I have been having trouble with truncation of data from one field of a
form. The culprit turned out to be the IS_MATCH() validator, which was
truncating a valid value to return a shorter valid value. I'm not sure
whether to call this a bug or just unexpected behavior, but if I had
trouble with it, someone else may.
The data in question were spreadsheet-style coordinate values with
letters for rows and numbers for columns, in the range A1 to J10.
Initially, I used a validator like IS_MATCH('^[A-J][1-9]|[A-J]10$').
This checks first for the two-character combinations A1 to J9, then
checks for A10 to J10. If I test this in a web2py shell, it accepts
and returns the two-character combinations, but it accepts and
truncates any values ending in 10.
In [1] : vdtr = IS_MATCH('^[A-J][1-9]|[A-J]10$')
In [2] : vdtr('A1')
('A1', None)
In [3] : vdtr('J1')
('J1', None)
In [4] : vdtr('A10')
('A1', None)
In [5] : vdtr('J10')
('J1', None)
It seems to me that A1 and J1 are not proper matches because the '1'
does not appear at the end of the validated string. In any case, I am
surprised that IS_MATCH() would modify a value under any
circumstances.
If I turn the regex around, so that it tests for the three-character
combinations first, like IS_MATCH('^[A-J]10|[A-J][1-9]$'), then things
work better.
In [6] : vdtr = IS_MATCH('^[A-J]10|[A-J][1-9]$')
In [7] : vdtr('A1')
('A1', None)
In [8] : vdtr('J1')
('J1', None)
In [9] : vdtr('A10')
('A10', None)
In [10] : vdtr('J10')
('J10', None)
