resolveEnvDefault

private fnResolvedDefault resolveEnvDefault(string spec) @safe

Resolves a default value specification possibly referencing an environment variable.

Supported forms (case-insensitive or keyword):

  • $VAR → use value of environment variable VAR if set; otherwise no default.
  • $VAR or fallback → use env VAR if set; otherwise use literal fallback.
  • literal → use the literal as-is.

Quotes around parts are stripped when present (e.g., "$HOME/file").

Parameters

specThe contents captured from [default: ...] (without brackets).

Returns

A ResolvedDefault indicating whether a default is present and its value.