Thanks Bernardo

That construct works as required, however I���m not sure what the semantic difference is to my original.�� I seems counterintuitive.�� Could you expand on what is going on for my benefit (if you have time).

Again thanks.

Also do you have a view on my description of the asDate result, and whether it should self-validate the receiver and raise an exception?

Regards

R

From: Bernardo Ezequiel Contreras <vonbecmann@gmail.com>
Reply to: Any question about pharo is welcome <pharo-users@lists.pharo.org>
Date: Tuesday, 1 March 2022 at 15:05
To: Any question about pharo is welcome <pharo-users@lists.pharo.org>
Subject: [Pharo-users] Re: ByteString asDate

try to send the #on:do: message  to a block. try this

^ [ (Date readFrom: self pattern: ���dd/mm/yyyy���). 

     true ]  on: DateError do: [ false].

On Tue, Mar 1, 2022 at 11:52 AM Robert Briggs via Pharo-users <pharo-users@lists.pharo.org> wrote:

I may be being stupid but the current Date Class does not appear to protect itself against a ByteString that is not in valid date format, e.g. by raising an Error.

e.g. the code  ���ABC��� asDate opens the Debugger on #isLetter was sent to nil because it appears to expect more letters after $C but the peek returns nil instead.

This seems to me to require a more defensive programming approach.

I would like to validate a user input as a valid date in a number of different formats before converting it to a Date and storing it in my model.

I���ve tried using the Date parser, e.g.

Date readFrom: '04/02/2013' readStream pattern: 'dd/mm/yyyy'.

This is fine for simply parsing a valid string but rates a DateError if it doesn���t match the .  So entering ���04/13/2013��� cleverly raises ���DateError: There is no 13^th month���.

My thought was I could use this to return a simple true/false result in a ByteString extension in my application for example as follows:

ByteString >> isValdiDate

(Date readFrom: self pattern: ���dd/mm/yyyy���) on: DateError do: [^ false].

^ true

However this doesn���t intercept the DateError which is simply reported in the Debugger as before.   This may be my lack of uncderstaning of the Exception handling in Pharo.

Any and all thoughts welcome.

R

--

Bernardo E.C.

Sent from a cheap desktop computer in South America.