Travis.Meta

High level

preprocessIO :: FilePath -> FilePath -> IO ()

preprocess :: ByteString -> Either String ByteString

preprocessYaml :: Value -> Either String Value

Internal

type Env = [(Text, Text)]

parseEnv :: Text -> Either String Env

Parse environment string.

>>> parseEnv "CABALVER=1.18 GHCVER=7.8.4"
Right [("CABALVER","1.18"),("GHCVER","7.8.4")]

interpolateEnv :: Env -> Text -> Either String Text

Interpolate env. Substitute all $VAR occurrences with values from Env. If variable is not in the environment, return Nothing.

>>> interpolateEnv [("FOO", "foo")] "res-$FOO-bar"
Just "res-foo-bar"

>>> interpolateEnv [("FOO","foo")] "yes-$FOOBAR-$FOO"
Nothing