diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index 631ebb9..73cb03a 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -4,6 +4,9 @@ on:
   push:
     branches:
     - main
+  pull_request:
+    branches:
+    - main
 
 
 jobs:
diff --git a/pkg/ast/ast.go b/pkg/ast/ast.go
index 09ae1d5..af376bd 100644
--- a/pkg/ast/ast.go
+++ b/pkg/ast/ast.go
@@ -4,6 +4,7 @@ package ast
 import (
 	"fmt"
 	"math/rand"
+	"slices"
 	"strings"
 )
 
@@ -105,12 +106,20 @@ func (ai *AddInstructionNode) Instruction() string { return "ADD" }
 
 // ARG
 type ArgInstructionNode struct {
-	Name  string
-	Value string // optional default
+	Pairs map[string]string
 }
 
 func (ai *ArgInstructionNode) ToString() string {
-	return fmt.Sprintf("%sARG%s %s %s %s", colorPurple, colorCyan, ai.Name, ai.Value, colorNone)
+	mapStrings := []string{}
+	keys := make([]string, 0, len(ai.Pairs))
+	for k := range ai.Pairs {
+		keys = append(keys, k)
+	}
+	slices.Sort(keys)
+	for _, k := range keys {
+		mapStrings = append(mapStrings, fmt.Sprintf("%s=%s", k, ai.Pairs[k]))
+	}
+	return fmt.Sprintf("%sARG%s %s %s", colorPurple, colorCyan, strings.Join(mapStrings, ","), colorNone)
 }
 
 func (ai *ArgInstructionNode) Instruction() string { return "ARG" }
diff --git a/pkg/ast/reconstruct.go b/pkg/ast/reconstruct.go
index 45c040d..109a4a0 100644
--- a/pkg/ast/reconstruct.go
+++ b/pkg/ast/reconstruct.go
@@ -26,11 +26,12 @@ func escapeSlice[T any](slice []T) string {
 func (sn *StageNode) Reconstruct() []string {
 	reconstructed := []string{}
 	if sn.Image != "" {
-		fromInstruction := fmt.Sprintf("FROM %s", sn.Image)
+		var fromInstruction strings.Builder
+		fromInstruction.WriteString(fmt.Sprintf("FROM %s", sn.Image))
 		if sn.Name != "" {
-			fromInstruction += fmt.Sprintf(" AS %s", sn.Name)
+			fromInstruction.WriteString(fmt.Sprintf(" AS %s", sn.Name))
 		}
-		reconstructed = append(reconstructed, fromInstruction)
+		reconstructed = append(reconstructed, fromInstruction.String())
 	}
 	for _, instructionNode := range sn.Instructions {
 		reconstructed = append(reconstructed, instructionNode.Reconstruct()...)
@@ -55,7 +56,17 @@ func (ai *AddInstructionNode) Reconstruct() []string {
 }
 
 func (ai *ArgInstructionNode) Reconstruct() []string {
-	reconstructed := fmt.Sprintf("%s %s=%s", ai.Instruction(), ai.Name, ai.Value)
+	reconstructed := fmt.Sprintf("%s", ai.Instruction())
+	keys := make([]string, len(ai.Pairs))
+	index := 0
+	for k := range ai.Pairs {
+		keys[index] = k
+		index++
+	}
+	slices.Sort(keys)
+	for _, k := range keys {
+		reconstructed += fmt.Sprintf(" %s=%s", k, ai.Pairs[k])
+	}
 	return []string{reconstructed}
 }
 
@@ -64,22 +75,24 @@ func (ci *CmdInstructionNode) Reconstruct() []string {
 	return []string{reconstructed}
 }
 func (ci *CopyInstructionNode) Reconstruct() []string {
-	reconstructed := fmt.Sprintf("%s ", ci.Instruction())
+	var reconstructed strings.Builder
+	reconstructed.WriteString(fmt.Sprintf("%s ", ci.Instruction()))
 
-	reconstructed += formatIfValue("--keep-git-dir=%s ", strconv.FormatBool(ci.KeepGitDir))
-	reconstructed += formatIfValue("--chown=%s ", ci.Chown)
-	reconstructed += formatIfValue("--link=%s ", strconv.FormatBool(ci.Link))
-	reconstructed += formatIfValue("--from=%s ", ci.From)
-	reconstructed += fmt.Sprintf("%s ", strings.Join(ci.Source, " "))
-	reconstructed += fmt.Sprintf("%s", ci.Destination)
-	return []string{reconstructed}
+	reconstructed.WriteString(formatIfValue("--keep-git-dir=%s ", strconv.FormatBool(ci.KeepGitDir)))
+	reconstructed.WriteString(formatIfValue("--chown=%s ", ci.Chown))
+	reconstructed.WriteString(formatIfValue("--link=%s ", strconv.FormatBool(ci.Link)))
+	reconstructed.WriteString(formatIfValue("--from=%s ", ci.From))
+	reconstructed.WriteString(fmt.Sprintf("%s ", strings.Join(ci.Source, " ")))
+	reconstructed.WriteString(fmt.Sprintf("%s", ci.Destination))
+	return []string{reconstructed.String()}
 }
 func (ei *EntrypointInstructionNode) Reconstruct() []string {
 	reconstructed := fmt.Sprintf("%s %s", ei.Instruction(), escapeSlice(ei.Exec))
 	return []string{reconstructed}
 }
 func (ei *EnvInstructionNode) Reconstruct() []string {
-	reconstructed := fmt.Sprintf("%s", ei.Instruction())
+	var reconstructed strings.Builder
+	reconstructed.WriteString(fmt.Sprintf("%s", ei.Instruction()))
 	keys := make([]string, len(ei.Pairs))
 	index := 0
 	for k := range ei.Pairs {
@@ -88,41 +101,52 @@ func (ei *EnvInstructionNode) Reconstruct() []string {
 	}
 	slices.Sort(keys)
 	for _, k := range keys {
-		reconstructed += fmt.Sprintf(" %s=%s", k, ei.Pairs[k])
+		reconstructed.WriteString(fmt.Sprintf(" %s=%s", k, ei.Pairs[k]))
 	}
-	return []string{reconstructed}
+	return []string{reconstructed.String()}
 }
 
 func (ei *ExposeInstructionNode) Reconstruct() []string {
-	reconstructed := fmt.Sprintf("%s", ei.Instruction())
+	var reconstructed strings.Builder
+	reconstructed.WriteString(fmt.Sprintf("%s", ei.Instruction()))
 	for _, port := range ei.Ports {
 		protocol := "tcp"
 		if !port.IsTCP {
 			protocol = "udp"
 		}
-		reconstructed += fmt.Sprintf(" %s/%s", port.Port, protocol)
+		reconstructed.WriteString(fmt.Sprintf(" %s/%s", port.Port, protocol))
 	}
-	return []string{reconstructed}
+	return []string{reconstructed.String()}
 }
 func (hi *HealthcheckInstructionNode) Reconstruct() []string {
-	reconstructed := fmt.Sprintf("%s ", hi.Instruction())
+	var reconstructed strings.Builder
+	reconstructed.WriteString(fmt.Sprintf("%s ", hi.Instruction()))
 	if hi.CancelStatement {
-		return []string{reconstructed + "NONE"}
+		reconstructed.WriteString("NONE")
+		return []string{reconstructed.String()}
 	}
-	reconstructed += formatIfValue("--interval=%s ", hi.Interval)
-	reconstructed += formatIfValue("--timeout=%s ", hi.Timeout)
-	reconstructed += formatIfValue("--start-period=%s ", hi.StartPeriod)
-	reconstructed += formatIfValue("--start-interval=%s ", hi.StartInterval)
-	reconstructed += formatIfValue("--retries=%s ", strconv.Itoa(hi.Retries))
-	reconstructed += escapeSlice(hi.Cmd)
-	return []string{reconstructed}
+	reconstructed.WriteString(formatIfValue("--interval=%s ", hi.Interval))
+	reconstructed.WriteString(formatIfValue("--timeout=%s ", hi.Timeout))
+	reconstructed.WriteString(formatIfValue("--start-period=%s ", hi.StartPeriod))
+	reconstructed.WriteString(formatIfValue("--start-interval=%s ", hi.StartInterval))
+	reconstructed.WriteString(formatIfValue("--retries=%s ", strconv.Itoa(hi.Retries)))
+	reconstructed.WriteString(escapeSlice(hi.Cmd))
+	return []string{reconstructed.String()}
 }
 func (li *LabelInstructionNode) Reconstruct() []string {
-	reconstructed := fmt.Sprintf("%s", li.Instruction())
-	for k, v := range li.Pairs {
-		reconstructed += fmt.Sprintf(" %s=%s", k, v)
+	var reconstructed strings.Builder
+	reconstructed.WriteString(fmt.Sprintf("%s", li.Instruction()))
+	keys := make([]string, len(li.Pairs))
+	index := 0
+	for k := range li.Pairs {
+		keys[index] = k
+		index++
 	}
-	return []string{reconstructed}
+	slices.Sort(keys)
+	for _, k := range keys {
+		reconstructed.WriteString(fmt.Sprintf(" %s=%s", k, li.Pairs[k]))
+	}
+	return []string{reconstructed.String()}
 }
 func (mi *MaintainerInstructionNode) Reconstruct() []string {
 	reconstructed := fmt.Sprintf("%s %s", mi.Instruction(), mi.Name)
@@ -135,14 +159,16 @@ func (oi *OnbuildInstructionNode) Reconstruct() []string {
 	return nested
 }
 func (ri *RunInstructionNode) Reconstruct() []string {
-	reconstructed := fmt.Sprintf("%s ", ri.Instruction())
+	var reconstructed strings.Builder
+	reconstructed.WriteString(fmt.Sprintf("%s ", ri.Instruction()))
 	if !ri.ShellForm && !ri.IsHeredoc {
-		return []string{reconstructed + escapeSlice(ri.Cmd)}
+		reconstructed.WriteString(escapeSlice(ri.Cmd))
+		return []string{reconstructed.String()}
 	}
 	if ri.IsHeredoc {
-		reconstructed += "<< "
+		reconstructed.WriteString("<< ")
 	}
-	ri.Cmd[0] = reconstructed + ri.Cmd[0]
+	ri.Cmd[0] = reconstructed.String() + ri.Cmd[0]
 	return ri.Cmd
 }
 func (si *ShellInstructionNode) Reconstruct() []string {
diff --git a/pkg/ast/reconstruct_test.go b/pkg/ast/reconstruct_test.go
index 120645c..1657fb6 100644
--- a/pkg/ast/reconstruct_test.go
+++ b/pkg/ast/reconstruct_test.go
@@ -58,13 +58,28 @@ func TestReconstructInstruction(t *testing.T) {
 			Input: ast.StageNode{
 				Instructions: []ast.InstructionNode{
 					&ast.ArgInstructionNode{
-						Name:  "abc",
-						Value: "def",
+						Pairs: map[string]string{
+							"abc": "def",
+						},
 					},
 				},
 			},
 			Expected: []string{"ARG abc=def"},
 		},
+		{
+			Input: ast.StageNode{
+				Instructions: []ast.InstructionNode{
+					&ast.ArgInstructionNode{
+						Pairs: map[string]string{
+							"abc": "def",
+							"xy":  "z",
+						},
+					},
+				},
+			},
+			Expected: []string{"ARG abc=def xy=z"},
+		},
+
 		{
 			Input: ast.StageNode{
 				Instructions: []ast.InstructionNode{
diff --git a/pkg/parser/parser.go b/pkg/parser/parser.go
index 298e3fa..3127868 100644
--- a/pkg/parser/parser.go
+++ b/pkg/parser/parser.go
@@ -155,13 +155,12 @@ func (p Parser) parseAdd(t token.Token) ast.InstructionNode {
 }
 
 func (p Parser) parseArg(t token.Token) ast.InstructionNode {
-	key, value := util.ParseAssign(t.Content)
-	if len(key)+len(value) == 0 {
-		key = t.Content
+	pairs := util.ParseAssigns(t.Content)
+	if len(pairs) == 0 {
+		pairs[t.Content] = ""
 	}
 	return &ast.ArgInstructionNode{
-		Name:  key,
-		Value: value,
+		Pairs: pairs,
 	}
 }
 
diff --git a/pkg/parser/parser_test.go b/pkg/parser/parser_test.go
index df5c13d..5a97ff6 100644
--- a/pkg/parser/parser_test.go
+++ b/pkg/parser/parser_test.go
@@ -116,7 +116,7 @@ func compareInstructionNode(expected, actual ast.InstructionNode) string {
 	case *ast.AddInstructionNode:
 		return compareAddInstructionNode(expected.(*ast.AddInstructionNode), ac)
 	case *ast.ArgInstructionNode:
-		if *expected.(*ast.ArgInstructionNode) != *ac {
+		if !reflect.DeepEqual(expected.(*ast.ArgInstructionNode).Pairs, ac.Pairs) {
 			return fmt.Sprintf("ARG instruction mismatch: Expected %v Got %v", expected, ac)
 		}
 	case *ast.CmdInstructionNode:
@@ -314,8 +314,7 @@ func TestInstructionParsing(t *testing.T) {
 				},
 			},
 			Expected: []ast.InstructionNode{&ast.ArgInstructionNode{
-				Name:  "test",
-				Value: "value",
+				Pairs: map[string]string{"test": "value"},
 			}},
 		},
 		{
@@ -326,8 +325,7 @@ func TestInstructionParsing(t *testing.T) {
 				},
 			},
 			Expected: []ast.InstructionNode{&ast.ArgInstructionNode{
-				Name:  "test",
-				Value: "",
+				Pairs: map[string]string{"test": ""},
 			}},
 		},
 		{