#import "@preview/prooftrees:0.1.0": *

#let db(x) = $bracket.l.double #x bracket.r.double$
#let isValue(x) = $#x "value"$
#let mapsto = $arrow.r.long.bar$
#let mapstostar = $op(arrow.r.long.bar)^*$
#let subst(x, v, e) = $#e [#v\/#x]$
#let TODO = text(fill: red)[*TODO*]

#let conf(title, doc) = {
  show link: underline
  set page(width: 6in, height: 9in, margin: 0.3in)

  text(size: 30pt)[#title]
  doc
}