Dailog & user input selection

[chigurh]

I have a calendar event file in a local directory which looks like this -

Feb 01  Ignác
Feb 01  День единения народов
Feb 01  День российской гвардии
Feb 01  Новогодние каникулы
Feb 01  День разгрома советскими войсками немецко-фашистских войск в Сталинградской битве (1943 год)
Feb 01  День окончания Второй мировой войны (1945 год)
Feb 01  Перунов День
Feb 02  Candlemas
Feb 02  Graham Nash is born in Lancashire, England, 1942
Feb 02  1st Cross-Quarter Day
Feb 02  Imbolg / Imbolc (other Celtic names) / Brighid / Oimelc
Feb 02  Diomidis D. Spinellis <dds@FreeBSD.org> born in Athens, Greece, 1967
Feb 02  Michael W Lucas <mwlucas@FreeBSD.org> born in Detroit, Michigan, United States, 1967
Feb 02  Dmitry Chagin <dchagin@FreeBSD.org> born in Stalingrad, USSR, 1976
Feb 02  Yoichi Nakayama <yoichi@FreeBSD.org> born in Tsu, Mie, Japan, 1976
Feb 02  Yoshihiro Takahashi <nyan@FreeBSD.org> born in Yokohama, Kanagawa, Japan, 1976
Feb 02  Bonne fête aux Théophane !
Feb 02  Chandeleur claire, hiver derrière*;
        Chandeleur trouble, hiver redouble.
Feb 02  Karolina, Aida

I will like to pick certain days thru dialog or any other program with [x]/spacebar selection and pass the selection to another program. Please let me know how to do this.

[chigurh]

I am able to bring up the dialogbox with -

dialog --textbox calendar.txt 20 80

No idea how to insert selection box for picking up day, month & events.