forked from rust-lang/rust
/
expand.rs
772 lines (673 loc) · 28.4 KB
/
expand.rs
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// Copyright 2012-2014 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.
use ast::{Block, Crate, Ident, Mac_, PatKind};
use ast::{MacStmtStyle, StmtKind, ItemKind};
use ast;
use ext::hygiene::Mark;
use ext::placeholders::{placeholder, PlaceholderExpander};
use attr::{self, HasAttrs};
use codemap::{ExpnInfo, NameAndSpan, MacroBang, MacroAttribute};
use syntax_pos::{self, Span, ExpnId};
use config::StripUnconfigured;
use ext::base::*;
use feature_gate::{self, Features};
use fold;
use fold::*;
use parse::token::{intern, keywords};
use ptr::P;
use tokenstream::TokenTree;
use util::small_vector::SmallVector;
use visit::Visitor;
use std::mem;
use std::path::PathBuf;
use std::rc::Rc;
macro_rules! expansions {
($($kind:ident: $ty:ty [$($vec:ident, $ty_elt:ty)*], $kind_name:expr, .$make:ident,
$(.$fold:ident)* $(lift .$fold_elt:ident)*,
$(.$visit:ident)* $(lift .$visit_elt:ident)*;)*) => {
#[derive(Copy, Clone)]
pub enum ExpansionKind { OptExpr, $( $kind, )* }
pub enum Expansion { OptExpr(Option<P<ast::Expr>>), $( $kind($ty), )* }
impl ExpansionKind {
fn name(self) -> &'static str {
match self {
ExpansionKind::OptExpr => "expression",
$( ExpansionKind::$kind => $kind_name, )*
}
}
fn make_from<'a>(self, result: Box<MacResult + 'a>) -> Option<Expansion> {
match self {
ExpansionKind::OptExpr => result.make_expr().map(Some).map(Expansion::OptExpr),
$( ExpansionKind::$kind => result.$make().map(Expansion::$kind), )*
}
}
}
impl Expansion {
pub fn make_opt_expr(self) -> Option<P<ast::Expr>> {
match self {
Expansion::OptExpr(expr) => expr,
_ => panic!("Expansion::make_* called on the wrong kind of expansion"),
}
}
$( pub fn $make(self) -> $ty {
match self {
Expansion::$kind(ast) => ast,
_ => panic!("Expansion::make_* called on the wrong kind of expansion"),
}
} )*
pub fn fold_with<F: Folder>(self, folder: &mut F) -> Self {
use self::Expansion::*;
match self {
OptExpr(expr) => OptExpr(expr.and_then(|expr| folder.fold_opt_expr(expr))),
$($( $kind(ast) => $kind(folder.$fold(ast)), )*)*
$($( $kind(ast) => {
$kind(ast.into_iter().flat_map(|ast| folder.$fold_elt(ast)).collect())
}, )*)*
}
}
pub fn visit_with<V: Visitor>(&self, visitor: &mut V) {
match *self {
Expansion::OptExpr(Some(ref expr)) => visitor.visit_expr(expr),
Expansion::OptExpr(None) => {}
$($( Expansion::$kind(ref ast) => visitor.$visit(ast), )*)*
$($( Expansion::$kind(ref ast) => for ast in ast.as_slice() {
visitor.$visit_elt(ast);
}, )*)*
}
}
}
impl<'a, 'b> Folder for MacroExpander<'a, 'b> {
fn fold_opt_expr(&mut self, expr: P<ast::Expr>) -> Option<P<ast::Expr>> {
self.expand(Expansion::OptExpr(Some(expr))).make_opt_expr()
}
$($(fn $fold(&mut self, node: $ty) -> $ty {
self.expand(Expansion::$kind(node)).$make()
})*)*
$($(fn $fold_elt(&mut self, node: $ty_elt) -> $ty {
self.expand(Expansion::$kind(SmallVector::one(node))).$make()
})*)*
}
}
}
expansions! {
Expr: P<ast::Expr> [], "expression", .make_expr, .fold_expr, .visit_expr;
Pat: P<ast::Pat> [], "pattern", .make_pat, .fold_pat, .visit_pat;
Ty: P<ast::Ty> [], "type", .make_ty, .fold_ty, .visit_ty;
Stmts: SmallVector<ast::Stmt> [SmallVector, ast::Stmt],
"statement", .make_stmts, lift .fold_stmt, lift .visit_stmt;
Items: SmallVector<P<ast::Item>> [SmallVector, P<ast::Item>],
"item", .make_items, lift .fold_item, lift .visit_item;
TraitItems: SmallVector<ast::TraitItem> [SmallVector, ast::TraitItem],
"trait item", .make_trait_items, lift .fold_trait_item, lift .visit_trait_item;
ImplItems: SmallVector<ast::ImplItem> [SmallVector, ast::ImplItem],
"impl item", .make_impl_items, lift .fold_impl_item, lift .visit_impl_item;
}
impl ExpansionKind {
fn dummy(self, span: Span) -> Expansion {
self.make_from(DummyResult::any(span)).unwrap()
}
fn expect_from_annotatables<I: IntoIterator<Item = Annotatable>>(self, items: I) -> Expansion {
let items = items.into_iter();
match self {
ExpansionKind::Items =>
Expansion::Items(items.map(Annotatable::expect_item).collect()),
ExpansionKind::ImplItems =>
Expansion::ImplItems(items.map(Annotatable::expect_impl_item).collect()),
ExpansionKind::TraitItems =>
Expansion::TraitItems(items.map(Annotatable::expect_trait_item).collect()),
_ => unreachable!(),
}
}
}
pub struct Invocation {
pub kind: InvocationKind,
expansion_kind: ExpansionKind,
expansion_data: ExpansionData,
}
pub enum InvocationKind {
Bang {
attrs: Vec<ast::Attribute>,
mac: ast::Mac,
ident: Option<Ident>,
span: Span,
},
Attr {
attr: ast::Attribute,
item: Annotatable,
},
}
impl Invocation {
fn span(&self) -> Span {
match self.kind {
InvocationKind::Bang { span, .. } => span,
InvocationKind::Attr { ref attr, .. } => attr.span,
}
}
pub fn mark(&self) -> Mark {
self.expansion_data.mark
}
}
pub struct MacroExpander<'a, 'b:'a> {
pub cx: &'a mut ExtCtxt<'b>,
monotonic: bool, // c.f. `cx.monotonic_expander()`
}
impl<'a, 'b> MacroExpander<'a, 'b> {
pub fn new(cx: &'a mut ExtCtxt<'b>, monotonic: bool) -> Self {
MacroExpander { cx: cx, monotonic: monotonic }
}
fn expand_crate(&mut self, mut krate: ast::Crate) -> ast::Crate {
let err_count = self.cx.parse_sess.span_diagnostic.err_count();
let krate_item = Expansion::Items(SmallVector::one(P(ast::Item {
attrs: krate.attrs,
span: krate.span,
node: ast::ItemKind::Mod(krate.module),
ident: keywords::Invalid.ident(),
id: ast::DUMMY_NODE_ID,
vis: ast::Visibility::Public,
})));
match self.expand(krate_item).make_items().pop().unwrap().unwrap() {
ast::Item { attrs, node: ast::ItemKind::Mod(module), .. } => {
krate.attrs = attrs;
krate.module = module;
},
_ => unreachable!(),
};
krate.exported_macros = mem::replace(&mut self.cx.exported_macros, Vec::new());
for def in &mut krate.exported_macros {
def.id = self.cx.resolver.next_node_id()
}
if self.cx.parse_sess.span_diagnostic.err_count() > err_count {
self.cx.parse_sess.span_diagnostic.abort_if_errors();
}
krate
}
// Fully expand all the invocations in `expansion`.
fn expand(&mut self, expansion: Expansion) -> Expansion {
let orig_expansion_data = self.cx.current_expansion.clone();
self.cx.current_expansion.depth = 0;
let (expansion, mut invocations) = self.collect_invocations(expansion);
invocations.reverse();
let mut expansions = vec![vec![(0, expansion)]];
while let Some(invoc) = invocations.pop() {
let ExpansionData { depth, mark, .. } = invoc.expansion_data;
self.cx.current_expansion = invoc.expansion_data.clone();
let expansion = match self.cx.resolver.resolve_invoc(&invoc) {
Some(ext) => self.expand_invoc(invoc, ext),
None => invoc.expansion_kind.dummy(invoc.span()),
};
self.cx.current_expansion.depth = depth + 1;
let (expansion, new_invocations) = self.collect_invocations(expansion);
if expansions.len() == depth {
expansions.push(Vec::new());
}
expansions[depth].push((mark.as_u32(), expansion));
if !self.cx.ecfg.single_step {
invocations.extend(new_invocations.into_iter().rev());
}
}
self.cx.current_expansion = orig_expansion_data;
let mut placeholder_expander = PlaceholderExpander::new(self.cx, self.monotonic);
while let Some(expansions) = expansions.pop() {
for (mark, expansion) in expansions.into_iter().rev() {
let expansion = expansion.fold_with(&mut placeholder_expander);
placeholder_expander.add(ast::NodeId::from_u32(mark), expansion);
}
}
placeholder_expander.remove(ast::NodeId::from_u32(0))
}
fn collect_invocations(&mut self, expansion: Expansion) -> (Expansion, Vec<Invocation>) {
let crate_config = mem::replace(&mut self.cx.cfg, Vec::new());
let result = {
let mut collector = InvocationCollector {
cfg: StripUnconfigured {
config: &crate_config,
should_test: self.cx.ecfg.should_test,
sess: self.cx.parse_sess,
features: self.cx.ecfg.features,
},
cx: self.cx,
invocations: Vec::new(),
monotonic: self.monotonic,
};
(expansion.fold_with(&mut collector), collector.invocations)
};
self.cx.cfg = crate_config;
let mark = self.cx.current_expansion.mark;
self.cx.resolver.visit_expansion(mark, &result.0);
result
}
fn expand_invoc(&mut self, invoc: Invocation, ext: Rc<SyntaxExtension>) -> Expansion {
match invoc.kind {
InvocationKind::Bang { .. } => self.expand_bang_invoc(invoc, ext),
InvocationKind::Attr { .. } => self.expand_attr_invoc(invoc, ext),
}
}
fn expand_attr_invoc(&mut self, invoc: Invocation, ext: Rc<SyntaxExtension>) -> Expansion {
let Invocation { expansion_kind: kind, .. } = invoc;
let (attr, item) = match invoc.kind {
InvocationKind::Attr { attr, item } => (attr, item),
_ => unreachable!(),
};
attr::mark_used(&attr);
self.cx.bt_push(ExpnInfo {
call_site: attr.span,
callee: NameAndSpan {
format: MacroAttribute(intern(&attr.name())),
span: Some(attr.span),
allow_internal_unstable: false,
}
});
match *ext {
MultiModifier(ref mac) => {
let item = mac.expand(self.cx, attr.span, &attr.node.value, item);
kind.expect_from_annotatables(item)
}
MultiDecorator(ref mac) => {
let mut items = Vec::new();
mac.expand(self.cx, attr.span, &attr.node.value, &item,
&mut |item| items.push(item));
items.push(item);
kind.expect_from_annotatables(items)
}
_ => unreachable!(),
}
}
/// Expand a macro invocation. Returns the result of expansion.
fn expand_bang_invoc(&mut self, invoc: Invocation, ext: Rc<SyntaxExtension>) -> Expansion {
let (mark, kind) = (invoc.mark(), invoc.expansion_kind);
let (attrs, mac, ident, span) = match invoc.kind {
InvocationKind::Bang { attrs, mac, ident, span } => (attrs, mac, ident, span),
_ => unreachable!(),
};
let Mac_ { path, tts, .. } = mac.node;
// Detect use of feature-gated or invalid attributes on macro invoations
// since they will not be detected after macro expansion.
for attr in attrs.iter() {
feature_gate::check_attribute(&attr, &self.cx.parse_sess.span_diagnostic,
&self.cx.parse_sess.codemap(),
&self.cx.ecfg.features.unwrap());
}
if path.segments.len() > 1 || path.global || !path.segments[0].parameters.is_empty() {
self.cx.span_err(path.span, "expected macro name without module separators");
return kind.dummy(span);
}
let extname = path.segments[0].identifier.name;
let ident = ident.unwrap_or(keywords::Invalid.ident());
let marked_tts = mark_tts(&tts, mark);
let opt_expanded = match *ext {
NormalTT(ref expandfun, exp_span, allow_internal_unstable) => {
if ident.name != keywords::Invalid.name() {
let msg =
format!("macro {}! expects no ident argument, given '{}'", extname, ident);
self.cx.span_err(path.span, &msg);
return kind.dummy(span);
}
self.cx.bt_push(ExpnInfo {
call_site: span,
callee: NameAndSpan {
format: MacroBang(extname),
span: exp_span,
allow_internal_unstable: allow_internal_unstable,
},
});
kind.make_from(expandfun.expand(self.cx, span, &marked_tts))
}
IdentTT(ref expander, tt_span, allow_internal_unstable) => {
if ident.name == keywords::Invalid.name() {
self.cx.span_err(path.span,
&format!("macro {}! expects an ident argument", extname));
return kind.dummy(span);
};
self.cx.bt_push(ExpnInfo {
call_site: span,
callee: NameAndSpan {
format: MacroBang(extname),
span: tt_span,
allow_internal_unstable: allow_internal_unstable,
}
});
kind.make_from(expander.expand(self.cx, span, ident, marked_tts, attrs))
}
MultiDecorator(..) | MultiModifier(..) => {
self.cx.span_err(path.span,
&format!("`{}` can only be used in attributes", extname));
return kind.dummy(span);
}
};
let expanded = if let Some(expanded) = opt_expanded {
expanded
} else {
let msg = format!("non-{kind} macro in {kind} position: {name}",
name = path.segments[0].identifier.name, kind = kind.name());
self.cx.span_err(path.span, &msg);
return kind.dummy(span);
};
expanded.fold_with(&mut Marker {
mark: mark,
expn_id: Some(self.cx.backtrace()),
})
}
}
struct InvocationCollector<'a, 'b: 'a> {
cx: &'a mut ExtCtxt<'b>,
cfg: StripUnconfigured<'a>,
invocations: Vec<Invocation>,
monotonic: bool,
}
macro_rules! fully_configure {
($this:ident, $node:ident, $noop_fold:ident) => {
match $noop_fold($node, &mut $this.cfg).pop() {
Some(node) => node,
None => return SmallVector::zero(),
}
}
}
impl<'a, 'b> InvocationCollector<'a, 'b> {
fn collect(&mut self, expansion_kind: ExpansionKind, kind: InvocationKind) -> Expansion {
let mark = Mark::fresh();
self.invocations.push(Invocation {
kind: kind,
expansion_kind: expansion_kind,
expansion_data: ExpansionData { mark: mark, ..self.cx.current_expansion.clone() },
});
placeholder(expansion_kind, ast::NodeId::from_u32(mark.as_u32()))
}
fn collect_bang(
&mut self, mac: ast::Mac, attrs: Vec<ast::Attribute>, span: Span, kind: ExpansionKind,
) -> Expansion {
self.collect(kind, InvocationKind::Bang { attrs: attrs, mac: mac, ident: None, span: span })
}
fn collect_attr(&mut self, attr: ast::Attribute, item: Annotatable, kind: ExpansionKind)
-> Expansion {
self.collect(kind, InvocationKind::Attr { attr: attr, item: item })
}
// If `item` is an attr invocation, remove and return the macro attribute.
fn classify_item<T: HasAttrs>(&mut self, mut item: T) -> (T, Option<ast::Attribute>) {
let mut attr = None;
item = item.map_attrs(|mut attrs| {
attr = self.cx.resolver.find_attr_invoc(&mut attrs);
attrs
});
(item, attr)
}
fn configure<T: HasAttrs>(&mut self, node: T) -> Option<T> {
self.cfg.configure(node)
}
}
impl<'a, 'b> Folder for InvocationCollector<'a, 'b> {
fn fold_expr(&mut self, expr: P<ast::Expr>) -> P<ast::Expr> {
let mut expr = self.cfg.configure_expr(expr).unwrap();
expr.node = self.cfg.configure_expr_kind(expr.node);
if let ast::ExprKind::Mac(mac) = expr.node {
self.collect_bang(mac, expr.attrs.into(), expr.span, ExpansionKind::Expr).make_expr()
} else {
P(noop_fold_expr(expr, self))
}
}
fn fold_opt_expr(&mut self, expr: P<ast::Expr>) -> Option<P<ast::Expr>> {
let mut expr = configure!(self, expr).unwrap();
expr.node = self.cfg.configure_expr_kind(expr.node);
if let ast::ExprKind::Mac(mac) = expr.node {
self.collect_bang(mac, expr.attrs.into(), expr.span, ExpansionKind::OptExpr)
.make_opt_expr()
} else {
Some(P(noop_fold_expr(expr, self)))
}
}
fn fold_pat(&mut self, pat: P<ast::Pat>) -> P<ast::Pat> {
match pat.node {
PatKind::Mac(_) => {}
_ => return noop_fold_pat(pat, self),
}
pat.and_then(|pat| match pat.node {
PatKind::Mac(mac) =>
self.collect_bang(mac, Vec::new(), pat.span, ExpansionKind::Pat).make_pat(),
_ => unreachable!(),
})
}
fn fold_stmt(&mut self, stmt: ast::Stmt) -> SmallVector<ast::Stmt> {
let stmt = match self.cfg.configure_stmt(stmt) {
Some(stmt) => stmt,
None => return SmallVector::zero(),
};
let (mac, style, attrs) = if let StmtKind::Mac(mac) = stmt.node {
mac.unwrap()
} else {
// The placeholder expander gives ids to statements, so we avoid folding the id here.
let ast::Stmt { id, node, span } = stmt;
return noop_fold_stmt_kind(node, self).into_iter().map(|node| {
ast::Stmt { id: id, node: node, span: span }
}).collect()
};
let mut placeholder =
self.collect_bang(mac, attrs.into(), stmt.span, ExpansionKind::Stmts).make_stmts();
// If this is a macro invocation with a semicolon, then apply that
// semicolon to the final statement produced by expansion.
if style == MacStmtStyle::Semicolon {
if let Some(stmt) = placeholder.pop() {
placeholder.push(stmt.add_trailing_semicolon());
}
}
placeholder
}
fn fold_block(&mut self, block: P<Block>) -> P<Block> {
let orig_in_block = mem::replace(&mut self.cx.current_expansion.in_block, true);
let result = noop_fold_block(block, self);
self.cx.current_expansion.in_block = orig_in_block;
result
}
fn fold_item(&mut self, item: P<ast::Item>) -> SmallVector<P<ast::Item>> {
let item = configure!(self, item);
let (item, attr) = self.classify_item(item);
if let Some(attr) = attr {
let item = Annotatable::Item(fully_configure!(self, item, noop_fold_item));
return self.collect_attr(attr, item, ExpansionKind::Items).make_items();
}
match item.node {
ast::ItemKind::Mac(..) => {
if match item.node {
ItemKind::Mac(ref mac) => mac.node.path.segments.is_empty(),
_ => unreachable!(),
} {
return SmallVector::one(item);
}
item.and_then(|item| match item.node {
ItemKind::Mac(mac) => {
self.collect(ExpansionKind::Items, InvocationKind::Bang {
mac: mac,
attrs: item.attrs,
ident: Some(item.ident),
span: item.span,
}).make_items()
}
_ => unreachable!(),
})
}
ast::ItemKind::Mod(ast::Mod { inner, .. }) => {
if item.ident == keywords::Invalid.ident() {
return noop_fold_item(item, self);
}
let mut module = (*self.cx.current_expansion.module).clone();
module.mod_path.push(item.ident);
// Detect if this is an inline module (`mod m { ... }` as opposed to `mod m;`).
// In the non-inline case, `inner` is never the dummy span (c.f. `parse_item_mod`).
// Thus, if `inner` is the dummy span, we know the module is inline.
let inline_module = item.span.contains(inner) || inner == syntax_pos::DUMMY_SP;
if inline_module {
module.directory.push(&*{
::attr::first_attr_value_str_by_name(&item.attrs, "path")
.unwrap_or(item.ident.name.as_str())
});
} else {
module.directory =
PathBuf::from(self.cx.parse_sess.codemap().span_to_filename(inner));
module.directory.pop();
}
let orig_module =
mem::replace(&mut self.cx.current_expansion.module, Rc::new(module));
let result = noop_fold_item(item, self);
self.cx.current_expansion.module = orig_module;
return result;
}
ast::ItemKind::ExternCrate(..) => {
// We need to error on `#[macro_use] extern crate` when it isn't at the
// crate root, because `$crate` won't work properly.
let is_crate_root = self.cx.current_expansion.module.mod_path.len() == 1;
for def in self.cx.resolver.load_crate(&*item, is_crate_root) {
match def {
LoadedMacro::Def(def) => self.cx.insert_macro(def),
LoadedMacro::CustomDerive(name, ext) => {
self.cx.insert_custom_derive(&name, ext, item.span);
}
}
}
noop_fold_item(item, self)
},
_ => noop_fold_item(item, self),
}
}
fn fold_trait_item(&mut self, item: ast::TraitItem) -> SmallVector<ast::TraitItem> {
let item = configure!(self, item);
let (item, attr) = self.classify_item(item);
if let Some(attr) = attr {
let item =
Annotatable::TraitItem(P(fully_configure!(self, item, noop_fold_trait_item)));
return self.collect_attr(attr, item, ExpansionKind::TraitItems).make_trait_items()
}
match item.node {
ast::TraitItemKind::Macro(mac) => {
let ast::TraitItem { attrs, span, .. } = item;
self.collect_bang(mac, attrs, span, ExpansionKind::TraitItems).make_trait_items()
}
_ => fold::noop_fold_trait_item(item, self),
}
}
fn fold_impl_item(&mut self, item: ast::ImplItem) -> SmallVector<ast::ImplItem> {
let item = configure!(self, item);
let (item, attr) = self.classify_item(item);
if let Some(attr) = attr {
let item = Annotatable::ImplItem(P(fully_configure!(self, item, noop_fold_impl_item)));
return self.collect_attr(attr, item, ExpansionKind::ImplItems).make_impl_items();
}
match item.node {
ast::ImplItemKind::Macro(mac) => {
let ast::ImplItem { attrs, span, .. } = item;
self.collect_bang(mac, attrs, span, ExpansionKind::ImplItems).make_impl_items()
}
_ => fold::noop_fold_impl_item(item, self),
}
}
fn fold_ty(&mut self, ty: P<ast::Ty>) -> P<ast::Ty> {
let ty = match ty.node {
ast::TyKind::Mac(_) => ty.unwrap(),
_ => return fold::noop_fold_ty(ty, self),
};
match ty.node {
ast::TyKind::Mac(mac) =>
self.collect_bang(mac, Vec::new(), ty.span, ExpansionKind::Ty).make_ty(),
_ => unreachable!(),
}
}
fn fold_foreign_mod(&mut self, foreign_mod: ast::ForeignMod) -> ast::ForeignMod {
noop_fold_foreign_mod(self.cfg.configure_foreign_mod(foreign_mod), self)
}
fn fold_item_kind(&mut self, item: ast::ItemKind) -> ast::ItemKind {
noop_fold_item_kind(self.cfg.configure_item_kind(item), self)
}
fn new_id(&mut self, id: ast::NodeId) -> ast::NodeId {
if self.monotonic {
assert_eq!(id, ast::DUMMY_NODE_ID);
self.cx.resolver.next_node_id()
} else {
id
}
}
}
pub struct ExpansionConfig<'feat> {
pub crate_name: String,
pub features: Option<&'feat Features>,
pub recursion_limit: usize,
pub trace_mac: bool,
pub should_test: bool, // If false, strip `#[test]` nodes
pub single_step: bool,
pub keep_macs: bool,
}
macro_rules! feature_tests {
($( fn $getter:ident = $field:ident, )*) => {
$(
pub fn $getter(&self) -> bool {
match self.features {
Some(&Features { $field: true, .. }) => true,
_ => false,
}
}
)*
}
}
impl<'feat> ExpansionConfig<'feat> {
pub fn default(crate_name: String) -> ExpansionConfig<'static> {
ExpansionConfig {
crate_name: crate_name,
features: None,
recursion_limit: 64,
trace_mac: false,
should_test: false,
single_step: false,
keep_macs: false,
}
}
feature_tests! {
fn enable_quotes = quote,
fn enable_asm = asm,
fn enable_log_syntax = log_syntax,
fn enable_concat_idents = concat_idents,
fn enable_trace_macros = trace_macros,
fn enable_allow_internal_unstable = allow_internal_unstable,
fn enable_custom_derive = custom_derive,
fn enable_pushpop_unsafe = pushpop_unsafe,
fn enable_rustc_macro = rustc_macro,
}
}
pub fn expand_crate(cx: &mut ExtCtxt,
user_exts: Vec<NamedSyntaxExtension>,
c: Crate) -> Crate {
cx.initialize(user_exts, &c);
cx.monotonic_expander().expand_crate(c)
}
// Expands crate using supplied MacroExpander - allows for
// non-standard expansion behaviour (e.g. step-wise).
pub fn expand_crate_with_expander(expander: &mut MacroExpander,
user_exts: Vec<NamedSyntaxExtension>,
c: Crate) -> Crate {
expander.cx.initialize(user_exts, &c);
expander.expand_crate(c)
}
// A Marker adds the given mark to the syntax context and
// sets spans' `expn_id` to the given expn_id (unless it is `None`).
struct Marker { mark: Mark, expn_id: Option<ExpnId> }
impl Folder for Marker {
fn fold_ident(&mut self, mut ident: Ident) -> Ident {
ident.ctxt = ident.ctxt.apply_mark(self.mark);
ident
}
fn fold_mac(&mut self, mac: ast::Mac) -> ast::Mac {
noop_fold_mac(mac, self)
}
fn new_span(&mut self, mut span: Span) -> Span {
if let Some(expn_id) = self.expn_id {
span.expn_id = expn_id;
}
span
}
}
// apply a given mark to the given token trees. Used prior to expansion of a macro.
fn mark_tts(tts: &[TokenTree], m: Mark) -> Vec<TokenTree> {
noop_fold_tts(tts, &mut Marker{mark:m, expn_id: None})
}