Proving as Editing HOL Tactics

We introduce an Emacs interface for writing HOL proof scripts in SML based on the Computing-as-Editing paradigm. Tactics in a proof script are considered as constraints, and the process of interactive theorem proving becomes that of solving constraints. In addition, constraint solving is subsumed by the process of editing a proof script. Tactics are executed while the script is being edited. The user does not have to pay attention to the status of the HOL prover. In our interface, the user can also enjoy proof-by-pointing. The result of proof-by-pointing is inserted as a tactic into a proof script. We expect that our interface will be widely used as an extension of the familiar HOL mode on Emacs.