Allow system values to create new BQN types even in a non-extended implementation

1 files changed, 2 insertions, 1 deletions

diff --git a/docs/spec/types.html b/docs/spec/types.html
index ce432dbd..50d96bf0 100644
--- a/docs/spec/types.html
+++ b/docs/spec/types.html
@@ -15,7 +15,8 @@
 <li>2-Modifier</li>
 <li>Namespace</li>
 </ul>
-<p>Of these, the first three are considered <em>data types</em> and the next three <em>operation types</em>. We first describe the operation types and the namespace; the remainder of this page will be dedicated to the data types. A member of any operation type accepts some number of <em>inputs</em> and either returns a <em>result</em> or causes an error; inputs and the result are values of any type. When a function is given inputs (<em>called</em>), it may produce side effects before returning, such as manipulating variables and calling other functions within its scope, or performing I/O.</p>
+<p>Beyond these, an implementation may define <a href="system.html">system values</a> that create values of other types. The behavior of such values is not specified and is left up to the implementation.</p>
+<p>Of the types specified, the first three are considered <em>data types</em> and the next three <em>operation types</em>. We first describe the operation types and the namespace; the remainder of this page will be dedicated to the data types. A member of any operation type accepts some number of <em>inputs</em> and either returns a <em>result</em> or causes an error; inputs and the result are values of any type. When a function is given inputs (<em>called</em>), it may produce side effects before returning, such as manipulating variables and calling other functions within its scope, or performing I/O.</p>
 <ul>
 <li>A <em>function</em> takes one (monadic call) or two (dyadic call) <em>arguments</em>.</li>
 <li>A <em>1-modifier</em> takes one <em>operand</em>.</li>