From: Jason Self <j@jxself.org>
Date: Sun, 2 Jun 2019 22:35:11 +0000 (-0700)
Subject: Add Library constants
X-Git-Url: https://jxself.org/git/?a=commitdiff_plain;h=0fa050c78301278308a5d2897cb9660a6db821c0;p=inform-resources.git

Add Library constants
---

diff --git a/inflibqr/inflibqr.md b/inflibqr/inflibqr.md
index a5eaf7d..67fdb4e 100644
--- a/inflibqr/inflibqr.md
+++ b/inflibqr/inflibqr.md
@@ -40,4 +40,11 @@ Library objects
 variable, which usually refers to `selfobj`.
 
 `thedark` - A pseudo-room which becomes the `location` when there is
-no light (although the player object is not moved there).
\ No newline at end of file
+no light (although the player object is not moved there).
+
+Library constants
+-----------------
+
+In addition to the standard constants `true` (1), `false` (0) and
+`nothing` (0), the Library defines `NULL` (-1) for an action, property
+or pronoun whose current value is undefined.
\ No newline at end of file