Penny.Steel.Expressions.RPN

Postfix, or RPN, expression parsing.

This module parses RPN expressions where the operands are predicates and the operators are one of and, or, or not, where and and or are binary and not is unary.

Documentation

type Error = Text

data RPNToken a

Constructors

TokOperand (Pdct a)

TokOperator Operator

data Operator

Constructors

OpAnd

OpOr

OpNot

Instances

Show Operator

pushOperand :: Pdct a -> [Pdct a] -> [Pdct a]

pushOperator :: Operator -> [Pdct a] -> Exceptional Error [Pdct a]

pushToken :: [Pdct a] -> RPNToken a -> Exceptional Error [Pdct a]

pushTokens :: Foldable f => f (RPNToken a) -> Exceptional Error (Pdct a)