Usage & API

The module path is github.com/go-puppet/puppet. Packages:

Package	Role
github.com/go-puppet/puppet	façade: Parse, ParseExpression
…/lexer	tokenizer (Lex)
…/parser	recursive-descent parser (Parse, ParseExpression)
…/ast	Puppet::Pops-style node model + Sexpr renderer
…/eval	evaluator (EvalString, Evaluator, RegisterFunction, WithFacts/WithHiera/WithNodeName)
…/catalog	catalog model + Puppet catalog JSON

Parse a manifest

prog, err := puppet.Parse(`file { '/tmp/x': ensure => present }`)
// prog is an *ast.Program; walk it, transform it, or render it:
fmt.Println(ast.Sexpr(prog))

Compile to a catalog

cat, logs, err := eval.EvalString(src,
    eval.WithNodeName("web1"),
    eval.WithFacts(eval.MapFacts{"os": map[string]any{"family": "Debian"}}))
fmt.Println(cat.JSON())

Wire in Hiera

h, _ := hiera.Load("hiera.yaml", hiera.MapScope{})
cat, _, _ := eval.EvalString(src, eval.WithHiera(h)) // backs lookup() and class data binding

Custom functions

e := eval.New()
e.RegisterFunction("double", func(c *eval.Context, args []eval.Value, _ *eval.Block) (eval.Value, error) {
    return args[0].(int64) * 2, nil
})
prog, _ := parser.Parse(`notice(double(21))`)
e.EvalProgram(prog) // logs "42"

Value model

Values use the same representation as go-pcore: bool, int64, float64, string for scalars; []any for arrays; map[string]any for hashes; pcore.Undef for undef; and the pcore wrapper types (*pcore.Regexp, pcore.Type, …) for the rest.