AbapToolset

ABAP Toolset - utilities, helpers for ABAP

Bool Expressions

Classes and interfaces

ZCL_ABAP_BOOLEXPR_PARSER
ZIF_ABAP_BOOLEXPR_PARSER
ZCL_ABAP_BOOLEXPR_UTILS
ZIF_ABAP_BOOLEXPR_TERM_EVAL

Simple boolean expression parser and evaluator. We often need to add complex rules into customizing, e.g.: record is relevant if:

• both status1 and status2 are active
• or both status3 and status4 are active
• or status5 is inactive.

Thanks to Bool Expression tool we can put this complex rule directly to customizing as text:

(status1&status2)|(status3&status4)|!status5

Bool expression tool parses the input string and uses these special characters:

• & - operator AND
• | - operator OR (as an alternative character we can use ,)
• ! - operator NOT (alternative char is ^ - because table maintenance removes ! at the beginning of field)
• ( ) - parenthesys

Operator ! has the highest precedence, then & and finally |.

Parser will split up the expression, but can't evaluate the value of the terms in the expression (is status X true or false?). It will call an object with interface ZIF_ABAP_BOOLEXPR_TERM_EVAL, which has to return ABAP_TRUE or ABAP_FALSE for given term. In most cases we can use methods of class ZCL_ABAP_BOOLEXPR_UTILS...

Consider an example when we have to check whether an object has active statuses: ( (s1 or s2) and s3 ) or (s4 but not s5). Our bool expression should look like: ((s1|s2)&s3)|(s4&!s5). We know the active status list of this object is s1,s3,s7. We can use the abovementioned class to check the expression:

DATA:
  lt_active_status TYPE STANDARD TABLE OF string WITH DEFAULT KEY.

lt_active_status = VALUE #( ( `s1` ) ( `s3` ) ( `s7` ) ).

TRY.
    DATA(lv_result) = zcl_abap_boolexpr_utils=>evaluate_boolexpr_table(
      iv_expression = `((s1|s2)&s3)|(s4&!s5)`
      it_values     = lt_active_status ).
  CATCH zcx_abap_boolexpr_error. " Error during expression parsing
ENDTRY.

WRITE lv_result.