Parse and store suffixes on literals.

This adds an optional suffix at the end of a literal token:
`"foo"bar`. An actual use of a suffix in a expression (or other literal
that the compiler reads) is rejected in the parser.

This doesn't switch the handling of numbers to this system, and doesn't
outlaw illegal suffixes for them yet.

1 files changed, 79 insertions, 30 deletions

diff --git a/src/libsyntax/parse/parser.rs b/src/libsyntax/parse/parser.rs
index 4edcb182e53..b9e1fe07e71 100644
--- a/src/libsyntax/parse/parser.rs
+++ b/src/libsyntax/parse/parser.rs
@@ -646,6 +646,20 @@ impl<'a> Parser<'a> {
         }
     }
 
+    pub fn expect_no_suffix(&mut self, sp: Span, kind: &str, suffix: Option<ast::Name>) {
+        match suffix {
+            None => {/* everything ok */}
+            Some(suf) => {
+                let text = suf.as_str();
+                if text.is_empty() {
+                    self.span_bug(sp, "found empty non-None literal suffix")
+                }
+                self.span_err(sp, &*format!("a {} with a suffix is illegal", kind));
+            }
+        }
+    }
+
+
     /// Attempt to consume a `<`. If `<<` is seen, replace it with a single
     /// `<` and continue. If a `<` is not seen, return false.
     ///
@@ -968,6 +982,9 @@ impl<'a> Parser<'a> {
     pub fn span_err(&mut self, sp: Span, m: &str) {
         self.sess.span_diagnostic.span_err(sp, m)
     }
+    pub fn span_bug(&mut self, sp: Span, m: &str) -> ! {
+        self.sess.span_diagnostic.span_bug(sp, m)
+    }
     pub fn abort_if_errors(&mut self) {
         self.sess.span_diagnostic.handler().abort_if_errors();
     }
@@ -1640,24 +1657,40 @@ impl<'a> Parser<'a> {
     /// Matches token_lit = LIT_INTEGER | ...
     pub fn lit_from_token(&mut self, tok: &token::Token) -> Lit_ {
         match *tok {
-            token::Literal(token::Byte(i)) => LitByte(parse::byte_lit(i.as_str()).val0()),
-            token::Literal(token::Char(i)) => LitChar(parse::char_lit(i.as_str()).val0()),
-            token::Literal(token::Integer(s)) => parse::integer_lit(s.as_str(),
-                                                        &self.sess.span_diagnostic,
-                                                       self.last_span),
-            token::Literal(token::Float(s)) => parse::float_lit(s.as_str()),
-            token::Literal(token::Str_(s)) => {
-                LitStr(token::intern_and_get_ident(parse::str_lit(s.as_str()).as_slice()),
-                       ast::CookedStr)
-            }
-            token::Literal(token::StrRaw(s, n)) => {
-                LitStr(token::intern_and_get_ident(parse::raw_str_lit(s.as_str()).as_slice()),
-                       ast::RawStr(n))
+            token::Literal(lit, suf) => {
+                let (suffix_illegal, out) = match lit {
+                    token::Byte(i) => (true, LitByte(parse::byte_lit(i.as_str()).val0())),
+                    token::Char(i) => (true, LitChar(parse::char_lit(i.as_str()).val0())),
+                    token::Integer(s) => (false, parse::integer_lit(s.as_str(),
+                                                            &self.sess.span_diagnostic,
+                                                            self.last_span)),
+                    token::Float(s) => (false, parse::float_lit(s.as_str())),
+                    token::Str_(s) => {
+                        (true,
+                         LitStr(token::intern_and_get_ident(parse::str_lit(s.as_str()).as_slice()),
+                                ast::CookedStr))
+                    }
+                    token::StrRaw(s, n) => {
+                        (true,
+                         LitStr(
+                            token::intern_and_get_ident(
+                                parse::raw_str_lit(s.as_str()).as_slice()),
+                            ast::RawStr(n)))
+                    }
+                    token::Binary(i) =>
+                        (true, LitBinary(parse::binary_lit(i.as_str()))),
+                    token::BinaryRaw(i, _) =>
+                        (true,
+                         LitBinary(Rc::new(i.as_str().as_bytes().iter().map(|&x| x).collect()))),
+                };
+
+                if suffix_illegal {
+                    let sp = self.last_span;
+                    self.expect_no_suffix(sp, &*format!("{} literal", lit.short_name()), suf)
+                }
+
+                out
             }
-            token::Literal(token::Binary(i)) =>
-                LitBinary(parse::binary_lit(i.as_str())),
-            token::Literal(token::BinaryRaw(i, _)) =>
-                LitBinary(Rc::new(i.as_str().as_bytes().iter().map(|&x| x).collect())),
             _ => { self.unexpected_last(tok); }
         }
     }
@@ -2424,7 +2457,10 @@ impl<'a> Parser<'a> {
                         }
                     }
                   }
-                  token::Literal(token::Integer(n)) => {
+                  token::Literal(token::Integer(n), suf) => {
+                    let sp = self.span;
+                    self.expect_no_suffix(sp, "tuple index", suf);
+
                     let index = n.as_str();
                     let dot = self.last_span.hi;
                     hi = self.span.hi;
@@ -2449,7 +2485,7 @@ impl<'a> Parser<'a> {
                         }
                     }
                   }
-                  token::Literal(token::Float(n)) => {
+                  token::Literal(token::Float(n), _suf) => {
                     self.bump();
                     let last_span = self.last_span;
                     let fstr = n.as_str();
@@ -5085,12 +5121,17 @@ impl<'a> Parser<'a> {
                 self.expect(&token::Semi);
                 (path, the_ident)
             },
-            token::Literal(token::Str_(..)) | token::Literal(token::StrRaw(..)) => {
-                let path = self.parse_str();
+            token::Literal(token::Str_(..), suf) | token::Literal(token::StrRaw(..), suf) => {
+                let sp = self.span;
+                self.expect_no_suffix(sp, "extern crate name", suf);
+                // forgo the internal suffix check of `parse_str` to
+                // avoid repeats (this unwrap will always succeed due
+                // to the restriction of the `match`)
+                let (s, style, _) = self.parse_optional_str().unwrap();
                 self.expect_keyword(keywords::As);
                 let the_ident = self.parse_ident();
                 self.expect(&token::Semi);
-                (Some(path), the_ident)
+                (Some((s, style)), the_ident)
             },
             _ => {
                 let span = self.span;
@@ -5267,7 +5308,9 @@ impl<'a> Parser<'a> {
     /// the `extern` keyword, if one is found.
     fn parse_opt_abi(&mut self) -> Option<abi::Abi> {
         match self.token {
-            token::Literal(token::Str_(s)) | token::Literal(token::StrRaw(s, _)) => {
+            token::Literal(token::Str_(s), suf) | token::Literal(token::StrRaw(s, _), suf) => {
+                let sp = self.span;
+                self.expect_no_suffix(sp, "ABI spec", suf);
                 self.bump();
                 let the_string = s.as_str();
                 match abi::lookup(the_string) {
@@ -5902,21 +5945,27 @@ impl<'a> Parser<'a> {
     }
 
     pub fn parse_optional_str(&mut self)
-                              -> Option<(InternedString, ast::StrStyle)> {
-        let (s, style) = match self.token {
-            token::Literal(token::Str_(s)) => (self.id_to_interned_str(s.ident()), ast::CookedStr),
-            token::Literal(token::StrRaw(s, n)) => {
-                (self.id_to_interned_str(s.ident()), ast::RawStr(n))
+                              -> Option<(InternedString, ast::StrStyle, Option<ast::Name>)> {
+        let ret = match self.token {
+            token::Literal(token::Str_(s), suf) => {
+                (self.id_to_interned_str(s.ident()), ast::CookedStr, suf)
+            }
+            token::Literal(token::StrRaw(s, n), suf) => {
+                (self.id_to_interned_str(s.ident()), ast::RawStr(n), suf)
             }
             _ => return None
         };
         self.bump();
-        Some((s, style))
+        Some(ret)
     }
 
     pub fn parse_str(&mut self) -> (InternedString, StrStyle) {
         match self.parse_optional_str() {
-            Some(s) => { s }
+            Some((s, style, suf)) => {
+                let sp = self.last_span;
+                self.expect_no_suffix(sp, "str literal", suf);
+                (s, style)
+            }
             _ =>  self.fatal("expected string literal")
         }
     }