perl7 vs. raku: Sibling Rivalry?

It was an emotional moment to see the keynote talk at TPRCiC from Sawyer X announcing that perl 7.00 === 5.32. Elation because of the ability of the hardcore perl community to finally break free of the frustrating perl6 roadblock. Pleasure in seeing how the risky decision to rename perl6 to raku has paid off and hopefully is beginning to defuse the tensions between the two rival communities. And Fear that improvements to perl7 will undermine the reasons for many to try out raku and may cannibalise raku usage. (Kudos to Sawyer to recognising that usage is an important design goal).

Then the left side of my brain kicked in. Raku took 15 years of total commitment of genius linguists to ingest 361 RFCs and then synthesise a new kind of programming language. If perl7 seeks the same level of completeness and perfection as raku, surely that will take the same amount of effort. And I do not see the perl community going for the same level of breaking changes that raku did. (OK maybe they could steal some stuff from raku to speed things up…)

And that brought me to Sadness. To reflect that perl Osborned sometime around 2005. That broke the community in two – let’s say the visionaries and the practical-cats. And it drove a mass emigration to Python. Ancient history.

So now we have two sister languages, and each will find a niche in the programming ecosystem via a process of Darwinism. They both inherit the traits (https://en.wikipedia.org/wiki/Perl#Design) that made perl great in the first place….

The design of Perl can be understood as a response to three broad trends in the computer industry: falling hardware costs, rising labor costs, and improvements in compiler technology. Many earlier computer languages, such as Fortran and C, aimed to make efficient use of expensive computer hardware. In contrast, Perl was designed so that computer programmers could write programs more quickly and easily.

Perl has many features that ease the task of the programmer at the expense of greater CPU and memory requirements. These include automatic memory management; dynamic typing; strings, lists, and hashes; regular expressions; introspection; and an eval() function. Perl follows the theory of “no built-in limits,” an idea similar to the Zero One Infinity rule.

Wall was trained as a linguist, and the design of Perl is very much informed by linguistic principles. Examples include Huffman coding(common constructions should be short), good end-weighting (the important information should come first), and a large collection of language primitives. Perl favours language constructs that are concise and natural for humans to write.

Perl’s syntax reflects the idea that “things that are different should look different.” For example, scalars, arrays, and hashes have different leading sigils. Array indices and hash keys use different kinds of braces. Strings and regular expressions have different standard delimiters. This approach can be contrasted with a language such as Lisp, where the same basic syntax, composed of simple and universal symbolic expressions, is used for all purposes.

Perl does not enforce any particular programming paradigm (procedural, object-oriented, functional, or others) or even require the programmer to choose among them.

But perl7 and raku serve distinct interests & needs:

Thing…	perl7	raku
compilation	static parser	one pass compiler
compile speed	super fast	relies on pre-c0mp
execution	interpreted	virtual machine
execution speed	super fast	relies on jit
module library	CPAN native	CPAN import
closures	yes	yes
OO philosophy	Cor not module	pervasive
OO inheritance	Roles + Is	Roles + Is + multiple
method invocation	->	.
type checking	no	gradual
sigils	idiosyncratic	consistent
references	manual	automatic
unicode	feature guard	core
signatures	feature guard	core
lazy execution	nope	core
Junctions	nope	core
Rat math	nope	core
Sets & Mixes	nope	core
Complex math	nope	core
Grammars	nope	core
mutability	nope	core
concurrency	nope	core
variable scope	“notched”	cleaner
operators	C-like	cleaner (e.g. for ->)
switch	no	gather/when
regexen	classic	cleaner
eval	yes	shell
AST macros	huh?	…

…and so on

A long list and perhaps a little harsh on perl since many things may be got from CPAN – but when you use raku in anger, you do see the benefit if having a large core language. Only when I made this table, did I truly realise just what a comprehensive language raku is, and that perl will genuinely be the lean and mean option.

perl7

raku

And, lest we forget our strengths:

When I first saw Python code, I thought that using indents to define the scope seemed like a good idea. However, there’s a huge downside. Deep nesting is permitted, but lines can get so wide that they wrap lines in the text editor. Long functions and long conditional actions may make it hard to match the start to the end. And I pity anyone who miscounts spaces and accidentally puts in three spaces instead of four somewhere — this can take hours to debug and track down. [Source: here]

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