YAML to JSON Converter

It handles block-style YAML: key: value maps, - item lists, nesting by indentation, and full-line # comments. The sample gives:

Nested maps and lists of maps work too, the shape you find in many Compose and CI files. Indentation is compared by counting leading characters, so keep it consistent within a block:

Unquoted values are typed by a short, strict set of rules. Only the exact words true and false are booleans, only plain digits with an optional minus and decimal point are numbers, and an empty value, ~ or null becomes null. Everything else is a string:

Two of these may differ from what other tools give you. Older YAML 1.1 parsers read yes and no as booleans; here they stay text. And a number with leading zeros loses them, so quote ZIP codes, version numbers like 1.10 and anything else that must stay exactly as written. Quotes are removed but escape sequences inside them are not processed, so \n stays a backslash and an n.

The parser is deliberately small. Some valid YAML is skipped or kept as plain text, and you won't get a warning:

• Keys containing spaces or wrapped in quotes are dropped, which is why my key is missing.
• Inline lists and maps such as [a, b] stay as one string. Only the empty forms [] and {} are understood.
• Multi-line blocks after | or > become an empty object.
• A comment after a value is kept as part of the value.
• Anchors and aliases (& and *) are not resolved.
• Several documents separated by --- are merged into one object.

Compare the key count of your input and output when converting a file you didn't write yourself.