docs: function(forms) {
      if (forms.length < 2)  {
        forms.error("missing argument for operator");
      }
      if(forms.length > 2) {
        // it's a normal binary (or more) minus
        return handleArithOperator.call(this, forms);
      }
  
      // it's a unary minus
      this.transpileSubExpressions(forms)
      var generated = sl.generated()
      generated.push(["-", sl.valueOf(forms[1])]);
      generated.callable = false;
      return generated;
  }