mathlib documentation

core.init.meta.ref

meta constant tactic.ref  :
Type uType u

A ref performs the role of a mutable variable within a tactic.

meta constant tactic.using_new_ref {α : Type u} {β : Type v} :
α → (tactic.ref αtactic β)tactic β

Create a new reference r with initial value a, execute t r, and then delete r.

meta constant tactic.read_ref {α : Type u} :
tactic.ref αtactic α

Read the value stored in the given reference.

meta constant tactic.write_ref {α : Type u} :
tactic.ref αα → tactic unit

Update the value stored in the given reference.