From 69e515326f139fda7746c9e3444100a643410ede Mon Sep 17 00:00:00 2001
From: Elara Musayelyan <elara@elara.ws>
Date: Mon, 30 Oct 2023 21:06:17 -0700
Subject: [PATCH] Make macros per-template-execution

---
 macro_tag.go | 12 ++++++------
 namespace.go | 18 +++++++-----------
 salix.go     | 20 +++++++++++++++++++-
 3 files changed, 32 insertions(+), 18 deletions(-)

diff --git a/macro_tag.go b/macro_tag.go
index fbcafd7..ad53027 100644
--- a/macro_tag.go
+++ b/macro_tag.go
@@ -30,17 +30,17 @@ func (mt macroTag) Run(tc *TagContext, block, args []ast.Node) error {
 	}
 
 	if len(block) == 0 {
-		tc.t.ns.mu.Lock()
-		macro, ok := tc.t.ns.macros[name]
+		tc.t.macroMtx.Lock()
+		macro, ok := tc.t.macros[name]
 		if !ok {
 			return ErrNoSuchMacro
 		}
-		tc.t.ns.mu.Unlock()
+		tc.t.macroMtx.Unlock()
 		return tc.Execute(macro, nil)
 	} else {
-		tc.t.ns.mu.Lock()
-		tc.t.ns.macros[name] = block
-		tc.t.ns.mu.Unlock()
+		tc.t.macroMtx.Lock()
+		tc.t.macros[name] = block
+		tc.t.macroMtx.Unlock()
 	}
 
 	return nil
diff --git a/namespace.go b/namespace.go
index b530980..68e458b 100644
--- a/namespace.go
+++ b/namespace.go
@@ -21,26 +21,22 @@ package salix
 import (
 	"reflect"
 	"sync"
-
-	"go.elara.ws/salix/ast"
 )
 
 // Namespace represents a collection of templates that can include each other
 type Namespace struct {
-	mu     sync.Mutex
-	tmpls  map[string]*Template
-	vars   map[string]reflect.Value
-	tags   map[string]Tag
-	macros map[string][]ast.Node
+	mu    sync.Mutex
+	tmpls map[string]*Template
+	vars  map[string]reflect.Value
+	tags  map[string]Tag
 }
 
 // New returns a new template namespace
 func New() *Namespace {
 	return &Namespace{
-		tmpls:  map[string]*Template{},
-		vars:   map[string]reflect.Value{},
-		tags:   map[string]Tag{},
-		macros: map[string][]ast.Node{},
+		tmpls: map[string]*Template{},
+		vars:  map[string]reflect.Value{},
+		tags:  map[string]Tag{},
 	}
 }
 
diff --git a/salix.go b/salix.go
index 70c023d..8460890 100644
--- a/salix.go
+++ b/salix.go
@@ -24,6 +24,7 @@ import (
 	"html"
 	"io"
 	"reflect"
+	"sync"
 
 	"go.elara.ws/salix/ast"
 )
@@ -61,6 +62,9 @@ type Template struct {
 
 	tags map[string]Tag
 	vars map[string]reflect.Value
+
+	macroMtx sync.Mutex
+	macros   map[string][]ast.Node
 }
 
 // WithVarMap returns a copy of the template with its variable map set to m.
@@ -124,7 +128,21 @@ func (t *Template) WithEscapeHTML(b bool) *Template {
 // Execute executes a parsed template and writes
 // the result to w.
 func (t *Template) Execute(w io.Writer) error {
-	return t.execute(w, t.ast, nil)
+	// Create a new template to give each execution
+	// its own macros
+	tmpl := &Template{
+		ns:   t.ns,
+		name: t.name,
+		ast:  t.ast,
+
+		escapeHTML: t.escapeHTML,
+
+		tags:   t.tags,
+		vars:   t.vars,
+		macros: map[string][]ast.Node{},
+	}
+
+	return tmpl.execute(w, t.ast, nil)
 }
 
 func (t *Template) execute(w io.Writer, nodes []ast.Node, local map[string]any) error {