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use ast::{self, TokenTree, TtDelimited, TtSequence, TtToken};
use codemap::{Span, DUMMY_SP};
use ext::base::{ExtCtxt, MacResult, SyntaxExtension};
use ext::base::{NormalTT, TTMacroExpander};
use ext::tt::macro_parser::{Success, Error, Failure};
use ext::tt::macro_parser::{NamedMatch, MatchedSeq, MatchedNonterminal};
use ext::tt::macro_parser::{parse, parse_or_else};
use parse::lexer::{new_tt_reader, new_tt_reader_with_doc_flag};
use parse::parser::Parser;
use parse::attr::ParserAttr;
use parse::token::{self, special_idents, gensym_ident, NtTT, Token};
use parse::token::Token::*;
use print;
use ptr::P;
use util::small_vector::SmallVector;
use std::cell::RefCell;
use std::rc::Rc;
struct ParserAnyMacro<'a> {
parser: RefCell<Parser<'a>>,
}
impl<'a> ParserAnyMacro<'a> {
fn ensure_complete_parse(&self, allow_semi: bool) {
let mut parser = self.parser.borrow_mut();
if allow_semi && parser.token == token::Semi {
parser.bump()
}
if parser.token != token::Eof {
let token_str = parser.this_token_to_string();
let msg = format!("macro expansion ignores token `{}` and any \
following",
token_str);
let span = parser.span;
parser.span_err(span, &msg[..]);
}
}
}
impl<'a> MacResult for ParserAnyMacro<'a> {
fn make_expr(self: Box<ParserAnyMacro<'a>>) -> Option<P<ast::Expr>> {
let ret = self.parser.borrow_mut().parse_expr();
self.ensure_complete_parse(true);
Some(ret)
}
fn make_pat(self: Box<ParserAnyMacro<'a>>) -> Option<P<ast::Pat>> {
let ret = self.parser.borrow_mut().parse_pat();
self.ensure_complete_parse(false);
Some(ret)
}
fn make_items(self: Box<ParserAnyMacro<'a>>) -> Option<SmallVector<P<ast::Item>>> {
let mut ret = SmallVector::zero();
loop {
let mut parser = self.parser.borrow_mut();
match parser.parse_item_with_outer_attributes() {
Some(item) => ret.push(item),
None => break
}
}
self.ensure_complete_parse(false);
Some(ret)
}
fn make_methods(self: Box<ParserAnyMacro<'a>>) -> Option<SmallVector<P<ast::Method>>> {
let mut ret = SmallVector::zero();
loop {
let mut parser = self.parser.borrow_mut();
match parser.token {
token::Eof => break,
_ => {
ret.push(parser.parse_method_with_outer_attributes());
}
}
}
self.ensure_complete_parse(false);
Some(ret)
}
fn make_stmt(self: Box<ParserAnyMacro<'a>>) -> Option<P<ast::Stmt>> {
let attrs = self.parser.borrow_mut().parse_outer_attributes();
let ret = self.parser.borrow_mut().parse_stmt(attrs);
self.ensure_complete_parse(true);
Some(ret)
}
}
struct MacroRulesMacroExpander {
name: ast::Ident,
imported_from: Option<ast::Ident>,
lhses: Vec<Rc<NamedMatch>>,
rhses: Vec<Rc<NamedMatch>>,
}
impl TTMacroExpander for MacroRulesMacroExpander {
fn expand<'cx>(&self,
cx: &'cx mut ExtCtxt,
sp: Span,
arg: &[ast::TokenTree])
-> Box<MacResult+'cx> {
generic_extension(cx,
sp,
self.name,
self.imported_from,
arg,
&self.lhses,
&self.rhses)
}
}
fn generic_extension<'cx>(cx: &'cx ExtCtxt,
sp: Span,
name: ast::Ident,
imported_from: Option<ast::Ident>,
arg: &[ast::TokenTree],
lhses: &[Rc<NamedMatch>],
rhses: &[Rc<NamedMatch>])
-> Box<MacResult+'cx> {
if cx.trace_macros() {
println!("{}! {{ {} }}",
token::get_ident(name),
print::pprust::tts_to_string(arg));
}
let mut best_fail_spot = DUMMY_SP;
let mut best_fail_msg = "internal error: ran no matchers".to_string();
for (i, lhs) in lhses.iter().enumerate() {
match **lhs {
MatchedNonterminal(NtTT(ref lhs_tt)) => {
let lhs_tt = match **lhs_tt {
TtDelimited(_, ref delim) => &delim.tts[..],
_ => cx.span_fatal(sp, "malformed macro lhs")
};
let arg_rdr = new_tt_reader_with_doc_flag(&cx.parse_sess().span_diagnostic,
None,
None,
arg.iter()
.cloned()
.collect(),
true);
match parse(cx.parse_sess(), cx.cfg(), arg_rdr, lhs_tt) {
Success(named_matches) => {
let rhs = match *rhses[i] {
MatchedNonterminal(NtTT(ref tt)) => {
match **tt {
TtDelimited(_, ref delimed) => delimed.tts.clone(),
_ => cx.span_fatal(sp, "macro rhs must be delimited"),
}
},
_ => cx.span_bug(sp, "bad thing in rhs")
};
let trncbr = new_tt_reader(&cx.parse_sess().span_diagnostic,
Some(named_matches),
imported_from,
rhs);
let mut p = Parser::new(cx.parse_sess(), cx.cfg(), box trncbr);
p.check_unknown_macro_variable();
return box ParserAnyMacro {
parser: RefCell::new(p),
} as Box<MacResult+'cx>
}
Failure(sp, ref msg) => if sp.lo >= best_fail_spot.lo {
best_fail_spot = sp;
best_fail_msg = (*msg).clone();
},
Error(sp, ref msg) => cx.span_fatal(sp, &msg[..])
}
}
_ => cx.bug("non-matcher found in parsed lhses")
}
}
cx.span_fatal(best_fail_spot, &best_fail_msg[..]);
}
pub fn compile<'cx>(cx: &'cx mut ExtCtxt,
def: &ast::MacroDef) -> SyntaxExtension {
let lhs_nm = gensym_ident("lhs");
let rhs_nm = gensym_ident("rhs");
let match_lhs_tok = MatchNt(lhs_nm, special_idents::tt, token::Plain, token::Plain);
let match_rhs_tok = MatchNt(rhs_nm, special_idents::tt, token::Plain, token::Plain);
let argument_gram = vec!(
TtSequence(DUMMY_SP,
Rc::new(ast::SequenceRepetition {
tts: vec![
TtToken(DUMMY_SP, match_lhs_tok),
TtToken(DUMMY_SP, token::FatArrow),
TtToken(DUMMY_SP, match_rhs_tok)],
separator: Some(token::Semi),
op: ast::OneOrMore,
num_captures: 2
})),
TtSequence(DUMMY_SP,
Rc::new(ast::SequenceRepetition {
tts: vec![TtToken(DUMMY_SP, token::Semi)],
separator: None,
op: ast::ZeroOrMore,
num_captures: 0
})));
let arg_reader = new_tt_reader(&cx.parse_sess().span_diagnostic,
None,
None,
def.body.clone());
let argument_map = parse_or_else(cx.parse_sess(),
cx.cfg(),
arg_reader,
argument_gram);
let lhses = match *argument_map[lhs_nm] {
MatchedSeq(ref s, _) => (*s).clone(),
_ => cx.span_bug(def.span, "wrong-structured lhs")
};
for lhs in &lhses {
check_lhs_nt_follows(cx, &**lhs, def.span);
}
let rhses = match *argument_map[rhs_nm] {
MatchedSeq(ref s, _) => (*s).clone(),
_ => cx.span_bug(def.span, "wrong-structured rhs")
};
let exp = box MacroRulesMacroExpander {
name: def.ident,
imported_from: def.imported_from,
lhses: lhses,
rhses: rhses,
};
NormalTT(exp, Some(def.span))
}
fn check_lhs_nt_follows(cx: &mut ExtCtxt, lhs: &NamedMatch, sp: Span) {
match lhs {
&MatchedNonterminal(NtTT(ref inner)) => match &**inner {
&TtDelimited(_, ref tts) => {
check_matcher(cx, tts.tts.iter(), &Eof);
},
tt @ &TtSequence(..) => {
check_matcher(cx, Some(tt).into_iter(), &Eof);
},
_ => cx.span_bug(sp, "wrong-structured lhs for follow check (didn't find \
a TtDelimited or TtSequence)")
},
_ => cx.span_bug(sp, "wrong-structured lhs for follow check (didn't find a \
MatchedNonterminal)")
};
}
fn check_matcher<'a, I>(cx: &mut ExtCtxt, matcher: I, follow: &Token)
-> Option<(Span, Token)> where I: Iterator<Item=&'a TokenTree> {
use print::pprust::token_to_string;
let mut last = None;
let mut tokens = matcher.peekable();
while let Some(token) = tokens.next() {
last = match *token {
TtToken(sp, MatchNt(ref name, ref frag_spec, _, _)) => {
let next_token = match tokens.peek() {
Some(&&TtToken(_, CloseDelim(_))) => follow.clone(),
Some(&&TtToken(_, ref tok)) => tok.clone(),
Some(&&TtSequence(sp, _)) => {
cx.span_err(sp,
&format!("`${0}:{1}` is followed by a \
sequence repetition, which is not \
allowed for `{1}` fragments",
name.as_str(), frag_spec.as_str())
);
Eof
},
Some(&&TtDelimited(_, ref delim)) => delim.close_token(),
None => follow.clone()
};
let tok = if let TtToken(_, ref tok) = *token { tok } else { unreachable!() };
match (&next_token, is_in_follow(cx, &next_token, frag_spec.as_str())) {
(&Eof, _) => return Some((sp, tok.clone())),
(_, Ok(true)) => continue,
(next, Ok(false)) => {
cx.span_err(sp, &format!("`${0}:{1}` is followed by `{2}`, which \
is not allowed for `{1}` fragments",
name.as_str(), frag_spec.as_str(),
token_to_string(next)));
continue
},
(_, Err(msg)) => {
cx.span_err(sp, &msg);
continue
}
}
},
TtSequence(sp, ref seq) => {
match seq.separator {
Some(ref u) => {
let last = check_matcher(cx, seq.tts.iter(), u);
match last {
Some((span, tok)) => {
let fol = match tokens.peek() {
Some(&&TtToken(_, ref tok)) => tok.clone(),
Some(&&TtDelimited(_, ref delim)) => delim.close_token(),
Some(_) => {
cx.span_err(sp, "sequence repetition followed by \
another sequence repetition, which is not allowed");
Eof
},
None => Eof
};
check_matcher(cx, Some(&TtToken(span, tok.clone())).into_iter(),
&fol)
},
None => last,
}
},
None => {
let fol = match tokens.peek() {
Some(&&TtToken(_, ref tok)) => tok.clone(),
Some(&&TtDelimited(_, ref delim)) => delim.close_token(),
Some(_) => {
cx.span_err(sp, "sequence repetition followed by another \
sequence repetition, which is not allowed");
Eof
},
None => Eof
};
check_matcher(cx, seq.tts.iter(), &fol)
}
}
},
TtToken(..) => {
continue
},
TtDelimited(_, ref tts) => {
check_matcher(cx, tts.tts.iter(), &tts.close_token())
}
}
}
last
}
fn is_in_follow(_: &ExtCtxt, tok: &Token, frag: &str) -> Result<bool, String> {
if let &CloseDelim(_) = tok {
Ok(true)
} else {
match frag {
"item" => {
Ok(true)
},
"block" => {
Ok(true)
},
"stmt" | "expr" => {
match *tok {
FatArrow | Comma | Semi => Ok(true),
_ => Ok(false)
}
},
"pat" => {
match *tok {
FatArrow | Comma | Eq => Ok(true),
_ => Ok(false)
}
},
"path" | "ty" => {
match *tok {
Comma | FatArrow | Colon | Eq | Gt => Ok(true),
Ident(i, _) if i.as_str() == "as" => Ok(true),
_ => Ok(false)
}
},
"ident" => {
Ok(true)
},
"meta" | "tt" => {
Ok(true)
},
_ => Err(format!("invalid fragment specifier `{}`", frag))
}
}
}