910 lines
30 KiB
Rust
910 lines
30 KiB
Rust
// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
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// file at the top-level directory of this distribution and at
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// http://rust-lang.org/COPYRIGHT.
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//
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// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
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// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
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// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
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// option. This file may not be copied, modified, or distributed
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// except according to those terms.
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pub use self::SyntaxExtension::*;
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use ast;
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use ast::Name;
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use codemap;
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use codemap::{CodeMap, Span, ExpnId, ExpnInfo, NO_EXPANSION};
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use ext;
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use ext::expand;
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use ext::tt::macro_rules;
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use feature_gate::GatedCfgAttr;
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use parse;
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use parse::parser;
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use parse::token;
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use parse::token::{InternedString, intern, str_to_ident};
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use ptr::P;
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use util::small_vector::SmallVector;
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use util::lev_distance::{lev_distance, max_suggestion_distance};
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use ext::mtwt;
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use fold::Folder;
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use std::collections::{HashMap, HashSet};
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use std::rc::Rc;
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use std::default::Default;
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#[derive(Debug,Clone)]
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pub enum Annotatable {
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Item(P<ast::Item>),
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TraitItem(P<ast::TraitItem>),
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ImplItem(P<ast::ImplItem>),
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}
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impl Annotatable {
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pub fn attrs(&self) -> &[ast::Attribute] {
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match *self {
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Annotatable::Item(ref i) => &i.attrs,
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Annotatable::TraitItem(ref ti) => &ti.attrs,
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Annotatable::ImplItem(ref ii) => &ii.attrs,
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}
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}
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pub fn fold_attrs(self, attrs: Vec<ast::Attribute>) -> Annotatable {
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match self {
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Annotatable::Item(i) => Annotatable::Item(i.map(|i| ast::Item {
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attrs: attrs,
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..i
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})),
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Annotatable::TraitItem(i) => Annotatable::TraitItem(i.map(|ti| {
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ast::TraitItem { attrs: attrs, ..ti }
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})),
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Annotatable::ImplItem(i) => Annotatable::ImplItem(i.map(|ii| {
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ast::ImplItem { attrs: attrs, ..ii }
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})),
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}
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}
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pub fn expect_item(self) -> P<ast::Item> {
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match self {
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Annotatable::Item(i) => i,
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_ => panic!("expected Item")
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}
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}
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pub fn map_item_or<F, G>(self, mut f: F, mut or: G) -> Annotatable
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where F: FnMut(P<ast::Item>) -> P<ast::Item>,
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G: FnMut(Annotatable) -> Annotatable
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{
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match self {
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Annotatable::Item(i) => Annotatable::Item(f(i)),
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_ => or(self)
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}
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}
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pub fn expect_trait_item(self) -> P<ast::TraitItem> {
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match self {
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Annotatable::TraitItem(i) => i,
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_ => panic!("expected Item")
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}
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}
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pub fn expect_impl_item(self) -> P<ast::ImplItem> {
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match self {
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Annotatable::ImplItem(i) => i,
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_ => panic!("expected Item")
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}
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}
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}
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// A more flexible ItemDecorator.
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pub trait MultiItemDecorator {
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fn expand(&self,
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ecx: &mut ExtCtxt,
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sp: Span,
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meta_item: &ast::MetaItem,
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item: &Annotatable,
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push: &mut FnMut(Annotatable));
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}
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impl<F> MultiItemDecorator for F
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where F : Fn(&mut ExtCtxt, Span, &ast::MetaItem, &Annotatable, &mut FnMut(Annotatable))
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{
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fn expand(&self,
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ecx: &mut ExtCtxt,
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sp: Span,
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meta_item: &ast::MetaItem,
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item: &Annotatable,
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push: &mut FnMut(Annotatable)) {
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(*self)(ecx, sp, meta_item, item, push)
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}
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}
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// A more flexible ItemModifier (ItemModifier should go away, eventually, FIXME).
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// meta_item is the annotation, item is the item being modified, parent_item
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// is the impl or trait item is declared in if item is part of such a thing.
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// FIXME Decorators should follow the same pattern too.
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pub trait MultiItemModifier {
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fn expand(&self,
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ecx: &mut ExtCtxt,
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span: Span,
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meta_item: &ast::MetaItem,
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item: Annotatable)
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-> Annotatable;
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}
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impl<F> MultiItemModifier for F
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where F: Fn(&mut ExtCtxt,
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Span,
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&ast::MetaItem,
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Annotatable) -> Annotatable
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{
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fn expand(&self,
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ecx: &mut ExtCtxt,
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span: Span,
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meta_item: &ast::MetaItem,
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item: Annotatable)
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-> Annotatable {
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(*self)(ecx, span, meta_item, item)
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}
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}
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/// Represents a thing that maps token trees to Macro Results
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pub trait TTMacroExpander {
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fn expand<'cx>(&self,
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ecx: &'cx mut ExtCtxt,
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span: Span,
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token_tree: &[ast::TokenTree])
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-> Box<MacResult+'cx>;
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}
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pub type MacroExpanderFn =
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for<'cx> fn(&'cx mut ExtCtxt, Span, &[ast::TokenTree]) -> Box<MacResult+'cx>;
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impl<F> TTMacroExpander for F
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where F : for<'cx> Fn(&'cx mut ExtCtxt, Span, &[ast::TokenTree]) -> Box<MacResult+'cx>
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{
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fn expand<'cx>(&self,
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ecx: &'cx mut ExtCtxt,
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span: Span,
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token_tree: &[ast::TokenTree])
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-> Box<MacResult+'cx> {
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(*self)(ecx, span, token_tree)
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}
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}
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pub trait IdentMacroExpander {
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fn expand<'cx>(&self,
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cx: &'cx mut ExtCtxt,
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sp: Span,
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ident: ast::Ident,
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token_tree: Vec<ast::TokenTree> )
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-> Box<MacResult+'cx>;
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}
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pub type IdentMacroExpanderFn =
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for<'cx> fn(&'cx mut ExtCtxt, Span, ast::Ident, Vec<ast::TokenTree>) -> Box<MacResult+'cx>;
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impl<F> IdentMacroExpander for F
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where F : for<'cx> Fn(&'cx mut ExtCtxt, Span, ast::Ident,
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Vec<ast::TokenTree>) -> Box<MacResult+'cx>
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{
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fn expand<'cx>(&self,
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cx: &'cx mut ExtCtxt,
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sp: Span,
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ident: ast::Ident,
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token_tree: Vec<ast::TokenTree> )
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-> Box<MacResult+'cx>
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{
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(*self)(cx, sp, ident, token_tree)
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}
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}
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// Use a macro because forwarding to a simple function has type system issues
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macro_rules! make_stmts_default {
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($me:expr) => {
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$me.make_expr().map(|e| {
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SmallVector::one(P(codemap::respan(
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e.span, ast::StmtExpr(e, ast::DUMMY_NODE_ID))))
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})
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}
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}
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/// The result of a macro expansion. The return values of the various
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/// methods are spliced into the AST at the callsite of the macro.
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pub trait MacResult {
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/// Create an expression.
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fn make_expr(self: Box<Self>) -> Option<P<ast::Expr>> {
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None
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}
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/// Create zero or more items.
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fn make_items(self: Box<Self>) -> Option<SmallVector<P<ast::Item>>> {
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None
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}
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/// Create zero or more impl items.
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fn make_impl_items(self: Box<Self>) -> Option<SmallVector<P<ast::ImplItem>>> {
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None
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}
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/// Create a pattern.
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fn make_pat(self: Box<Self>) -> Option<P<ast::Pat>> {
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None
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}
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/// Create zero or more statements.
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///
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/// By default this attempts to create an expression statement,
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/// returning None if that fails.
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fn make_stmts(self: Box<Self>) -> Option<SmallVector<P<ast::Stmt>>> {
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make_stmts_default!(self)
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}
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fn make_ty(self: Box<Self>) -> Option<P<ast::Ty>> {
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None
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}
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}
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macro_rules! make_MacEager {
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( $( $fld:ident: $t:ty, )* ) => {
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/// `MacResult` implementation for the common case where you've already
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/// built each form of AST that you might return.
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#[derive(Default)]
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pub struct MacEager {
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$(
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pub $fld: Option<$t>,
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)*
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}
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impl MacEager {
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$(
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pub fn $fld(v: $t) -> Box<MacResult> {
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Box::new(MacEager {
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$fld: Some(v),
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..Default::default()
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})
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}
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)*
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}
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}
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}
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make_MacEager! {
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expr: P<ast::Expr>,
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pat: P<ast::Pat>,
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items: SmallVector<P<ast::Item>>,
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impl_items: SmallVector<P<ast::ImplItem>>,
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stmts: SmallVector<P<ast::Stmt>>,
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ty: P<ast::Ty>,
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}
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impl MacResult for MacEager {
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fn make_expr(self: Box<Self>) -> Option<P<ast::Expr>> {
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self.expr
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}
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fn make_items(self: Box<Self>) -> Option<SmallVector<P<ast::Item>>> {
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self.items
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}
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fn make_impl_items(self: Box<Self>) -> Option<SmallVector<P<ast::ImplItem>>> {
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self.impl_items
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}
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fn make_stmts(self: Box<Self>) -> Option<SmallVector<P<ast::Stmt>>> {
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match self.stmts.as_ref().map_or(0, |s| s.len()) {
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0 => make_stmts_default!(self),
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_ => self.stmts,
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}
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}
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fn make_pat(self: Box<Self>) -> Option<P<ast::Pat>> {
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if let Some(p) = self.pat {
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return Some(p);
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}
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if let Some(e) = self.expr {
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if let ast::ExprLit(_) = e.node {
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return Some(P(ast::Pat {
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id: ast::DUMMY_NODE_ID,
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span: e.span,
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node: ast::PatLit(e),
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}));
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}
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}
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None
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}
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fn make_ty(self: Box<Self>) -> Option<P<ast::Ty>> {
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self.ty
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}
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}
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/// Fill-in macro expansion result, to allow compilation to continue
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/// after hitting errors.
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#[derive(Copy, Clone)]
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pub struct DummyResult {
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expr_only: bool,
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span: Span
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}
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impl DummyResult {
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/// Create a default MacResult that can be anything.
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///
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/// Use this as a return value after hitting any errors and
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/// calling `span_err`.
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pub fn any(sp: Span) -> Box<MacResult+'static> {
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Box::new(DummyResult { expr_only: false, span: sp })
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}
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/// Create a default MacResult that can only be an expression.
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///
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/// Use this for macros that must expand to an expression, so even
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/// if an error is encountered internally, the user will receive
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/// an error that they also used it in the wrong place.
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pub fn expr(sp: Span) -> Box<MacResult+'static> {
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Box::new(DummyResult { expr_only: true, span: sp })
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}
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/// A plain dummy expression.
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pub fn raw_expr(sp: Span) -> P<ast::Expr> {
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P(ast::Expr {
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id: ast::DUMMY_NODE_ID,
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node: ast::ExprLit(P(codemap::respan(sp, ast::LitBool(false)))),
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span: sp,
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attrs: None,
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})
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}
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/// A plain dummy pattern.
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pub fn raw_pat(sp: Span) -> ast::Pat {
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ast::Pat {
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id: ast::DUMMY_NODE_ID,
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node: ast::PatWild,
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span: sp,
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}
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}
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pub fn raw_ty(sp: Span) -> P<ast::Ty> {
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P(ast::Ty {
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id: ast::DUMMY_NODE_ID,
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node: ast::TyInfer,
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span: sp
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})
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}
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}
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impl MacResult for DummyResult {
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fn make_expr(self: Box<DummyResult>) -> Option<P<ast::Expr>> {
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Some(DummyResult::raw_expr(self.span))
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}
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fn make_pat(self: Box<DummyResult>) -> Option<P<ast::Pat>> {
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Some(P(DummyResult::raw_pat(self.span)))
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}
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fn make_items(self: Box<DummyResult>) -> Option<SmallVector<P<ast::Item>>> {
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// this code needs a comment... why not always just return the Some() ?
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if self.expr_only {
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None
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} else {
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Some(SmallVector::zero())
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}
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}
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fn make_impl_items(self: Box<DummyResult>) -> Option<SmallVector<P<ast::ImplItem>>> {
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if self.expr_only {
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None
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} else {
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Some(SmallVector::zero())
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}
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}
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fn make_stmts(self: Box<DummyResult>) -> Option<SmallVector<P<ast::Stmt>>> {
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Some(SmallVector::one(P(
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codemap::respan(self.span,
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ast::StmtExpr(DummyResult::raw_expr(self.span),
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ast::DUMMY_NODE_ID)))))
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}
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}
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/// An enum representing the different kinds of syntax extensions.
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pub enum SyntaxExtension {
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/// A syntax extension that is attached to an item and creates new items
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/// based upon it.
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///
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/// `#[derive(...)]` is a `MultiItemDecorator`.
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MultiDecorator(Box<MultiItemDecorator + 'static>),
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/// A syntax extension that is attached to an item and modifies it
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/// in-place. More flexible version than Modifier.
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MultiModifier(Box<MultiItemModifier + 'static>),
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/// A normal, function-like syntax extension.
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///
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/// `bytes!` is a `NormalTT`.
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///
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/// The `bool` dictates whether the contents of the macro can
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/// directly use `#[unstable]` things (true == yes).
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NormalTT(Box<TTMacroExpander + 'static>, Option<Span>, bool),
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/// A function-like syntax extension that has an extra ident before
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/// the block.
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///
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IdentTT(Box<IdentMacroExpander + 'static>, Option<Span>, bool),
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/// Represents `macro_rules!` itself.
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MacroRulesTT,
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}
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pub type NamedSyntaxExtension = (Name, SyntaxExtension);
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pub struct BlockInfo {
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/// Should macros escape from this scope?
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pub macros_escape: bool,
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/// What are the pending renames?
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pub pending_renames: mtwt::RenameList,
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}
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impl BlockInfo {
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pub fn new() -> BlockInfo {
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BlockInfo {
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macros_escape: false,
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pending_renames: Vec::new(),
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}
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}
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}
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/// The base map of methods for expanding syntax extension
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/// AST nodes into full ASTs
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fn initial_syntax_expander_table<'feat>(ecfg: &expand::ExpansionConfig<'feat>)
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-> SyntaxEnv {
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// utility function to simplify creating NormalTT syntax extensions
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fn builtin_normal_expander(f: MacroExpanderFn) -> SyntaxExtension {
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NormalTT(Box::new(f), None, false)
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}
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let mut syntax_expanders = SyntaxEnv::new();
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syntax_expanders.insert(intern("macro_rules"), MacroRulesTT);
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if ecfg.enable_quotes() {
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// Quasi-quoting expanders
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syntax_expanders.insert(intern("quote_tokens"),
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builtin_normal_expander(
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ext::quote::expand_quote_tokens));
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syntax_expanders.insert(intern("quote_expr"),
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builtin_normal_expander(
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ext::quote::expand_quote_expr));
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syntax_expanders.insert(intern("quote_ty"),
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builtin_normal_expander(
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ext::quote::expand_quote_ty));
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syntax_expanders.insert(intern("quote_item"),
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builtin_normal_expander(
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ext::quote::expand_quote_item));
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syntax_expanders.insert(intern("quote_pat"),
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builtin_normal_expander(
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ext::quote::expand_quote_pat));
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syntax_expanders.insert(intern("quote_arm"),
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builtin_normal_expander(
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ext::quote::expand_quote_arm));
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syntax_expanders.insert(intern("quote_stmt"),
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builtin_normal_expander(
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ext::quote::expand_quote_stmt));
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syntax_expanders.insert(intern("quote_matcher"),
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builtin_normal_expander(
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ext::quote::expand_quote_matcher));
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syntax_expanders.insert(intern("quote_attr"),
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builtin_normal_expander(
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ext::quote::expand_quote_attr));
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syntax_expanders.insert(intern("quote_arg"),
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builtin_normal_expander(
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ext::quote::expand_quote_arg));
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syntax_expanders.insert(intern("quote_block"),
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builtin_normal_expander(
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ext::quote::expand_quote_block));
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syntax_expanders.insert(intern("quote_meta_item"),
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builtin_normal_expander(
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ext::quote::expand_quote_meta_item));
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syntax_expanders.insert(intern("quote_path"),
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builtin_normal_expander(
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ext::quote::expand_quote_path));
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}
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syntax_expanders.insert(intern("line"),
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builtin_normal_expander(
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ext::source_util::expand_line));
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syntax_expanders.insert(intern("column"),
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builtin_normal_expander(
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ext::source_util::expand_column));
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syntax_expanders.insert(intern("file"),
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builtin_normal_expander(
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ext::source_util::expand_file));
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syntax_expanders.insert(intern("stringify"),
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builtin_normal_expander(
|
|
ext::source_util::expand_stringify));
|
|
syntax_expanders.insert(intern("include"),
|
|
builtin_normal_expander(
|
|
ext::source_util::expand_include));
|
|
syntax_expanders.insert(intern("include_str"),
|
|
builtin_normal_expander(
|
|
ext::source_util::expand_include_str));
|
|
syntax_expanders.insert(intern("include_bytes"),
|
|
builtin_normal_expander(
|
|
ext::source_util::expand_include_bytes));
|
|
syntax_expanders.insert(intern("module_path"),
|
|
builtin_normal_expander(
|
|
ext::source_util::expand_mod));
|
|
syntax_expanders
|
|
}
|
|
|
|
/// One of these is made during expansion and incrementally updated as we go;
|
|
/// when a macro expansion occurs, the resulting nodes have the backtrace()
|
|
/// -> expn_info of their expansion context stored into their span.
|
|
pub struct ExtCtxt<'a> {
|
|
pub parse_sess: &'a parse::ParseSess,
|
|
pub cfg: ast::CrateConfig,
|
|
pub backtrace: ExpnId,
|
|
pub ecfg: expand::ExpansionConfig<'a>,
|
|
pub crate_root: Option<&'static str>,
|
|
pub feature_gated_cfgs: &'a mut Vec<GatedCfgAttr>,
|
|
|
|
pub mod_path: Vec<ast::Ident> ,
|
|
pub exported_macros: Vec<ast::MacroDef>,
|
|
|
|
pub syntax_env: SyntaxEnv,
|
|
pub recursion_count: usize,
|
|
}
|
|
|
|
impl<'a> ExtCtxt<'a> {
|
|
pub fn new(parse_sess: &'a parse::ParseSess, cfg: ast::CrateConfig,
|
|
ecfg: expand::ExpansionConfig<'a>,
|
|
feature_gated_cfgs: &'a mut Vec<GatedCfgAttr>) -> ExtCtxt<'a> {
|
|
let env = initial_syntax_expander_table(&ecfg);
|
|
ExtCtxt {
|
|
parse_sess: parse_sess,
|
|
cfg: cfg,
|
|
backtrace: NO_EXPANSION,
|
|
mod_path: Vec::new(),
|
|
ecfg: ecfg,
|
|
crate_root: None,
|
|
feature_gated_cfgs: feature_gated_cfgs,
|
|
exported_macros: Vec::new(),
|
|
syntax_env: env,
|
|
recursion_count: 0,
|
|
}
|
|
}
|
|
|
|
/// Returns a `Folder` for deeply expanding all macros in an AST node.
|
|
pub fn expander<'b>(&'b mut self) -> expand::MacroExpander<'b, 'a> {
|
|
expand::MacroExpander::new(self)
|
|
}
|
|
|
|
pub fn new_parser_from_tts(&self, tts: &[ast::TokenTree])
|
|
-> parser::Parser<'a> {
|
|
parse::tts_to_parser(self.parse_sess, tts.to_vec(), self.cfg())
|
|
}
|
|
|
|
pub fn codemap(&self) -> &'a CodeMap { self.parse_sess.codemap() }
|
|
pub fn parse_sess(&self) -> &'a parse::ParseSess { self.parse_sess }
|
|
pub fn cfg(&self) -> ast::CrateConfig { self.cfg.clone() }
|
|
pub fn call_site(&self) -> Span {
|
|
self.codemap().with_expn_info(self.backtrace, |ei| match ei {
|
|
Some(expn_info) => expn_info.call_site,
|
|
None => self.bug("missing top span")
|
|
})
|
|
}
|
|
pub fn backtrace(&self) -> ExpnId { self.backtrace }
|
|
|
|
/// Original span that caused the current exapnsion to happen.
|
|
pub fn original_span(&self) -> Span {
|
|
let mut expn_id = self.backtrace;
|
|
let mut call_site = None;
|
|
loop {
|
|
match self.codemap().with_expn_info(expn_id, |ei| ei.map(|ei| ei.call_site)) {
|
|
None => break,
|
|
Some(cs) => {
|
|
call_site = Some(cs);
|
|
expn_id = cs.expn_id;
|
|
}
|
|
}
|
|
}
|
|
call_site.expect("missing expansion backtrace")
|
|
}
|
|
|
|
/// Returns span for the macro which originally caused the current expansion to happen.
|
|
///
|
|
/// Stops backtracing at include! boundary.
|
|
pub fn expansion_cause(&self) -> Span {
|
|
let mut expn_id = self.backtrace;
|
|
let mut last_macro = None;
|
|
loop {
|
|
if self.codemap().with_expn_info(expn_id, |info| {
|
|
info.map_or(None, |i| {
|
|
if i.callee.name().as_str() == "include" {
|
|
// Stop going up the backtrace once include! is encountered
|
|
return None;
|
|
}
|
|
expn_id = i.call_site.expn_id;
|
|
last_macro = Some(i.call_site);
|
|
return Some(());
|
|
})
|
|
}).is_none() {
|
|
break
|
|
}
|
|
}
|
|
last_macro.expect("missing expansion backtrace")
|
|
}
|
|
|
|
pub fn mod_push(&mut self, i: ast::Ident) { self.mod_path.push(i); }
|
|
pub fn mod_pop(&mut self) { self.mod_path.pop().unwrap(); }
|
|
pub fn mod_path(&self) -> Vec<ast::Ident> {
|
|
let mut v = Vec::new();
|
|
v.push(token::str_to_ident(&self.ecfg.crate_name));
|
|
v.extend(self.mod_path.iter().cloned());
|
|
return v;
|
|
}
|
|
pub fn bt_push(&mut self, ei: ExpnInfo) {
|
|
self.recursion_count += 1;
|
|
if self.recursion_count > self.ecfg.recursion_limit {
|
|
self.span_fatal(ei.call_site,
|
|
&format!("recursion limit reached while expanding the macro `{}`",
|
|
ei.callee.name()));
|
|
}
|
|
|
|
let mut call_site = ei.call_site;
|
|
call_site.expn_id = self.backtrace;
|
|
self.backtrace = self.codemap().record_expansion(ExpnInfo {
|
|
call_site: call_site,
|
|
callee: ei.callee
|
|
});
|
|
}
|
|
pub fn bt_pop(&mut self) {
|
|
match self.backtrace {
|
|
NO_EXPANSION => self.bug("tried to pop without a push"),
|
|
expn_id => {
|
|
self.recursion_count -= 1;
|
|
self.backtrace = self.codemap().with_expn_info(expn_id, |expn_info| {
|
|
expn_info.map_or(NO_EXPANSION, |ei| ei.call_site.expn_id)
|
|
});
|
|
}
|
|
}
|
|
}
|
|
|
|
pub fn insert_macro(&mut self, def: ast::MacroDef) {
|
|
if def.export {
|
|
self.exported_macros.push(def.clone());
|
|
}
|
|
if def.use_locally {
|
|
let ext = macro_rules::compile(self, &def);
|
|
self.syntax_env.insert(def.ident.name, ext);
|
|
}
|
|
}
|
|
|
|
/// Emit `msg` attached to `sp`, and stop compilation immediately.
|
|
///
|
|
/// `span_err` should be strongly preferred where-ever possible:
|
|
/// this should *only* be used when
|
|
/// - continuing has a high risk of flow-on errors (e.g. errors in
|
|
/// declaring a macro would cause all uses of that macro to
|
|
/// complain about "undefined macro"), or
|
|
/// - there is literally nothing else that can be done (however,
|
|
/// in most cases one can construct a dummy expression/item to
|
|
/// substitute; we never hit resolve/type-checking so the dummy
|
|
/// value doesn't have to match anything)
|
|
pub fn span_fatal(&self, sp: Span, msg: &str) -> ! {
|
|
panic!(self.parse_sess.span_diagnostic.span_fatal(sp, msg));
|
|
}
|
|
|
|
/// Emit `msg` attached to `sp`, without immediately stopping
|
|
/// compilation.
|
|
///
|
|
/// Compilation will be stopped in the near future (at the end of
|
|
/// the macro expansion phase).
|
|
pub fn span_err(&self, sp: Span, msg: &str) {
|
|
self.parse_sess.span_diagnostic.span_err(sp, msg);
|
|
}
|
|
pub fn span_warn(&self, sp: Span, msg: &str) {
|
|
self.parse_sess.span_diagnostic.span_warn(sp, msg);
|
|
}
|
|
pub fn span_unimpl(&self, sp: Span, msg: &str) -> ! {
|
|
self.parse_sess.span_diagnostic.span_unimpl(sp, msg);
|
|
}
|
|
pub fn span_bug(&self, sp: Span, msg: &str) -> ! {
|
|
self.parse_sess.span_diagnostic.span_bug(sp, msg);
|
|
}
|
|
pub fn span_note(&self, sp: Span, msg: &str) {
|
|
self.parse_sess.span_diagnostic.span_note(sp, msg);
|
|
}
|
|
pub fn span_help(&self, sp: Span, msg: &str) {
|
|
self.parse_sess.span_diagnostic.span_help(sp, msg);
|
|
}
|
|
pub fn fileline_help(&self, sp: Span, msg: &str) {
|
|
self.parse_sess.span_diagnostic.fileline_help(sp, msg);
|
|
}
|
|
pub fn bug(&self, msg: &str) -> ! {
|
|
self.parse_sess.span_diagnostic.handler().bug(msg);
|
|
}
|
|
pub fn trace_macros(&self) -> bool {
|
|
self.ecfg.trace_mac
|
|
}
|
|
pub fn set_trace_macros(&mut self, x: bool) {
|
|
self.ecfg.trace_mac = x
|
|
}
|
|
pub fn ident_of(&self, st: &str) -> ast::Ident {
|
|
str_to_ident(st)
|
|
}
|
|
pub fn std_path(&self, components: &[&str]) -> Vec<ast::Ident> {
|
|
let mut v = Vec::new();
|
|
if let Some(s) = self.crate_root {
|
|
v.push(self.ident_of(s));
|
|
}
|
|
v.extend(components.iter().map(|s| self.ident_of(s)));
|
|
return v
|
|
}
|
|
pub fn name_of(&self, st: &str) -> ast::Name {
|
|
token::intern(st)
|
|
}
|
|
|
|
pub fn suggest_macro_name(&mut self, name: &str, span: Span) {
|
|
let mut min: Option<(Name, usize)> = None;
|
|
let max_dist = max_suggestion_distance(name);
|
|
for macro_name in self.syntax_env.names.iter() {
|
|
let dist = lev_distance(name, ¯o_name.as_str());
|
|
if dist <= max_dist && (min.is_none() || min.unwrap().1 > dist) {
|
|
min = Some((*macro_name, dist));
|
|
}
|
|
}
|
|
if let Some((suggestion, _)) = min {
|
|
self.fileline_help(span, &format!("did you mean `{}!`?", suggestion));
|
|
}
|
|
}
|
|
}
|
|
|
|
/// Extract a string literal from the macro expanded version of `expr`,
|
|
/// emitting `err_msg` if `expr` is not a string literal. This does not stop
|
|
/// compilation on error, merely emits a non-fatal error and returns None.
|
|
pub fn expr_to_string(cx: &mut ExtCtxt, expr: P<ast::Expr>, err_msg: &str)
|
|
-> Option<(InternedString, ast::StrStyle)> {
|
|
// we want to be able to handle e.g. concat("foo", "bar")
|
|
let expr = cx.expander().fold_expr(expr);
|
|
match expr.node {
|
|
ast::ExprLit(ref l) => match l.node {
|
|
ast::LitStr(ref s, style) => return Some(((*s).clone(), style)),
|
|
_ => cx.span_err(l.span, err_msg)
|
|
},
|
|
_ => cx.span_err(expr.span, err_msg)
|
|
}
|
|
None
|
|
}
|
|
|
|
/// Non-fatally assert that `tts` is empty. Note that this function
|
|
/// returns even when `tts` is non-empty, macros that *need* to stop
|
|
/// compilation should call
|
|
/// `cx.parse_sess.span_diagnostic.abort_if_errors()` (this should be
|
|
/// done as rarely as possible).
|
|
pub fn check_zero_tts(cx: &ExtCtxt,
|
|
sp: Span,
|
|
tts: &[ast::TokenTree],
|
|
name: &str) {
|
|
if !tts.is_empty() {
|
|
cx.span_err(sp, &format!("{} takes no arguments", name));
|
|
}
|
|
}
|
|
|
|
/// Extract the string literal from the first token of `tts`. If this
|
|
/// is not a string literal, emit an error and return None.
|
|
pub fn get_single_str_from_tts(cx: &mut ExtCtxt,
|
|
sp: Span,
|
|
tts: &[ast::TokenTree],
|
|
name: &str)
|
|
-> Option<String> {
|
|
let mut p = cx.new_parser_from_tts(tts);
|
|
if p.token == token::Eof {
|
|
cx.span_err(sp, &format!("{} takes 1 argument", name));
|
|
return None
|
|
}
|
|
let ret = cx.expander().fold_expr(panictry!(p.parse_expr()));
|
|
if p.token != token::Eof {
|
|
cx.span_err(sp, &format!("{} takes 1 argument", name));
|
|
}
|
|
expr_to_string(cx, ret, "argument must be a string literal").map(|(s, _)| {
|
|
s.to_string()
|
|
})
|
|
}
|
|
|
|
/// Extract comma-separated expressions from `tts`. If there is a
|
|
/// parsing error, emit a non-fatal error and return None.
|
|
pub fn get_exprs_from_tts(cx: &mut ExtCtxt,
|
|
sp: Span,
|
|
tts: &[ast::TokenTree]) -> Option<Vec<P<ast::Expr>>> {
|
|
let mut p = cx.new_parser_from_tts(tts);
|
|
let mut es = Vec::new();
|
|
while p.token != token::Eof {
|
|
es.push(cx.expander().fold_expr(panictry!(p.parse_expr())));
|
|
if panictry!(p.eat(&token::Comma)){
|
|
continue;
|
|
}
|
|
if p.token != token::Eof {
|
|
cx.span_err(sp, "expected token: `,`");
|
|
return None;
|
|
}
|
|
}
|
|
Some(es)
|
|
}
|
|
|
|
/// In order to have some notion of scoping for macros,
|
|
/// we want to implement the notion of a transformation
|
|
/// environment.
|
|
///
|
|
/// This environment maps Names to SyntaxExtensions.
|
|
pub struct SyntaxEnv {
|
|
chain: Vec<MapChainFrame>,
|
|
/// All bang-style macro/extension names
|
|
/// encountered so far; to be used for diagnostics in resolve
|
|
pub names: HashSet<Name>,
|
|
}
|
|
|
|
// impl question: how to implement it? Initially, the
|
|
// env will contain only macros, so it might be painful
|
|
// to add an empty frame for every context. Let's just
|
|
// get it working, first....
|
|
|
|
// NB! the mutability of the underlying maps means that
|
|
// if expansion is out-of-order, a deeper scope may be
|
|
// able to refer to a macro that was added to an enclosing
|
|
// scope lexically later than the deeper scope.
|
|
|
|
struct MapChainFrame {
|
|
info: BlockInfo,
|
|
map: HashMap<Name, Rc<SyntaxExtension>>,
|
|
}
|
|
|
|
impl SyntaxEnv {
|
|
fn new() -> SyntaxEnv {
|
|
let mut map = SyntaxEnv { chain: Vec::new() , names: HashSet::new()};
|
|
map.push_frame();
|
|
map
|
|
}
|
|
|
|
pub fn push_frame(&mut self) {
|
|
self.chain.push(MapChainFrame {
|
|
info: BlockInfo::new(),
|
|
map: HashMap::new(),
|
|
});
|
|
}
|
|
|
|
pub fn pop_frame(&mut self) {
|
|
assert!(self.chain.len() > 1, "too many pops on MapChain!");
|
|
self.chain.pop();
|
|
}
|
|
|
|
fn find_escape_frame(&mut self) -> &mut MapChainFrame {
|
|
for (i, frame) in self.chain.iter_mut().enumerate().rev() {
|
|
if !frame.info.macros_escape || i == 0 {
|
|
return frame
|
|
}
|
|
}
|
|
unreachable!()
|
|
}
|
|
|
|
pub fn find(&self, k: Name) -> Option<Rc<SyntaxExtension>> {
|
|
for frame in self.chain.iter().rev() {
|
|
match frame.map.get(&k) {
|
|
Some(v) => return Some(v.clone()),
|
|
None => {}
|
|
}
|
|
}
|
|
None
|
|
}
|
|
|
|
pub fn insert(&mut self, k: Name, v: SyntaxExtension) {
|
|
if let NormalTT(..) = v {
|
|
self.names.insert(k);
|
|
}
|
|
self.find_escape_frame().map.insert(k, Rc::new(v));
|
|
}
|
|
|
|
pub fn info(&mut self) -> &mut BlockInfo {
|
|
let last_chain_index = self.chain.len() - 1;
|
|
&mut self.chain[last_chain_index].info
|
|
}
|
|
}
|