RexNode simplify()

in core/src/main/java/org/apache/calcite/rex/RexSimplify.java [265:339]
73 lines of code
41 McCabe index (conditional complexity)

  RexNode simplify(RexNode e, RexUnknownAs unknownAs) {
    if (STRONG.isNull(e)) {
      // Only boolean NULL (aka UNKNOWN) can be converted to FALSE. Even in
      // unknownAs=FALSE mode, we must not convert a NULL integer (say) to FALSE
      if (e.getType().getSqlTypeName() == SqlTypeName.BOOLEAN) {
        switch (unknownAs) {
        case FALSE:
        case TRUE:
          return rexBuilder.makeLiteral(unknownAs.toBoolean());
        default:
          break;
        }
      }
      return rexBuilder.makeNullLiteral(e.getType());
    }
    switch (e.getKind()) {
    case AND:
      return simplifyAnd((RexCall) e, unknownAs);
    case OR:
      return simplifyOr((RexCall) e, unknownAs);
    case NOT:
      return simplifyNot((RexCall) e, unknownAs);
    case CASE:
      return simplifyCase((RexCall) e, unknownAs);
    case COALESCE:
      return simplifyCoalesce((RexCall) e);
    case CAST:
    case SAFE_CAST:
      return simplifyCast((RexCall) e);
    case CEIL:
    case FLOOR:
      return simplifyCeilFloor((RexCall) e);
    case IS_NULL:
    case IS_NOT_NULL:
    case IS_TRUE:
    case IS_NOT_TRUE:
    case IS_FALSE:
    case IS_NOT_FALSE:
      assert e instanceof RexCall;
      return simplifyIs((RexCall) e, unknownAs);
    case EQUALS:
    case GREATER_THAN:
    case GREATER_THAN_OR_EQUAL:
    case LESS_THAN:
    case LESS_THAN_OR_EQUAL:
    case NOT_EQUALS:
      return simplifyComparison((RexCall) e, unknownAs);
    case SEARCH:
      return simplifySearch((RexCall) e, unknownAs);
    case LIKE:
      return simplifyLike((RexCall) e, unknownAs);
    case MINUS_PREFIX:
    case CHECKED_MINUS_PREFIX:
      return simplifyUnaryMinus((RexCall) e, unknownAs);
    case PLUS_PREFIX:
      return simplifyUnaryPlus((RexCall) e, unknownAs);
    case PLUS:
    case MINUS:
    case TIMES:
    case DIVIDE:
    case CHECKED_PLUS:
    case CHECKED_MINUS:
    case CHECKED_TIMES:
    case CHECKED_DIVIDE:
      return simplifyArithmetic((RexCall) e);
    case M2V:
      return simplifyM2v((RexCall) e);
    default:
      if (e.getClass() == RexCall.class) {
        return simplifyGenericNode((RexCall) e);
      } else {
        return e;
      }
    }
  }