std.yaml

import std.yaml

data = yaml.parse(text)
text = yaml.stringify(value)
data = yaml.read("compose.yaml")
yaml.write("out.yaml", value)

Identical in shape to std.toml and std.json.

Mostly for reading other people's files

YAML is what CI configuration, Kubernetes manifests and Compose files are written in, so this module exists so you can read them. For a file you control, prefer TOML or std.defaults.

The reason is that YAML is a large, surprising format:

  • Unquoted scalars are typed by shape. yes, no, on, off may read as

booleans; 1.0 is a number; a version like 1.10 loses its trailing zero.

  • null, ~ and an empty value all mean null.
  • Indentation is structure, so a stray space changes the shape.
  • A postal code or a country code like NO can become something other than a

string.

None of that is a bug in this module - it is YAML. The defence is quoting anything that must stay a string, on both sides.

Errors

Malformed input raises { kind: "parse", format: "yaml" }, with path from yaml.read. Because indentation is significant, the message's line number is usually the fastest route to the problem.

Multiple documents

A stream of ----separated documents is not a single value. Split before parsing if you need to handle every document.

Untrusted YAML

Parsing produces plain Ecko data - maps, lists, strings, numbers - and nothing executable. There is no tag mechanism that constructs objects here, so the class of attack that plagues some YAML libraries does not apply. Deeply nested input is still bounded by ECKO_MAX_PARSE_DEPTH; see Resource limits.