ALV Function modules

Hi Gurus,

I am trying to learn ALV, can anyone of you please explain me the following different ALV function modules in detail, I mean what exactly these function modules are doing along with an example:

1. REUSE_ALV_VARIANT_DEFAULT_GET

2. REUSE_ALV_VARIANT_F4

4. REUSE_ALV_EVENTS_GET

5. REUSE_ALV_COMMENTARY_WRITE

6. REUSE_ALV_FIELDCATALOG_MERGE

7. REUSE_ALV_LIST_DISPLAY

8. REUSE_ALV_GRID_DISPLAY

9. REUSE_ALV_POPUP_TO_SELECT

reuse_alv_block_init,

reuse_alv_block_append,

reuse_alv_block_display,

reuse_alv_hierque_list_display

Any help will really be appreciated.

Thanks,

Rajeev