Documentation for Psych to_yaml options?

Question

Ruby 1.9.3 defaults to using Psych for YAML. While the ruby-doc documentation for it is completely lacking, I was able to find one external piece of documentation that hinted that the indentation option is supported. This was borne out in testing:

irb(main):001:0> RUBY_VERSION
#=> "1.9.3"
irb(main):002:0> require 'yaml'
#=> true
irb(main):003:0> [[[1]]].to_yaml
#=> "---\n- - - 1\n"
irb(main):009:0> [[[1]]].to_yaml indentation:9
#=> "---\n-        -        - 1\n"

There are presumably more options supported. Specifically, I want to know how to change the line wrap width or disable it altogether.

What are the options available?

After looking at the source of 2.2.0, a short update: It seems there are very few options right now, hence little documentation still. — Eric Platon, Mar 17 '15 at 03:52

Phrogz · Accepted Answer · 2012-03-18T22:53:47.897

43

Deep in the guts of ruby-1.9.3-p125/ext/psych/emitter.c I found three options:

indentation - The level must be less than 10 and greater than 1.
line_width - Set the preferred line width.
canonical - Set the output style to canonical, or not (true/false).

And they work!

edited Mar 18 '12 at 22:53

answered Mar 18 '12 at 14:59

Phrogz

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So, it seems you can't disable line wrap? I tried `line_width: 0` and with `nil` which do not have any effect. `true` returns an error. – sawa Mar 18 '12 at 16:47
@sawa You want `line_width:999` or some other sufficiently large number. – Phrogz Mar 18 '12 at 17:35
It seems Syck options doesn't work too. So these ones for Psych are only avalible for 1.9.3 – sashaegorov Dec 04 '12 at 00:21
2

I had line_width to 999, which still had some weird newlines. -1 worked, thanks @sawa – Peter Ehrlich Jul 08 '13 at 21:10

score 19 · Answer 2 · answered Sep 27 '12 at 03:22

19

When you want to disable line wrap, use this option:

line_width: -1

answered Sep 27 '12 at 03:22

sawa

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Neither `foo.to_yaml(line_width: -1)` or `foo.to_yaml(options = {line_width: -1})` is working for me in ruby 2.5.x – spuder Jan 09 '19 at 20:52

Documentation for Psych to_yaml options?

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