# Ihs-utilities

Utility macros and functions used throughout the IHS books.

### Subtopics

- Defun-type/exec-theory
- Collects and returns a special set of runes.
- Defun-theory
- Collects and returns a special set of runes.
- Definition-free-theory
- Returns the theory with all :DEFINITION rules deleted.
- Rewrite-theory
- Collects all of the :REWRITE runes from theory.
- Rewrite-free-theory
- Returns the theory with all :REWRITE rules deleted.
- Definition-theory
- Collects all of the :DEFINITION runes from theory.
- Mlambda
- Macro LAMBDA form.
- Enable-theory
- Creates an in-theory event that is equivalent to ENABLEing the
theory-expression. Note that theory-expression is evaluated.
- Disable-theory
- Creates an IN-THEORY event that is equivalent to DISABLEing the
theory-expression. Note that theory-expression is evaluated.