salmon-core-0.1.0.0: src/Salmon/Op/Eval.hs

{-# LANGUAGE ApplicativeDo #-}

module Salmon.Op.Eval where

import Control.Comonad.Cofree (Cofree, unfoldM)

import Salmon.Op.Graph
import Salmon.Op.OpGraph

-- | Expands all predecessors of an operation graph.
expand :: (Monad m) => OpGraph m node -> m (Cofree Graph (OpGraph m node))
expand = unfoldM expandOne
  where
    expandOne :: (Applicative m) => OpGraph m node -> m (OpGraph m node, (Graph (OpGraph m node)))
    expandOne op = do
        preds <- op.predecessors
        pure (op, preds)