Safe Haskell	Safe-Inferred
Language	Haskell2010

Math.Haskellator.Internal.Expr

Description

Models an expression tree

Examples:

>>> show $ BinOp (Val $ Value 1.0 $ meter 1) Plus (BinOp (Val $ Value 2 $ multiplier 1) Mult (Val $ Value 3.0 $ meter 1))
"(1.0 m + (2.0 * 3.0 m))"

>>> show $ BinOp (BinOp (Val $ Value 1.0 $ meter 1) Plus (Val $ Value 2.0 $ meter 1)) Mult (Val $ Value 3.0 $ multiplier 1)
"((1.0 m + 2.0 m) * 3.0)"

Synopsis

type AstFold a b = ExceptT Error (State (Stack (Map String (Thunk a)))) b
type AstValue = Value Dimension
type Bindings a = [(String, a)]
data Expr
- = Val AstValue
- | BinOp Expr Op Expr
- | UnaryOp Op Expr
- | Conversion Expr Dimension
- | VarBindings (Bindings Expr) Expr
- | Var String
type SimpleAstFold a = AstFold a a
data Thunk a
- = Expr Expr
- | Result a
data Value u = Value {
- value :: Double
- unit :: u
}
bindVar :: String -> Thunk a -> AstFold a ()
bindVars :: Bindings (Thunk a) -> AstFold a ()
foldExpr :: (AstValue -> a) -> (a -> Op -> a -> a) -> (Op -> a -> a) -> (a -> Dimension -> a) -> (Bindings a -> a -> a) -> (String -> a) -> Expr -> a
getVarBinding :: String -> AstFold a (Thunk a)
partiallyFoldExprM :: (AstValue -> SimpleAstFold a) -> (a -> Op -> a -> SimpleAstFold a) -> (Op -> a -> SimpleAstFold a) -> (a -> Dimension -> SimpleAstFold a) -> (Bindings Expr -> Expr -> SimpleAstFold a) -> (String -> SimpleAstFold a) -> Expr -> SimpleAstFold a
runAstFold :: SimpleAstFold a -> Either Error a
runInNewScope :: SimpleAstFold a -> SimpleAstFold a

Documentation

type AstFold a b = ExceptT Error (State (Stack (Map String (Thunk a)))) b Source #

Encapsulates the result b of folding an expression tree and holds the current state of variable bindings to values of type a

type AstValue = Value Dimension Source #

The specific Value type used in the expression tree

type Bindings a = [(String, a)] Source #

A list of variable bindings, mapping a name to an arbitrary value

data Expr Source #

The expression tree

Constructors

Val AstValue	a literal value
BinOp Expr Op Expr	a binary expression (like +, -, *, /, ^)
UnaryOp Op Expr	a unary expression (like -)
Conversion Expr Dimension	a conversion (1m [km]). If present, this node is the root of the tree.
VarBindings (Bindings Expr) Expr	a variable binding expression
Var String

Instances

Instances details

Show Expr Source #
Instance details Defined in Math.Haskellator.Internal.Expr Methods showsPrec :: Int -> Expr -> ShowS # show :: Expr -> String # showList :: [Expr] -> ShowS #
Eq Expr Source #
Instance details Defined in Math.Haskellator.Internal.Expr Methods (==) :: Expr -> Expr -> Bool # (/=) :: Expr -> Expr -> Bool #

type SimpleAstFold a = AstFold a a Source #

Simplified version of AstFold that returns the same type as it binds to variables

data Thunk a Source #

A Value wrapped in a Thunk to allow for lazy evaluation

Constructors

Expr Expr	The unevaluated expression
Result a

data Value u Source #

A simple representation of a value with a unit. The unit's type is parameterized, since the unit can be a simple Unit or a Dimension.

Constructors

Value
Fields value :: Double unit :: u

Instances

Instances details

Show u => Show (Value u) Source #
Instance details Defined in Math.Haskellator.Internal.TH.UnitGeneration Methods showsPrec :: Int -> Value u -> ShowS # show :: Value u -> String # showList :: [Value u] -> ShowS #

bindVar :: String -> Thunk a -> AstFold a () Source #

Binds a Thunk to a variable name

bindVars :: Bindings (Thunk a) -> AstFold a () Source #

Binds multiple variable names

foldExpr Source #

Arguments

:: (AstValue -> a)	function that folds a value
-> (a -> Op -> a -> a)	function that folds a binary expression
-> (Op -> a -> a)	function that folds a unary expression
-> (a -> Dimension -> a)	function that folds a conversion expression
-> (Bindings a -> a -> a)	function that folds variable bindings
-> (String -> a)	function that folds a variable
-> Expr	the `Expr` to fold over
-> a	the resulting value

Folds an expression tree

getVarBinding Source #

Arguments

:: String	the variable name
-> AstFold a (Thunk a)	the `Thunk` bound to the variable

Retrieves the Thunk bound to a variable name

partiallyFoldExprM :: (AstValue -> SimpleAstFold a) -> (a -> Op -> a -> SimpleAstFold a) -> (Op -> a -> SimpleAstFold a) -> (a -> Dimension -> SimpleAstFold a) -> (Bindings Expr -> Expr -> SimpleAstFold a) -> (String -> SimpleAstFold a) -> Expr -> SimpleAstFold a Source #

Like foldExpr, but does not fold into variable bindings and returns a monadic result

runAstFold Source #

Arguments

:: SimpleAstFold a	the computation to run
-> Either Error a	the computation's result or an error

Runs an SimpleAstFold computation

runInNewScope Source #

Arguments

:: SimpleAstFold a	the computation to run
-> SimpleAstFold a	the computation's result

Evaluates a SimpleAstFold inside a new (and empty) scope