static WoodyRule getWoodyRuleFromSource(L<S> lines, int lineIndex) {
  S s = lines.get(lineIndex);
  Explain e = explain(s, ctxParsingRules(), "rule");
  if (e == null)
    fail("Bad rule: " + s);
    
  new WoodyRule rule;
  rule.nameInFile = e.sub(0).string();
  rule.lineInFile = lineIndex;
  rule.condition = e.sub(1).string();
  pcall {
    rule.parsedCondition = ctxParseExpression(e.sub(1));
  }
  
  Pair<SS, Int> p = ctxParseProperties(lines, lineIndex+1);
  rule.properties.putAll(p.a);
  
  int opening = indexOfTrim(lines, "{", lineIndex);
  if (opening >= 0) {
    int closing = indexOfClosingCurlyBracket(lines, opening);
    rule.body = lines(subList(lines, opening+1, closing));
  }
  ret rule;
}