I ran into an issue while writing property validation methods for a Core Data
stack where the methods simply weren’t being called. After a bit of head
scratching I realised it was because the methods needed to be annotated with
@objc. This wasn’t needed in Swift 3 because @objc was inferred on all
methods of subclasses of NSObject; however, the behaviour of @objc inference
changed in Swift 4. Now, subclasses of NSObject
must explicitly mark methods that need to be accessible from Objective-C. This
took longer to realise than it should have since the Core Data
documentation’s sample code for property-level
validation hasn’t been updated for Swift 4.
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While working on rewriting Spotijack in Swift, I started to
feel dissatisfied with
Foundation’s notification API. It’s a stringly typed
API that makes heavy use of Any and as someone who loves their types this
makes me sad. To cheer myself up, I set about writing a more strongly typed
notification system.
The end result is a small
library—TypedNotification—that
provides a set of protocols defining a more descriptive type system for
notifications. Check out the GitHub project if you’re interested. There’s a
Playground in it demoing the protocols. The rest of this blog post will cover
them in a bit more detail.
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The other week I had to set up a new installation of MATLAB r2016a on a
(somewhat) fresh Fedora installation. After running the installer, I ran into a
bunch of library errors when trying to run external C++ programs
from MATLAB or when trying to plot something. When running an external C++
program, MATLAB would complain about missing versions of CXXABI and GLIBCXX
in libstdc++. When plotting something, MATLAB would complain about
libmwosgserver.so.
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I’ve written a couple of functions for Emacs’ ledger-mode that make working with
receipts a bit easier. With the cursor on a transaction, calling
alex/ledger-attach-receipt will prompt for a file. This function copies the
file to a receipts directory, renaming it to its hash and sorting it in
subdirectories according to the transaction’s year and month. Finally,
the function adds a comment to the transaction with the hash of the file. The
function alex/ledger-open-attached-receipt reads this comment and opens the
associated file in Emacs. The receipts folder can be customised through the
variable alex/ledger-receipt-folder.
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I’m a pretty big fan of Ledger, a command line
accounting system based on the double entry bookkeeping system. One of
its strengths lies in the fact that the journal file that contains
your transactions is a plain text file. This makes it super easy to
sync the journal using your favourite file syncing service. Of course,
before putting the journal file on a remote server, you’ll probably
want to encrypt it. Ledger program doesn’t support encrypted journal
files but, using GPG and a shell alias, you can get
the vast majority of Ledger’s functionality to work with an encrypted
journal.
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