more defined fromRows/fromColumns/fromBlocks

1 files changed, 7 insertions, 1 deletions

diff --git a/lib/Data/Packed/Internal/Common.hs b/lib/Data/Packed/Internal/Common.hs
index 629016d..972cd7d 100644
--- a/lib/Data/Packed/Internal/Common.hs
+++ b/lib/Data/Packed/Internal/Common.hs
@@ -18,7 +18,7 @@ module Data.Packed.Internal.Common(
   Adapt,
   app1, app2, app3, app4,
   (//), check,
-  partit, common,
+  partit, common, compatdim,
   fi
 ) where
 
@@ -41,6 +41,12 @@ common f = commonval . map f where
     commonval [a] = Just a
     commonval (a:b:xs) = if a==b then commonval (b:xs) else Nothing
 
+-- | common value with \"adaptable\" 1
+compatdim :: [Int] -> Maybe Int
+compatdim [] = Nothing
+compatdim [a] = Just a
+compatdim (a:b:xs) = if a==b || a==1 || b==1 then compatdim (max a b:xs) else Nothing
+
 -- | postfix function application (@flip ($)@)
 (//) :: x -> (x -> y) -> y
 infixl 0 //