Vec<FieldInfo>>(); |
| |
| // Now, for some given VariantK, we have built up |
| // expressions for referencing every field of every |
| // Self arg, assuming all are instances of VariantK. |
| // Build up code associated with such a case. |
| let substructure = EnumMatching(index, |
| &**variant, |
| field_tuples); |
| let arm_expr = self.call_substructure_method( |
| cx, trait_, type_ident, &self_args[], nonself_args, |
| &substructure); |
| |
| cx.arm(sp, vec![single_pat], arm_expr) |
| }).collect(); |
| |
| // We will usually need the catch-all after matching the |
| // tuples `(VariantK, VariantK, ...)` for each VariantK of the |
| // enum. But: |
| // |
| // * when there is only one Self arg, the arms above suffice |
| // (and the deriving we call back into may not be prepared to |
| // handle EnumNonMatchCollapsed), and, |
| // |
| // * when the enum has only one variant, the single arm that |
| // is already present always suffices. |
| // |
| // * In either of the two cases above, if we *did* add a |
| // catch-all `_` match, it would trigger the |
| // unreachable-pattern error. |
| // |
| if variants.len() > 1 && self_args.len() > 1 { |
| let arms: Vec<ast::Arm> = variants.iter().enumerate() |
| .map(|(index, variant)| { |
| let pat = variant_to_pat(cx, sp, type_ident, &**variant); |
| let lit = ast::LitInt(index as u64, ast::UnsignedIntLit(ast::TyUs(false))); |
| cx.arm(sp, vec![pat], cx.expr_lit(sp, lit)) |
| }).collect(); |
| |
| // Build a series of let statements mapping each self_arg |
| // to a uint corresponding to its variant index. |
| // i.e. for `enum E<T> { A, B(1), C(T, T) }`, and a deriving |
| // with three Self args, builds three statements: |
| // |
| // ``` |
| // let __self0_vi = match self { |
| // A => 0u, B(..) => 1u, C(..) => 2u |
| // }; |
| // let __self1_vi = match __arg1 { |
| // A => 0u, B(..) => 1u, C(..) => 2u |
| // }; |
| // let __self2_vi = match __arg2 { |
| // A => 0u, B(..) => 1u, C(..) => 2u |
| // }; |
| // ``` |
| let mut index_let_stmts: Vec<P<ast::Stmt>> = Vec::new(); |
| for (&ident, self_arg) in vi_idents.iter().zip(self_args.iter()) { |
| let variant_idx = cx.expr_match(sp, self_arg.clone(), arms.clone()); |
| let let_stmt = cx.stmt_let(sp, false, ident, variant_idx); |
| index_let_stmts.push(let_stmt); |
| } |
| |
| let arm_expr = self.call_substructure_method( |
| cx, trait_, type_ident, &self_args[], nonself_args, |
| &catch_all_substructure); |
| |
| // Builds the expression: |
| // { |
| // let __self0_vi = ...; |
| // let __self1_vi = ...; |
| // ... |
| // <delegated expression referring to __self0_vi, et al.> |
| // } |
| let arm_expr = cx.expr_block( |
| cx.block_all(sp, Vec::new(), index_let_stmts, Some(arm_expr))); |
| |
| // Builds arm: |
| // _ => { let __self0_vi = ...; |
| // let __self1_vi = ...; |
| // ... |
| // <delegated expression as above> } |
| let catch_all_match_arm = |
| cx.arm(sp, vec![cx.pat_wild(sp)], arm_expr); |
| |
| match_arms.push(catch_all_match_arm); |
| |
| } else if variants.len() == 0 { |
| // As an additional wrinkle, For a zero-variant enum A, |
| // currently the compiler |
| // will accept `fn (a: &Self) { match *a { } }` |
| // but rejects `fn (a: &Self) { match (&*a,) { } }` |
| // as well as `fn (a: &Self) { match ( *a,) { } }` |
| // |
| // This means that the strategy of building up a tuple of |
| // all Self arguments fails when Self is a zero variant |
| // enum: rustc rejects the expanded program, even though |
| // the actual code tends to be impossible to execute (at |
| // least safely), according to the type system. |
| // |
| // The most expedient fix for this is to just let the |
| // code fall through to the catch-all. But even this is |
| // error-prone, since the catch-all as defined above would |
| // generate code like this: |
| // |
| // _ => { let __self0 = match *self { }; |
| // let __self1 = match *__arg_0 { }; |
| // <catch-all-expr> } |
| // |
| // Which is yields bindings for variables which type |
| // inference cannot resolve to unique types. |
| // |
| // One option to the above might be to add explicit type |
| // annotations. But the *only* reason to go down that path |
| // would be to try to make the expanded output consistent |
| // with the case when the number of enum variants >= 1. |
| // |
| // That just isn't worth it. In fact, trying to generate |
| // sensible code for *any* deriving on a zero-variant enum |
| // does not make sense. But at the same time, for now, we |
| // do not want to cause a compile failure just because the |
| // user happened to attach a deriving to their |
| // zero-variant enum. |
| // |
| // Instead, just generate a failing expression for the |
| // zero variant case, skipping matches and also skipping |
| // delegating back to the end user code entirely. |
| // |
| // (See also #4499 and #12609; note that some of the |
| // discussions there influence what choice we make here; |
| // e.g. if we feature-gate `match x { ... }` when x refers |
| // to an uninhabited type (e.g. a zero-variant enum or a |
| // type holding such an enum), but do not feature-gate |
| // zero-variant enums themselves, then attempting to |
| // derive Show on such a type could here generate code |
| // that needs the feature gate enabled.) |
| |
| return cx.expr_unreachable(sp); |
| } |
| |
| // Final wrinkle: the self_args are expressions that deref |
| // down to desired l-values, but we cannot actually deref |
| // them when they are fed as r-values into a tuple |
| // expression; here add a layer of borrowing, turning |
| // `(*self, *__arg_0, ...)` into `(&*self, &*__arg_0, ...)`. |
| let borrowed_self_args = self_args.move_map(|self_arg| cx.expr_addr_of(sp, self_arg)); |
| let match_arg = cx.expr(sp, ast::ExprTup(borrowed_self_args)); |
| cx.expr_match(sp, match_arg, match_arms) |
| } |
| |
| fn expand_static_enum_method_body(&self, |
| cx: &mut ExtCtxt, |
| trait_: &TraitDef, |
| enum_def: &EnumDef, |
| type_ident: Ident, |
| self_args: &[P<Expr>], |
| nonself_args: &[P<Expr>]) |
| -> P<Expr> { |
| let summary = enum_def.variants.iter().map(|v| { |
| let ident = v.node.name; |
| let summary = match v.node.kind { |
| ast::TupleVariantKind(ref args) => { |
| Unnamed(args.iter().map(|va| trait_.set_expn_info(cx, va.ty.span)).collect()) |
| } |
| ast::StructVariantKind(ref struct_def) => { |
| trait_.summarise_struct(cx, &**struct_def) |
| } |
| }; |
| (ident, v.span, summary) |
| }).collect(); |
| self.call_substructure_method(cx, trait_, type_ident, |
| self_args, nonself_args, |
| &StaticEnum(enum_def, summary)) |
| } |
| } |
| |
| #[derive(PartialEq)] // dogfooding! |
| enum StructType { |
| Unknown, Record, Tuple |
| } |
| |
| // general helper methods. |
| impl<'a> TraitDef<'a> { |
| fn set_expn_info(&self, |
| cx: &mut ExtCtxt, |
| mut to_set: Span) -> Span { |
| let trait_name = match self.path.path.last() { |
| None => cx.span_bug(self.span, "trait with empty path in generic `derive`"), |
| Some(name) => *name |
| }; |
| to_set.expn_id = cx.codemap().record_expansion(codemap::ExpnInfo { |
| call_site: to_set, |
| callee: codemap::NameAndSpan { |
| name: format!("deriving({})", trait_name), |
| format: codemap::MacroAttribute, |
| span: Some(self.span) |
| } |
| }); |
| to_set |
| } |
| |
| fn summarise_struct(&self, |
| cx: &mut ExtCtxt, |
| struct_def: &StructDef) -> StaticFields { |
| let mut named_idents = Vec::new(); |
| let mut just_spans = Vec::new(); |
| for field in struct_def.fields.iter(){ |
| let sp = self.set_expn_info(cx, field.span); |
| match field.node.kind { |
| ast::NamedField(ident, _) => named_idents.push((ident, sp)), |
| ast::UnnamedField(..) => just_spans.push(sp), |
| } |
| } |
| |
| match (just_spans.is_empty(), named_idents.is_empty()) { |
| (false, false) => cx.span_bug(self.span, |
| "a struct with named and unnamed \ |
| fields in generic `derive`"), |
| // named fields |
| (_, false) => Named(named_idents), |
| // tuple structs (includes empty structs) |
| (_, _) => Unnamed(just_spans) |
| } |
| } |
| |
| fn create_subpatterns(&self, |
| cx: &mut ExtCtxt, |
| field_paths: Vec<ast::SpannedIdent> , |
| mutbl: ast::Mutability) |
| -> Vec<P<ast::Pat>> { |
| field_paths.iter().map(|path| { |
| cx.pat(path.span, |
| ast::PatIdent(ast::BindByRef(mutbl), (*path).clone(), None)) |
| }).collect() |
| } |
| |
| fn create_struct_pattern(&self, |
| cx: &mut ExtCtxt, |
| struct_path: ast::Path, |
| struct_def: &StructDef, |
| prefix: &str, |
| mutbl: ast::Mutability) |
| -> (P<ast::Pat>, Vec<(Span, Option<Ident>, P<Expr>)>) { |
| if struct_def.fields.is_empty() { |
| return (cx.pat_enum(self.span, struct_path, vec![]), vec![]); |
| } |
| |
| let mut paths = Vec::new(); |
| let mut ident_expr = Vec::new(); |
| let mut struct_type = Unknown; |
| |
| for (i, struct_field) in struct_def.fields.iter().enumerate() { |
| let sp = self.set_expn_info(cx, struct_field.span); |
| let opt_id = match struct_field.node.kind { |
| ast::NamedField(ident, _) if (struct_type == Unknown || |
| struct_type == Record) => { |
| struct_type = Record; |
| Some(ident) |
| } |
| ast::UnnamedField(..) if (struct_type == Unknown || |
| struct_type == Tuple) => { |
| struct_type = Tuple; |
| None |
| } |
| _ => { |
| cx.span_bug(sp, "a struct with named and unnamed fields in `derive`"); |
| } |
| }; |
| let ident = cx.ident_of(&format!("{}_{}", prefix, i)[]); |
| paths.push(codemap::Spanned{span: sp, node: ident}); |
| let val = cx.expr( |
| sp, ast::ExprParen(cx.expr_deref(sp, cx.expr_path(cx.path_ident(sp,ident))))); |
| ident_expr.push((sp, opt_id, val)); |
| } |
| |
| let subpats = self.create_subpatterns(cx, paths, mutbl); |
| |
| // struct_type is definitely not Unknown, since struct_def.fields |
| // must be nonempty to reach here |
| let pattern = if struct_type == Record { |
| let field_pats = subpats.into_iter().zip(ident_expr.iter()).map(|(pat, &(_, id, _))| { |
| // id is guaranteed to be Some |
| codemap::Spanned { |
| span: pat.span, |
| node: ast::FieldPat { ident: id.unwrap(), pat: pat, is_shorthand: false }, |
| } |
| }).collect(); |
| cx.pat_struct(self.span, struct_path, field_pats) |
| } else { |
| cx.pat_enum(self.span, struct_path, subpats) |
| }; |
| |
| (pattern, ident_expr) |
| } |
| |
| fn create_enum_variant_pattern(&self, |
| cx: &mut ExtCtxt, |
| enum_ident: ast::Ident, |
| variant: &ast::Variant, |
| prefix: &str, |
| mutbl: ast::Mutability) |
| -> (P<ast::Pat>, Vec<(Span, Option<Ident>, P<Expr>)>) { |
| let variant_ident = variant.node.name; |
| let variant_path = cx.path(variant.span, vec![enum_ident, variant_ident]); |
| match variant.node.kind { |
| ast::TupleVariantKind(ref variant_args) => { |
| if variant_args.is_empty() { |
| return (cx.pat_enum(variant.span, variant_path, vec![]), vec![]); |
| } |
| |
| let mut paths = Vec::new(); |
| let mut ident_expr = Vec::new(); |
| for (i, va) in variant_args.iter().enumerate() { |
| let sp = self.set_expn_info(cx, va.ty.span); |
| let ident = cx.ident_of(&format!("{}_{}", prefix, i)[]); |
| let path1 = codemap::Spanned{span: sp, node: ident}; |
| paths.push(path1); |
| let expr_path = cx.expr_path(cx.path_ident(sp, ident)); |
| let val = cx.expr(sp, ast::ExprParen(cx.expr_deref(sp, expr_path))); |
| ident_expr.push((sp, None, val)); |
| } |
| |
| let subpats = self.create_subpatterns(cx, paths, mutbl); |
| |
| (cx.pat_enum(variant.span, variant_path, subpats), |
| ident_expr) |
| } |
| ast::StructVariantKind(ref struct_def) => { |
| self.create_struct_pattern(cx, variant_path, &**struct_def, |
| prefix, mutbl) |
| } |
| } |
| } |
| } |
| |
| /* helpful premade recipes */ |
| |
| /// Fold the fields. `use_foldl` controls whether this is done |
| /// left-to-right (`true`) or right-to-left (`false`). |
| pub fn cs_fold<F>(use_foldl: bool, |
| mut f: F, |
| base: P<Expr>, |
| mut enum_nonmatch_f: EnumNonMatchCollapsedFunc, |
| cx: &mut ExtCtxt, |
| trait_span: Span, |
| substructure: &Substructure) |
| -> P<Expr> where |
| F: FnMut(&mut ExtCtxt, Span, P<Expr>, P<Expr>, &[P<Expr>]) -> P<Expr>, |
| { |
| match *substructure.fields { |
| EnumMatching(_, _, ref all_fields) | Struct(ref all_fields) => { |
| if use_foldl { |
| all_fields.iter().fold(base, |old, field| { |
| f(cx, |
| field.span, |
| old, |
| field.self_.clone(), |
| &field.other[]) |
| }) |
| } else { |
| all_fields.iter().rev().fold(base, |old, field| { |
| f(cx, |
| field.span, |
| old, |
| field.self_.clone(), |
| &field.other[]) |
| }) |
| } |
| }, |
| EnumNonMatchingCollapsed(ref all_args, _, tuple) => |
| enum_nonmatch_f(cx, trait_span, (&all_args[], tuple), |
| substructure.nonself_args), |
| StaticEnum(..) | StaticStruct(..) => { |
| cx.span_bug(trait_span, "static function in `derive`") |
| } |
| } |
| } |
| |
| |
| /// Call the method that is being derived on all the fields, and then |
| /// process the collected results. i.e. |
| /// |
| /// ``` |
| /// f(cx, span, vec![self_1.method(__arg_1_1, __arg_2_1), |
| /// self_2.method(__arg_1_2, __arg_2_2)]) |
| /// ``` |
| #[inline] |
| pub fn cs_same_method<F>(f: F, |
| mut enum_nonmatch_f: EnumNonMatchCollapsedFunc, |
| cx: &mut ExtCtxt, |
| trait_span: Span, |
| substructure: &Substructure) |
| -> P<Expr> where |
| F: FnOnce(&mut ExtCtxt, Span, Vec<P<Expr>>) -> P<Expr>, |
| { |
| match *substructure.fields { |
| EnumMatching(_, _, ref all_fields) | Struct(ref all_fields) => { |
| // call self_n.method(other_1_n, other_2_n, ...) |
| let called = all_fields.iter().map(|field| { |
| cx.expr_method_call(field.span, |
| field.self_.clone(), |
| substructure.method_ident, |
| field.other.iter() |
| .map(|e| cx.expr_addr_of(field.span, e.clone())) |
| .collect()) |
| }).collect(); |
| |
| f(cx, trait_span, called) |
| }, |
| EnumNonMatchingCollapsed(ref all_self_args, _, tuple) => |
| enum_nonmatch_f(cx, trait_span, (&all_self_args[], tuple), |
| substructure.nonself_args), |
| StaticEnum(..) | StaticStruct(..) => { |
| cx.span_bug(trait_span, "static function in `derive`") |
| } |
| } |
| } |
| |
| /// Fold together the results of calling the derived method on all the |
| /// fields. `use_foldl` controls whether this is done left-to-right |
| /// (`true`) or right-to-left (`false`). |
| #[inline] |
| pub fn cs_same_method_fold<F>(use_foldl: bool, |
| mut f: F, |
| base: P<Expr>, |
| enum_nonmatch_f: EnumNonMatchCollapsedFunc, |
| cx: &mut ExtCtxt, |
| trait_span: Span, |
| substructure: &Substructure) |
| -> P<Expr> where |
| F: FnMut(&mut ExtCtxt, Span, P<Expr>, P<Expr>) -> P<Expr>, |
| { |
| cs_same_method( |
| |cx, span, vals| { |
| if use_foldl { |
| vals.into_iter().fold(base.clone(), |old, new| { |
| f(cx, span, old, new) |
| }) |
| } else { |
| vals.into_iter().rev().fold(base.clone(), |old, new| { |
| f(cx, span, old, new) |
| }) |
| } |
| }, |
| enum_nonmatch_f, |
| cx, trait_span, substructure) |
| } |
| |
| /// Use a given binop to combine the result of calling the derived method |
| /// on all the fields. |
| #[inline] |
| pub fn cs_binop(binop: ast::BinOp, base: P<Expr>, |
| enum_nonmatch_f: EnumNonMatchCollapsedFunc, |
| cx: &mut ExtCtxt, trait_span: Span, |
| substructure: &Substructure) -> P<Expr> { |
| cs_same_method_fold( |
| true, // foldl is good enough |
| |cx, span, old, new| { |
| cx.expr_binary(span, |
| binop, |
| old, new) |
| |
| }, |
| base, |
| enum_nonmatch_f, |
| cx, trait_span, substructure) |
| } |
| |
| /// cs_binop with binop == or |
| #[inline] |
| pub fn cs_or(enum_nonmatch_f: EnumNonMatchCollapsedFunc, |
| cx: &mut ExtCtxt, span: Span, |
| substructure: &Substructure) -> P<Expr> { |
| cs_binop(ast::BiOr, cx.expr_bool(span, false), |
| enum_nonmatch_f, |
| cx, span, substructure) |
| } |
| |
| /// cs_binop with binop == and |
| #[inline] |
| pub fn cs_and(enum_nonmatch_f: EnumNonMatchCollapsedFunc, |
| cx: &mut ExtCtxt, span: Span, |
| substructure: &Substructure) -> P<Expr> { |
| cs_binop(ast::BiAnd, cx.expr_bool(span, true), |
| enum_nonmatch_f, |
| cx, span, substructure) |
| } |
