diff --git a/src/current/calc.xsd b/src/current/calc.xsd
index 9ff9f67a..c5b95723 100644
--- a/src/current/calc.xsd
+++ b/src/current/calc.xsd
@@ -235,6 +235,16 @@
                 </xs:documentation>
               </xs:annotation>
             </xs:attribute>
+
+            <xs:attribute name="dim" type="xs:string">
+              <xs:annotation>
+                <xs:documentation xml:lang="en">
+                  Specify the dimension of each index of the generator result.
+                  Disables casting and truncating with @precision if greater
+                  than 0 or 'scaler'.  This expands into c:sum/@dim.
+                </xs:documentation>
+              </xs:annotation>
+            </xs:attribute>
           </xs:extension>
         </xs:complexContent>
       </xs:complexType>
diff --git a/src/current/compiler/js-calc.xsl b/src/current/compiler/js-calc.xsl
index f760fbcb..219c8a40 100644
--- a/src/current/compiler/js-calc.xsl
+++ b/src/current/compiler/js-calc.xsl
@@ -36,6 +36,7 @@
 -->
 <stylesheet version="2.0"
             xmlns="http://www.w3.org/1999/XSL/Transform"
+            xmlns:xs="http://www.w3.org/2001/XMLSchema"
             xmlns:c="http://www.lovullo.com/calc"
             xmlns:lv="http://www.lovullo.com/rater"
             xmlns:preproc="http://www.lovullo.com/rater/preproc"
@@ -187,6 +188,9 @@
     </choose>
   </variable>
 
+  <variable name="dim" as="xs:integer"
+            select="if ( @dim ) then @dim else 0" />
+
   <!-- introduce scope both to encapsulate values and so we can insert this as
        part of a larger expression (will return a value) -->
   <text>( function() {</text>
@@ -245,7 +249,12 @@
       <value-of select="$value" />
     <text> ) {</text>
 
-    <text>var result = +(+( </text>
+    <text>var result = </text>
+    <!-- if caller wants to yield a vector, don't cast -->
+    <sequence select="if ( not( $dim gt 0 ) ) then
+                          '+(+( '
+                        else
+                          '(( '" />
       <choose>
         <!-- if there are child nodes, use that as the summand/expression -->
         <when test="./c:*">
@@ -260,9 +269,16 @@
           <text>]</text>
         </otherwise>
       </choose>
-    <text> )).toFixed(</text>
-      <value-of select="$precision" />
-    <text>);</text>
+    <text> ))</text>
+
+    <!-- if caller wants to yield a vector, don't truncate -->
+    <if test="not( $dim gt 0 )">
+      <text>.toFixed(</text>
+        <value-of select="$precision" />
+      <text>)</text>
+    </if>
+
+    <text>;</text>
 
     <!-- if generating a set, store this result -->
     <if test="@generates">
diff --git a/src/current/include/preproc/expand.xsl b/src/current/include/preproc/expand.xsl
index f023df15..c43fcc2d 100644
--- a/src/current/include/preproc/expand.xsl
+++ b/src/current/include/preproc/expand.xsl
@@ -122,6 +122,46 @@
 </xsl:template>
 
 
+<!--
+  Translate dimension aliases (e.g. scaler, vector, matrix) into respective
+  numeric representations.
+-->
+<xsl:template mode="preproc:expand" priority="8"
+              match="c:*[ @dim
+                          and not( string( @dim ) castable as xs:integer ) ]">
+  <xsl:copy>
+    <xsl:sequence select="@*" />
+
+    <!-- replace dim with numeric -->
+    <xsl:attribute name="dim">
+      <xsl:choose>
+        <xsl:when test="@dim = 'scaler' or @dim = ''">
+          <xsl:sequence select="0" />
+        </xsl:when>
+
+        <xsl:when test="@dim = 'vector'">
+          <xsl:sequence select="1" />
+        </xsl:when>
+
+        <xsl:when test="@dim = 'matrix'">
+          <xsl:sequence select="2" />
+        </xsl:when>
+
+        <xsl:otherwise>
+          <xsl:message terminate="yes"
+                       select="concat(
+                                 '!!! [preproc] error: ',
+                                 'unknown dimension alias ''',
+                                 @dim, '''' )" />
+        </xsl:otherwise>
+      </xsl:choose>
+    </xsl:attribute>
+
+    <xsl:sequence select="node()" />
+  </xsl:copy>
+</xsl:template>
+
+
 <!--
   Give let's a name so that they may be easily referenced uniquely
 -->
diff --git a/src/current/include/preproc/macros.xsl b/src/current/include/preproc/macros.xsl
index e58f247c..234632f5 100644
--- a/src/current/include/preproc/macros.xsl
+++ b/src/current/include/preproc/macros.xsl
@@ -402,7 +402,7 @@
 
     <xsl:sequence select="./lv:class" />
 
-    <c:sum of="_CMATCH_" index="{@index}" sym="{@gensym}">
+    <c:sum of="_CMATCH_" index="{@index}" sym="{@gensym}" dim="{@dim}">
       <!-- copy @generates, if it exists (has the benefit of copying nothing
            if it does not exist) -->
       <xsl:sequence select="@generates" />
diff --git a/src/current/include/preproc/symtable.xsl b/src/current/include/preproc/symtable.xsl
index 432c3abd..7635c9a3 100644
--- a/src/current/include/preproc/symtable.xsl
+++ b/src/current/include/preproc/symtable.xsl
@@ -688,9 +688,12 @@
 <xsl:template match="c:*[ @generates ]" mode="preproc:symtable" priority="5">
   <xsl:variable name="parent" select="ancestor::lv:rate" />
 
+  <xsl:variable name="dim" as="xs:integer"
+                select="if ( @dim ) then @dim else 1" />
+
   <preproc:sym name="{@generates}"
     parent="{$parent/@yields}"
-    type="gen" dtype="float" dim="1" desc="{@desc}" tex="{@sym}" />
+    type="gen" dtype="float" dim="{$dim}" desc="{@desc}" tex="{@sym}" />
 
   <xsl:apply-templates mode="preproc:symtable" />
 </xsl:template>