Refactor the parser to consume token trees.

Author: jseyfried

src/librustc/session/config.rs

@@ -25,6 +25,7 @@ use lint;
 use middle::cstore;
 
 use syntax::ast::{self, IntTy, UintTy};
+use syntax::parse::token;
 use syntax::parse;
 use syntax::symbol::Symbol;
 use syntax::feature_gate::UnstableFeatures;
@@ -1259,7 +1260,7 @@ pub fn parse_cfgspecs(cfgspecs: Vec<String> ) -> ast::CrateConfig {
 
         let meta_item = panictry!(parser.parse_meta_item());
 
-        if !parser.reader.is_eof() {
+        if parser.token != token::Eof {
             early_error(ErrorOutputType::default(), &format!("invalid --cfg argument: {}", s))
         } else if meta_item.is_meta_item_list() {
             let msg =

src/librustc_metadata/cstore_impl.rs

@@ -29,7 +29,7 @@ use rustc_back::PanicStrategy;
 
 use syntax::ast;
 use syntax::attr;
-use syntax::parse::new_parser_from_source_str;
+use syntax::parse::filemap_to_tts;
 use syntax::symbol::Symbol;
 use syntax_pos::{mk_sp, Span};
 use rustc::hir::svh::Svh;
@@ -395,19 +395,9 @@ impl<'tcx> CrateStore<'tcx> for cstore::CStore {
         let (name, def) = data.get_macro(id.index);
         let source_name = format!("<{} macros>", name);
 
-        // NB: Don't use parse_tts_from_source_str because it parses with quote_depth > 0.
-        let mut parser = new_parser_from_source_str(&sess.parse_sess, source_name, def.body);
-
-        let lo = parser.span.lo;
-        let body = match parser.parse_all_token_trees() {
-            Ok(body) => body,
-            Err(mut err) => {
-                err.emit();
-                sess.abort_if_errors();
-                unreachable!();
-            }
-        };
-        let local_span = mk_sp(lo, parser.prev_span.hi);
+        let filemap = sess.parse_sess.codemap().new_filemap(source_name, None, def.body);
+        let local_span = mk_sp(filemap.start_pos, filemap.end_pos);
+        let body = filemap_to_tts(&sess.parse_sess, filemap);
 
         // Mark the attrs as used
         let attrs = data.get_item_attrs(id.index);

src/libsyntax/ext/base.rs

@@ -615,9 +615,7 @@ impl<'a> ExtCtxt<'a> {
 
     pub fn new_parser_from_tts(&self, tts: &[tokenstream::TokenTree])
         -> parser::Parser<'a> {
-        let mut parser = parse::tts_to_parser(self.parse_sess, tts.to_vec());
-        parser.allow_interpolated_tts = false; // FIXME(jseyfried) `quote!` can't handle these yet
-        parser
+        parse::tts_to_parser(self.parse_sess, tts.to_vec())
     }
     pub fn codemap(&self) -> &'a CodeMap { self.parse_sess.codemap() }
     pub fn parse_sess(&self) -> &'a parse::ParseSess { self.parse_sess }

src/libsyntax/ext/tt/macro_parser.rs

@@ -82,7 +82,6 @@ use ast::Ident;
 use syntax_pos::{self, BytePos, mk_sp, Span};
 use codemap::Spanned;
 use errors::FatalError;
-use parse::lexer::*; //resolve bug?
 use parse::{Directory, ParseSess};
 use parse::parser::{PathStyle, Parser};
 use parse::token::{DocComment, MatchNt, SubstNt};
@@ -407,9 +406,9 @@ fn inner_parse_loop(cur_eis: &mut SmallVector<Box<MatcherPos>>,
     Success(())
 }
 
-pub fn parse(sess: &ParseSess, rdr: TtReader, ms: &[TokenTree], directory: Option<Directory>)
+pub fn parse(sess: &ParseSess, tts: Vec<TokenTree>, ms: &[TokenTree], directory: Option<Directory>)
              -> NamedParseResult {
-    let mut parser = Parser::new(sess, Box::new(rdr), directory, true);
+    let mut parser = Parser::new(sess, tts, directory, true);
     let mut cur_eis = SmallVector::one(initial_matcher_pos(ms.to_owned(), parser.span.lo));
     let mut next_eis = Vec::new(); // or proceed normally
 
@@ -527,7 +526,7 @@ fn parse_nt<'a>(p: &mut Parser<'a>, sp: Span, name: &str) -> Nonterminal {
         "ident" => match p.token {
             token::Ident(sn) => {
                 p.bump();
-                token::NtIdent(Spanned::<Ident>{node: sn, span: p.span})
+                token::NtIdent(Spanned::<Ident>{node: sn, span: p.prev_span})
             }
             _ => {
                 let token_str = pprust::token_to_string(&p.token);

src/libsyntax/ext/tt/macro_rules.rs

@@ -16,8 +16,8 @@ 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::transcribe::new_tt_reader;
 use parse::{Directory, ParseSess};
-use parse::lexer::new_tt_reader;
 use parse::parser::Parser;
 use parse::token::{self, NtTT, Token};
 use parse::token::Token::*;
@@ -113,13 +113,21 @@ fn generic_extension<'cx>(cx: &'cx ExtCtxt,
                     _ => cx.span_bug(sp, "malformed macro rhs"),
                 };
                 // rhs has holes ( `$id` and `$(...)` that need filled)
-                let trncbr =
+                let mut trncbr =
                     new_tt_reader(&cx.parse_sess.span_diagnostic, Some(named_matches), rhs);
+                let mut tts = Vec::new();
+                loop {
+                    let tok = trncbr.real_token();
+                    if tok.tok == token::Eof {
+                        break
+                    }
+                    tts.push(TokenTree::Token(tok.sp, tok.tok));
+                }
                 let directory = Directory {
                     path: cx.current_expansion.module.directory.clone(),
                     ownership: cx.current_expansion.directory_ownership,
                 };
-                let mut p = Parser::new(cx.parse_sess(), Box::new(trncbr), Some(directory), false);
+                let mut p = Parser::new(cx.parse_sess(), tts, Some(directory), false);
                 p.root_module_name = cx.current_expansion.module.mod_path.last()
                     .map(|id| (*id.name.as_str()).to_owned());
 
@@ -187,10 +195,8 @@ pub fn compile(sess: &ParseSess, def: &ast::MacroDef) -> SyntaxExtension {
         })),
     ];
 
-    // Parse the macro_rules! invocation (`none` is for no interpolations):
-    let arg_reader = new_tt_reader(&sess.span_diagnostic, None, def.body.clone());
-
-    let argument_map = match parse(sess, arg_reader, &argument_gram, None) {
+    // Parse the macro_rules! invocation
+    let argument_map = match parse(sess, def.body.clone(), &argument_gram, None) {
         Success(m) => m,
         Failure(sp, tok) => {
             let s = parse_failure_msg(tok);

src/libsyntax/ext/tt/transcribe.rs

@@ -10,7 +10,7 @@
 use self::LockstepIterSize::*;
 
 use ast::Ident;
-use errors::{Handler, DiagnosticBuilder};
+use errors::Handler;
 use ext::tt::macro_parser::{NamedMatch, MatchedSeq, MatchedNonterminal};
 use parse::token::{self, MatchNt, SubstNt, Token, NtIdent};
 use parse::lexer::TokenAndSpan;
@@ -44,8 +44,12 @@ pub struct TtReader<'a> {
     /* cached: */
     pub cur_tok: Token,
     pub cur_span: Span,
-    /// Transform doc comments. Only useful in macro invocations
-    pub fatal_errs: Vec<DiagnosticBuilder<'a>>,
+}
+
+impl<'a> TtReader<'a> {
+    pub fn real_token(&mut self) -> TokenAndSpan {
+        tt_next_token(self)
+    }
 }
 
 /// This can do Macro-By-Example transcription. On the other hand, if
@@ -76,7 +80,6 @@ pub fn new_tt_reader(sp_diag: &Handler,
         /* dummy values, never read: */
         cur_tok: token::Eof,
         cur_span: DUMMY_SP,
-        fatal_errs: Vec::new(),
     };
     tt_next_token(&mut r); /* get cur_tok and cur_span set up */
     r

src/libsyntax/parse/lexer/mod.rs

@@ -12,7 +12,6 @@ use ast::{self, Ident};
 use syntax_pos::{self, BytePos, CharPos, Pos, Span};
 use codemap::CodeMap;
 use errors::{FatalError, DiagnosticBuilder};
-use ext::tt::transcribe::tt_next_token;
 use parse::{token, ParseSess};
 use str::char_at;
 use symbol::{Symbol, keywords};
@@ -23,53 +22,10 @@ use std::char;
 use std::mem::replace;
 use std::rc::Rc;
 
-pub use ext::tt::transcribe::{TtReader, new_tt_reader};
-
 pub mod comments;
 mod tokentrees;
 mod unicode_chars;
 
-pub trait Reader {
-    fn is_eof(&self) -> bool;
-    fn try_next_token(&mut self) -> Result<TokenAndSpan, ()>;
-    fn next_token(&mut self) -> TokenAndSpan where Self: Sized {
-        let res = self.try_next_token();
-        self.unwrap_or_abort(res)
-    }
-    /// Report a fatal error with the current span.
-    fn fatal(&self, &str) -> FatalError;
-    /// Report a non-fatal error with the current span.
-    fn err(&self, &str);
-    fn emit_fatal_errors(&mut self);
-    fn unwrap_or_abort(&mut self, res: Result<TokenAndSpan, ()>) -> TokenAndSpan {
-        match res {
-            Ok(tok) => tok,
-            Err(_) => {
-                self.emit_fatal_errors();
-                panic!(FatalError);
-            }
-        }
-    }
-    fn peek(&self) -> TokenAndSpan;
-    /// Get a token the parser cares about.
-    fn try_real_token(&mut self) -> Result<TokenAndSpan, ()> {
-        let mut t = self.try_next_token()?;
-        loop {
-            match t.tok {
-                token::Whitespace | token::Comment | token::Shebang(_) => {
-                    t = self.try_next_token()?;
-                }
-                _ => break,
-            }
-        }
-        Ok(t)
-    }
-    fn real_token(&mut self) -> TokenAndSpan {
-        let res = self.try_real_token();
-        self.unwrap_or_abort(res)
-    }
-}
-
 #[derive(Clone, PartialEq, Eq, Debug)]
 pub struct TokenAndSpan {
     pub tok: token::Token,
@@ -182,36 +138,6 @@ impl<'a> StringReader<'a> {
     }
 }
 
-impl<'a> Reader for TtReader<'a> {
-    fn is_eof(&self) -> bool {
-        self.peek().tok == token::Eof
-    }
-    fn try_next_token(&mut self) -> Result<TokenAndSpan, ()> {
-        assert!(self.fatal_errs.is_empty());
-        let r = tt_next_token(self);
-        debug!("TtReader: r={:?}", r);
-        Ok(r)
-    }
-    fn fatal(&self, m: &str) -> FatalError {
-        self.sp_diag.span_fatal(self.cur_span, m)
-    }
-    fn err(&self, m: &str) {
-        self.sp_diag.span_err(self.cur_span, m);
-    }
-    fn emit_fatal_errors(&mut self) {
-        for err in &mut self.fatal_errs {
-            err.emit();
-        }
-        self.fatal_errs.clear();
-    }
-    fn peek(&self) -> TokenAndSpan {
-        TokenAndSpan {
-            tok: self.cur_tok.clone(),
-            sp: self.cur_span,
-        }
-    }
-}
-
 impl<'a> StringReader<'a> {
     /// For comments.rs, which hackily pokes into next_pos and ch
     pub fn new_raw<'b>(sess: &'a ParseSess, filemap: Rc<syntax_pos::FileMap>) -> Self {

src/libsyntax/parse/mod.rs

@@ -45,7 +45,7 @@ pub mod obsolete;
 
 /// Info about a parsing session.
 pub struct ParseSess {
-    pub span_diagnostic: Handler, // better be the same as the one in the reader!
+    pub span_diagnostic: Handler,
     pub unstable_features: UnstableFeatures,
     pub config: CrateConfig,
     /// Used to determine and report recursive mod inclusions
@@ -227,8 +227,7 @@ pub fn filemap_to_tts(sess: &ParseSess, filemap: Rc<FileMap>) -> Vec<tokenstream
 
 /// Given tts and the ParseSess, produce a parser
 pub fn tts_to_parser<'a>(sess: &'a ParseSess, tts: Vec<tokenstream::TokenTree>) -> Parser<'a> {
-    let trdr = lexer::new_tt_reader(&sess.span_diagnostic, None, tts);
-    let mut p = Parser::new(sess, Box::new(trdr), None, false);
+    let mut p = Parser::new(sess, tts, None, false);
     p.check_unknown_macro_variable();
     p
 }