AbapToolset

ABAP Toolset: utilities and helper classes for ABAP.

Boolean expressions

Classes and interfaces

ZCL_ABAP_BOOLEXPR_PARSER
ZIF_ABAP_BOOLEXPR_PARSER
ZCL_ABAP_BOOLEXPR_UTILS
ZIF_ABAP_BOOLEXPR_TERM_EVAL

A simple boolean-expression parser and evaluator.

We often need to maintain complex rules in customizing, for example:

A record is relevant if:

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

With the Boolean Expression tool, you can store this rule directly in customizing as plain text:

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

Syntax

The parser supports the following special characters:

• & — logical AND
• | — logical OR (, can be used as an alternative)
• ! — logical NOT (^ can be used as an alternative because table maintenance may remove ! at the beginning of a field)
• ( ) — parentheses

Operator precedence is: ! (highest), then &, and finally |.

Term evaluation

The parser can split the expression, but it cannot determine the truth value of individual terms (for example, whether status X is true or false). For this, it calls an object implementing ZIF_ABAP_BOOLEXPR_TERM_EVAL, which must return ABAP_TRUE or ABAP_FALSE for a given term.

In most cases, you can use the helper methods in ZCL_ABAP_BOOLEXPR_UTILS.

Example

Suppose you want to check whether an object has active statuses matching:

• ((s1 OR s2) AND s3) OR (s4 AND NOT s5)

The corresponding boolean expression is:

• ((s1|s2)&s3)|(s4&!s5)

If the object’s active status list is s1, s3, s7, you can evaluate the expression like this:

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.