Tree.drop_nil: def of bend-collections-laws-crypto@1.0.0.0
Import: import bend-collections-laws-crypto@1.0.0.0/proofs/crypto/blake/blake3/tree.bend as Tree
Lines 157-160 of bend-collections-laws-crypto@1.0.0.0/proofs/crypto/blake/blake3/tree.bend: https://jend.leeeet.dev/read.txt?path=bend-collections-laws-crypto@1.0.0.0/proofs/crypto/blake/blake3/tree.bend&start_line=157&end_line=160

import Base
import bend-collections-laws-crypto@1.0.0.0/src/crypto/blake/blake3/types.bend as T
import bend-collections-laws-crypto@1.0.0.0/spec/lib/common.bend as SC
import bend-collections-laws-crypto@1.0.0.0/spec/crypto/blake/blake3.bend as S
import bend-collections-laws-crypto@1.0.0.0/proofs/crypto/blake/blake3/lists.bend as LS

# The drop is empty exactly when the list fits.
def drop_nil(+xs: List<&2,T.Out>, +k: Nat) -> {S.is_nil(SC.drop(T.Out,xs,k)) == Nat.is_le(SC.length(T.Out,xs),k) : Bool}:
  %Equal.sym(Bool,S.is_nil(SC.drop(T.Out,xs,k)),LS.is_empty(T.Out,SC.drop(T.Out,xs,k)),nil_is_empty(SC.drop(T.Out,xs,k))) : {_ == Nat.is_le(SC.length(T.Out,xs),k) : Bool}
  LS.empty_drop(T.Out,xs,k)

Uses (12):
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Bool
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Equal.sym
  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.is_le
  https://jend.leeeet.dev/definition.txt?path=bend-collections-laws-crypto@1.0.0.0/proofs/crypto/blake/blake3/lists.bend&name=empty_drop
  https://jend.leeeet.dev/definition.txt?path=bend-collections-laws-crypto@1.0.0.0/proofs/crypto/blake/blake3/lists.bend&name=is_empty
  https://jend.leeeet.dev/definition.txt?path=bend-collections-laws-crypto@1.0.0.0/proofs/crypto/blake/blake3/tree.bend&name=nil_is_empty
  https://jend.leeeet.dev/definition.txt?path=bend-collections-laws-crypto@1.0.0.0/spec/crypto/blake/blake3.bend&name=is_nil
  https://jend.leeeet.dev/definition.txt?path=bend-collections-laws-crypto@1.0.0.0/spec/lib/common.bend&name=drop
  https://jend.leeeet.dev/definition.txt?path=bend-collections-laws-crypto@1.0.0.0/spec/lib/common.bend&name=length
  https://jend.leeeet.dev/definition.txt?path=bend-collections-laws-crypto@1.0.0.0/src/crypto/blake/blake3/types.bend&name=Out