YAML as a JSON superset and TAB characters

Question

I am unable to find a reference to this error exactly, but YAML 1.2 says it\'s a JSON superset, and if I use tab characters in a JSON it treats it like an error.

e.g.

Answer 1

Tabs ARE allowed in YAML, but only where indentation does not apply.

According to YAML 1.2 Section 5.5:

YAML recognizes two white space characters: space and tab.

The following examples will use · to denote spaces and → to denote tabs. All examples can be validated using the official YAML Reference Parser.

YAML has a block style and flow style. In block style, indentation determines the structure of a document. The following document uses block style.

root:
··key: value

Validate

In flow style, special characters indicate the structure of the document. The following equivalent document uses flow style.

{
→ root: {
→ → key: value
→ }
}

Validate

You can even mix indentation in flow style.

{
→ root: {
··→ key: value
····}
}

Validate

If you're mixing block and flow style, the entire flow style part must respect the block style indentation.

root:
··{
····key: value
··}

Validate

But you can still mix your indentation within the flow style part.

root:
··{
··→ key: value
··}

Validate

If you have a single value document, you can surround the value with all manner of whitespace.

→ ··value··→ 

Validate

The point is, every JSON document that is parsed as YAML will put the document into flow style (because of the initial { or [ character) which supports tabs, unless it is a single value JSON document, in which case YAML still allows padding with whitespace.

If a YAML parser throws because of tabs in a JSON document, then it is not a valid parser.

That being said, your example is failing because a block style mapping value must always be indented if it's not on the same line as the mapping name.

root: {
··key: value
}

is not valid, however

root:
··{
····key: value
··}

is valid, and

root: { key: value }

is also valid.