zkas: Add a field definition on top of the circuit file.

Currently unused, but will probably be expanded to define proofs over
different fields.

contrib/zk.lang

@@ -24,6 +24,7 @@
   <definitions>
     <context id="keywords" style-ref="keyword">
       <keyword>k</keyword>
+      <keyword>field</keyword>
       <keyword>constant</keyword>
       <keyword>witness</keyword>
       <keyword>circuit</keyword>

contrib/zk.lua

@@ -20,7 +20,7 @@ local number = token(l.NUMBER, l.integer)
 
 -- Keywords.
 local keyword = token(l.KEYWORD, word_match{
-  'k', 'constant', 'witness', 'circuit',
+  'k', "field", 'constant', 'witness', 'circuit',
 })
 
 -- Constants.

contrib/zk.vim

@@ -9,6 +9,7 @@ endif
 
 syn keyword zkasKeyword 
     \ k
+    \ field
     \ constant
     \ witness
     \ circuit