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mirror of https://github.com/github/semantic.git synced 2024-12-26 16:33:03 +03:00
semantic/semantic-python/test/Directive.hs
2019-10-21 14:09:20 -04:00

76 lines
2.5 KiB
Haskell

module Directive ( Directive (..)
, parseDirective
, describe
, toProcess
) where
import Control.Applicative
import Control.Monad
import Core.Core (Core)
import qualified Core.Parser
import qualified Core.Pretty
import Core.Name (Name)
import Data.ByteString.Char8 (ByteString)
import qualified Data.ByteString.Char8 as ByteString
import Syntax.Term (Term)
import System.Process
import qualified Text.Trifecta as Trifecta
{- |
Directives are parsed from magic comments in test files and
describe to the test suite how to query the results of a given test
case. A directive that looks like this:
@
# CHECK-JQ: has("mach")
@
would, after converting the contents of the file to a Core expression,
dump that expression to JSON and pipe said JSON to @jq -e
'has("mach")@, which will return an error code unless the passed JSON
is a hash containing the @"mach"@ key.
This syntax was inspired by LLVM's
[FileCheck](https://llvm.org/docs/CommandGuide/FileCheck.html). This
approach is less direct than tests that pattern-match over an AST, but
enable us to keep the text of test cases in close proximity to the
assertions we want to make, which improves maintainability
significantly and has been a successful strategy for the LLVM and Rust
projects.
-}
data Directive = JQ ByteString -- | @# CHECK-JQ: expr@
| Tree (Term Core Name) -- | @# CHECK-TREE: core@
| Fails -- | @# CHECK-FAILS@ fails unless translation fails.
deriving (Eq, Show)
describe :: Directive -> String
describe Fails = "<expect failure>"
describe (Tree t) = Core.Pretty.showCore t
describe (JQ b) = ByteString.unpack b
fails :: Trifecta.Parser Directive
fails = Fails <$ Trifecta.string "# CHECK-FAILS"
jq :: Trifecta.Parser Directive
jq = do
void $ Trifecta.string "# CHECK-JQ: "
JQ . ByteString.pack <$> many (Trifecta.noneOf "\n")
tree :: Trifecta.Parser Directive
tree = do
void $ Trifecta.string "# CHECK-TREE: "
Tree <$> Core.Parser.core
directive :: Trifecta.Parser Directive
directive = Trifecta.choice [ fails, jq, tree ]
parseDirective :: ByteString -> Either String Directive
parseDirective = Trifecta.foldResult (Left . show) Right
. Trifecta.parseByteString (directive <* Trifecta.eof) mempty
toProcess :: Directive -> CreateProcess
toProcess (JQ d) = proc "jq" ["-e", ByteString.unpack d]
toProcess x = error ("can't call toProcess on " <> show x)