Supported by
Supported by Inetum

Use a dictionary instead of IF or CASE

images/thumbnail.png - Thumbnail

The fewer IFs and CASEs the better, right? Every branch of an IF or a CASE is an exception. And we like rules better than exceptions. Here’s one more technique to achieve that.

Consider this code:

METHOD get_tax_value_by_code.
IF tax_code = 'VAT23'.
  result = 23.
ELSEIF tax_code = 'VAT6'.
  result = 6.

As it is, it’s a pretty innocuous IF. But the day after tomorrow another tax type appears, and then another, and then another. Of course, quickly a CASE would be preferable to the IF. But there is still a better way.

  BEGIN OF ty_tax,
    tax_code TYPE mwskz,
    ratio TYPE f,
  END OF ty_tax,
  ty_taxes TYPE SORTED TABLE OF ty_tax with unique key tax_code.

METHOD get_taxes.
  result = VALUE ty_taxes(
   ( tax_code = 'VAT23' ratio = 23 )
   ( tax_code = 'VAT6' ratio = 6 ) ).

METHOD get_tax_value_by_code.
  DATA(taxes) = get_taxes( ).
  result = taxes[ tax_code = tax_code ].


  • It no longer subdivides into multiple branches as it did with IF or CASE making it much easier to test;
  • What used to be completely imperative is now almost all declarative and so is much easier to read and understand;
  • You separate the definition of the data from the choice of one of them and so you have a lot more freedom to change the way you define that relationship. You can, for example, very easily choose to define the relationship in a ZTAX table:
METHOD get_taxes.
  SELECT * FROM ztax INTO TABLE result.

You dig?

Greetings from Abapinho.