INF564 - TD 4 - Static Typing of mini-C (in OCaml)

The goal of this lab is to implement the static typing of mini-C.

Typing rules are given in the project assignment.

Provided Code

The parser is already implemented: parser-ocaml.tar.gz

It is important to read and understand the abstract syntax of mini-C, that is files Ptree.mli (parsed trees) and Ttree.mli (typed trees).

A Makefile is provided, which calls dune. The executable is minic.exe. It expects a file with extension .c on the command line, possibly with options --debug, --parse-only, and --type-only.

If a lexical or syntax error is detected, it is reported and the program exits with code 1.

If the parsing is successful and option --parse-only is on the command line, then the program exits with code 0.

Lab Assignment

Implement the type checking in file typing.ml, as a function program that takes a Ptree.file as input and returns a Ttree.file.

If a type error is detected, it is signaled using exception Error defined in typing.ml, with a suitable message string. This exception is caught in main.ml and displayed as

     error: ... your message here ...

and the program exits with code 1.

Indications

It is strongly advised to proceed step by step, with systematic testing. As a first goal, consider a C program as simple as

int main() { return 0; }

This means you only have to consider integer literals in expressions and return statements.

In the provided tarball, the command make compiles minic.exe and then runs it on file test.c (also provided). So you simply have to modify test.c as you make progress.

Tests

Some tests are provided: tests-v1.tar.gz. This archive contains

C files organized in various categories:

  syntax/bad/    rejected at parsing
  syntax/good/   accepted at parsing
  typing/bad/    rejected at type checking
  typing/good/   accepted at type checking
  exec-fail/     compiled successfully, with a failed execution
  exec/          compiled successfully, and run successfully with
                 the expected output (file .out)

a script run to run your compiler on these files. This script expects option -2 (for this lab) and the name of your compiler. You should get the following:

> ./run -2 my/path/to/minic.exe
Test de mon/chemin/vers/minic.exe

Partie 2
mauvais ...........................
bons .................................................................
Typage  : 92/92 : 100%

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