Formatter calculates the width of a fullwidth character as 1

[yous]

Original file (Note that the third character is fullwidth):

require "spec"

describe ".ord" do
  it "runs for each character" do
    "ABＡ".chars.map(&.ord).should eq([65,
                                       66,
                                       65313])
  end
end

After running crystal tool format:

require "spec"

describe ".ord" do
  it "runs for each character" do
    "ABＡ".chars.map(&.ord).should eq([65,
                                      66,
                                      65313])
  end
end

This file passes crystal tool format:

require "spec"

describe ".ord" do
  it "runs for each character" do
    "ABC".chars.map(&.ord).should eq([65,
                                      66,
                                      67])
  end
end

You can replace Ａ with either 가 or 😀 as they're also treated as halfwidth characters by formatter.

[asterite]

Sorry, I don't understand what's the issue.

Could you provide the description like this?

• I have this code
• When I format it I get this
• But I was expecting it to format it like this

[yous]

Okay, I have this code, and this is what I want after the formatting:

require "spec"

describe ".ord" do
  it "runs for each character" do
    "ABＡ".chars.map(&.ord).should eq([65,
                                       66,
                                       65313])
  end
end

But when I format it, I get this:

require "spec"

describe ".ord" do
  it "runs for each character" do
    "ABＡ".chars.map(&.ord).should eq([65,
                                      66,
                                      65313])
  end
end

Note that 66, line and 65313]) line are changed.

[asterite]

What about the character 你? It seems its width is bewteen 1 and 2:

require "spec"

describe ".ord" do
  it "runs for each character" do
    "AB你".chars.map(&.ord).should eq([65,
                                      66, # Not well aligned
                                      65313])
  end
end

Still not correctly aligned:

require "spec"

describe ".ord" do
  it "runs for each character" do
    "AB你".chars.map(&.ord).should eq([65,
                                       66,
                                       65313])
  end
end

There's no possible way it will look right.

The formatter considers each char to be width 1. If things don't look well like that, it's fine. They are small exceptions. And it's impossible to fix in the general case.

Just my opinion, though!

[yous]

What about terminal emulators? They should select exact 1 or 2 column to show a character.

This is from preferences in iTerm2:

cat example.cr shows fullwidth characters with 2 columns:

Of course there are ambiguous characters in Unicode, but I think we can usually use 1 for them.

[asterite]

I see, that makes sense.

We can leave this open. We first need to have support in the standard library to compute the width of unicode characters.

[straight-shoota]

Looks like a good use case for https://forum.crystal-lang.org/t/unicode-character-string-width/3286