[ruby-core:56301] [ruby-trunk - Feature #8430] Rational number literal

Issue #8430 has been updated by takuto_h (Takuto Hayashi).

File ratio_lit.patch added

Hello.
I wrote a patch for the rational number literal and recognized that a part of the proposed feature is confusable.

If we accept "1.2r" as "Rational(12, 10)":
    1/3r      #=> (1/3)
    0.4/1.2r  #=> 0.33333333333333337

I think this feature's point is that "1/3r" can be seen as "1/3" followed by "r",
so it can make us confusing that "0.4/1.2" followed by "r" is not a rational number.

The attached file is a patch which accept "3r" and doesn't accept "1.2r".
The implementation is also available at:
https://github.com/takuto-h/ruby/commit/6827688ee642c3afd57af35af481377a0038a402

Thank you.

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Feature #8430: Rational number literal
https://bugs.ruby-lang.org/issues/8430#change-40791

Author: mrkn (Kenta Murata)
Status: Assigned
Priority: Normal
Assignee: mrkn (Kenta Murata)
Category: core
Target version: current: 2.1.0


I would like to propose a new literal syntax for rational numbers.
The implementation is available in my github repository:
https://github.com/mrkn/ruby/commit/8ca0c9a53593e55d67f509fc403df616e2276e3a

This patch implements a notation that consists of an integer, "//", and another integer, in a row.
The first integer is the numerator, and the second is the denominator.
Whitespaces are permitted between them.

For example:
    1 // 2 == Rational(1, 2)
    1 // 1 == Rational(1, 1)
    0 // 1 == Rational(0, 1)

"0 // 0" occurs syntax error.

I think this new syntax isn't conflict with an empty regexp
because this implementation doesn't treat // as a binary operator.



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