Perl 6 interpreting the output of the split function as an integer list / array

Question

say "1 10".split(" ") 

returns (1,10)

When I use those 1 and 10 as arguments to the sequence operator [...]

say [...] "1 10".split(" ")

returns just (1) while it's supposed to return (1 2 3 4 5 6 7 8 9 10) I guess it's because the output of the split function is interpreted as string.

How to solve that problem? Thank you.

Answer 1

If you want numeric behavior then coerce to numerics:

say [...] +<< "1 10".split(" "); # (1 2 3 4 5 6 7 8 9 10)

This uses a << hyperop to apply a numeric coercion (prefix +) to each element of the sequence generated by the split.

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Regarding sequence and range behavior with string endpoints:

• SO Why does the Perl 6 sequence 'A' … 'AA' have only one element?. What's described in the linked SO applies to the sequence you've specified, namely "1"..."10".

• The open Rakudo issue Sequence operator with string endpoints and no explicit generator produces unintuitive/undocumented results.

• SO Why are some of my ranges insane?.

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What you've written is equivalent to:

put gist "1"..."10";

(say is equivalent to put gist.)

A gist of "1"..."10" is (1).

That's because the gist of List.new("1") is (1) just like the gist of List.new("a") is (a).

And "1"..."10" evaluates to a List.new("1").

Why? I'm not sure yet but I'm exploring the available info.

Let's start with the doc. The doc for the infix ... op says:

The default generator is *.succ or *.pred, depending on how the end points compare

Well:

say "1" cmp "10"; # Less

which presumably means the sequence starts calling *.succ.

And then:

say "1".succ;     # 2

and:

say "2" cmp "10"; # More

It seems this results in the sequence immediately terminating after the "1" rather than including the "2" and continuing.

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I'm continuing to search the bug queues and examine the code around the area that @wamba++ linked in their answer to the above linked SO "Why does the Perl 6 sequence 'A' … 'AA' have only one element?".