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------------------------------------------------------------------------------ --- This library contains a definition for representing Haskell programs --- in Curry (type "Prog"). --- --- @author Michael Hanus, Björn Peemöller --- @version May 2017 ------------------------------------------------------------------------------ module AbstractHaskell.Types where ------------------------------------------------------------------------------ -- Definition of data types for representing abstract Haskell programs: -- ==================================================================== --- Data type for representing a Haskell module in the intermediate form. --- A value of this data type has the form --- --- (CProg modname imports typedecls functions opdecls) --- --- where modname: name of this module, --- imports: list of modules names that are imported, --- typedecls, opdecls, functions: see below data Prog = Prog String [String] [TypeDecl] [FuncDecl] [OpDecl] deriving Show --- The data type for representing qualified names. --- In AbstractHaskell all names are qualified to avoid name clashes. --- The first component is the module name and the second component the --- unqualified name as it occurs in the source program. type QName = (String, String) --- Data type to specify the visibility of various entities. data Visibility = Public -- exported entity | Private -- private entity deriving (Eq,Show) --- The data type for representing type variables. --- They are represented by (i,n) where i is a type variable index --- which is unique inside a function and n is a name (if possible, --- the name written in the source program). type TVarIName = (Int, String) --- Data type for representing definitions of algebraic data types --- and type synonyms. --- --- A data type definition of the form --- --- data t x1...xn = ...| c t1....tkc |... --- --- is represented by the Curry term --- --- (Type t v [i1,...,in] [...(ons c kc v [t1,...,tkc])...]) --- --- where each `ij` is the index of the type variable `xj`. --- --- Note: the type variable indices are unique inside each type declaration --- and are usually numbered from 0 --- --- Thus, a data type declaration consists of the name of the data type, --- a list of type parameters and a list of constructor declarations. data TypeDecl = Type QName Visibility [TVarIName] [ConsDecl] | TypeSyn QName Visibility [TVarIName] TypeExpr | Instance QName TypeExpr [Context] [(QName, Rule)] deriving Show --- A single type context is class name applied to type variables. data Context = Context QName [TypeExpr] deriving (Eq,Show) --- A constructor declaration consists of the name and arity of the --- constructor and a list of the argument types of the constructor. data ConsDecl = Cons QName Int Visibility [TypeExpr] deriving Show --- Data type for type expressions. --- A type expression is either a type variable, a function type, --- or a type constructor application. --- --- Note: the names of the predefined type constructors are --- "Int", "Float", "Bool", "Char", "IO", --- "()" (unit type), "(,...,)" (tuple types), "[]" (list type) data TypeExpr = TVar TVarIName -- type variable | FuncType TypeExpr TypeExpr -- function type t1->t2 | TCons QName [TypeExpr] -- type constructor application -- (TCons (module,name) arguments) | ForallType [TVarIName] [Context] TypeExpr -- explicitly quantified type expression deriving (Eq,Show) --- Data type to represent the type signature of a defined function. --- The type can be missing or a type with an optional context. data TypeSig = Untyped | CType [Context] TypeExpr deriving Show --- Data type for operator declarations. --- An operator declaration "fix p n" in Haskell corresponds to the --- AbstractHaskell term (Op n fix p). data OpDecl = Op QName Fixity Int deriving Show data Fixity = InfixOp -- non-associative infix operator | InfixlOp -- left-associative infix operator | InfixrOp -- right-associative infix operator deriving Show --- Data types for representing object variables. --- Object variables occurring in expressions are represented by (Var i) --- where i is a variable index. type VarIName = (Int, String) --- Data type for representing function declarations. --- --- A function declaration in AbstractHaskell is a term of the form --- --- (Func cmt name arity visibility type (Rules eval [Rule rule1,...,rulek])) --- --- and represents the function `name` defined by the rules `rule1,...,rulek`. --- --- Note: the variable indices are unique inside each rule --- --- External functions are represented as --- --- (Func cmt name arity type External) --- --- Thus, a function declaration consists of the comment, name, arity, type, --- and a list of rules. The type is optional according to its occurrence in --- the source text. The comment could be used --- by pretty printers that generate a readable Haskell program --- containing documentation comments. data FuncDecl = Func String QName Int Visibility TypeSig Rules deriving Show --- Rules are either a list of single rules or no rule at all --- if then function is defined externally. data Rules = Rules [Rule] | External deriving Show --- The most general form of a rule. It consists of a list of patterns --- (left-hand side), a list of guards ("True" if not present in the --- source text) with their corresponding right-hand sides, and --- a list of local declarations. data Rule = Rule [Pattern] Rhs [LocalDecl] deriving Show data Rhs = SimpleRhs Expr | GuardedRhs [(Expr, Expr)] deriving Show --- Data type for representing local (let/where) declarations data LocalDecl = LocalFunc FuncDecl -- local function declaration | LocalPat Pattern Expr [LocalDecl] -- local pattern declaration deriving Show --- Data type for representing Haskell expressions. data Expr = Var VarIName -- variable (unique index / name) | Lit Literal -- literal (Integer/Float/Char constant) | Symbol QName -- a defined symbol with module and name | Apply Expr Expr -- application (e1 e2) | InfixApply Expr QName Expr -- infix application | Lambda [Pattern] Expr -- lambda abstraction | Let [LocalDecl] Expr -- local let declarations | DoExpr [Statement] -- do expression | ListComp Expr [Statement] -- list comprehension | Case Expr [BranchExpr] -- case expression | Typed Expr TypeExpr -- typed expression | IfThenElse Expr Expr Expr -- if-then-else expression | Tuple [Expr] | List [Expr] deriving Show --- Data type for representing statements in do expressions and --- list comprehensions. data Statement = SExpr Expr -- an expression (I/O action or boolean) | SPat Pattern Expr -- a pattern definition | SLet [LocalDecl] -- a local let declaration deriving Show --- Data type for representing pattern expressions. data Pattern = PVar VarIName -- pattern variable (unique index / name) | PLit Literal -- literal (Integer/Float/Char constant) | PComb QName [Pattern] -- application (m.c e1 ... en) of n-ary -- constructor m.c (PComb (m,c) [e1,...,en]) | PAs VarIName Pattern -- as-pattern | PTuple [Pattern] | PList [Pattern] deriving Show --- Data type for representing branches in case expressions. data BranchExpr = Branch Pattern Expr deriving Show --- Data type for representing literals occurring in an expression. --- It is either an integer, a float, a character, or a string constant. data Literal = Intc Int | Floatc Float | Charc Char | Stringc String deriving Show |