Translating a MOOL program

The last step in writing a MOOL compiler is the translation to a C program. Observe that the translation of at least the following MOOL constructs is trivial, since they are very similar in C:

• ArithmeticExpression ,
• BooleanExpression,
• Alternative,
• WhileLoop,
• MethodCall.

The only non trivial translations will be those of the following MOOL constructs.

ClassDeclaration

which will be replaced by a struct and one function per NewDeclaration or MethodDeclaration.

NewDeclaration

which will have a returned type in C (i.e. the suitable struct)

MethodDeclaration

which will have the return type int.

Assignment

for which we need to say how we manage objects. A possible and reasonable solution is to use a pointer to a struct.

We give some precisions for the translation of assignments. Let us consider a checked assignment

LeftValue := RightValue

In the translated C code the LeftValue will be

• a variable of type int if LeftValue is an id and RightValue has type int
• a field of a strcut if LeftValue is an AttributeCall
• a pointer to a strcut if LeftValue is an id and RightValue refers to an object.

In the latter case, the assignment means simply that the object referred by RightValue is pointed to by the id of LeftValue. Hence this is just a pointer assignment, no new object is created.