Feature #17769: Proposal: numeric coefficient syntax

• Status: Rejected
• Priority: Normal
• Assignee: -
• Target version: -
• Tags: joke

[mrkn (Kenta Murata)]

When we write a mathematical equation, we often omit a multiplication operator between a coefficient and a variable like 2x.
I guess this convention can be useful in computer programming. Practically, Julia employs this notation:

julia> 2pi
6.283185307179586

julia> x = 3
3

julia> 2x
6

julia> pi
π = 3.1415926535897...

julia> 2pi
6.283185307179586

I wrote a proof-of-concept patch to introduce this notation in Ruby.
We can write the following with this patch:

irb(main):001:0> x = 3
=> 3
irb(main):002:0> 2x
=> 6
irb(main):003:0> def pi = Math::PI
=> :pi
irb(main):004:0> 2pi
=> 6.283185307179586

[mame (Yusuke Endoh)]

• Tags set to joke

[matz (Yukihiro Matsumoto)]

i = 10
p 2i # => 20 or Complex(0,2)?

Matz.

[mrkn (Kenta Murata)]

2i is an imaginary number literal so it is Complex(0, 2).

[mrkn (Kenta Murata)]

• File deleted (num_coeff.patch)

[mrkn (Kenta Murata)]

• File num_coeff.patch added

I replaced the attached patch with changes to accept not only 2x but also 2(x + 1).

[mrkn (Kenta Murata)]

• File num_coeff.patch num_coeff.patch added

Replace the patch with refactoring.

[mrkn (Kenta Murata)]

• File deleted (num_coeff.patch)

[mrkn (Kenta Murata)]

• Status changed from Open to Rejected