Despite the interesting discussing which has followed this question I think that in orde to approach this specific problem the use of a specific compiler-writers toolset such as the uuagc (http://hackage.haskell.org/package/uuagc-0.9.29)) system is to be preferred; it provides aneffiicent and modular way of constructing sch complicated compositions. The complete Utrecht haskell compiler is constructed in this way. Doaitse 1) If you are brave hearted you may try to use the http://hackage.haskell.org/package/AspectAG road ;-} 2) If you are interested in an (albeit old) Tiger compiler built using uuagc see: http://hackage.haskell.org/package/tiger On 19 jul 2010, at 18:51, José Romildo Malaquias wrote:
Hello.
In his book "Modern Compilder Implementation in ML", Appel presents a compiler project for the Tiger programming language where type checking and intermediate code generation are intrinsically coupled.
There is a function
transExp :: Absyn.Exp -> (Tree.Exp,Types.Type)
that do semantic analysis, translating an expression to the Tree intermediate representation language and also do type checking, calculating the type of the expression.
Maybe the compiler can be made more didatic if these phases are separate phases of compilation.
The type checker would annotate the abstract syntax tree (ast) with type annotations, that could be used later by the translater to intermediate representation.
In an imperative language probably each relevant ast node would have a field for the type annotation, and the type checker would assign the type of the node to this field after computing it.
I am writing here to ask suggestions on how to annotate an ast with types (or any other information that would be relevant in a compiler phase) in Haskell.
As an example, consider the simplified ast types:
data Exp = IntExp Integer | VarExp Symbol | AssignExp Symbol Exp | IfExp Exp Exp (Maybe Exp) | CallExp Symbol [Exp] | LetExp [Dec] Exp
data Dec = TypeDec Symbol Ty | FunctionDec Symbol [(Symbol,Symbol)] (Mybe Symbol) Exp | VarDec Symbol (Maybe Symbol) Exp
Expressions can have type annotations, but declarations can not.
Comments?
Regards,
Romildo -- Computer Science Department Universidade Federal de Ouro Preto, Brasil _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe