Understanding Foxpro IF Statement - visual-foxpro

Question

I wasn't sure what my title should be, feel free to edit my post and change it if you can come up with something better.
There aren't many resources available on the use of Foxpro and what I'm trying to do is understand what is going on.
lldisdead=.t.
Select .f. as chkbox, * from a_counties ;
order by cn_area, cn_desc ;
into dbf (StrTmpFile1)
scan while !EOF()
IF ChkBox
selected_some_cnty = .t
endif
endscan
Here is my understanding:
Do the following as long as you are not in the last record of the
table:
IF ChkBox
Set selected_some_cnty equal to .t
Stop Check next record
Keep doing this until you are out of records.
What does IF CHKBOX mean?
Is it saying if the column CHKBOX is not null, do the following,
otherwise, do nothing.
Edit: Added additional code

Answer 1

If chkBox
in VFP, means:
if (chkBox)
also in all other well known languages, like C, C++, C#, Java, Go, Dart, Ruby, ... you name it - some languages parentheses are mandatory and some not. It simply mean "if chkBox is true". Sometimes you would see it written as:
If chkBox = .T.
like:
If chkBox == true
as in other languages, but it is more verbose than needed, and seasoned developers do not write it like that (after all writing like "if true is true" is awkward, simply "if true" is fine).
This is explained with comments placed in code:
* Initialize a memory variable named lldisdead as .t. (true)
lldisdead=.t.
* Select some fields into a table named m.StrTmpFile1
* StrTmpFile1 is a variable holding a string name of the table
* selecting all fields of a_counties table
* plus a boolean field named "chkBox" which is initially
* filled with .F. (false) value
Select .f. as chkbox, * from a_counties ;
order by cn_area, cn_desc ;
into dbf (StrTmpFile1)
* select's result table is table open in the current
* work area and by default located on first record.
* scanning the whole table
* with an unnecessary "while !EOF()" addition
* Default scope of scan is until EOF
scan while !EOF()
* Checking if chkBox field has a value of true
IF ChkBox
* if it has, than set "selected_some_cnty" memory variable to true
selected_some_cnty = .t
endif
endscan
Having said that, this part:
scan while !EOF()
IF ChkBox
selected_some_cnty = .t.
endif
endscan
could be written as:
scan
IF ChkBox
selected_some_cnty = .t
endif
endscan
further:
LOCATE FOR ChkBox
selected_some_cnty = !EOF()
However, since we know all chkBox values are .F., that piece of code is totally useless and could be deleted all together.

Answer 2

From the SQL query, the data is going into a physical table based on whatever the name "StrTmpFile1" variable is pointing to. Also note, the first column in this select statement is ".f. as ChkBox". So this is prepping EVERY RECORD in the query with a leading column that is ALWAYS False (hence .f.)
Select .f. as chkbox, * from a_counties ;
order by cn_area, cn_desc ;
into dbf (StrTmpFile1)
Now, I would suspect there is some other user interface action that is using this result table such as presenting in a grid in a form and allowing a checkbox on a column to let a user pick one or more entries to do something further.
After said selection (again, speculating intent), it is going through the loop to only find those records where the "ChkBox" COLUMN IN THE TABLE has been set to true and setting a flag as .t. that something WAS selected.
Overall, a very novice approach, but that is a different issue. A shortcut to getting the answer if a record as marked would be
select (the table)
Locate for ChkBox
selected_some_cnty = found()
Hope this helps, and if you need additional clarification, shoot a comment.