Range expression parsing

1 files changed, 74 insertions, 0 deletions

diff --git a/src/Expression.hs b/src/Expression.hs
index 6b1adc9..95ba815 100644
--- a/src/Expression.hs
+++ b/src/Expression.hs
@@ -9,14 +9,28 @@ module Expression (
     evaluateDeclaredRevision, evaluateDeclaredRange,
     evaluateRevision, evaluateRange,
     getRangeCommits, getAddedRangeCommits,
+
+    isRangeExpressionDynamic,
+    isRevisionExpressionDynamic,
+
+    parseRangeExpression,
 ) where
 
 import Control.Concurrent.STM
 import Control.Monad.IO.Class
 
+import Data.Bifunctor
+import Data.Char
 import Data.Kind
+import Data.List.NonEmpty qualified as NE
 import Data.Maybe
+import Data.Proxy
 import Data.Text (Text)
+import Data.Text qualified as T
+import Data.Void
+
+import Text.Megaparsec
+import Text.Megaparsec.Char
 
 import Job.Types
 import Output
@@ -112,3 +126,63 @@ getAddedRangeCommits repo (CommitRange ar br) (CommitRange ar' br') = do
     (++)
         <$> listCommitsFrom repo a'b (catMaybes [ b' ]) -- added by moving B to B'
         <*> listCommitsFrom repo (catMaybes [ a' ]) (catMaybes [ a, b, b' ]) -- added by moving A to A'
+
+
+isRangeExpressionDynamic :: RangeExpression -> Bool
+isRangeExpressionDynamic = \case
+    RangeExpression x y -> isRevisionExpressionDynamic x || isRevisionExpressionDynamic y
+
+isRevisionExpressionDynamic :: RevisionExpression -> Bool
+isRevisionExpressionDynamic = \case
+    StaticRef _ -> False
+    WatchedRef _ -> True
+    ModifiedRevision _ e -> isRevisionExpressionDynamic e
+
+
+type ExprParser = Parsec Void Text
+
+parseRangeExpression :: Text -> Either String DeclaredRangeExpression
+parseRangeExpression = bimap errorBundlePretty id . runParser parser ""
+  where
+    parser :: ExprParser DeclaredRangeExpression
+    parser = do
+        rev1 <- parseRevision
+        expr <- choice
+          [ do
+              _ <- string ".."
+              rev2 <- parseRevision
+              return $ RangeExpression rev2 rev1
+          , do
+              return $ RangeExpression rev1 (ModifiedRevision "^" rev1)
+          ]
+
+        (char ':' >> eof) <|> eof
+        return expr
+
+    parseRevision :: ExprParser DeclaredRevisionExpression
+    parseRevision = do
+        tok <- fmap T.concat $ some $ choice
+            [ takeWhile1P Nothing (\x -> isAlphaNum x || x `elem` [ '_', '-', '/' ])
+            , try $ string "." <* notFollowedBy (char '.')
+            ]
+
+        rev <- choice
+            [ do
+                _ <- char '('
+                arg <- takeWhileP Nothing (\x -> isAlphaNum x || x `elem` [ '_', '-', '/', '.' ])
+                _ <- char ')'
+                case tok of
+                    "watch" -> return $ WatchedRef arg
+                    _ -> unexpected $ Tokens $ NE.fromList $ chunkToTokens @Text Proxy tok
+
+            , do
+                return $ StaticRef tok
+            ]
+
+        choice
+            [ do
+                suffix <- takeWhile1P Nothing (\x -> isNumber x || x `elem` [ '~', '^', '@', '{', '}' ])
+                return $ ModifiedRevision suffix rev
+            , do
+                return rev
+            ]