quaternion fix; add v>q and q>v words

CHANGES.html

@@ -20,6 +20,17 @@
 
 </li>
 
+<li>User interface:
+
+<ul>
+
+<li>Added expandable outliners. Used by the inspector, <code>.s</code>, <code>usage.</code>, <code>uses.</code>, <code>vocabs.</code>, and various other words.</li>
+<li>Added word completion to the listener pane; press <code>TAB</code>.</li>
+<li>Added word navigation shortcuts to the listener pane; press <code>C+LEFT</code> and <code>C+RIGHT</code> to move a word at a time, and <code>C+BACKSPACE</code> and <code>C+DELETE</code> to delete the previous and next word, respectively.</li>
+</ul>
+
+</li>
+
 <li>Collections:
 
 <ul>
@@ -33,6 +44,29 @@
 <li>Everything else:
 
 <ul>
+<li>Quaternions added to math library.
+
+Quaternions are represented as pairs of real numbers. Literal syntax is <code>Q{ a b c d }Q</code>, where <code>a</code>, <code>b</code>, <code>c</code> and <code>d</code> are real numbers.
+
+Many quaternion operations can be done using Factor's existing vector algebra words; this follows from the mathematical fact that the quaternions are a 2-dimensional vector space over the complex numbers:
+<ul>
+<li>Addition: <code>v+</code></li>
+<li>Subtraction: <code>v-</code></li>
+<li>Negation: <code>vneg</code></li>
+<li>Norm: <code>norm</code></li>
+<li>Multiplication by a complex number on the left: <code>n*v</code></li>
+</ul>
+A few new words are also needed:
+<ul>
+<li>Convert complex number to quaternion: <code>c&gt;n</code></li>
+<li>Multiply by a complex number on the right: <code>q*n</code></li>
+<li>Quaternion multiplication: <code>q*</code></li>
+<li>Quaternion division: <code>q/</code></li>
+<li>Quaternion conjugate: <code>qconjugate</code></li>
+</ul>
+
+</li>
+
 <li>Easier exception handling. The <code>cleanup ( try cleanup -- )</code> word encapsulates the following idiom:
 <pre>
 [ A ] [ B rethrow ] catch
@@ -55,7 +89,7 @@ However, most uses of <code>catch</code> can be replaced by <code>cleanup</code>
 <li>The distinct <code>t</code> type is gone. Now, the <code>t</code> object is just a symbol.</li>
 <li>A new <code>with-server ( port ident quot -- )</code> combinator takes care of listening on a network socket, logging client connections, spawning client handler threads, and error handling. The quotation is called for each client, in a new scope with the client socket as the default stream.</li>
 <li>New <code>1+</code>, <code>1-</code> words are a bit faster than <code>1 +</code> and <code>1 -</code> since there is one less generic dispatch involved.</li>
-<li>On Windows, FFI errors would raise a signal 11 instead of reporting a nice message</li>
+<li>On Windows, FFI errors would raise a signal 11 instead of reporting a nice message.</li>
 </ul>
 
 <li>Contributed code:

examples/factorbot.factor

@@ -66,7 +66,7 @@ M: ping handle-irc ( line -- )
         " " % dup definer word-name %
         " " % dup word-name %
         "stack-effect" word-prop [ " (" % % ")" % ] when*
-    ] make-string ;
+    ] "" make ;
 
 : word-url ( word -- url )
     [
@@ -74,7 +74,7 @@ M: ping handle-irc ( line -- )
         dup word-vocabulary url-encode %
         "&word=" %
         word-name url-encode %
-    ] make-string ;
+    ] "" make ;
 
 : irc-loop ( -- )
     irc-stream get stream-readln

examples/turing.factor

@@ -13,14 +13,14 @@ SYMBOL: states
 SYMBOL: halt
 
 ! This is a simple program that outputs 5 1's
-[
+{{
     [[ [[ 1 0 ]] << state f 1 1 2 >> ]]
     [[ [[ 2 0 ]] << state f 1 1 3 >> ]]
     [[ [[ 3 0 ]] << state f 1 -1 1 >> ]]
     [[ [[ 1 1 ]] << state f 1 -1 2 >> ]]
     [[ [[ 2 1 ]] << state f 1 -1 3 >> ]]
     [[ [[ 3 1 ]] << state f 1 -1 halt >> ]]
-] states set
+}} states set
 
 ! Current state
 SYMBOL: state
@@ -38,7 +38,7 @@ SYMBOL: position
 SYMBOL: tape
 
 ! Initial tape
-20 zero-vector tape set
+20 0 <repeated> >vector tape set
 
 : sym ( -- sym )
     #! Symbol at head position.
@@ -50,7 +50,7 @@ SYMBOL: tape
 
 : next-state ( -- state )
     #! Look up the next state/symbol/direction triplet.
-    state get sym cons states get assoc ;
+    state get sym cons states get hash ;
 
 : turing-step ( -- )
     #! Do one step of the turing machine.

library/math/quaternions.factor

@@ -7,11 +7,11 @@
 USING: arrays kernel math sequences ;
 IN: math-internals
 
-: 2q [ first2 ] 2apply ;
+: 2q [ first2 ] 2apply ; inline
 
-: q*a 2q swapd ** >r * r> - ;
+: q*a 2q swapd ** >r * r> - ; inline
 
-: q*b 2q >r ** swap r> * + ;
+: q*b 2q >r ** swap r> * + ; inline
 
 IN: math
 
@@ -19,14 +19,20 @@ IN: math
     dup length 2 = [
         first2 [ number? ] 2apply and
     ] [
-        2drop f
+        drop f
     ] if ;
 
-: q* ( u v -- u*v ) [ q*a ] 2keep q*b 2array ;
+: q* ( u v -- u*v )
+    #! Multiply quaternions.
+    [ q*a ] 2keep q*b 2array ;
 
-: qconjugate ( u -- u' ) first2 neg >r conjugate r> 2array ;
+: qconjugate ( u -- u' )
+    #! Quaternion conjugate.
+    first2 neg >r conjugate r> 2array ;
 
-: q/ ( u v -- u/v ) [ qconjugate q* ] keep norm-sq v/n ;
+: q/ ( u v -- u/v )
+    #! Divide quaternions.
+    [ qconjugate q* ] keep norm-sq v/n ;
 
 : q*n ( q n -- q )
     #! Note: you will get the wrong result if you try to
@@ -39,6 +45,15 @@ IN: math
     #! Turn a complex number into a quaternion.
     0 2array ;
 
+: v>q ( v -- q )
+    #! Turn a 3-vector into a quaternion with real part 0.
+    first3 rect> >r 0 swap rect> r> 2array ;
+
+: q>v ( q -- v )
+    #! Get the vector part of a quaternion, discarding the real
+    #! part.
+    first2 >r imaginary r> >rect 3array ;
+
 ! Zero
 : q0 Q{ 0 0 0 0 }Q ;