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go-pcore documentation

A pure-Go reimplementation of Puppet's Pcore type system — the data-type and value model that underpins Puppet, Hiera and Facter values, built with zero cgo.

go-pcore/pcore gives a Go program the Puppet type calculus: a type model, a type parser, a value model, and the load-bearing operations — instance-of, assignability, inference and rich-data serialization. Type names and semantics track Puppet's Puppet::Pops::Types, so it is a drop-in for Puppet type expressions. The module path is github.com/go-pcore/pcore.

Status: v0.2 — full Pcore type calculus

The complete Puppet Puppet::Pops::Types set is implemented: type model, round-trippable parser, value model, and IsInstance / IsAssignable / Infer / Generalize / CommonType / ToData / FromData, plus recursive type aliases and TypeSet via a Loader type environment, Timestamp / Timespan ranges, SemVer / SemVerRange, Init, Object, RichData, Runtime, URI, Iterable / Iterator, Error and Callable — at 100% coverage, gofmt + go vet clean, CI green across the six 64-bit Go targets (amd64, arm64, riscv64, loong64, ppc64le, s390x).

Install

go get github.com/go-pcore/pcore

Quick taste

package main

import (
    "fmt"

    "github.com/go-pcore/pcore"
)

func main() {
    t, _ := pcore.Parse("Variant[Integer[0,10], Enum['a','b']]")

    fmt.Println(pcore.IsInstance(t, int64(7))) // true
    fmt.Println(pcore.IsInstance(t, "a"))      // true
    fmt.Println(pcore.IsInstance(t, int64(99))) // false

    fmt.Println(pcore.Infer([]pcore.Value{int64(1), int64(2)}))
    // Array[Integer[1, 2], 2, 2]

    fmt.Println(t.String()) // round-trips through Parse
}

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