The switch code structure below:

switch nLine 
   case 1
      sLine = '&s' + 'Easter Sunday'                
   case 2
      sLine = '&s' + 'Ascension'                
   case 3
      sLine = '&s' + 'Whit Sunday'   
   else
      sLine = ''             
endswitch         

will generate the following compiled code:

0015 CALL b002=$0BI(@nLine|1)  //EqualN
0015 IF_002 @b002 jne+0003
0016 CALL sLine=$0AL(&s|Easter Sunday)  //Concat
0017 JMP+0012  //ELSE_002
0017 CALL b003=$0BI(@nLine|2)  //EqualN
0017 IF_003 @b003 jne+0003
0018 CALL sLine=$0AL(&s|Ascension)  //Concat
0019 JMP+0007  //ELSE_003
0019 CALL b004=$0BI(@nLine|3)  //EqualN
0019 IF_004 @b004 jne+0003
0020 CALL sLine=$0AL(&s|Whit Sunday)  //Concat
0021 JMP+0002  //ELSE_004
0022 MOV sLine=
0023 ENDF_004
0023 ENDF_003
0023 ENDF_002

Note how the switch statement has been replaced by a series of nested IF_xxx instructions. In effect, the compiler has generated the same code as if we had written the macro below:

    if nLine == 1 
        sLine = '&s' + 'Easter Sunday'
    else
        if nLine == 2 
            sLine = '&s' + 'Ascension'
        else
            if nLine == 3 
                sLine = '&s' + 'Whit Sunday'
            else
                sLine = '' 
            endif
        endif
    endif      

This shows that the switch statement is a convenience for the writing, and legibility, of macros, but not a necessity in the definition of the language.

Topic 123100, last updated on 22-Apr-2020