Typing of > >= < <=
Evaluation of >. Praparation of >+, < and <= for Ludovic to complete.
Result of typing now written at output.
Typing of == and !=
Typing of the unary operator : "-".
Evaluation of the unary operator "-".
Evaluation of == and != for non-reference types.
Evaluation of expression sequences.
Evaluation of If and preparation of the evaluation of the others expressions.