Grammar for my proposal for a DSL for laying out websites written in HTML/CSS. I'm just looking for feedback on the grammar, not on the proposal itself (I'm sure there are lots who think it's a stupid idea) nor the beginnings of the implementation.

layout.jison

%{
    require("Layout");
    // just ignore this line, it's related to my plans to implement the language, but I just want feedback on the grammar right now.
    var layout = new Layout();
%}

%lex

%%
\s+							        /* Skip whitespace */
"position"                          return "position";
"rotation"                          return "rotation";
"origin"                            return "origin";
"scew"                              return "scew";
"scale"                             return "scale";
"relative to"|"rel"                 return "relative to";
"absolute"|"relative to $viewport"  return "absolute";
"x"                                 return "x";
"y"                                 return "y";
"z"                                 return "z";
"xy"                                return "xy";
"xyz"|"all"                         return "all";
"%"                                 return "%";
"px"                                return "px";
"f"                                 return "f";
"$viewport"                         return "$viewport";
"$self"                             return "$self";
"$window"                           return "$window";
"$page"                             return "$page";
"$screen"                           return "$screen";
"$parent"|"$$"                      return "$parent";
[0-9]+\.[0-9]+                      return "number";
[0-9]+                              return "integer";
.                                   return "selector";


/lex

%start layout

%% /* language grammar */

layout
    : statements EOF
        {{ layout.compile(); }}
    ;

statements
    : statement
    | statements statement
    ;

statements
    : "selector" command relationship value
    ;

command
    : "position"
    | "origin"
    | "scale"
    | "rotation"
    | "scew"
    ;

relationship
    : "relative to" selector
    | "relative to" special_selector
    | "absolute"
    ;

value
    : '{' properties '}'
    ;

properties
    : property
    | properties property
    ;

property
    : "x" ":" rvalue
    | "y" ":" rvalue
    | "z" ":" rvalue
    | "xy" ":" rvalue
    | "all" ":" rvalue
    ;

rvalue
    : "number" "%"
    | "integer" "px"
    | "number" "f"
    ;

special_selector
    : "$viewport"
    | "$self"
    | "$window"
    | "$page"
    | "$screen"
    | "$parent"
    ;