Track character and byte positions together in the parser

4 files changed, 42 insertions, 34 deletions

diff --git a/src/libsyntax/codemap.rs b/src/libsyntax/codemap.rs
index 8333849b21d..fa01a15af5a 100644
--- a/src/libsyntax/codemap.rs
+++ b/src/libsyntax/codemap.rs
@@ -184,20 +184,20 @@ pub struct FileMap {
 pub impl FileMap {
     static fn new_w_substr(+filename: FileName, +substr: FileSubstr,
                            src: @~str,
-                           +start_pos_ch: CharPos, +start_pos_byte: BytePos)
+                           +start_pos: FilePos)
         -> FileMap {
         return FileMap {
             name: filename, substr: substr, src: src,
-            start_pos: FilePos {ch: start_pos_ch, byte: start_pos_byte},
-            mut lines: ~[FilePos {ch: start_pos_ch, byte: start_pos_byte}]
+            start_pos: start_pos,
+            mut lines: ~[start_pos]
         };
     }
 
     static fn new(+filename: FileName, src: @~str,
-                  +start_pos_ch: CharPos, +start_pos_byte: BytePos)
+                  +start_pos: FilePos)
         -> FileMap {
         return FileMap::new_w_substr(filename, FssNone, src,
-                                     start_pos_ch, start_pos_byte);
+                                     start_pos);
     }
 
     fn next_line(@self, +chpos: CharPos, +byte_pos: BytePos) {
diff --git a/src/libsyntax/parse.rs b/src/libsyntax/parse.rs
index 27338b86bea..fbd67e6ebce 100644
--- a/src/libsyntax/parse.rs
+++ b/src/libsyntax/parse.rs
@@ -20,16 +20,15 @@ use util::interner;
 use diagnostic::{span_handler, mk_span_handler, mk_handler, emitter};
 use lexer::{reader, string_reader};
 use parse::token::{ident_interner, mk_ident_interner};
-use codemap::{CodeMap, FileMap, CharPos, BytePos};
+use codemap::{CodeMap, FileMap, CharPos, BytePos, FilePos};
 
 type parse_sess = @{
     cm: @codemap::CodeMap,
     mut next_id: node_id,
     span_diagnostic: span_handler,
     interner: @ident_interner,
-    // these two must be kept up to date
-    mut chpos: CharPos,
-    mut byte_pos: BytePos
+    // must be kept up to date
+    mut pos: FilePos
 };
 
 fn new_parse_sess(demitter: Option<emitter>) -> parse_sess {
@@ -38,7 +37,10 @@ fn new_parse_sess(demitter: Option<emitter>) -> parse_sess {
              mut next_id: 1,
              span_diagnostic: mk_span_handler(mk_handler(demitter), cm),
              interner: mk_ident_interner(),
-             mut chpos: CharPos(0u), mut byte_pos: BytePos(0u)};
+             mut pos: FilePos {
+                 ch: CharPos(0u),
+                 byte: BytePos(0u)
+             }};
 }
 
 fn new_parse_sess_special_handler(sh: span_handler, cm: @codemap::CodeMap)
@@ -47,7 +49,10 @@ fn new_parse_sess_special_handler(sh: span_handler, cm: @codemap::CodeMap)
              mut next_id: 1,
              span_diagnostic: sh,
              interner: mk_ident_interner(),
-             mut chpos: CharPos(0u), mut byte_pos: BytePos(0u)};
+             mut pos: FilePos {
+                 ch: CharPos(0u),
+                 byte: BytePos(0u)
+             }};
 }
 
 fn parse_crate_from_file(input: &Path, cfg: ast::crate_cfg,
@@ -71,8 +76,7 @@ fn parse_crate_from_crate_file(input: &Path, cfg: ast::crate_cfg,
     let leading_attrs = p.parse_inner_attrs_and_next();
     let { inner: crate_attrs, next: first_cdir_attr } = leading_attrs;
     let cdirs = p.parse_crate_directives(token::EOF, first_cdir_attr);
-    sess.chpos = rdr.chpos;
-    sess.byte_pos = sess.byte_pos + rdr.pos;
+    eval::update_parse_sess_position(&sess, &rdr);
     let cx = @{sess: sess, cfg: /* FIXME (#2543) */ copy p.cfg};
     let companionmod = input.filestem().map(|s| Path(*s));
     let (m, attrs) = eval::eval_crate_directives_to_mod(
@@ -92,8 +96,7 @@ fn parse_crate_from_source_file(input: &Path, cfg: ast::crate_cfg,
     let (p, rdr) = new_parser_etc_from_file(sess, cfg, input,
                                             parser::SOURCE_FILE);
     let r = p.parse_crate_mod(cfg);
-    sess.chpos = rdr.chpos;
-    sess.byte_pos = sess.byte_pos + rdr.pos;
+    eval::update_parse_sess_position(&sess, &rdr);
     return r;
 }
 
@@ -103,8 +106,7 @@ fn parse_crate_from_source_str(name: ~str, source: @~str, cfg: ast::crate_cfg,
                                                   codemap::FssNone, source);
     let r = p.parse_crate_mod(cfg);
     p.abort_if_errors();
-    sess.chpos = rdr.chpos;
-    sess.byte_pos = sess.byte_pos + rdr.pos;
+    eval::update_parse_sess_position(&sess, &rdr);
     return r;
 }
 
@@ -114,8 +116,7 @@ fn parse_expr_from_source_str(name: ~str, source: @~str, cfg: ast::crate_cfg,
                                                   codemap::FssNone, source);
     let r = p.parse_expr();
     p.abort_if_errors();
-    sess.chpos = rdr.chpos;
-    sess.byte_pos = sess.byte_pos + rdr.pos;
+    eval::update_parse_sess_position(&sess, &rdr);
     return r;
 }
 
@@ -126,8 +127,7 @@ fn parse_item_from_source_str(name: ~str, source: @~str, cfg: ast::crate_cfg,
                                                   codemap::FssNone, source);
     let r = p.parse_item(attrs);
     p.abort_if_errors();
-    sess.chpos = rdr.chpos;
-    sess.byte_pos = sess.byte_pos + rdr.pos;
+    eval::update_parse_sess_position(&sess, &rdr);
     return r;
 }
 
@@ -138,8 +138,7 @@ fn parse_stmt_from_source_str(name: ~str, source: @~str, cfg: ast::crate_cfg,
                                                   codemap::FssNone, source);
     let r = p.parse_stmt(attrs);
     p.abort_if_errors();
-    sess.chpos = rdr.chpos;
-    sess.byte_pos = sess.byte_pos + rdr.pos;
+    eval::update_parse_sess_position(&sess, &rdr);
     return r;
 }
 
@@ -156,8 +155,7 @@ fn parse_from_source_str<T>(f: fn (p: Parser) -> T,
         p.reader.fatal(~"expected end-of-string");
     }
     p.abort_if_errors();
-    sess.chpos = rdr.chpos;
-    sess.byte_pos = sess.byte_pos + rdr.pos;
+    eval::update_parse_sess_position(&sess, &rdr);
     move r
 }
 
@@ -174,7 +172,7 @@ fn new_parser_etc_from_source_str(sess: parse_sess, cfg: ast::crate_cfg,
                                   source: @~str) -> (Parser, string_reader) {
     let ftype = parser::SOURCE_FILE;
     let filemap = @FileMap::new_w_substr
-        (name, ss, source, sess.chpos, sess.byte_pos);
+        (name, ss, source, sess.pos);
     sess.cm.files.push(filemap);
     let srdr = lexer::new_string_reader(sess.span_diagnostic, filemap,
                                         sess.interner);
@@ -199,7 +197,7 @@ fn new_parser_etc_from_file(sess: parse_sess, cfg: ast::crate_cfg,
     }
     let src = @result::unwrap(res);
     let filemap = @FileMap::new(path.to_str(), src,
-                                sess.chpos, sess.byte_pos);
+                                sess.pos);
     sess.cm.files.push(filemap);
     let srdr = lexer::new_string_reader(sess.span_diagnostic, filemap,
                                         sess.interner);
diff --git a/src/libsyntax/parse/comments.rs b/src/libsyntax/parse/comments.rs
index 06b042a468a..ba36e6f88e2 100644
--- a/src/libsyntax/parse/comments.rs
+++ b/src/libsyntax/parse/comments.rs
@@ -292,9 +292,13 @@ fn gather_comments_and_literals(span_diagnostic: diagnostic::span_handler,
    {cmnts: ~[cmnt], lits: ~[lit]} {
     let src = @str::from_bytes(srdr.read_whole_stream());
     let itr = parse::token::mk_fake_ident_interner();
-    let rdr = lexer::new_low_level_string_reader
-        (span_diagnostic, @FileMap::new(path, src,
-                                        CharPos(0u), BytePos(0u)), itr);
+    let filemap = @FileMap::new(path, src,
+                                FilePos {
+                                    ch: CharPos(0u),
+                                    byte: BytePos(0u)
+                                });
+    let rdr = lexer::new_low_level_string_reader(
+        span_diagnostic, filemap, itr);
 
     let mut comments: ~[cmnt] = ~[];
     let mut literals: ~[lit] = ~[];
diff --git a/src/libsyntax/parse/eval.rs b/src/libsyntax/parse/eval.rs
index 56c9d4de9f3..bfbec5c530f 100644
--- a/src/libsyntax/parse/eval.rs
+++ b/src/libsyntax/parse/eval.rs
@@ -2,6 +2,7 @@ use parser::{Parser, SOURCE_FILE};
 use attr::parser_attr;
 
 export eval_crate_directives_to_mod;
+export update_parse_sess_position;
 
 type ctx =
     @{sess: parse::parse_sess,
@@ -66,14 +67,20 @@ fn parse_companion_mod(cx: ctx, prefix: &Path, suffix: &Option<Path>)
                                                 modpath, SOURCE_FILE);
         let inner_attrs = p0.parse_inner_attrs_and_next();
         let m0 = p0.parse_mod_items(token::EOF, inner_attrs.next);
-        cx.sess.chpos = r0.chpos;
-        cx.sess.byte_pos = cx.sess.byte_pos + r0.pos;
+        update_parse_sess_position(&cx.sess, &r0);
         return (m0.view_items, m0.items, inner_attrs.inner);
     } else {
         return (~[], ~[], ~[]);
     }
 }
 
+fn update_parse_sess_position(sess: &parse_sess, r: &lexer::string_reader) {
+    sess.pos = FilePos {
+        ch: r.chpos,
+        byte: sess.pos.byte + r.pos
+    };
+}
+
 fn cdir_path_opt(default: ~str, attrs: ~[ast::attribute]) -> ~str {
     match ::attr::first_attr_value_str_by_name(attrs, ~"path") {
       Some(d) => d,
@@ -105,8 +112,7 @@ fn eval_crate_directive(cx: ctx, cdir: @ast::crate_directive, prefix: &Path,
                            /* FIXME (#2543) */ copy id,
                            ast::item_mod(m0), vis, mod_attrs);
         // Thread defids, chpos and byte_pos through the parsers
-        cx.sess.chpos = r0.chpos;
-        cx.sess.byte_pos = cx.sess.byte_pos + r0.pos;
+        update_parse_sess_position(&cx.sess, &r0);
         items.push(i);
       }
       ast::cdir_dir_mod(vis, id, cdirs, attrs) => {