how to extend structures at runtime

Former Member — Fri, 04 Mar 2005 11:57:26 GMT

hello,

is there any chance to

extend a data structure at runtime?

normally you define a structure with

data: begin of x,

field1 type c,

field2 type n.

data: end of x.

this structure is the basis for your internal tables etc.

it would be definitely nice to add a third field at runtime if it is needed.

in other programming languages it would also be possible to add elements to an array. the question ist: how can i add fields to the structure dynamically?

it could be useful for a lot of situations.

dynamically generated fieldcatalogue for example.

i think i could succeed in changing the structure by using field symbols in combination with dynamically creating data objects by the "CREATE DATA" statement.

has anyone already done something similar?

Re: how to extend structures at runtime

MauricioMiao — Fri, 04 Mar 2005 12:10:48 GMT

Hello Gideon,

It is possible using ABAP runtime program generation like in code below.

This program generate a dinamic ALV with N fields. There is a parameter where the user type how many fields he wants to display (or generate).

Then form f_create_dynamic_table generate an internal table with N fields according to the number in the parameter.

You can change the program to generate a dinamic structure if you want, in fact it already does it.

Just cut and paste the program and execute in your system.

Regards,

Mauricio

REPORT zasmm008.

$$ Declarações -

TYPE-POOLS:

kkblo. "Tipos para lista especial

FIELD-SYMBOLS:

TYPE table.

PARAMETERS p_qtd TYPE i OBLIGATORY DEFAULT 10.

$$ Eventos -

INITIALIZATION.

%_p_qtd_%_app_%-text = 'Dinamic fields quantity'.

START-OF-SELECTION.

CHECK p_qtd > 0 AND p_qtd < 100.

PERFORM f_create_dynamic_table.

PERFORM f_fill_dynamic_table.

PERFORM f_create_alv.

$$ Forms -

*&----

*& Form f_create_dynamic_table

*&----

FORM f_create_dynamic_table.

DATA:

lv_line TYPE i,

lv_word(72) TYPE c,

lv_form(30) TYPE c VALUE 'TABLE_CREATE',

lv_message(240) TYPE c,

lp_table TYPE REF TO data,

lp_struc TYPE REF TO data,

lv_name LIKE sy-repid,

lv_cont(02) TYPE n,

lv_lng TYPE i,

lv_typesrting(6) TYPE c.

The dynamic internal table stucture

DATA: BEGIN OF lt_struct OCCURS 0,

fildname(8) TYPE c,

abptype TYPE c,

length TYPE i,

END OF lt_struct.

The dynamic program source table

DATA: BEGIN OF lt_inctabl OCCURS 0,

line(72),

END OF lt_inctabl.

Sample dynamic internal table stucture

DO p_qtd TIMES.

ADD 1 TO lv_cont.

CONCATENATE 'FIELD' lv_cont INTO lt_struct-fildname.

lt_struct-abptype = 'C'.

lt_struct-length = '4'.

APPEND lt_struct.

ENDDO.

Create the dynamic internal table definition in the dyn. program

lt_inctabl-line = 'PROGRAM ZDYNPRO.'.

APPEND lt_inctabl.

lt_inctabl-line = 'FORM TABLE_CREATE CHANGING P_TABLE P_STRUC.'.

APPEND lt_inctabl.

lt_inctabl-line = 'DATA: BEGIN OF DYNTAB OCCURS 0,'.

APPEND lt_inctabl.

LOOP AT lt_struct.

lt_inctabl-line = lt_struct-fildname.

lv_lng = strlen( lt_struct-fildname ).

IF NOT lt_struct-length IS INITIAL .

lv_typesrting(1) = '('.

lv_typesrting+1 = lt_struct-length.

lv_typesrting+5 = ')'.

CONDENSE lv_typesrting NO-GAPS.

lt_inctabl-line+lv_lng = lv_typesrting.

ENDIF.

lt_inctabl-line+15 = 'TYPE'.

lt_inctabl-line+21 = lt_struct-abptype.

lt_inctabl-line+22 = ','.

APPEND lt_inctabl.

ENDLOOP.

lt_inctabl-line = 'END OF DYNTAB.'.

APPEND lt_inctabl.

lt_inctabl-line = 'DATA: POINTER TYPE REF TO DATA.'.

APPEND lt_inctabl.

lt_inctabl-line = 'CREATE DATA POINTER LIKE DYNTAB[].'.

APPEND lt_inctabl.

lt_inctabl-line = 'P_TABLE = POINTER.'.

APPEND lt_inctabl.

lt_inctabl-line = 'CREATE DATA POINTER LIKE LINE OF DYNTAB.'.

APPEND lt_inctabl.

lt_inctabl-line = 'P_STRUC = POINTER.'.

APPEND lt_inctabl.

lt_inctabl-line = 'ENDFORM.'.

APPEND lt_inctabl.

CATCH SYSTEM-EXCEPTIONS generate_subpool_dir_full = 9.

GENERATE SUBROUTINE POOL lt_inctabl[] NAME lv_name

MESSAGE lv_message LINE lv_line WORD lv_word.

ENDCATCH.

PERFORM (lv_form) IN PROGRAM (lv_name) CHANGING lp_table lp_struc.

Dynamic table in <tb> and its header line in <st>

ASSIGN lp_table->* TO .

ENDFORM. " f_create_dynamic_table

*&----

*& Form f_create_alv

*&----

FORM f_create_alv.

DATA:

ls_layout TYPE slis_layout_alv,

lv_cont(02) TYPE n,

lt_fieldcat TYPE slis_t_fieldcat_alv WITH HEADER LINE.

DO p_qtd TIMES.

CLEAR lt_fieldcat.

ADD 1 TO lv_cont.

CONCATENATE 'FIELD' lv_cont INTO lt_fieldcat-fieldname.

CONCATENATE 'Campo' lv_cont INTO lt_fieldcat-seltext_s

SEPARATED BY space.

lt_fieldcat-seltext_m = lt_fieldcat-seltext_s.

lt_fieldcat-seltext_l = lt_fieldcat-seltext_s.

lt_fieldcat-outputlen = 10.

APPEND lt_fieldcat.

ENDDO.

ls_layout-zebra = 'X'.

CALL FUNCTION 'REUSE_ALV_GRID_DISPLAY'

EXPORTING

is_layout = ls_layout

it_fieldcat = lt_fieldcat[]

TABLES

t_outtab =

EXCEPTIONS

program_error = 1

OTHERS = 2.

ENDFORM. " f_create_alv

*&----

*& Form f_fill_dynamic_table

*&----

FORM f_fill_dynamic_table.

DATA:

lv_line(2) TYPE n,

lv_field(2) TYPE n.

DO 20 TIMES.

ADD 1 TO lv_line.

CLEAR lv_field.

DO p_qtd TIMES.

ADD 1 TO lv_field.

ASSIGN COMPONENT lv_field OF STRUCTURE .

ENDDO.

ENDFORM. " f_fill_dynamic_table

Re: how to extend structures at runtime

Former Member — Fri, 04 Mar 2005 13:23:40 GMT

hey mauricio, thanks for your quick and useful answer.

all problems are solved.

i didn´t know

the statement

"GENERATE SUBROUTINE POOL" before.

have a nice weekend!

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