ProofSums.gsum: def of minebender-game@1.0.0.0
Import: import minebender-game@1.0.0.0/proof_sums.bend as ProofSums
Lines 63-69 of minebender-game@1.0.0.0/proof_sums.bend: https://jend.leeeet.dev/read.txt?path=minebender-game@1.0.0.0/proof_sums.bend&start_line=63&end_line=69

import Base
import minebender-game@1.0.0.0/types.bend as T

# The sum of f over the grid, row by row.
def gsum(~A: Data, ~f: A -> Nat, g: T.Grid(A)) -> Nat:
  match g:
    case Nil{}:
      0n
    case r <> t:
      Nat.add(rsum(~A, ~f, r), gsum(~A, ~f, t))

Uses (5):
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=List
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Nat
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Nat.add
  https://jend.leeeet.dev/definition.txt?path=minebender-game@1.0.0.0/proof_sums.bend&name=rsum
  https://jend.leeeet.dev/definition.txt?path=minebender-game@1.0.0.0/types.bend&name=Grid