Base.hs

module Calculator.Evaluator.Base (evaluate, evalTest) where

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import           Calculator.Evaluator.Statement (evalStat)
import           Calculator.Parser.Statement    (parseStat)
import           Calculator.Prim.Bindings       (Bindings, mkBind)
import           Calculator.Prim.Result         (Result (..))

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import           Control.Applicative            ((<*))
import           Text.ParserCombinators.Parsec  (eof, parse, spaces)

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evaluate :: Bindings -> String -> Result
evaluate b i = case parse (spaces >> parseStat <* spaces <* eof) "Statement" i of
                 Left e  -> Error . show $ e
                 Right s -> evalStat b s

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evalTest :: String -> String
evalTest s = case evaluate (mkBind [] []) s of
               Value n -> show n
               _       -> ""

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