XML Considered Harmful

[Jon Ribbens]

On 2021-09-24, Chris Angelico <rosuav at gmail.com> wrote:
> On Sat, Sep 25, 2021 at 8:53 AM dn via Python-list
><python-list at python.org> wrote:
>> On 25/09/2021 06.59, Peter J. Holzer wrote:
>> > CSV: Good for tabular data of a single data type (strings). As soon as
>> > there's a second data type (numbers, dates, ...) you leave standard
>> > territory and are into "private agreements".

CSV is not good for strings, as there is no one specification of how to
encode things like newlines and commas within the strings, so you may
find that your CSV data transfer fails or even silently corrupts data.

>> > JSON: Has a few primitive data types (bool, number, string) and a two
>> > compound types (list, dict(string -> any)). Still missing many
>> > frequently used data types (e.g. dates) and has no standard way to
>> > denote composite types. But its simple and if it's sufficient for your
>> > needs, use it.

JSON Schema provides a way to denote composite types.

>> > XML: Originally invented for text markup, and that shows. Can represent
>> > different types (via tags), can define those types (via DTD and/or
>> > schemas), can identify schemas in a globally-unique way and you can mix
>> > them all in a single document (and there are tools available to validate
>> > your files). But those features make it very complex (you almost
>> > certainly don't want to write your own parser) and you really have to
>> > understand the data model (especiall namespaces) to use it.
>>
>> and YAML?
>
> Invented because there weren't enough markup languages, so we needed
> another?

Invented as a drunken bet that got out of hand, and used by people who
don't realise this.