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+#$EPIC: using_symbolctl.txt,v 1.1 2008/11/30 19:14:38 jnelson Exp $
+======Things you can do with symbolctl:======
+=====Create your own SETs======
+You can create your own [[set]] with symbolctl.  The [[addset]] script makes
+this very simple for you.
+   alias addset (name, type, ...) {
+        if (@name && type) {
+                @ symbolctl(create $name);
+                @ symbolctl(set $name 1 builtin_variable type $type);
+                if (@) {
+                        @ symbolctl(set $name 1 builtin_variable script $*);
+                };
+        };
+   };
+Creating a set requires three steps:
+    @ symbolctl(create $name)
+First you have to make sure that the symbol name exists in the symbol table.
+You can't manipulate a symbol name that doesn't exist.
+    @ symbolctl(set $name 1 builtin_variable type $type)
+Next you have to define the type of [[set]] that your [[set]] will be.  This
+can either be BOOL, CHAR, INT, or STR.  BOOL mean you can [[set]] it to OFF
+or ON.  CHAR means you can set it to a single character.  INT means you can
+set it to a number.  STR means you can set it to any string.   By defining
+its type, you implicitly create the [[set]].
+    @ symbolctl(set $name 1 builtin_variable script $*)
+Finally you can give it some code that you want to have executed every time the
+[[set]] is changed.  You would ordinarily pass in a block statement, surrounded
+by curly braces {....}.  The new value is already set, and is passed in as $*,
+and you can overrule it by changing the set in your own code.
+=====Example:=====
+    addset cantturnmeoff bool {
+        if (* == [ON]) {
+	    echo Sorry dave, I can't let you do that.
+	    set cantturnmeoff off
+	}
+    }
+=====Doing command completion:=====
+$symbolctl(PMATCH <type> <pattern>)
+   $symbolctl(PMATCH BUILTIN_COMMANDS li*)
+returns
+   "LICENSE LINKS LIST"
+=====Checking to see if something exists before using it:=====
+====Usage:====
+$symbolctl(GET <symbol> <level> BUILTIN_COMMAND) \\
+$symbolctl(GET <symbol> <level> BUILTIN_FUNCTION) \\
+$symbolctl(GET <symbol> <level> BUILTIN_EXPANDO)
+====Synopsis:====
+Returns 0 if these types are not in use (ie, if there is not a
+built in command), and returns non-zero if there is.  If you're
+smart, you won't try to do anything with the non-zero value.