Documents starting with a triple dash

[stevebleazard]

I came across a behaviour I am not sure is expected or an issue: When a yaml document starts with a triple dash (---) the parser seems to return an empty document. So,

---
test: 1

Has no children with a key of test. The reason I came across this is ansible yaml documents start with three dashes and a new line. I am using the python API. Is this expected?

[biojppm]

Yes, this is expected behavior -- but not exactly like you describe. The explanation is this: documents must be nested in a stream node. So when a --- token appears, a STREAM node is created as the tree's root, and the document is provided as a child of the root node. This is because a --- token has a semantic role, so its presence/absence will have an impact in the tree.

To be clear:

ryml::Tree withoutStream = ryml::parse_in_arena("test: 1\n");
//  node0 MAP
//   ` node1 KEYVAL "test" "1"

ryml::Tree withStream = ryml::parse_in_arena("---\ntest: 1\n");
// node0 STREAM
//  ` node1 DOCMAP
//     ` node2 KEYVAL "test" "1"

By the way, to get at the document, you can use the Tree::docref() method, which does the jump for you.

[stevebleazard]

Thanks for the quick response, this was what I suspected but wasn't sure of the why