From 1852073f29a6bdfa5a4176694589263c595b0190 Mon Sep 17 00:00:00 2001
From: Mike Farah <mikefarah@gmail.com>
Date: Sun, 7 Dec 2025 14:52:30 +1100
Subject: [PATCH] hcl - sorted decoding

---
 pkg/yqlib/decoder_hcl.go | 38 +++++++++++++++++++++++++++++-------
 pkg/yqlib/format.go      |  6 ++++++
 pkg/yqlib/hcl_test.go    | 42 ++++++++++++++++++++++++++++++++++++++++
 3 files changed, 79 insertions(+), 7 deletions(-)

diff --git a/pkg/yqlib/decoder_hcl.go b/pkg/yqlib/decoder_hcl.go
index fa6d3010..d9213e20 100644
--- a/pkg/yqlib/decoder_hcl.go
+++ b/pkg/yqlib/decoder_hcl.go
@@ -4,6 +4,7 @@ import (
 	"fmt"
 	"io"
 	"math/big"
+	"sort"
 	"strconv"
 	"strings"
 
@@ -23,6 +24,23 @@ func NewHclDecoder() Decoder {
 	return &hclDecoder{}
 }
 
+// sortedAttributes returns attributes in declaration order by source position
+func sortedAttributes(attrs hclsyntax.Attributes) []*attributeWithName {
+	var sorted []*attributeWithName
+	for name, attr := range attrs {
+		sorted = append(sorted, &attributeWithName{Name: name, Attr: attr})
+	}
+	sort.Slice(sorted, func(i, j int) bool {
+		return sorted[i].Attr.Range().Start.Byte < sorted[j].Attr.Range().Start.Byte
+	})
+	return sorted
+}
+
+type attributeWithName struct {
+	Name string
+	Attr *hclsyntax.Attribute
+}
+
 func (dec *hclDecoder) Init(reader io.Reader) error {
 	data, err := io.ReadAll(reader)
 	if err != nil {
@@ -51,11 +69,11 @@ func (dec *hclDecoder) Decode() (*CandidateNode, error) {
 
 	root := &CandidateNode{Kind: MappingNode}
 
-	// process attributes
+	// process attributes in declaration order
 	body := dec.file.Body.(*hclsyntax.Body)
-	for name, attr := range body.Attributes {
-		keyNode := createStringScalarNode(name)
-		valNode := convertHclExprToNode(attr.Expr, dec.fileBytes)
+	for _, attrWithName := range sortedAttributes(body.Attributes) {
+		keyNode := createStringScalarNode(attrWithName.Name)
+		valNode := convertHclExprToNode(attrWithName.Attr.Expr, dec.fileBytes)
 		root.AddKeyValueChild(keyNode, valNode)
 	}
 
@@ -78,9 +96,9 @@ func (dec *hclDecoder) Decode() (*CandidateNode, error) {
 
 func hclBodyToNode(body *hclsyntax.Body, src []byte) *CandidateNode {
 	node := &CandidateNode{Kind: MappingNode}
-	for name, attr := range body.Attributes {
-		key := createStringScalarNode(name)
-		val := convertHclExprToNode(attr.Expr, src)
+	for _, attrWithName := range sortedAttributes(body.Attributes) {
+		key := createStringScalarNode(attrWithName.Name)
+		val := convertHclExprToNode(attrWithName.Attr.Expr, src)
 		node.AddKeyValueChild(key, val)
 	}
 	for _, block := range body.Blocks {
@@ -209,6 +227,12 @@ func convertHclExprToNode(expr hclsyntax.Expression, src []byte) *CandidateNode
 		combined := strings.Join(parts, "")
 		return createScalarNode(combined, combined)
 	default:
+		// try to evaluate the expression (handles unary, binary ops, etc.)
+		val, diags := expr.Value(nil)
+		if diags == nil || !diags.HasErrors() {
+			// successfully evaluated, convert cty.Value to node
+			return convertCtyValueToNode(val)
+		}
 		// fallback: extract source text for the expression
 		r := expr.Range()
 		start := r.Start.Byte
diff --git a/pkg/yqlib/format.go b/pkg/yqlib/format.go
index 67cc1e22..030ba48d 100644
--- a/pkg/yqlib/format.go
+++ b/pkg/yqlib/format.go
@@ -67,6 +67,11 @@ var TomlFormat = &Format{"toml", []string{},
 	func() Decoder { return NewTomlDecoder() },
 }
 
+var HclFormat = &Format{"hcl", []string{"h", "hcl"},
+	nil,
+	func() Decoder { return NewHclDecoder() },
+}
+
 var ShellVariablesFormat = &Format{"shell", []string{"s", "sh"},
 	func() Encoder { return NewShellVariablesEncoder() },
 	nil,
@@ -93,6 +98,7 @@ var Formats = []*Format{
 	UriFormat,
 	ShFormat,
 	TomlFormat,
+	HclFormat,
 	ShellVariablesFormat,
 	LuaFormat,
 	INIFormat,
diff --git a/pkg/yqlib/hcl_test.go b/pkg/yqlib/hcl_test.go
index 35db2f4c..ad7fa5ba 100644
--- a/pkg/yqlib/hcl_test.go
+++ b/pkg/yqlib/hcl_test.go
@@ -49,6 +49,48 @@ var hclFormatScenarios = []formatScenario{
 		expected:     "server:\n  port: 8080\n",
 		scenarioType: "decode",
 	},
+	{
+		description:  "multiple attributes",
+		input:        "name = \"app\"\nversion = 1\nenabled = true",
+		expected:     "name: app\nversion: 1\nenabled: true\n",
+		scenarioType: "decode",
+	},
+	{
+		description:  "binary expression",
+		input:        `count = 0 - 42`,
+		expected:     "count: -42\n",
+		scenarioType: "decode",
+	},
+	{
+		description:  "negative number",
+		input:        `count = -42`,
+		expected:     "count: -42\n",
+		scenarioType: "decode",
+	},
+	{
+		description:  "scientific notation",
+		input:        `value = 1e-3`,
+		expected:     "value: 0.001\n",
+		scenarioType: "decode",
+	},
+	{
+		description:  "nested object",
+		input:        `config = { db = { host = "localhost", port = 5432 } }`,
+		expected:     "config:\n  db:\n    host: localhost\n    port: 5432\n",
+		scenarioType: "decode",
+	},
+	{
+		description:  "mixed list",
+		input:        `values = [1, "two", true]`,
+		expected:     "values:\n  - 1\n  - two\n  - true\n",
+		scenarioType: "decode",
+	},
+	{
+		description:  "block with labels",
+		input:        `resource "aws_instance" "example" { ami = "ami-12345" }`,
+		expected:     "resource aws_instance example:\n  ami: ami-12345\n",
+		scenarioType: "decode",
+	},
 }
 
 func testHclScenario(t *testing.T, s formatScenario) {