prednote-0.14.0.0: Build and evaluate trees of predicates

Safe Haskell	None

Data.Prednote.Expressions

Description

Handles parsing of both infix and RPN Pdct expressions.

Synopsis

Documentation

data ExprDesc Source

Is this an infix or RPN expression?

Constructors

Infix
RPN

Instances

Eq ExprDesc
Show ExprDesc

type Error = Text Source

data Token a Source

A single type for both RPN tokens and infix tokens.

operand :: Pdct a -> Token aSource

Creates Operands from Pdct.

opAnd :: Token aSource

The And operator

opOr :: Token aSource

The Or operator

opNot :: Token aSource

The Not operator

openParen :: Token aSource

Open parentheses

closeParen :: Token aSource

Close parentheses

parseExpression :: ExprDesc -> [Token a] -> Exceptional Error (Pdct a)Source

Parses expressions. Fails if the expression is nonsensical in some way (for example, unbalanced parentheses, parentheses in an RPN expression, or multiple stack values remaining.) Works by first changing infix expressions to RPN ones.