use {ast, attr};
use syntax_pos::{Span, DUMMY_SP};
use ext::base::{DummyResult, ExtCtxt, MacResult, SyntaxExtension};
use ext::base::{NormalTT, TTMacroExpander};
use ext::expand::{Expansion, ExpansionKind};
use ext::tt::macro_parser::{Success, Error, Failure};
use ext::tt::macro_parser::{MatchedSeq, MatchedNonterminal};
use ext::tt::macro_parser::{parse, parse_failure_msg};
use ext::tt::quoted;
use ext::tt::transcribe::transcribe;
use feature_gate::{self, emit_feature_err, Features, GateIssue};
use parse::{Directory, ParseSess};
use parse::parser::Parser;
use parse::token::{self, NtTT};
use parse::token::Token::*;
use symbol::Symbol;
use tokenstream::{TokenStream, TokenTree};
use std::cell::RefCell;
use std::collections::HashMap;
use std::collections::hash_map::Entry;
use std::rc::Rc;
pub struct ParserAnyMacro<'a> {
parser: Parser<'a>,
site_span: Span,
macro_ident: ast::Ident
}
impl<'a> ParserAnyMacro<'a> {
pub fn make(mut self: Box<ParserAnyMacro<'a>>, kind: ExpansionKind) -> Expansion {
let ParserAnyMacro { site_span, macro_ident, ref mut parser } = *self;
let expansion = panictry!(parser.parse_expansion(kind, true));
if kind == ExpansionKind::Expr && parser.token == token::Semi {
parser.bump();
}
let path = ast::Path::from_ident(site_span, macro_ident);
parser.ensure_complete_parse(&path, kind.name(), site_span);
expansion
}
}
struct MacroRulesMacroExpander {
name: ast::Ident,
lhses: Vec<quoted::TokenTree>,
rhses: Vec<quoted::TokenTree>,
valid: bool,
}
impl TTMacroExpander for MacroRulesMacroExpander {
fn expand<'cx>(&self,
cx: &'cx mut ExtCtxt,
sp: Span,
input: TokenStream)
-> Box<MacResult+'cx> {
if !self.valid {
return DummyResult::any(sp);
}
generic_extension(cx,
sp,
self.name,
input,
&self.lhses,
&self.rhses)
}
}
fn trace_macros_note(cx: &mut ExtCtxt, sp: Span, message: String) {
let sp = sp.macro_backtrace().last().map(|trace| trace.call_site).unwrap_or(sp);
let mut values: &mut Vec<String> = cx.expansions.entry(sp).or_insert_with(Vec::new);
values.push(message);
}
fn generic_extension<'cx>(cx: &'cx mut ExtCtxt,
sp: Span,
name: ast::Ident,
arg: TokenStream,
lhses: &[quoted::TokenTree],
rhses: &[quoted::TokenTree])
-> Box<MacResult+'cx> {
if cx.trace_macros() {
trace_macros_note(cx, sp, format!("expanding `{}! {{ {} }}`", name, arg));
}
let mut best_fail_spot = DUMMY_SP;
let mut best_fail_tok = None;
for (i, lhs) in lhses.iter().enumerate() {
let lhs_tt = match *lhs {
quoted::TokenTree::Delimited(_, ref delim) => &delim.tts[..],
_ => cx.span_bug(sp, "malformed macro lhs")
};
match TokenTree::parse(cx, lhs_tt, arg.clone()) {
Success(named_matches) => {
let rhs = match rhses[i] {
quoted::TokenTree::Delimited(_, ref delimed) => delimed.tts.clone(),
_ => cx.span_bug(sp, "malformed macro rhs"),
};
let tts = transcribe(&cx.parse_sess.span_diagnostic, Some(named_matches), rhs);
if cx.trace_macros() {
trace_macros_note(cx, sp, format!("to `{}`", tts));
}
let directory = Directory {
path: cx.current_expansion.module.directory.clone(),
ownership: cx.current_expansion.directory_ownership,
};
let mut p = Parser::new(cx.parse_sess(), tts, Some(directory), true, false);
p.root_module_name = cx.current_expansion.module.mod_path.last()
.map(|id| id.name.as_str().to_string());
p.process_potential_macro_variable();
return Box::new(ParserAnyMacro {
parser: p,
site_span: sp,
macro_ident: name
})
}
Failure(sp, tok) => if sp.lo >= best_fail_spot.lo {
best_fail_spot = sp;
best_fail_tok = Some(tok);
},
Error(err_sp, ref msg) => {
cx.span_fatal(err_sp.substitute_dummy(sp), &msg[..])
}
}
}
let best_fail_msg = parse_failure_msg(best_fail_tok.expect("ran no matchers"));
cx.span_fatal(best_fail_spot.substitute_dummy(sp), &best_fail_msg);
}
pub fn compile(sess: &ParseSess, features: &RefCell<Features>, def: &ast::Item) -> SyntaxExtension {
let lhs_nm = ast::Ident::with_empty_ctxt(Symbol::gensym("lhs"));
let rhs_nm = ast::Ident::with_empty_ctxt(Symbol::gensym("rhs"));
let body = match def.node {
ast::ItemKind::MacroDef(ref body) => body,
_ => unreachable!(),
};
let argument_gram = vec![
quoted::TokenTree::Sequence(DUMMY_SP, Rc::new(quoted::SequenceRepetition {
tts: vec![
quoted::TokenTree::MetaVarDecl(DUMMY_SP, lhs_nm, ast::Ident::from_str("tt")),
quoted::TokenTree::Token(DUMMY_SP, token::FatArrow),
quoted::TokenTree::MetaVarDecl(DUMMY_SP, rhs_nm, ast::Ident::from_str("tt")),
],
separator: Some(if body.legacy { token::Semi } else { token::Comma }),
op: quoted::KleeneOp::OneOrMore,
num_captures: 2,
})),
quoted::TokenTree::Sequence(DUMMY_SP, Rc::new(quoted::SequenceRepetition {
tts: vec![quoted::TokenTree::Token(DUMMY_SP, token::Semi)],
separator: None,
op: quoted::KleeneOp::ZeroOrMore,
num_captures: 0
})),
];
let argument_map = match parse(sess, body.stream(), &argument_gram, None, true) {
Success(m) => m,
Failure(sp, tok) => {
let s = parse_failure_msg(tok);
panic!(sess.span_diagnostic.span_fatal(sp.substitute_dummy(def.span), &s));
}
Error(sp, s) => {
panic!(sess.span_diagnostic.span_fatal(sp.substitute_dummy(def.span), &s));
}
};
let mut valid = true;
let lhses = match *argument_map[&lhs_nm] {
MatchedSeq(ref s, _) => {
s.iter().map(|m| {
if let MatchedNonterminal(ref nt) = **m {
if let NtTT(ref tt) = **nt {
let tt = quoted::parse(tt.clone().into(), true, sess).pop().unwrap();
valid &= check_lhs_nt_follows(sess, features, &tt);
return tt;
}
}
sess.span_diagnostic.span_bug(def.span, "wrong-structured lhs")
}).collect::<Vec<quoted::TokenTree>>()
}
_ => sess.span_diagnostic.span_bug(def.span, "wrong-structured lhs")
};
let rhses = match *argument_map[&rhs_nm] {
MatchedSeq(ref s, _) => {
s.iter().map(|m| {
if let MatchedNonterminal(ref nt) = **m {
if let NtTT(ref tt) = **nt {
return quoted::parse(tt.clone().into(), false, sess).pop().unwrap();
}
}
sess.span_diagnostic.span_bug(def.span, "wrong-structured lhs")
}).collect::<Vec<quoted::TokenTree>>()
}
_ => sess.span_diagnostic.span_bug(def.span, "wrong-structured rhs")
};
for rhs in &rhses {
valid &= check_rhs(sess, rhs);
}
for lhs in &lhses {
valid &= check_lhs_no_empty_seq(sess, &[lhs.clone()])
}
let exp: Box<_> = Box::new(MacroRulesMacroExpander {
name: def.ident,
lhses: lhses,
rhses: rhses,
valid: valid,
});
if body.legacy {
let allow_internal_unstable = attr::contains_name(&def.attrs, "allow_internal_unstable");
NormalTT(exp, Some((def.id, def.span)), allow_internal_unstable)
} else {
SyntaxExtension::DeclMacro(exp, Some(def.span))
}
}
fn check_lhs_nt_follows(sess: &ParseSess,
features: &RefCell<Features>,
lhs: "ed::TokenTree) -> bool {
if let quoted::TokenTree::Delimited(_, ref tts) = *lhs {
check_matcher(sess, features, &tts.tts)
} else {
let msg = "invalid macro matcher; matchers must be contained in balanced delimiters";
sess.span_diagnostic.span_err(lhs.span(), msg);
false
}
}
fn check_lhs_no_empty_seq(sess: &ParseSess, tts: &[quoted::TokenTree]) -> bool {
use self::quoted::TokenTree;
for tt in tts {
match *tt {
TokenTree::Token(..) | TokenTree::MetaVarDecl(..) => (),
TokenTree::Delimited(_, ref del) => if !check_lhs_no_empty_seq(sess, &del.tts) {
return false;
},
TokenTree::Sequence(span, ref seq) => {
if seq.separator.is_none() && seq.tts.iter().all(|seq_tt| {
match *seq_tt {
TokenTree::Sequence(_, ref sub_seq) =>
sub_seq.op == quoted::KleeneOp::ZeroOrMore,
_ => false,
}
}) {
sess.span_diagnostic.span_err(span, "repetition matches empty token tree");
return false;
}
if !check_lhs_no_empty_seq(sess, &seq.tts) {
return false;
}
}
}
}
true
}
fn check_rhs(sess: &ParseSess, rhs: "ed::TokenTree) -> bool {
match *rhs {
quoted::TokenTree::Delimited(..) => return true,
_ => sess.span_diagnostic.span_err(rhs.span(), "macro rhs must be delimited")
}
false
}
fn check_matcher(sess: &ParseSess,
features: &RefCell<Features>,
matcher: &[quoted::TokenTree]) -> bool {
let first_sets = FirstSets::new(matcher);
let empty_suffix = TokenSet::empty();
let err = sess.span_diagnostic.err_count();
check_matcher_core(sess, features, &first_sets, matcher, &empty_suffix);
err == sess.span_diagnostic.err_count()
}
struct FirstSets {
first: HashMap<Span, Option<TokenSet>>,
}
impl FirstSets {
fn new(tts: &[quoted::TokenTree]) -> FirstSets {
use self::quoted::TokenTree;
let mut sets = FirstSets { first: HashMap::new() };
build_recur(&mut sets, tts);
return sets;
fn build_recur(sets: &mut FirstSets, tts: &[TokenTree]) -> TokenSet {
let mut first = TokenSet::empty();
for tt in tts.iter().rev() {
match *tt {
TokenTree::Token(..) | TokenTree::MetaVarDecl(..) => {
first.replace_with(tt.clone());
}
TokenTree::Delimited(span, ref delimited) => {
build_recur(sets, &delimited.tts[..]);
first.replace_with(delimited.open_tt(span));
}
TokenTree::Sequence(sp, ref seq_rep) => {
let subfirst = build_recur(sets, &seq_rep.tts[..]);
match sets.first.entry(sp) {
Entry::Vacant(vac) => {
vac.insert(Some(subfirst.clone()));
}
Entry::Occupied(mut occ) => {
occ.insert(None);
}
}
if let (Some(ref sep), true) = (seq_rep.separator.clone(),
subfirst.maybe_empty) {
first.add_one_maybe(TokenTree::Token(sp, sep.clone()));
}
if subfirst.maybe_empty || seq_rep.op == quoted::KleeneOp::ZeroOrMore {
first.add_all(&TokenSet { maybe_empty: true, ..subfirst });
} else {
first = subfirst;
}
}
}
}
first
}
}
fn first(&self, tts: &[quoted::TokenTree]) -> TokenSet {
use self::quoted::TokenTree;
let mut first = TokenSet::empty();
for tt in tts.iter() {
assert!(first.maybe_empty);
match *tt {
TokenTree::Token(..) | TokenTree::MetaVarDecl(..) => {
first.add_one(tt.clone());
return first;
}
TokenTree::Delimited(span, ref delimited) => {
first.add_one(delimited.open_tt(span));
return first;
}
TokenTree::Sequence(sp, ref seq_rep) => {
match self.first.get(&sp) {
Some(&Some(ref subfirst)) => {
if let (Some(ref sep), true) = (seq_rep.separator.clone(),
subfirst.maybe_empty) {
first.add_one_maybe(TokenTree::Token(sp, sep.clone()));
}
assert!(first.maybe_empty);
first.add_all(subfirst);
if subfirst.maybe_empty ||
seq_rep.op == quoted::KleeneOp::ZeroOrMore {
first.maybe_empty = true;
continue;
} else {
return first;
}
}
Some(&None) => {
panic!("assume all sequences have (unique) spans for now");
}
None => {
panic!("We missed a sequence during FirstSets construction");
}
}
}
}
}
assert!(first.maybe_empty);
first
}
}
#[derive(Clone, Debug)]
struct TokenSet {
tokens: Vec<quoted::TokenTree>,
maybe_empty: bool,
}
impl TokenSet {
fn empty() -> Self { TokenSet { tokens: Vec::new(), maybe_empty: true } }
fn singleton(tok: quoted::TokenTree) -> Self {
TokenSet { tokens: vec![tok], maybe_empty: false }
}
fn replace_with(&mut self, tok: quoted::TokenTree) {
self.tokens.clear();
self.tokens.push(tok);
self.maybe_empty = false;
}
fn replace_with_irrelevant(&mut self) {
self.tokens.clear();
self.maybe_empty = false;
}
fn add_one(&mut self, tok: quoted::TokenTree) {
if !self.tokens.contains(&tok) {
self.tokens.push(tok);
}
self.maybe_empty = false;
}
fn add_one_maybe(&mut self, tok: quoted::TokenTree) {
if !self.tokens.contains(&tok) {
self.tokens.push(tok);
}
}
fn add_all(&mut self, other: &Self) {
for tok in &other.tokens {
if !self.tokens.contains(tok) {
self.tokens.push(tok.clone());
}
}
if !other.maybe_empty {
self.maybe_empty = false;
}
}
}
fn check_matcher_core(sess: &ParseSess,
features: &RefCell<Features>,
first_sets: &FirstSets,
matcher: &[quoted::TokenTree],
follow: &TokenSet) -> TokenSet {
use self::quoted::TokenTree;
let mut last = TokenSet::empty();
'each_token: for i in 0..matcher.len() {
let token = &matcher[i];
let suffix = &matcher[i+1..];
let build_suffix_first = || {
let mut s = first_sets.first(suffix);
if s.maybe_empty { s.add_all(follow); }
s
};
let suffix_first;
match *token {
TokenTree::Token(..) | TokenTree::MetaVarDecl(..) => {
let can_be_followed_by_any;
if let Err(bad_frag) = has_legal_fragment_specifier(sess, features, token) {
let msg = format!("invalid fragment specifier `{}`", bad_frag);
sess.span_diagnostic.struct_span_err(token.span(), &msg)
.help("valid fragment specifiers are `ident`, `block`, `stmt`, `expr`, \
`pat`, `ty`, `path`, `meta`, `tt`, `item` and `vis`")
.emit();
can_be_followed_by_any = true;
} else {
can_be_followed_by_any = token_can_be_followed_by_any(token);
}
if can_be_followed_by_any {
last.replace_with_irrelevant();
continue 'each_token;
} else {
last.replace_with(token.clone());
suffix_first = build_suffix_first();
}
}
TokenTree::Delimited(span, ref d) => {
let my_suffix = TokenSet::singleton(d.close_tt(span));
check_matcher_core(sess, features, first_sets, &d.tts, &my_suffix);
last.replace_with_irrelevant();
continue 'each_token;
}
TokenTree::Sequence(sp, ref seq_rep) => {
suffix_first = build_suffix_first();
let mut new;
let my_suffix = if let Some(ref u) = seq_rep.separator {
new = suffix_first.clone();
new.add_one_maybe(TokenTree::Token(sp, u.clone()));
&new
} else {
&suffix_first
};
let next = check_matcher_core(sess, features, first_sets, &seq_rep.tts, my_suffix);
if next.maybe_empty {
last.add_all(&next);
} else {
last = next;
}
continue 'each_token;
}
}
'each_last: for token in &last.tokens {
if let TokenTree::MetaVarDecl(_, ref name, ref frag_spec) = *token {
for next_token in &suffix_first.tokens {
match is_in_follow(next_token, &frag_spec.name.as_str()) {
Err((msg, help)) => {
sess.span_diagnostic.struct_span_err(next_token.span(), &msg)
.help(help).emit();
continue 'each_last;
}
Ok(true) => {}
Ok(false) => {
let may_be = if last.tokens.len() == 1 &&
suffix_first.tokens.len() == 1
{
"is"
} else {
"may be"
};
sess.span_diagnostic.span_err(
next_token.span(),
&format!("`${name}:{frag}` {may_be} followed by `{next}`, which \
is not allowed for `{frag}` fragments",
name=name,
frag=frag_spec,
next=quoted_tt_to_string(next_token),
may_be=may_be)
);
}
}
}
}
}
}
last
}
fn token_can_be_followed_by_any(tok: "ed::TokenTree) -> bool {
if let quoted::TokenTree::MetaVarDecl(_, _, frag_spec) = *tok {
frag_can_be_followed_by_any(&frag_spec.name.as_str())
} else {
true
}
}
fn frag_can_be_followed_by_any(frag: &str) -> bool {
match frag {
"item" |
"block" |
"ident" |
"meta" |
"tt" =>
true,
_ =>
false,
}
}
fn is_in_follow(tok: "ed::TokenTree, frag: &str) -> Result<bool, (String, &'static str)> {
use self::quoted::TokenTree;
if let TokenTree::Token(_, token::CloseDelim(_)) = *tok {
Ok(true)
} else {
match frag {
"item" => {
Ok(true)
},
"block" => {
Ok(true)
},
"stmt" | "expr" => match *tok {
TokenTree::Token(_, ref tok) => match *tok {
FatArrow | Comma | Semi => Ok(true),
_ => Ok(false)
},
_ => Ok(false),
},
"pat" => match *tok {
TokenTree::Token(_, ref tok) => match *tok {
FatArrow | Comma | Eq | BinOp(token::Or) => Ok(true),
Ident(i) if i.name == "if" || i.name == "in" => Ok(true),
_ => Ok(false)
},
_ => Ok(false),
},
"path" | "ty" => match *tok {
TokenTree::Token(_, ref tok) => match *tok {
OpenDelim(token::DelimToken::Brace) | OpenDelim(token::DelimToken::Bracket) |
Comma | FatArrow | Colon | Eq | Gt | Semi | BinOp(token::Or) => Ok(true),
Ident(i) if i.name == "as" || i.name == "where" => Ok(true),
_ => Ok(false)
},
TokenTree::MetaVarDecl(_, _, frag) if frag.name == "block" => Ok(true),
_ => Ok(false),
},
"ident" => {
Ok(true)
},
"meta" | "tt" => {
Ok(true)
},
"vis" => {
match *tok {
TokenTree::Token(_, ref tok) => match *tok {
Comma => Ok(true),
Ident(i) if i.name != "priv" => Ok(true),
ref tok => Ok(tok.can_begin_type())
},
TokenTree::MetaVarDecl(_, _, frag) if frag.name == "ident"
|| frag.name == "ty"
|| frag.name == "path" => Ok(true),
_ => Ok(false)
}
},
"" => Ok(true),
_ => Err((format!("invalid fragment specifier `{}`", frag),
"valid fragment specifiers are `ident`, `block`, \
`stmt`, `expr`, `pat`, `ty`, `path`, `meta`, `tt`, \
`item` and `vis`"))
}
}
}
fn has_legal_fragment_specifier(sess: &ParseSess,
features: &RefCell<Features>,
tok: "ed::TokenTree) -> Result<(), String> {
debug!("has_legal_fragment_specifier({:?})", tok);
if let quoted::TokenTree::MetaVarDecl(_, _, ref frag_spec) = *tok {
let frag_name = frag_spec.name.as_str();
let frag_span = tok.span();
if !is_legal_fragment_specifier(sess, features, &frag_name, frag_span) {
return Err(frag_name.to_string());
}
}
Ok(())
}
fn is_legal_fragment_specifier(sess: &ParseSess,
features: &RefCell<Features>,
frag_name: &str,
frag_span: Span) -> bool {
match frag_name {
"item" | "block" | "stmt" | "expr" | "pat" |
"path" | "ty" | "ident" | "meta" | "tt" | "" => true,
"vis" => {
if !features.borrow().macro_vis_matcher {
let explain = feature_gate::EXPLAIN_VIS_MATCHER;
emit_feature_err(sess,
"macro_vis_matcher",
frag_span,
GateIssue::Language,
explain);
}
true
},
_ => false,
}
}
fn quoted_tt_to_string(tt: "ed::TokenTree) -> String {
match *tt {
quoted::TokenTree::Token(_, ref tok) => ::print::pprust::token_to_string(tok),
quoted::TokenTree::MetaVarDecl(_, name, kind) => format!("${}:{}", name, kind),
_ => panic!("unexpected quoted::TokenTree::{{Sequence or Delimited}} \
in follow set checker"),
}
}