code: def p_case_def(self, p):
          '''case_def : CASE term COLON expr
                      | DEFAULT COLON expr'''
          if len(p) == 5:
              p[0] = ('case', (p[2], p[4]))
          elif len(p) == 4:
              p[0] = ('default', p[3]f p_case_def(self, p):
          '''case_def : CASE term COLON expr
                      | DEFAULT COLON expr'''
          if len(p) == 5:
              p[0] = ('case', (p[2], p[4]))
          elif len(p) == 4:
              p[0] = ('default', p[3])
docs: case_def : CASE term COLON expr
                      | DEFAULT COLON expr