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`, `EvalPlanString`, `Evaluator`, `RegisterFunction`, `WithFacts`/`WithHiera`/`WithNodeName`/`WithTemplateLoader`/`WithExportedStore`/`WithPlanExecutor`)
`…/catalog`	catalog model + Puppet catalog JSON
`…/hcl`	Terraform-style HCL2 front-end (`Parse`) → the same `ast.Program`

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())

HCL2 front-end

hcl.Parse reads a Terraform-style HCL2 manifest and produces the same *ast.Program the native Puppet parser produces, so it compiles to an identical catalog through the same evaluator:

prog, _ := hcl.Parse(`
	locals { mode = "0644" }
	resource "file" "app" {
		ensure  = "present"
		mode    = local.mode
		require = resource.package.app
	}
`)
cat, _ := eval.New().EvalProgram(prog)
fmt.Println(cat.JSON())

Constructs outside the v0.1 mapping (function calls, a ? b : c, for comprehensions, %{…} directives, unknown block types) return a clear unsupported in HCL2 v0.1: … error rather than a fake stub.

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.

Evaluation & catalog Roadmap