1 // Copyright 2014 The Rust Project Developers. See the COPYRIGHT
2 // file at the top-level directory of this distribution and at
3 // http://rust-lang.org/COPYRIGHT.
5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
8 // option. This file may not be copied, modified, or distributed
9 // except according to those terms.
11 //! This module provides a simplified abstraction for working with
12 //! code blocks identified by their integer node-id. In particular,
13 //! it captures a common set of attributes that all "function-like
14 //! things" (represented by `FnLike` instances) share. For example,
15 //! all `FnLike` instances have a type signature (be it explicit or
16 //! inferred). And all `FnLike` instances have a body, i.e. the code
17 //! that is run when the function-like thing it represents is invoked.
19 //! With the above abstraction in place, one can treat the program
20 //! text as a collection of blocks of code (and most such blocks are
21 //! nested within a uniquely determined `FnLike`), and users can ask
22 //! for the `Code` associated with a particular NodeId.
24 pub use self::Code::*;
27 use ast::{Block, FnDecl, NodeId};
31 use ast_util::PostExpansionMethod;
35 /// An FnLikeNode is a Node that is like a fn, in that it has a decl
36 /// and a body (as well as a NodeId, a span, etc).
38 /// More specifically, it is one of either:
39 /// - A function item,
40 /// - A closure expr (i.e. an ExprClosure or ExprProc), or
41 /// - The default implementation for a trait method.
43 /// To construct one, use the `Code::from_node` function.
44 pub struct FnLikeNode<'a> { node: ast_map::Node<'a> }
46 impl<'a> Copy for FnLikeNode<'a> {}
48 /// MaybeFnLike wraps a method that indicates if an object
49 /// corresponds to some FnLikeNode.
50 pub trait MaybeFnLike { fn is_fn_like(&self) -> bool; }
52 /// Components shared by fn-like things (fn items, methods, closures).
53 pub struct FnParts<'a> {
56 pub kind: visit::FnKind<'a>,
61 impl MaybeFnLike for ast::Item {
62 fn is_fn_like(&self) -> bool {
63 match self.node { ast::ItemFn(..) => true, _ => false, }
67 impl MaybeFnLike for ast::TraitItem {
68 fn is_fn_like(&self) -> bool {
69 match *self { ast::ProvidedMethod(_) => true, _ => false, }
73 impl MaybeFnLike for ast::Expr {
74 fn is_fn_like(&self) -> bool {
76 ast::ExprClosure(..) | ast::ExprProc(..) => true,
82 /// Carries either an FnLikeNode or a Block, as these are the two
83 /// constructs that correspond to "code" (as in, something from which
84 /// we can construct a control-flow graph).
86 FnLikeCode(FnLikeNode<'a>),
90 impl<'a> Copy for Code<'a> {}
93 pub fn id(&self) -> ast::NodeId {
95 FnLikeCode(node) => node.id(),
96 BlockCode(block) => block.id,
100 /// Attempts to construct a Code from presumed FnLike or Block node input.
101 pub fn from_node(node: Node) -> Option<Code> {
102 fn new(node: Node) -> FnLikeNode { FnLikeNode { node: node } }
104 ast_map::NodeItem(item) if item.is_fn_like() =>
105 Some(FnLikeCode(new(node))),
106 ast_map::NodeTraitItem(tm) if tm.is_fn_like() =>
107 Some(FnLikeCode(new(node))),
108 ast_map::NodeImplItem(_) =>
109 Some(FnLikeCode(new(node))),
110 ast_map::NodeExpr(e) if e.is_fn_like() =>
111 Some(FnLikeCode(new(node))),
112 ast_map::NodeBlock(block) =>
113 Some(BlockCode(block)),
120 /// These are all the components one can extract from a fn item for
121 /// use when implementing FnLikeNode operations.
122 struct ItemFnParts<'a> {
124 decl: &'a ast::FnDecl,
127 generics: &'a ast::Generics,
133 /// These are all the components one can extract from a closure expr
134 /// for use when implementing FnLikeNode operations.
135 struct ClosureParts<'a> {
142 impl<'a> ClosureParts<'a> {
143 fn new(d: &'a FnDecl, b: &'a Block, id: NodeId, s: Span) -> ClosureParts<'a> {
144 ClosureParts { decl: d, body: b, id: id, span: s }
148 impl<'a> FnLikeNode<'a> {
149 pub fn to_fn_parts(self) -> FnParts<'a> {
159 pub fn body(self) -> &'a Block {
160 self.handle(|i: ItemFnParts<'a>| &*i.body,
161 |m: &'a ast::Method| m.pe_body(),
162 |c: ClosureParts<'a>| c.body)
165 pub fn decl(self) -> &'a FnDecl {
166 self.handle(|i: ItemFnParts<'a>| &*i.decl,
167 |m: &'a ast::Method| m.pe_fn_decl(),
168 |c: ClosureParts<'a>| c.decl)
171 pub fn span(self) -> Span {
172 self.handle(|i: ItemFnParts| i.span,
173 |m: &'a ast::Method| m.span,
174 |c: ClosureParts| c.span)
177 pub fn id(self) -> NodeId {
178 self.handle(|i: ItemFnParts| i.id,
179 |m: &'a ast::Method| m.id,
180 |c: ClosureParts| c.id)
183 pub fn kind(self) -> visit::FnKind<'a> {
184 let item = |p: ItemFnParts<'a>| -> visit::FnKind<'a> {
185 visit::FkItemFn(p.ident, p.generics, p.style, p.abi)
187 let closure = |_: ClosureParts| {
190 let method = |m: &'a ast::Method| {
191 visit::FkMethod(m.pe_ident(), m.pe_generics(), m)
193 self.handle(item, method, closure)
197 item_fn: |ItemFnParts<'a>| -> A,
198 method: |&'a ast::Method| -> A,
199 closure: |ClosureParts<'a>| -> A) -> A {
201 ast_map::NodeItem(i) => match i.node {
202 ast::ItemFn(ref decl, style, abi, ref generics, ref block) =>
204 ident: i.ident, decl: &**decl, style: style, body: &**block,
205 generics: generics, abi: abi, id: i.id, span: i.span
207 _ => panic!("item FnLikeNode that is not fn-like"),
209 ast_map::NodeTraitItem(t) => match *t {
210 ast::ProvidedMethod(ref m) => method(&**m),
211 _ => panic!("trait method FnLikeNode that is not fn-like"),
213 ast_map::NodeImplItem(ii) => {
215 ast::MethodImplItem(ref m) => method(&**m),
216 ast::TypeImplItem(_) => {
217 panic!("impl method FnLikeNode that is not fn-like")
221 ast_map::NodeExpr(e) => match e.node {
222 ast::ExprClosure(_, _, ref decl, ref block) =>
223 closure(ClosureParts::new(&**decl, &**block, e.id, e.span)),
224 ast::ExprProc(ref decl, ref block) =>
225 closure(ClosureParts::new(&**decl, &**block, e.id, e.span)),
226 _ => panic!("expr FnLikeNode that is not fn-like"),
228 _ => panic!("other FnLikeNode that is not fn-like"),