Scoping (not really) rules for special names

1 files changed, 3 insertions, 0 deletions

diff --git a/docs/spec/scope.html b/docs/spec/scope.html
index 3893389e..57ea2aca 100644
--- a/docs/spec/scope.html
+++ b/docs/spec/scope.html
@@ -18,6 +18,9 @@
 </ul>
 <p>The definition for an identifier is chosen from the potential definitions based on their containing scopes: it is the one whose containing scope does not contain or match the containing scope of any other potential definition. If for any identifier there is no definition, then the program is not valid and results in an error. This can occur if the identifier has no potential definition, and also if two potential definitions appear in the same scope. In fact, under this scheme it is never valid to make two definitions with the same name at the top level of a single scope, because both definitions would be potential definitions for the one that comes second in program order. Both definitions have the same containing scope, and any potential definition must contain or match this scope, so no potential definition can be selected.</p>
 <p>The definition of <em>program order</em> for identifier tokens follows the order of BQN <a href="evaluate.html">execution</a>. It corresponds to the order of a particular traversal of the abstract syntax tree for a program. To find the relative ordering of two identifiers in a program, we consider the highest-depth node that they both belong to; in this node they must occur in different components, or that component would be a higher-depth node containing both of them. In most nodes, the program order goes from right to left: components further to the left come earlier in program order. The exceptions are <code><span class='Function'>PROGRAM</span></code>, <code><span class='Function'>BODY</span></code>, <code><span class='Value'>list</span></code>, <code><span class='Value'>subject</span></code> (for stranding), and body case (<code><span class='Function'>FCase</span></code>, <code><span class='Modifier'>_mCase</span></code>, <code><span class='Modifier2'>_cCase_</span></code>, <code><span class='Function'>FMain</span></code>, <code><span class='Modifier'>_mMain</span></code>, <code><span class='Modifier2'>_cMain_</span></code>, <code><span class='Value'>brSub</span></code>, <code><span class='Function'>BrFunc</span></code>, <code><span class='Modifier'>_brMod1</span></code>, and <code><span class='Modifier2'>_brMod2_</span></code>) nodes, in which program order goes in the opposite order, from left to right (some assignment target nodes also contain lists or strands, but their ordering is irrelevant because if two identifiers with the same name appear in such a list, then it can't be a definition).</p>
+<h2 id="special-names">Special names</h2>
+<p>Special names such as <code><span class='Value'>𝕩</span></code> or <code><span class='Value'>𝕣</span></code> refer to variables, but have no definition and do not use scoping. Instead, they always refer to the immediately enclosing scope, and are defined automatically when the block is evaluated.</p>
+<p>The six special names are <code><span class='Value'>𝕨𝕩𝕗𝕘𝕤𝕣</span></code>, and the tokens <code><span class='Function'>𝕎𝕏𝔽𝔾𝕊</span></code>, <code><span class='Modifier'>_𝕣</span></code>, and <code><span class='Modifier2'>_𝕣_</span></code> are alternate spellings of these names as described in the <a href="token.html">tokenization rules</a>. Special names may be modified with <code><span class='Gets'>↩</span></code> assignment but cannot appear as the target of other kinds of assignment. Two special names represent the same identifier if they are the same name and appear in the same body. The initial value these names have is defined by the <a href="evaluate.html">evaluation rules</a>; the grammar for blocks ensures that all special names used in a block will be defined (possibly as the special value <code><span class='Nothing'>·</span></code> in the case of <code><span class='Value'>𝕨</span></code>).</p>
 <h2 id="variables">Variables</h2>
 <p>A <em>variable</em> is an entity that permits two operations: it can be <em>set</em> to a particular value, and its <em>value</em> can be obtained, resulting in the last value it was set to. When either operation is performed it is referred to as <em>accessing</em> the variable.</p>
 <p>When a body in a block is evaluated, a variable is created for each definition (that is, defined identifier instance) the body contains. Whenever another block—the block itself, not its contents—is evaluated during the execution of the block, it is linked to the currently-evaluating block, so that it will use the variables defined in this instance. These links are recursive, so that every instance of a block is linked to exactly one instance of each block that contains it. These links form a tree that is not necessarily related to the call stack of functions and modifiers. Using these links, the variable an identifier refers to is the one corresponding to that variable's definition in the linked instance of the containing scope for the definition.</p>