YML syntax error - ruby

Question

I want to have a multi-line bit of markdown java in a yam file. I tried many things but I guess I don't quite get the quoting rules of Yaml.
{
title: Museum,
body: |
"```java
code code code
java2",
answers: [
"`museum`",
"`museum.getFloor(3)`",
"`museum.getFloor(3).getExhibit(5)`",
"`museum.getFloor(3).getExhibit(5).getCurator()`",
"`museum.getFloor(3).getExhibit(5).getCurator().name`",
"`museum.getFloor(3).getExhibit(5).getCurator().name.toUpper()`"
]
}
Produces:
/Users/pitosalas/.rbenv/versions/2.3.1/lib/ruby/2.3.0/psych.rb:377:in `parse': (generator/test.yml): found character that cannot start any token while scanning for the next token at line 3 column 9 (Psych::SyntaxError)

Answer 1

YAML has two styles: the JSON like flow style and the much better human readable block style.
Roughly speaking you can have nested structures each style nested within itself and can have flow style nested within block style, but block style nested within flow style is not allowed.
Your to level { and } are flow style but you try to introduce, with |, a literal block style scalar within that flow style. Replace the flow style with block style upwards from that scalar:
title: Museum
body: |
"```java
code code code
java2"
answers: [
"`museum`",
"`museum.getFloor(3)`",
"`museum.getFloor(3).getExhibit(5)`",
"`museum.getFloor(3).getExhibit(5).getCurator()`",
"`museum.getFloor(3).getExhibit(5).getCurator().name`",
"`museum.getFloor(3).getExhibit(5).getCurator().name.toUpper()`"
]
and your YAML is fine. Note that the double quotes "around" the value for the key body are not going to be stripped when loading, maybe that is not what you intended.
You should IMO not leave out the trailing , after the last value in the (flow style) sequence that is the value for answers. This will certainly lead to errors when you extend the list and forget to put in the trailing comma on the line above.
I would personally go for block style all the way:
title: Museum
body: |
"```java
code code code
java2"
answers:
- "`museum`"
- "`museum.getFloor(3)`"
- "`museum.getFloor(3).getExhibit(5)`"
- "`museum.getFloor(3).getExhibit(5).getCurator()`"
- "`museum.getFloor(3).getExhibit(5).getCurator().name`"
- "`museum.getFloor(3).getExhibit(5).getCurator().name.toUpper()`"

Answer 2

When dealing with YAML file generation that is convoluted or complex, or when it's not working as I expect, I revert to letting Ruby show me the way:
require 'yaml'
body = <<EOT
"```java
code code code
java2
"
EOT
answers = %w(
`museum`
`museum.getFloor(3)`
`museum.getFloor(3).getExhibit(5)`
`museum.getFloor(3).getExhibit(5).getCurator()`
`museum.getFloor(3).getExhibit(5).getCurator().name`
`museum.getFloor(3).getExhibit(5).getCurator().name.toUpper()`
)
obj = {
"title" => "Museum",
"body" => body,
"answers" => answers
}
puts obj.to_yaml
Which, in this case, outputs:
---
title: Museum
body: |
"```java
code code code
java2
"
answers:
- "`museum`"
- "`museum.getFloor(3)`"
- "`museum.getFloor(3).getExhibit(5)`"
- "`museum.getFloor(3).getExhibit(5).getCurator()`"
- "`museum.getFloor(3).getExhibit(5).getCurator().name`"
- "`museum.getFloor(3).getExhibit(5).getCurator().name.toUpper()`"
If you then pass that YAML back into the parser, you should get the original data structure back:
YAML.load(obj.to_yaml)
# => {"title"=>"Museum",
# "body"=>"\"```java\n" +
# "code code code\n" +
# "java2\n" +
# "\"\n",
# "answers"=>
# ["`museum`",
# "`museum.getFloor(3)`",
# "`museum.getFloor(3).getExhibit(5)`",
# "`museum.getFloor(3).getExhibit(5).getCurator()`",
# "`museum.getFloor(3).getExhibit(5).getCurator().name`",
# "`museum.getFloor(3).getExhibit(5).getCurator().name.toUpper()`"]}