Simplify lexer/parser structure to use stdio_reader.

src/comp/fe/parser.rs

@@ -1,3 +1,25 @@
+import std._io;
+
+state type parser =
+    state obj {
+          state fn peek() -> token.token;
+          state fn bump();
+    };
+
+fn new_parser(str path) -> parser {
+    state obj stdio_parser(mutable token.token tok,
+                           _io.stdio_reader rdr)
+        {
+            state fn peek() -> token.token {
+                ret tok;
+            }
+            state fn bump() {
+                tok = lexer.next_token(rdr);
+            }
+        }
+    auto rdr = _io.new_stdio_reader(path);
+    ret stdio_parser(lexer.next_token(rdr), rdr);
+}
 
 //
 // Local Variables: