Should I use YAML or JSON to store my Perl data? [closed]

Question

I've been using the YAML format with reasonable success in the last 6 months or so.

However, the pure Perl implementation of the YAML parser is fairly fidgety to hand-write a readable file for and has (in my opinion) annoying quirks such as requiring a newline at end of the file. It's also gigantically slow compared to the rest of my program.

I'm pondering the next evolution of my project, and I'm considering using JSON instead (a mostly strict subset of YAML, as it turns out). But which format has the most community traction and effort in Perl?

Which appears today to be the better long-term format for simple data description in Perl, YAML or JSON, and why?

Answer 1

YAML vs JSON is something very much not settled in Perl, and I will admit I tend to be in the middle of that. I would advice that either is going to get you about as much community traction. I'd make the decision based on the various pros and cons of the formats. I break down the various data serializing options like so (I'm going to community wiki this so people can add to it):

YAML Pros

• Human friendly, people write basic YAML without even knowing it
• WYSIWYG strings
• Expressive (it has the TMTOWDI nature)
• Expandable type/metadata system
• Perl compatible data types
• Portable
• Familiar (a lot of the inline and string syntax looks like Perl code)
• Good implementations if you have a compiler (YAML::XS)
• Good ability to dump Perl data
• Compact use of screen space (possible, you can format to fit in one line)

YAML Cons

• Large spec
• Unreliable/incomplete pure Perl implementations
• Whitespace as syntax can be contentious.

JSON Pros

• Human readable/writable
• Small spec
• Good implementations
• Portable
• Perlish syntax
• YAML 1.2 is a superset of JSON
• Compact use of screen space
• Perl friendly data types
• Lots of things handle JSON

JSON Cons

• Strings are not WYSIWYG
• No expandability
• Some Perl structures have to be expressed ad-hoc (objects & globs)
• Lack of expressibility

XML Pros

• Widespread use
• Syntax familiar to web developers
• Large corpus of good XML modules
• Schemas
• Technologies to search and transform the data
• Portable

XML Cons

• Tedious for humans to read and write
• Data structures foreign to Perl
• Lack of expressibility
• Large spec
• Verbose

Perl/Data::Dumper Pros

• No dependencies
• Surprisingly compact (with the right flags)
• Perl friendly
• Can dump pretty much anything (via DDS)
• Expressive
• Compact use of screen space
• WYSIWYG strings
• Familiar

Perl/Data::Dumper Cons

• Non-portable (to other languages)
• Insecure (without heroic measures)
• Inscrutable to non-Perl programmers

Storable Pros

• Compact? (don't have numbers to back it up)
• Fast? (don't have numbers to back it up)

Storable Cons

• Human hostile
• Incompatible across Storable versions
• Non-portable (to other languages)

Answer 2

As with most things, it depends. I think if you want speed and interoperability (with other languages), use JSON, in particular JSON::XS.

If you want something that's only ever going to be used by Perl modules, stick with YAML. It's much more common to find Perl modules on CPAN that support data description with YAML, or which depend on YAML, than JSON.

Note that I am not an authority and this opinion is based largely on hunch and conjecture. In particular, I have not profiled JSON::XS vs. YAML::XS. If I am offensively ignorant, I can only hope I will make someone irate enough to bring useful information to the discussion by correcting me.