module LoadEnv.Parse
( Environment
, Variable
, parseEnvironment
, parseVariable
) where
import Control.Monad (void)
import Data.Maybe (catMaybes)
import Text.Parsec
import Text.Parsec.String
type Environment = [Variable]
type Variable = (String, String)
parseEnvironment :: Parser Environment
parseEnvironment = catMaybes <$> many parseLine
parseLine :: Parser (Maybe Variable)
parseLine = possibly parseVariable
possibly :: Parser a -> Parser (Maybe a)
possibly p = try (Just <$> p) <|> ignored
where
ignored = Nothing <$ manyTill anyToken newline
parseVariable :: Parser Variable
parseVariable = do
optional $ between spaces spaces $ string "export"
i <- identifier
v <- char '=' *> value
void $ many $ oneOf " \t"
void newline
pure (i, v)
identifier :: Parser String
identifier = do
x <- upper <|> underscore
ys <- many $ upper <|> digit <|> underscore
pure (x:ys)
where
underscore = char '_'
value :: Parser String
value = quotedValue <|> unquotedValue <|> pure ""
quotedValue :: Parser String
quotedValue = do
q <- oneOf "'\""
manyTill (try (escaped q) <|> anyToken) (char q)
unquotedValue :: Parser String
unquotedValue = many1 $ try (escaped ' ') <|> noneOf "\"' \n"
escaped :: Char -> Parser Char
escaped c = c <$ string ("\\" ++ [c])