Up.tool.back.at: def of ezx@1.11.0.0
Import: import ezx@1.11.0.0/src/ws/up.bend as Up
Lines 80-84 of ezx@1.11.0.0/src/ws/up.bend: https://jend.leeeet.dev/read.txt?path=ezx@1.11.0.0/src/ws/up.bend&start_line=80&end_line=84

import Base
import ezx@1.11.0.0/src/ledger/manifest.bend as M

# a tool with the pin the joint ledger gives its name
def tool.back.at(own: M.Tool, joint: M.Tool) -> M.Tool:
  M.Tool{nn, ee, bb, os} = own
  M.Tool{_jn, _je, _jb, js} = joint
  M.Tool{nn, ee, bb, source.back(os, js)}

Uses (2):
  https://jend.leeeet.dev/definition.txt?path=ezx@1.11.0.0/src/ledger/manifest.bend&name=Tool
  https://jend.leeeet.dev/definition.txt?path=ezx@1.11.0.0/src/ws/up.bend&name=source.back