rust/src/libsyntax/ext/expand.rs

1380 lines
52 KiB
Rust

// 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, PatKind};
use ast::{Local, Ident, Mac_, Name, SpannedIdent};
use ast::{MacStmtStyle, Mrk, Stmt, StmtKind, ItemKind};
use ast;
use attr::HasAttrs;
use ext::mtwt;
use attr;
use attr::AttrMetaMethods;
use codemap::{Spanned, 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 util::move_map::MoveMap;
use parse::token::{fresh_mark, fresh_name, intern, keywords};
use ptr::P;
use tokenstream::TokenTree;
use util::small_vector::SmallVector;
use visit;
use visit::Visitor;
use std_inject;
use std::collections::HashSet;
// A trait for AST nodes and AST node lists into which macro invocations may expand.
trait MacroGenerable: Sized {
// Expand the given MacResult using its appropriate `make_*` method.
fn make_with<'a>(result: Box<MacResult + 'a>) -> Option<Self>;
// Fold this node or list of nodes using the given folder.
fn fold_with<F: Folder>(self, folder: &mut F) -> Self;
fn visit_with<V: Visitor>(&self, visitor: &mut V);
// The user-friendly name of the node type (e.g. "expression", "item", etc.) for diagnostics.
fn kind_name() -> &'static str;
// Return a placeholder expansion to allow compilation to continue after an erroring expansion.
fn dummy(span: Span) -> Self {
Self::make_with(DummyResult::any(span)).unwrap()
}
}
macro_rules! impl_macro_generable {
($($ty:ty: $kind_name:expr, .$make:ident,
$(.$fold:ident)* $(lift .$fold_elt:ident)*,
$(.$visit:ident)* $(lift .$visit_elt:ident)*;)*) => { $(
impl MacroGenerable for $ty {
fn kind_name() -> &'static str { $kind_name }
fn make_with<'a>(result: Box<MacResult + 'a>) -> Option<Self> { result.$make() }
fn fold_with<F: Folder>(self, folder: &mut F) -> Self {
$( folder.$fold(self) )*
$( self.into_iter().flat_map(|item| folder. $fold_elt (item)).collect() )*
}
fn visit_with<V: Visitor>(&self, visitor: &mut V) {
$( visitor.$visit(self) )*
$( for item in self.as_slice() { visitor. $visit_elt (item) } )*
}
}
)* }
}
impl_macro_generable! {
P<ast::Expr>: "expression", .make_expr, .fold_expr, .visit_expr;
P<ast::Pat>: "pattern", .make_pat, .fold_pat, .visit_pat;
P<ast::Ty>: "type", .make_ty, .fold_ty, .visit_ty;
SmallVector<ast::Stmt>: "statement", .make_stmts, lift .fold_stmt, lift .visit_stmt;
SmallVector<P<ast::Item>>: "item", .make_items, lift .fold_item, lift .visit_item;
SmallVector<ast::TraitItem>:
"trait item", .make_trait_items, lift .fold_trait_item, lift .visit_trait_item;
SmallVector<ast::ImplItem>:
"impl item", .make_impl_items, lift .fold_impl_item, lift .visit_impl_item;
}
impl MacroGenerable for Option<P<ast::Expr>> {
fn kind_name() -> &'static str { "expression" }
fn make_with<'a>(result: Box<MacResult + 'a>) -> Option<Self> {
result.make_expr().map(Some)
}
fn fold_with<F: Folder>(self, folder: &mut F) -> Self {
self.and_then(|expr| folder.fold_opt_expr(expr))
}
fn visit_with<V: Visitor>(&self, visitor: &mut V) {
self.as_ref().map(|expr| visitor.visit_expr(expr));
}
}
pub fn expand_expr(mut expr: ast::Expr, fld: &mut MacroExpander) -> P<ast::Expr> {
match expr.node {
// expr_mac should really be expr_ext or something; it's the
// entry-point for all syntax extensions.
ast::ExprKind::Mac(mac) => {
return expand_mac_invoc(mac, None, expr.attrs.into(), expr.span, fld);
}
ast::ExprKind::While(cond, body, opt_ident) => {
let cond = fld.fold_expr(cond);
let (body, opt_ident) = expand_loop_block(body, opt_ident, fld);
expr.node = ast::ExprKind::While(cond, body, opt_ident);
}
ast::ExprKind::WhileLet(pat, cond, body, opt_ident) => {
let pat = fld.fold_pat(pat);
let cond = fld.fold_expr(cond);
// Hygienic renaming of the body.
let ((body, opt_ident), mut rewritten_pats) =
rename_in_scope(vec![pat],
fld,
(body, opt_ident),
|rename_fld, fld, (body, opt_ident)| {
expand_loop_block(rename_fld.fold_block(body), opt_ident, fld)
});
assert!(rewritten_pats.len() == 1);
expr.node = ast::ExprKind::WhileLet(rewritten_pats.remove(0), cond, body, opt_ident);
}
ast::ExprKind::Loop(loop_block, opt_ident) => {
let (loop_block, opt_ident) = expand_loop_block(loop_block, opt_ident, fld);
expr.node = ast::ExprKind::Loop(loop_block, opt_ident);
}
ast::ExprKind::ForLoop(pat, head, body, opt_ident) => {
let pat = fld.fold_pat(pat);
// Hygienic renaming of the for loop body (for loop binds its pattern).
let ((body, opt_ident), mut rewritten_pats) =
rename_in_scope(vec![pat],
fld,
(body, opt_ident),
|rename_fld, fld, (body, opt_ident)| {
expand_loop_block(rename_fld.fold_block(body), opt_ident, fld)
});
assert!(rewritten_pats.len() == 1);
let head = fld.fold_expr(head);
expr.node = ast::ExprKind::ForLoop(rewritten_pats.remove(0), head, body, opt_ident);
}
ast::ExprKind::IfLet(pat, sub_expr, body, else_opt) => {
let pat = fld.fold_pat(pat);
// Hygienic renaming of the body.
let (body, mut rewritten_pats) =
rename_in_scope(vec![pat],
fld,
body,
|rename_fld, fld, body| {
fld.fold_block(rename_fld.fold_block(body))
});
assert!(rewritten_pats.len() == 1);
let else_opt = else_opt.map(|else_opt| fld.fold_expr(else_opt));
let sub_expr = fld.fold_expr(sub_expr);
expr.node = ast::ExprKind::IfLet(rewritten_pats.remove(0), sub_expr, body, else_opt);
}
ast::ExprKind::Closure(capture_clause, fn_decl, block, fn_decl_span) => {
let (rewritten_fn_decl, rewritten_block)
= expand_and_rename_fn_decl_and_block(fn_decl, block, fld);
expr.node = ast::ExprKind::Closure(capture_clause,
rewritten_fn_decl,
rewritten_block,
fn_decl_span);
}
_ => expr = noop_fold_expr(expr, fld),
};
P(expr)
}
/// Expand a macro invocation. Returns the result of expansion.
fn expand_mac_invoc<T>(mac: ast::Mac, ident: Option<Ident>, attrs: Vec<ast::Attribute>, span: Span,
fld: &mut MacroExpander) -> T
where T: MacroGenerable,
{
// It would almost certainly be cleaner to pass the whole macro invocation in,
// rather than pulling it apart and marking the tts and the ctxt separately.
let Mac_ { path, tts, .. } = mac.node;
let mark = fresh_mark();
fn mac_result<'a>(path: &ast::Path, ident: Option<Ident>, tts: Vec<TokenTree>, mark: Mrk,
attrs: Vec<ast::Attribute>, call_site: Span, fld: &'a mut MacroExpander)
-> Option<Box<MacResult + 'a>> {
// 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, &fld.cx.parse_sess.span_diagnostic,
&fld.cx.parse_sess.codemap(),
&fld.cx.ecfg.features.unwrap());
}
if path.segments.len() > 1 || path.global || !path.segments[0].parameters.is_empty() {
fld.cx.span_err(path.span, "expected macro name without module separators");
return None;
}
let extname = path.segments[0].identifier.name;
let extension = if let Some(extension) = fld.cx.syntax_env.find(extname) {
extension
} else {
let mut err = fld.cx.struct_span_err(path.span,
&format!("macro undefined: '{}!'", &extname));
fld.cx.suggest_macro_name(&extname.as_str(), &mut err);
err.emit();
return None;
};
let ident = ident.unwrap_or(keywords::Invalid.ident());
match *extension {
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);
fld.cx.span_err(path.span, &msg);
return None;
}
fld.cx.bt_push(ExpnInfo {
call_site: call_site,
callee: NameAndSpan {
format: MacroBang(extname),
span: exp_span,
allow_internal_unstable: allow_internal_unstable,
},
});
let marked_tts = mark_tts(&tts, mark);
Some(expandfun.expand(fld.cx, call_site, &marked_tts))
}
IdentTT(ref expander, tt_span, allow_internal_unstable) => {
if ident.name == keywords::Invalid.name() {
fld.cx.span_err(path.span,
&format!("macro {}! expects an ident argument", extname));
return None;
};
fld.cx.bt_push(ExpnInfo {
call_site: call_site,
callee: NameAndSpan {
format: MacroBang(extname),
span: tt_span,
allow_internal_unstable: allow_internal_unstable,
}
});
let marked_tts = mark_tts(&tts, mark);
Some(expander.expand(fld.cx, call_site, ident, marked_tts))
}
MacroRulesTT => {
if ident.name == keywords::Invalid.name() {
fld.cx.span_err(path.span,
&format!("macro {}! expects an ident argument", extname));
return None;
};
fld.cx.bt_push(ExpnInfo {
call_site: call_site,
callee: NameAndSpan {
format: MacroBang(extname),
span: None,
// `macro_rules!` doesn't directly allow unstable
// (this is orthogonal to whether the macro it creates allows it)
allow_internal_unstable: false,
}
});
// DON'T mark before expansion.
fld.cx.insert_macro(ast::MacroDef {
ident: ident,
id: ast::DUMMY_NODE_ID,
span: call_site,
imported_from: None,
use_locally: true,
body: tts,
export: attr::contains_name(&attrs, "macro_export"),
allow_internal_unstable: attr::contains_name(&attrs, "allow_internal_unstable"),
attrs: attrs,
});
// macro_rules! has a side effect but expands to nothing.
fld.cx.bt_pop();
None
}
MultiDecorator(..) | MultiModifier(..) => {
fld.cx.span_err(path.span,
&format!("`{}` can only be used in attributes", extname));
None
}
}
}
let opt_expanded = T::make_with(match mac_result(&path, ident, tts, mark, attrs, span, fld) {
Some(result) => result,
None => return T::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 = T::kind_name());
fld.cx.span_err(path.span, &msg);
return T::dummy(span);
};
let marked = expanded.fold_with(&mut Marker { mark: mark, expn_id: Some(fld.cx.backtrace()) });
let configured = marked.fold_with(&mut fld.strip_unconfigured());
fld.load_macros(&configured);
let fully_expanded = configured.fold_with(fld);
fld.cx.bt_pop();
fully_expanded
}
/// Rename loop label and expand its loop body
///
/// The renaming procedure for loop is different in the sense that the loop
/// body is in a block enclosed by loop head so the renaming of loop label
/// must be propagated to the enclosed context.
fn expand_loop_block(loop_block: P<Block>,
opt_ident: Option<SpannedIdent>,
fld: &mut MacroExpander) -> (P<Block>, Option<SpannedIdent>) {
match opt_ident {
Some(label) => {
let new_label = fresh_name(label.node);
let rename = (label.node, new_label);
// The rename *must not* be added to the pending list of current
// syntax context otherwise an unrelated `break` or `continue` in
// the same context will pick that up in the deferred renaming pass
// and be renamed incorrectly.
let mut rename_list = vec!(rename);
let mut rename_fld = IdentRenamer{renames: &mut rename_list};
let renamed_ident = rename_fld.fold_ident(label.node);
// The rename *must* be added to the enclosed syntax context for
// `break` or `continue` to pick up because by definition they are
// in a block enclosed by loop head.
fld.cx.syntax_env.push_frame();
fld.cx.syntax_env.info().pending_renames.push(rename);
let expanded_block = expand_block_elts(loop_block, fld);
fld.cx.syntax_env.pop_frame();
(expanded_block, Some(Spanned { node: renamed_ident, span: label.span }))
}
None => (fld.fold_block(loop_block), opt_ident)
}
}
// eval $e with a new exts frame.
// must be a macro so that $e isn't evaluated too early.
macro_rules! with_exts_frame {
($extsboxexpr:expr,$macros_escape:expr,$e:expr) =>
({$extsboxexpr.push_frame();
$extsboxexpr.info().macros_escape = $macros_escape;
let result = $e;
$extsboxexpr.pop_frame();
result
})
}
// When we enter a module, record it, for the sake of `module!`
pub fn expand_item(it: P<ast::Item>, fld: &mut MacroExpander)
-> SmallVector<P<ast::Item>> {
expand_annotatable(Annotatable::Item(it), fld)
.into_iter().map(|i| i.expect_item()).collect()
}
/// Expand item_kind
fn expand_item_kind(item: ast::ItemKind, fld: &mut MacroExpander) -> ast::ItemKind {
match item {
ast::ItemKind::Fn(decl, unsafety, constness, abi, generics, body) => {
let (rewritten_fn_decl, rewritten_body)
= expand_and_rename_fn_decl_and_block(decl, body, fld);
let expanded_generics = fold::noop_fold_generics(generics,fld);
ast::ItemKind::Fn(rewritten_fn_decl, unsafety, constness, abi,
expanded_generics, rewritten_body)
}
_ => noop_fold_item_kind(item, fld)
}
}
// does this attribute list contain "macro_use" ?
fn contains_macro_use(fld: &mut MacroExpander, attrs: &[ast::Attribute]) -> bool {
for attr in attrs {
let mut is_use = attr.check_name("macro_use");
if attr.check_name("macro_escape") {
let mut err =
fld.cx.struct_span_warn(attr.span,
"macro_escape is a deprecated synonym for macro_use");
is_use = true;
if let ast::AttrStyle::Inner = attr.node.style {
err.help("consider an outer attribute, \
#[macro_use] mod ...").emit();
} else {
err.emit();
}
};
if is_use {
match attr.node.value.node {
ast::MetaItemKind::Word(..) => (),
_ => fld.cx.span_err(attr.span, "arguments to macro_use are not allowed here"),
}
return true;
}
}
false
}
/// Expand a stmt
fn expand_stmt(stmt: Stmt, fld: &mut MacroExpander) -> SmallVector<Stmt> {
// perform all pending renames
let stmt = {
let pending_renames = &mut fld.cx.syntax_env.info().pending_renames;
let mut rename_fld = IdentRenamer{renames:pending_renames};
rename_fld.fold_stmt(stmt).expect_one("rename_fold didn't return one value")
};
let (mac, style, attrs) = match stmt.node {
StmtKind::Mac(mac) => mac.unwrap(),
_ => return expand_non_macro_stmt(stmt, fld)
};
let mut fully_expanded: SmallVector<ast::Stmt> =
expand_mac_invoc(mac, None, attrs.into(), stmt.span, fld);
// 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) = fully_expanded.pop() {
fully_expanded.push(stmt.add_trailing_semicolon());
}
}
fully_expanded
}
// expand a non-macro stmt. this is essentially the fallthrough for
// expand_stmt, above.
fn expand_non_macro_stmt(stmt: Stmt, fld: &mut MacroExpander)
-> SmallVector<Stmt> {
// is it a let?
match stmt.node {
StmtKind::Local(local) => {
// take it apart:
let rewritten_local = local.map(|Local {id, pat, ty, init, span, attrs}| {
// expand the ty since TyKind::FixedLengthVec contains an Expr
// and thus may have a macro use
let expanded_ty = ty.map(|t| fld.fold_ty(t));
// expand the pat (it might contain macro uses):
let expanded_pat = fld.fold_pat(pat);
// find the PatIdents in the pattern:
// oh dear heaven... this is going to include the enum
// names, as well... but that should be okay, as long as
// the new names are gensyms for the old ones.
// generate fresh names, push them to a new pending list
let idents = pattern_bindings(&expanded_pat);
let mut new_pending_renames =
idents.iter().map(|ident| (*ident, fresh_name(*ident))).collect();
// rewrite the pattern using the new names (the old
// ones have already been applied):
let rewritten_pat = {
// nested binding to allow borrow to expire:
let mut rename_fld = IdentRenamer{renames: &mut new_pending_renames};
rename_fld.fold_pat(expanded_pat)
};
// add them to the existing pending renames:
fld.cx.syntax_env.info().pending_renames
.extend(new_pending_renames);
Local {
id: id,
ty: expanded_ty,
pat: rewritten_pat,
// also, don't forget to expand the init:
init: init.map(|e| fld.fold_expr(e)),
span: span,
attrs: fold::fold_thin_attrs(attrs, fld),
}
});
SmallVector::one(Stmt {
id: stmt.id,
node: StmtKind::Local(rewritten_local),
span: stmt.span,
})
}
_ => noop_fold_stmt(stmt, fld),
}
}
// expand the arm of a 'match', renaming for macro hygiene
fn expand_arm(arm: ast::Arm, fld: &mut MacroExpander) -> ast::Arm {
// expand pats... they might contain macro uses:
let expanded_pats = arm.pats.move_map(|pat| fld.fold_pat(pat));
if expanded_pats.is_empty() {
panic!("encountered match arm with 0 patterns");
}
// apply renaming and then expansion to the guard and the body:
let ((rewritten_guard, rewritten_body), rewritten_pats) =
rename_in_scope(expanded_pats,
fld,
(arm.guard, arm.body),
|rename_fld, fld, (ag, ab)|{
let rewritten_guard = ag.map(|g| fld.fold_expr(rename_fld.fold_expr(g)));
let rewritten_body = fld.fold_expr(rename_fld.fold_expr(ab));
(rewritten_guard, rewritten_body)
});
ast::Arm {
attrs: fold::fold_attrs(arm.attrs, fld),
pats: rewritten_pats,
guard: rewritten_guard,
body: rewritten_body,
}
}
fn rename_in_scope<X, F>(pats: Vec<P<ast::Pat>>,
fld: &mut MacroExpander,
x: X,
f: F)
-> (X, Vec<P<ast::Pat>>)
where F: Fn(&mut IdentRenamer, &mut MacroExpander, X) -> X
{
// all of the pats must have the same set of bindings, so use the
// first one to extract them and generate new names:
let idents = pattern_bindings(&pats[0]);
let new_renames = idents.into_iter().map(|id| (id, fresh_name(id))).collect();
// apply the renaming, but only to the PatIdents:
let mut rename_pats_fld = PatIdentRenamer{renames:&new_renames};
let rewritten_pats = pats.move_map(|pat| rename_pats_fld.fold_pat(pat));
let mut rename_fld = IdentRenamer{ renames:&new_renames };
(f(&mut rename_fld, fld, x), rewritten_pats)
}
/// A visitor that extracts the PatKind::Ident (binding) paths
/// from a given thingy and puts them in a mutable
/// array
#[derive(Clone)]
struct PatIdentFinder {
ident_accumulator: Vec<ast::Ident>
}
impl Visitor for PatIdentFinder {
fn visit_pat(&mut self, pattern: &ast::Pat) {
match *pattern {
ast::Pat { id: _, node: PatKind::Ident(_, ref path1, ref inner), span: _ } => {
self.ident_accumulator.push(path1.node);
// visit optional subpattern of PatKind::Ident:
if let Some(ref subpat) = *inner {
self.visit_pat(subpat)
}
}
// use the default traversal for non-PatIdents
_ => visit::walk_pat(self, pattern)
}
}
}
/// find the PatKind::Ident paths in a pattern
fn pattern_bindings(pat: &ast::Pat) -> Vec<ast::Ident> {
let mut name_finder = PatIdentFinder{ident_accumulator:Vec::new()};
name_finder.visit_pat(pat);
name_finder.ident_accumulator
}
/// find the PatKind::Ident paths in a
fn fn_decl_arg_bindings(fn_decl: &ast::FnDecl) -> Vec<ast::Ident> {
let mut pat_idents = PatIdentFinder{ident_accumulator:Vec::new()};
for arg in &fn_decl.inputs {
pat_idents.visit_pat(&arg.pat);
}
pat_idents.ident_accumulator
}
// expand a block. pushes a new exts_frame, then calls expand_block_elts
pub fn expand_block(blk: P<Block>, fld: &mut MacroExpander) -> P<Block> {
// see note below about treatment of exts table
with_exts_frame!(fld.cx.syntax_env,false,
expand_block_elts(blk, fld))
}
// expand the elements of a block.
pub fn expand_block_elts(b: P<Block>, fld: &mut MacroExpander) -> P<Block> {
b.map(|Block {id, stmts, rules, span}| {
let new_stmts = stmts.into_iter().flat_map(|x| {
// perform pending renames and expand macros in the statement
fld.fold_stmt(x).into_iter()
}).collect();
Block {
id: fld.new_id(id),
stmts: new_stmts,
rules: rules,
span: span
}
})
}
fn expand_pat(p: P<ast::Pat>, fld: &mut MacroExpander) -> P<ast::Pat> {
match p.node {
PatKind::Mac(_) => {}
_ => return noop_fold_pat(p, fld)
}
p.and_then(|ast::Pat {node, span, ..}| {
match node {
PatKind::Mac(mac) => expand_mac_invoc(mac, None, Vec::new(), span, fld),
_ => unreachable!()
}
})
}
/// A tree-folder that applies every rename in its (mutable) list
/// to every identifier, including both bindings and varrefs
/// (and lots of things that will turn out to be neither)
pub struct IdentRenamer<'a> {
renames: &'a mtwt::RenameList,
}
impl<'a> Folder for IdentRenamer<'a> {
fn fold_ident(&mut self, id: Ident) -> Ident {
mtwt::apply_renames(self.renames, id)
}
fn fold_mac(&mut self, mac: ast::Mac) -> ast::Mac {
fold::noop_fold_mac(mac, self)
}
}
/// A tree-folder that applies every rename in its list to
/// the idents that are in PatKind::Ident patterns. This is more narrowly
/// focused than IdentRenamer, and is needed for FnDecl,
/// where we want to rename the args but not the fn name or the generics etc.
pub struct PatIdentRenamer<'a> {
renames: &'a mtwt::RenameList,
}
impl<'a> Folder for PatIdentRenamer<'a> {
fn fold_pat(&mut self, pat: P<ast::Pat>) -> P<ast::Pat> {
match pat.node {
PatKind::Ident(..) => {},
_ => return noop_fold_pat(pat, self)
}
pat.map(|ast::Pat {id, node, span}| match node {
PatKind::Ident(binding_mode, Spanned{span: sp, node: ident}, sub) => {
let new_ident = mtwt::apply_renames(self.renames, ident);
let new_node =
PatKind::Ident(binding_mode,
Spanned{span: sp, node: new_ident},
sub.map(|p| self.fold_pat(p)));
ast::Pat {
id: id,
node: new_node,
span: span,
}
},
_ => unreachable!()
})
}
fn fold_mac(&mut self, mac: ast::Mac) -> ast::Mac {
fold::noop_fold_mac(mac, self)
}
}
fn expand_multi_modified(a: Annotatable, fld: &mut MacroExpander) -> SmallVector<Annotatable> {
match a {
Annotatable::Item(it) => match it.node {
ast::ItemKind::Mac(..) => {
it.and_then(|it| match it.node {
ItemKind::Mac(mac) =>
expand_mac_invoc(mac, Some(it.ident), it.attrs, it.span, fld),
_ => unreachable!(),
})
}
ast::ItemKind::Mod(_) | ast::ItemKind::ForeignMod(_) => {
let valid_ident =
it.ident.name != keywords::Invalid.name();
if valid_ident {
fld.cx.mod_push(it.ident);
}
let macro_use = contains_macro_use(fld, &it.attrs);
let result = with_exts_frame!(fld.cx.syntax_env,
macro_use,
noop_fold_item(it, fld));
if valid_ident {
fld.cx.mod_pop();
}
result
},
_ => noop_fold_item(it, fld),
}.into_iter().map(|i| Annotatable::Item(i)).collect(),
Annotatable::TraitItem(it) => {
expand_trait_item(it.unwrap(), fld).into_iter().
map(|it| Annotatable::TraitItem(P(it))).collect()
}
Annotatable::ImplItem(ii) => {
expand_impl_item(ii.unwrap(), fld).into_iter().
map(|ii| Annotatable::ImplItem(P(ii))).collect()
}
}
}
fn expand_annotatable(mut item: Annotatable, fld: &mut MacroExpander) -> SmallVector<Annotatable> {
let mut multi_modifier = None;
item = item.map_attrs(|mut attrs| {
for i in 0..attrs.len() {
if let Some(extension) = fld.cx.syntax_env.find(intern(&attrs[i].name())) {
match *extension {
MultiModifier(..) | MultiDecorator(..) => {
multi_modifier = Some((attrs.remove(i), extension));
break;
}
_ => {}
}
}
}
attrs
});
match multi_modifier {
None => expand_multi_modified(item, fld),
Some((attr, extension)) => {
attr::mark_used(&attr);
fld.cx.bt_push(ExpnInfo {
call_site: attr.span,
callee: NameAndSpan {
format: MacroAttribute(intern(&attr.name())),
span: Some(attr.span),
// attributes can do whatever they like, for now
allow_internal_unstable: true,
}
});
let modified = match *extension {
MultiModifier(ref mac) => mac.expand(fld.cx, attr.span, &attr.node.value, item),
MultiDecorator(ref mac) => {
let mut items = Vec::new();
mac.expand(fld.cx, attr.span, &attr.node.value, &item,
&mut |item| items.push(item));
items.push(item);
items
}
_ => unreachable!(),
};
fld.cx.bt_pop();
let configured = modified.into_iter().flat_map(|it| {
it.fold_with(&mut fld.strip_unconfigured())
}).collect::<SmallVector<_>>();
configured.into_iter().flat_map(|it| expand_annotatable(it, fld)).collect()
}
}
}
fn expand_impl_item(ii: ast::ImplItem, fld: &mut MacroExpander)
-> SmallVector<ast::ImplItem> {
match ii.node {
ast::ImplItemKind::Method(..) => SmallVector::one(ast::ImplItem {
id: ii.id,
ident: ii.ident,
attrs: ii.attrs,
vis: ii.vis,
defaultness: ii.defaultness,
node: match ii.node {
ast::ImplItemKind::Method(sig, body) => {
let (sig, body) = expand_and_rename_method(sig, body, fld);
ast::ImplItemKind::Method(sig, body)
}
_ => unreachable!()
},
span: ii.span,
}),
ast::ImplItemKind::Macro(mac) => {
expand_mac_invoc(mac, None, ii.attrs, ii.span, fld)
}
_ => fold::noop_fold_impl_item(ii, fld)
}
}
fn expand_trait_item(ti: ast::TraitItem, fld: &mut MacroExpander)
-> SmallVector<ast::TraitItem> {
match ti.node {
ast::TraitItemKind::Method(_, Some(_)) => {
SmallVector::one(ast::TraitItem {
id: ti.id,
ident: ti.ident,
attrs: ti.attrs,
node: match ti.node {
ast::TraitItemKind::Method(sig, Some(body)) => {
let (sig, body) = expand_and_rename_method(sig, body, fld);
ast::TraitItemKind::Method(sig, Some(body))
}
_ => unreachable!()
},
span: ti.span,
})
}
ast::TraitItemKind::Macro(mac) => {
expand_mac_invoc(mac, None, ti.attrs, ti.span, fld)
}
_ => fold::noop_fold_trait_item(ti, fld)
}
}
/// Given a fn_decl and a block and a MacroExpander, expand the fn_decl, then use the
/// PatIdents in its arguments to perform renaming in the FnDecl and
/// the block, returning both the new FnDecl and the new Block.
fn expand_and_rename_fn_decl_and_block(fn_decl: P<ast::FnDecl>, block: P<ast::Block>,
fld: &mut MacroExpander)
-> (P<ast::FnDecl>, P<ast::Block>) {
let expanded_decl = fld.fold_fn_decl(fn_decl);
let idents = fn_decl_arg_bindings(&expanded_decl);
let renames =
idents.iter().map(|id| (*id,fresh_name(*id))).collect();
// first, a renamer for the PatIdents, for the fn_decl:
let mut rename_pat_fld = PatIdentRenamer{renames: &renames};
let rewritten_fn_decl = rename_pat_fld.fold_fn_decl(expanded_decl);
// now, a renamer for *all* idents, for the body:
let mut rename_fld = IdentRenamer{renames: &renames};
let rewritten_body = fld.fold_block(rename_fld.fold_block(block));
(rewritten_fn_decl,rewritten_body)
}
fn expand_and_rename_method(sig: ast::MethodSig, body: P<ast::Block>,
fld: &mut MacroExpander)
-> (ast::MethodSig, P<ast::Block>) {
let (rewritten_fn_decl, rewritten_body)
= expand_and_rename_fn_decl_and_block(sig.decl, body, fld);
(ast::MethodSig {
generics: fld.fold_generics(sig.generics),
abi: sig.abi,
unsafety: sig.unsafety,
constness: sig.constness,
decl: rewritten_fn_decl
}, rewritten_body)
}
pub fn expand_type(t: P<ast::Ty>, fld: &mut MacroExpander) -> P<ast::Ty> {
let t = match t.node.clone() {
ast::TyKind::Mac(mac) => {
if fld.cx.ecfg.features.unwrap().type_macros {
expand_mac_invoc(mac, None, Vec::new(), t.span, fld)
} else {
feature_gate::emit_feature_err(
&fld.cx.parse_sess.span_diagnostic,
"type_macros",
t.span,
feature_gate::GateIssue::Language,
"type macros are experimental");
DummyResult::raw_ty(t.span)
}
}
_ => t
};
fold::noop_fold_ty(t, fld)
}
/// A tree-folder that performs macro expansion
pub struct MacroExpander<'a, 'b:'a> {
pub cx: &'a mut ExtCtxt<'b>,
}
impl<'a, 'b> MacroExpander<'a, 'b> {
pub fn new(cx: &'a mut ExtCtxt<'b>) -> MacroExpander<'a, 'b> {
MacroExpander { cx: cx }
}
fn strip_unconfigured(&mut self) -> StripUnconfigured {
StripUnconfigured {
config: &self.cx.cfg,
should_test: self.cx.ecfg.should_test,
sess: self.cx.parse_sess,
features: self.cx.ecfg.features,
}
}
fn load_macros<T: MacroGenerable>(&mut self, node: &T) {
struct MacroLoadingVisitor<'a, 'b: 'a>{
cx: &'a mut ExtCtxt<'b>,
at_crate_root: bool,
}
impl<'a, 'b> Visitor for MacroLoadingVisitor<'a, 'b> {
fn visit_mac(&mut self, _: &ast::Mac) {}
fn visit_item(&mut self, item: &ast::Item) {
if let ast::ItemKind::ExternCrate(..) = item.node {
// We need to error on `#[macro_use] extern crate` when it isn't at the
// crate root, because `$crate` won't work properly.
for def in self.cx.loader.load_crate(item, self.at_crate_root) {
self.cx.insert_macro(def);
}
} else {
let at_crate_root = ::std::mem::replace(&mut self.at_crate_root, false);
visit::walk_item(self, item);
self.at_crate_root = at_crate_root;
}
}
fn visit_block(&mut self, block: &ast::Block) {
let at_crate_root = ::std::mem::replace(&mut self.at_crate_root, false);
visit::walk_block(self, block);
self.at_crate_root = at_crate_root;
}
}
node.visit_with(&mut MacroLoadingVisitor {
at_crate_root: self.cx.syntax_env.is_crate_root(),
cx: self.cx,
});
}
}
impl<'a, 'b> Folder for MacroExpander<'a, 'b> {
fn fold_crate(&mut self, c: Crate) -> Crate {
self.cx.filename = Some(self.cx.parse_sess.codemap().span_to_filename(c.span));
noop_fold_crate(c, self)
}
fn fold_expr(&mut self, expr: P<ast::Expr>) -> P<ast::Expr> {
expr.and_then(|expr| expand_expr(expr, self))
}
fn fold_opt_expr(&mut self, expr: P<ast::Expr>) -> Option<P<ast::Expr>> {
expr.and_then(|expr| match expr.node {
ast::ExprKind::Mac(mac) =>
expand_mac_invoc(mac, None, expr.attrs.into(), expr.span, self),
_ => Some(expand_expr(expr, self)),
})
}
fn fold_pat(&mut self, pat: P<ast::Pat>) -> P<ast::Pat> {
expand_pat(pat, self)
}
fn fold_item(&mut self, item: P<ast::Item>) -> SmallVector<P<ast::Item>> {
use std::mem::replace;
let result;
if let ast::ItemKind::Mod(ast::Mod { inner, .. }) = item.node {
if item.span.contains(inner) {
self.push_mod_path(item.ident, &item.attrs);
result = expand_item(item, self);
self.pop_mod_path();
} else {
let filename = if inner != syntax_pos::DUMMY_SP {
Some(self.cx.parse_sess.codemap().span_to_filename(inner))
} else { None };
let orig_filename = replace(&mut self.cx.filename, filename);
let orig_mod_path_stack = replace(&mut self.cx.mod_path_stack, Vec::new());
result = expand_item(item, self);
self.cx.filename = orig_filename;
self.cx.mod_path_stack = orig_mod_path_stack;
}
} else {
result = expand_item(item, self);
}
result
}
fn fold_item_kind(&mut self, item: ast::ItemKind) -> ast::ItemKind {
expand_item_kind(item, self)
}
fn fold_stmt(&mut self, stmt: ast::Stmt) -> SmallVector<ast::Stmt> {
expand_stmt(stmt, self)
}
fn fold_block(&mut self, block: P<Block>) -> P<Block> {
let was_in_block = ::std::mem::replace(&mut self.cx.in_block, true);
let result = expand_block(block, self);
self.cx.in_block = was_in_block;
result
}
fn fold_arm(&mut self, arm: ast::Arm) -> ast::Arm {
expand_arm(arm, self)
}
fn fold_trait_item(&mut self, i: ast::TraitItem) -> SmallVector<ast::TraitItem> {
expand_annotatable(Annotatable::TraitItem(P(i)), self)
.into_iter().map(|i| i.expect_trait_item()).collect()
}
fn fold_impl_item(&mut self, i: ast::ImplItem) -> SmallVector<ast::ImplItem> {
expand_annotatable(Annotatable::ImplItem(P(i)), self)
.into_iter().map(|i| i.expect_impl_item()).collect()
}
fn fold_ty(&mut self, ty: P<ast::Ty>) -> P<ast::Ty> {
expand_type(ty, self)
}
}
impl<'a, 'b> MacroExpander<'a, 'b> {
fn push_mod_path(&mut self, id: Ident, attrs: &[ast::Attribute]) {
let default_path = id.name.as_str();
let file_path = match ::attr::first_attr_value_str_by_name(attrs, "path") {
Some(d) => d,
None => default_path,
};
self.cx.mod_path_stack.push(file_path)
}
fn pop_mod_path(&mut self) {
self.cx.mod_path_stack.pop().unwrap();
}
}
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
}
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,
}
}
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,
}
}
pub fn expand_crate(mut cx: ExtCtxt,
user_exts: Vec<NamedSyntaxExtension>,
mut c: Crate) -> (Crate, HashSet<Name>) {
if std_inject::no_core(&c) {
cx.crate_root = None;
} else if std_inject::no_std(&c) {
cx.crate_root = Some("core");
} else {
cx.crate_root = Some("std");
}
let ret = {
let mut expander = MacroExpander::new(&mut cx);
for (name, extension) in user_exts {
expander.cx.syntax_env.insert(name, extension);
}
let items = SmallVector::many(c.module.items);
expander.load_macros(&items);
c.module.items = items.into();
let err_count = cx.parse_sess.span_diagnostic.err_count();
let mut ret = expander.fold_crate(c);
ret.exported_macros = expander.cx.exported_macros.clone();
if cx.parse_sess.span_diagnostic.err_count() > err_count {
cx.parse_sess.span_diagnostic.abort_if_errors();
}
ret
};
return (ret, cx.syntax_env.names);
}
// HYGIENIC CONTEXT EXTENSION:
// all of these functions are for walking over
// ASTs and making some change to the context of every
// element that has one. a CtxtFn is a trait-ified
// version of a closure in (SyntaxContext -> SyntaxContext).
// the ones defined here include:
// Marker - add a mark to a context
// 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: Mrk, expn_id: Option<ExpnId> }
impl Folder for Marker {
fn fold_ident(&mut self, id: Ident) -> Ident {
ast::Ident::new(id.name, mtwt::apply_mark(self.mark, id.ctxt))
}
fn fold_mac(&mut self, Spanned {node, span}: ast::Mac) -> ast::Mac {
Spanned {
node: Mac_ {
path: self.fold_path(node.path),
tts: self.fold_tts(&node.tts),
},
span: self.new_span(span),
}
}
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: Mrk) -> Vec<TokenTree> {
noop_fold_tts(tts, &mut Marker{mark:m, expn_id: None})
}
#[cfg(test)]
mod tests {
use super::{pattern_bindings, expand_crate};
use super::{PatIdentFinder, IdentRenamer, PatIdentRenamer, ExpansionConfig};
use ast;
use ast::Name;
use syntax_pos;
use ext::base::{ExtCtxt, DummyMacroLoader};
use ext::mtwt;
use fold::Folder;
use parse;
use parse::token;
use util::parser_testing::{string_to_parser};
use util::parser_testing::{string_to_pat, string_to_crate, strs_to_idents};
use visit;
use visit::Visitor;
// a visitor that extracts the paths
// from a given thingy and puts them in a mutable
// array (passed in to the traversal)
#[derive(Clone)]
struct PathExprFinderContext {
path_accumulator: Vec<ast::Path> ,
}
impl Visitor for PathExprFinderContext {
fn visit_expr(&mut self, expr: &ast::Expr) {
if let ast::ExprKind::Path(None, ref p) = expr.node {
self.path_accumulator.push(p.clone());
}
visit::walk_expr(self, expr);
}
}
// find the variable references in a crate
fn crate_varrefs(the_crate : &ast::Crate) -> Vec<ast::Path> {
let mut path_finder = PathExprFinderContext{path_accumulator:Vec::new()};
visit::walk_crate(&mut path_finder, the_crate);
path_finder.path_accumulator
}
/// A Visitor that extracts the identifiers from a thingy.
// as a side note, I'm starting to want to abstract over these....
struct IdentFinder {
ident_accumulator: Vec<ast::Ident>
}
impl Visitor for IdentFinder {
fn visit_ident(&mut self, _: syntax_pos::Span, id: ast::Ident){
self.ident_accumulator.push(id);
}
}
/// Find the idents in a crate
fn crate_idents(the_crate: &ast::Crate) -> Vec<ast::Ident> {
let mut ident_finder = IdentFinder{ident_accumulator: Vec::new()};
visit::walk_crate(&mut ident_finder, the_crate);
ident_finder.ident_accumulator
}
// these following tests are quite fragile, in that they don't test what
// *kind* of failure occurs.
fn test_ecfg() -> ExpansionConfig<'static> {
ExpansionConfig::default("test".to_string())
}
// make sure that macros can't escape fns
#[should_panic]
#[test] fn macros_cant_escape_fns_test () {
let src = "fn bogus() {macro_rules! z (() => (3+4));}\
fn inty() -> i32 { z!() }".to_string();
let sess = parse::ParseSess::new();
let crate_ast = parse::parse_crate_from_source_str(
"<test>".to_string(),
src,
Vec::new(), &sess).unwrap();
// should fail:
let mut loader = DummyMacroLoader;
let ecx = ExtCtxt::new(&sess, vec![], test_ecfg(), &mut loader);
expand_crate(ecx, vec![], crate_ast);
}
// make sure that macros can't escape modules
#[should_panic]
#[test] fn macros_cant_escape_mods_test () {
let src = "mod foo {macro_rules! z (() => (3+4));}\
fn inty() -> i32 { z!() }".to_string();
let sess = parse::ParseSess::new();
let crate_ast = parse::parse_crate_from_source_str(
"<test>".to_string(),
src,
Vec::new(), &sess).unwrap();
let mut loader = DummyMacroLoader;
let ecx = ExtCtxt::new(&sess, vec![], test_ecfg(), &mut loader);
expand_crate(ecx, vec![], crate_ast);
}
// macro_use modules should allow macros to escape
#[test] fn macros_can_escape_flattened_mods_test () {
let src = "#[macro_use] mod foo {macro_rules! z (() => (3+4));}\
fn inty() -> i32 { z!() }".to_string();
let sess = parse::ParseSess::new();
let crate_ast = parse::parse_crate_from_source_str(
"<test>".to_string(),
src,
Vec::new(), &sess).unwrap();
let mut loader = DummyMacroLoader;
let ecx = ExtCtxt::new(&sess, vec![], test_ecfg(), &mut loader);
expand_crate(ecx, vec![], crate_ast);
}
fn expand_crate_str(crate_str: String) -> ast::Crate {
let ps = parse::ParseSess::new();
let crate_ast = panictry!(string_to_parser(&ps, crate_str).parse_crate_mod());
// the cfg argument actually does matter, here...
let mut loader = DummyMacroLoader;
let ecx = ExtCtxt::new(&ps, vec![], test_ecfg(), &mut loader);
expand_crate(ecx, vec![], crate_ast).0
}
// find the pat_ident paths in a crate
fn crate_bindings(the_crate : &ast::Crate) -> Vec<ast::Ident> {
let mut name_finder = PatIdentFinder{ident_accumulator:Vec::new()};
visit::walk_crate(&mut name_finder, the_crate);
name_finder.ident_accumulator
}
#[test] fn macro_tokens_should_match(){
expand_crate_str(
"macro_rules! m((a)=>(13)) ;fn main(){m!(a);}".to_string());
}
// should be able to use a bound identifier as a literal in a macro definition:
#[test] fn self_macro_parsing(){
expand_crate_str(
"macro_rules! foo ((zz) => (287;));
fn f(zz: i32) {foo!(zz);}".to_string()
);
}
// create a really evil test case where a $x appears inside a binding of $x
// but *shouldn't* bind because it was inserted by a different macro....
// can't write this test case until we have macro-generating macros.
#[test]
fn fmt_in_macro_used_inside_module_macro() {
let crate_str = "macro_rules! fmt_wrap(($b:expr)=>($b.to_string()));
macro_rules! foo_module (() => (mod generated { fn a() { let xx = 147; fmt_wrap!(xx);}}));
foo_module!();
".to_string();
let cr = expand_crate_str(crate_str);
// find the xx binding
let bindings = crate_bindings(&cr);
let cxbinds: Vec<&ast::Ident> =
bindings.iter().filter(|b| b.name.as_str() == "xx").collect();
let cxbinds: &[&ast::Ident] = &cxbinds[..];
let cxbind = match (cxbinds.len(), cxbinds.get(0)) {
(1, Some(b)) => *b,
_ => panic!("expected just one binding for ext_cx")
};
let resolved_binding = mtwt::resolve(*cxbind);
let varrefs = crate_varrefs(&cr);
// the xx binding should bind all of the xx varrefs:
for (idx,v) in varrefs.iter().filter(|p| {
p.segments.len() == 1
&& p.segments[0].identifier.name.as_str() == "xx"
}).enumerate() {
if mtwt::resolve(v.segments[0].identifier) != resolved_binding {
println!("uh oh, xx binding didn't match xx varref:");
println!("this is xx varref \\# {}", idx);
println!("binding: {}", cxbind);
println!("resolves to: {}", resolved_binding);
println!("varref: {}", v.segments[0].identifier);
println!("resolves to: {}",
mtwt::resolve(v.segments[0].identifier));
mtwt::with_sctable(|x| mtwt::display_sctable(x));
}
assert_eq!(mtwt::resolve(v.segments[0].identifier),
resolved_binding);
};
}
#[test]
fn pat_idents(){
let pat = string_to_pat(
"(a,Foo{x:c @ (b,9),y:Bar(4,d)})".to_string());
let idents = pattern_bindings(&pat);
assert_eq!(idents, strs_to_idents(vec!("a","c","b","d")));
}
// test the list of identifier patterns gathered by the visitor. Note that
// 'None' is listed as an identifier pattern because we don't yet know that
// it's the name of a 0-ary variant, and that 'i' appears twice in succession.
#[test]
fn crate_bindings_test(){
let the_crate = string_to_crate("fn main (a: i32) -> i32 {|b| {
match 34 {None => 3, Some(i) | i => j, Foo{k:z,l:y} => \"banana\"}} }".to_string());
let idents = crate_bindings(&the_crate);
assert_eq!(idents, strs_to_idents(vec!("a","b","None","i","i","z","y")));
}
// test the IdentRenamer directly
#[test]
fn ident_renamer_test () {
let the_crate = string_to_crate("fn f(x: i32){let x = x; x}".to_string());
let f_ident = token::str_to_ident("f");
let x_ident = token::str_to_ident("x");
let int_ident = token::str_to_ident("i32");
let renames = vec!((x_ident,Name(16)));
let mut renamer = IdentRenamer{renames: &renames};
let renamed_crate = renamer.fold_crate(the_crate);
let idents = crate_idents(&renamed_crate);
let resolved : Vec<ast::Name> = idents.iter().map(|id| mtwt::resolve(*id)).collect();
assert_eq!(resolved, [f_ident.name,Name(16),int_ident.name,Name(16),Name(16),Name(16)]);
}
// test the PatIdentRenamer; only PatIdents get renamed
#[test]
fn pat_ident_renamer_test () {
let the_crate = string_to_crate("fn f(x: i32){let x = x; x}".to_string());
let f_ident = token::str_to_ident("f");
let x_ident = token::str_to_ident("x");
let int_ident = token::str_to_ident("i32");
let renames = vec!((x_ident,Name(16)));
let mut renamer = PatIdentRenamer{renames: &renames};
let renamed_crate = renamer.fold_crate(the_crate);
let idents = crate_idents(&renamed_crate);
let resolved : Vec<ast::Name> = idents.iter().map(|id| mtwt::resolve(*id)).collect();
let x_name = x_ident.name;
assert_eq!(resolved, [f_ident.name,Name(16),int_ident.name,Name(16),x_name,x_name]);
}
}