4.3.4 TC-1 Code to Write

Be sure to read Flex and Bison documentations and tutorials, see Flex & Bison.

configure.ac

Makefile.am

Include your own test suite in the tests directory, and hook it to make check.

src/parse/scantiger.ll

The scanner must be completed to read strings, identifiers etc. and track locations.

• − Strings will be stored as C++ std::string. See the following code for the basics.

  …
  \"          grown_string.clear(); BEGIN SC_STRING;
  
  <SC_STRING>{ /* Handling of the strings.  Initial " is eaten. */
       \" {
         BEGIN INITIAL;
         return TOKEN_VAL(STRING, grown_string);
       }
  …
       \\x[0-9a-fA-F]{2}  {
         grown_string.append(1, strtol(yytext + 2, 0, 16));
       }
  …
  }
  

• − Symbols (i.e., identifiers) must be returned as misc::symbol objects, not strings.
• − The locations are tracked. The class Location to use is produced by Bison: src/parse/location.hh.

  To track of locations, adjust your scanner, use YY_USER_ACTION and the yylex prologue:

  ...
  %%
  %{
    // Everything here is run each time yylex is invoked.
  %}
  "if"    return TOKEN(IF);
  ...
  %%
  ...
  

  See the lecture notes, and read the C++ chapter of http://www.gnu.org/software/bison/manual/bison.html, GNU Bison’s documentation. Note that the version being used for the Tiger project may differ from the latest public release, thus students should build their own documentation by running ‘make html’ in the provided Bison tarball.

  Pay special attention to its “Complete C++ Example” which is very much like our set up.

src/parse/parsetiger.yy

• − The grammar must be complete but without actions.
• − Use %printer to implement --parse-trace support for terminals (see TC-1 Samples)

src/parse/tiger-parser.cc

The class TigerParser drives the lexing and parsing of input file. Its implementation in src/parse/tiger-parser.cc is incomplete.

lib/misc/symbol.*

lib/misc/unique.*

The class misc::symbol keeps a single copy of identifiers, see lib/misc. Its implementation in lib/misc/symbol.hxx and lib/misc/symbol.cc is incomplete. Note that running ‘make check’ in lib/misc exercises lib/misc/test-symbol.cc: having this unit test pass should be a goal by itself. As a matter of fact, unit tests were left to help you: once they pass successfully you may proceed to the rest of the compiler. misc::symbol’s implementation is based on misc::unique, a generic class implementing the Flyweight design pattern. The definition of this class, lib/misc/unique.hxx, is also to be completed.

lib/misc/variant.*

The implementation of the class template misc::variant<T0, Ts...> lacks a couple of conversion operators that you have to supply.