253 lines
6.5 KiB
Go
253 lines
6.5 KiB
Go
/*
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Serene --- Yet an other Lisp
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Copyright (c) 2020 Sameer Rahmani <lxsameer@gnu.org>
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation, either version 2 of the License.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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package core
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import (
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"fmt"
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"serene-lang.org/bootstrap/pkg/ast"
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"serene-lang.org/bootstrap/pkg/hash"
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)
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type INamespace interface {
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// TODO: Add a method to fetch the source code based on the source value
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DefineGlobal()
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LookupGlobal()
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GetRootScope() IScope
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// return the fully qualified name of the namespace
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GetName() string
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getForms() *Block
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setForms(forms *Block)
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}
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type Namespace struct {
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// Fully qualified name of the ns. e.g `serene.core`
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name string
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// The root scope of the namespace which keeps the global definitions
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// and values of the scope. But not the external namespaces and values
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rootScope Scope
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// TODO: Add a method to fetch the source code based on this value
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// Path to the source of the name space, it can be a file path
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// or anything related to the ns loader (not implemented yet).
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source string
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externals map[string]*Namespace
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forms Block
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}
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func (n *Namespace) GetType() ast.NodeType {
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return ast.Namespace
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}
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func (n *Namespace) GetLocation() ast.Location {
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return ast.MakeUnknownLocation()
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}
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func (n *Namespace) String() string {
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return fmt.Sprintf("<ns: %s at %s>", n.name, n.source)
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}
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func (n *Namespace) ToDebugStr() string {
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return fmt.Sprintf("<ns: %s at %s>", n.name, n.source)
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}
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// DefineGlobal inserts the given expr `v` to the root scope of
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// `n`. The `public` parameter determines whether the public
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// value is accessable publicly or not (in other namespaces).
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func (n *Namespace) DefineGlobal(k string, v IExpr, public bool) {
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n.rootScope.Insert(k, v, public)
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}
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// LookupGlobal looks up the value represented by the ns qualified
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// symbol `sym` in the external symbols table. Simply looking up
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// a public value from an external namespace.
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func (n *Namespace) LookupGlobal(rt *Runtime, sym *Symbol) *Binding {
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// TODO: Find a better name for this method, `LookupExternal` maybe
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if !sym.IsNSQualified() {
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return nil
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}
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externalNS, ok := n.externals[sym.GetNSPart()]
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if !ok {
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return nil
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}
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externalScope := externalNS.GetRootScope()
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return externalScope.Lookup(rt, sym.GetName())
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}
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func (n *Namespace) GetRootScope() IScope {
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return &n.rootScope
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}
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func (n *Namespace) GetName() string {
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return n.name
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}
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func (n *Namespace) Hash() uint32 {
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return hash.HashOf([]byte(n.String()))
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}
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func (n *Namespace) hasExternal(nsName string) bool {
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_, ok := n.externals[nsName]
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return ok
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}
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// LookupExternal looks up the given `alias` in the `externals` table
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// of the namespace.
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func (n *Namespace) LookupExternal(alias string) *Namespace {
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if n.hasExternal(alias) {
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return n.externals[alias]
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}
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return nil
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}
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func (n *Namespace) setExternal(name string, ns *Namespace) {
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n.externals[name] = ns
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}
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func (n *Namespace) setForms(block *Block) {
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n.forms = *block
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}
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func (n *Namespace) getForms() *Block {
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return &n.forms
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}
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// requireNS finds and loads the namespace addressed by the given
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// `ns` string.
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func requireNS(rt *Runtime, ns string) (*Namespace, IError) {
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// TODO: use a hashing algorithm to avoid reloading an unchanged namespace
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loadedForms, err := rt.LoadNS(ns)
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if err != nil {
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return nil, err
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}
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body := loadedForms.forms
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source := loadedForms.source
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if body.Count() == 0 {
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return nil, MakeError(
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rt,
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fmt.Sprintf("The '%s' ns source code doesn't start with an 'ns' form.", ns),
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)
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}
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namespace := MakeNS(ns, source)
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namespace.setForms(body)
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return &namespace, nil
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}
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// RequireNamespace finds and loads the naemspace which is addressed by the
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// given expression `namespace` and add the loaded namespace to the list
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// of available namespaces on the runtime and add the correct reference
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// to the current namespace. If `namespace` is a symbol, then the name
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// of the symbol would be used as the ns name and an alias with the
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// same name will be added to the current namespace as the external
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// reference. If it is a IColl (List at the moment), then the symbol
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// in the first element would be the ns name and the second symbol
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// will be the name of the alias to be used.
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func RequireNamespace(rt *Runtime, namespace IExpr) (IExpr, IError) {
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var alias string
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var ns *Symbol
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switch namespace.GetType() {
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case ast.Symbol:
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ns = namespace.(*Symbol)
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alias = ns.GetName()
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case ast.List:
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list := namespace.(*List)
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first := list.First()
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if first.GetType() != ast.Symbol {
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return nil, MakeErrorFor(rt, first, "The first element has to be a symbol")
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}
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second := list.Rest().First()
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if second.GetType() != ast.Symbol {
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return nil, MakeErrorFor(rt, first, "The second element has to be a symbol")
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}
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ns = first.(*Symbol)
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alias = second.(*Symbol).GetName()
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default:
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return nil, MakeErrorFor(rt, ns, "Don't know how to load the given namespace")
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}
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loadedNS, err := requireNS(rt, ns.GetName())
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if err != nil {
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return nil, err
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}
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// Since we want to change the current ns to the loaded ns while evaluating it.
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prevNS := rt.CurrentNS()
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rt.InsertNS(ns.GetName(), loadedNS)
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inserted := rt.setCurrentNS(loadedNS.GetName())
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if !inserted {
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return nil, MakeError(
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rt,
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fmt.Sprintf(
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"the namespace '%s' didn't get inserted in the runtime.",
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loadedNS.GetName()),
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)
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}
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// Evaluating the body of the loaded ns (Check for ns validation happens here)
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loadedNS, e := EvalNSBody(rt, loadedNS)
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// Set the current ns back first and then check for an error
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inserted = rt.setCurrentNS(prevNS.GetName())
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if !inserted {
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return nil, MakeError(
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rt,
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fmt.Sprintf(
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"can't set the current ns back to '%s' from '%s'.",
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prevNS.GetName(),
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loadedNS.GetName()),
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)
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}
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if e != nil {
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return nil, e
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}
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// Set the external reference to the loaded ns in the current ns
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prevNS.setExternal(alias, loadedNS)
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return loadedNS, nil
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}
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// MakeNS creates a new namespace with the given `name` and `source`
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func MakeNS(name string, source string) Namespace {
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s := MakeScope(nil)
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return Namespace{
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name: name,
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rootScope: *s,
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source: source,
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externals: map[string]*Namespace{},
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}
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}
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