Refining

examples/sample.hcl

@@ -0,0 +1,8 @@
+# Arithmetic with literals and application-provided variables
+sum = 1 + addend
+
+# String interpolation and templates
+message = "Hello, ${name}!"
+
+# Application-provided functions
+shouty_message = upper(message)

pkg/yqlib/decoder_hcl.go

@@ -128,7 +128,9 @@ func convertHclExprToNode(expr hclsyntax.Expression, src []byte) *CandidateNode
 			// prefer to extract exact source (to avoid extra quoting) when available
 			// Prefer the actual cty string value
 			s := v.AsString()
-			return createScalarNode(s, s)
+			node := createScalarNode(s, s)
+			// Don't set style for regular quoted strings - let YAML handle naturally
+			return node
 		case v.Type().Equals(cty.Bool):
 			b := v.True()
 			return createScalarNode(b, strconv.FormatBool(b))
@@ -192,8 +194,8 @@ func convertHclExprToNode(expr hclsyntax.Expression, src []byte) *CandidateNode
 				r := item.KeyExpr.Range()
 				start := r.Start.Byte
 				end := r.End.Byte
-				if start > 0 && end >= start && end <= len(src) {
-					keyNode := createStringScalarNode(strings.TrimSpace(string(src[start-1 : end])))
+				if start >= 0 && end >= start && end <= len(src) {
+					keyNode := createStringScalarNode(strings.TrimSpace(string(src[start:end])))
 					valNode := convertHclExprToNode(item.ValueExpr, src)
 					m.AddKeyValueChild(keyNode, valNode)
 				}
@@ -206,7 +208,7 @@ func convertHclExprToNode(expr hclsyntax.Expression, src []byte) *CandidateNode
 		}
 		return m
 	case *hclsyntax.TemplateExpr:
-		// join parts; if single literal, return that string
+		// Reconstruct template string, preserving ${} syntax for interpolations
 		var parts []string
 		for _, p := range e.Parts {
 			switch lp := p.(type) {
@@ -217,18 +219,24 @@ func convertHclExprToNode(expr hclsyntax.Expression, src []byte) *CandidateNode
 					parts = append(parts, lp.Val.GoString())
 				}
 			default:
+				// Non-literal expression - reconstruct with ${} wrapper
 				r := p.Range()
 				start := r.Start.Byte
 				end := r.End.Byte
-				if start > 0 && end >= start && end <= len(src) {
-					parts = append(parts, strings.TrimSpace(string(src[start-1:end])))
+				if start >= 0 && end >= start && end <= len(src) {
+					exprText := string(src[start:end])
+					parts = append(parts, "${"+exprText+"}")
 				} else {
-					parts = append(parts, fmt.Sprintf("%v", p))
+					parts = append(parts, fmt.Sprintf("${%v}", p))
 				}
 			}
 		}
 		combined := strings.Join(parts, "")
-		return createScalarNode(combined, combined)
+		node := createScalarNode(combined, combined)
+		// Set DoubleQuotedStyle for all templates (which includes all quoted strings in HCL)
+		// This ensures HCL roundtrips preserve quotes, and YAML properly quotes strings with ${}
+		node.Style = DoubleQuotedStyle
+		return node
 	default:
 		// try to evaluate the expression (handles unary, binary ops, etc.)
 		val, diags := expr.Value(nil)
@@ -240,8 +248,9 @@ func convertHclExprToNode(expr hclsyntax.Expression, src []byte) *CandidateNode
 		r := expr.Range()
 		start := r.Start.Byte
 		end := r.End.Byte
-		if start > 0 && end >= start && end <= len(src) {
-			text := string(src[start-1 : end])
+		if start >= 0 && end >= start && end <= len(src) {
+			text := string(src[start:end])
+			// Unquoted identifier - no style
 			return createStringScalarNode(text)
 		}
 		return createStringScalarNode(fmt.Sprintf("%v", expr))

pkg/yqlib/encoder_hcl.go

@@ -6,7 +6,10 @@ import (
 	"fmt"
 	"io"
 	"regexp"
+	"strings"
 
+	"github.com/hashicorp/hcl/v2"
+	"github.com/hashicorp/hcl/v2/hclsyntax"
 	hclwrite "github.com/hashicorp/hcl/v2/hclwrite"
 	"github.com/zclconf/go-cty/cty"
 )
@@ -55,6 +58,36 @@ func (he *hclEncoder) compactSpacing(input []byte) []byte {
 	return re.ReplaceAll(input, []byte("$1 ="))
 }
 
+// Helper runes for unquoted identifiers
+func isHCLIdentifierStart(r rune) bool {
+	return (r >= 'a' && r <= 'z') || (r >= 'A' && r <= 'Z') || r == '_'
+}
+
+func isHCLIdentifierPart(r rune) bool {
+	return (r >= 'a' && r <= 'z') || (r >= 'A' && r <= 'Z') || (r >= '0' && r <= '9') || r == '_' || r == '-'
+}
+
+// isValidHCLIdentifier checks if a string is a valid HCL identifier (unquoted)
+func isValidHCLIdentifier(s string) bool {
+	if s == "" {
+		return false
+	}
+	// HCL identifiers must start with a letter or underscore
+	// and contain only letters, digits, underscores, and hyphens
+	for i, r := range s {
+		if i == 0 {
+			if !isHCLIdentifierStart(r) {
+				return false
+			}
+			continue
+		}
+		if !isHCLIdentifierPart(r) {
+			return false
+		}
+	}
+	return true
+}
+
 // encodeNode encodes a CandidateNode directly to HCL, preserving style information
 func (he *hclEncoder) encodeNode(body *hclwrite.Body, node *CandidateNode) error {
 	if node.Kind != MappingNode {
@@ -75,11 +108,79 @@ func (he *hclEncoder) encodeNode(body *hclwrite.Body, node *CandidateNode) error
 			}
 		} else {
 			// Render as attribute: key = value
-			ctyValue, err := nodeToCtyValue(valueNode)
-			if err != nil {
-				return err
+			// Check the style to determine how to encode strings
+			if valueNode.Kind == ScalarNode && valueNode.Tag == "!!str" {
+				// Check style: DoubleQuotedStyle means template, no style could be unquoted or regular
+				// To distinguish unquoted from regular, we check if the value is a valid identifier
+				if valueNode.Style&DoubleQuotedStyle != 0 && strings.Contains(valueNode.Value, "${") {
+					// Template string - use raw tokens to preserve ${} syntax
+					tokens := hclwrite.Tokens{
+						{Type: hclsyntax.TokenOQuote, Bytes: []byte{'"'}},
+					}
+					// Parse the string and add tokens
+					for i := 0; i < len(valueNode.Value); i++ {
+						if i < len(valueNode.Value)-1 && valueNode.Value[i] == '$' && valueNode.Value[i+1] == '{' {
+							// Start of template interpolation
+							tokens = append(tokens, &hclwrite.Token{
+								Type:  hclsyntax.TokenTemplateInterp,
+								Bytes: []byte("${"),
+							})
+							i++ // skip the '{'
+							// Find the matching '}'
+							start := i + 1
+							depth := 1
+							for i++; i < len(valueNode.Value) && depth > 0; i++ {
+								switch valueNode.Value[i] {
+								case '{':
+									depth++
+								case '}':
+									depth--
+								}
+							}
+							i-- // back up to the '}'
+							interpExpr := valueNode.Value[start:i]
+							tokens = append(tokens, &hclwrite.Token{
+								Type:  hclsyntax.TokenIdent,
+								Bytes: []byte(interpExpr),
+							})
+							tokens = append(tokens, &hclwrite.Token{
+								Type:  hclsyntax.TokenTemplateSeqEnd,
+								Bytes: []byte("}"),
+							})
+						} else {
+							// Regular character
+							tokens = append(tokens, &hclwrite.Token{
+								Type:  hclsyntax.TokenQuotedLit,
+								Bytes: []byte{valueNode.Value[i]},
+							})
+						}
+					}
+					tokens = append(tokens, &hclwrite.Token{Type: hclsyntax.TokenCQuote, Bytes: []byte{'"'}})
+					body.SetAttributeRaw(key, tokens)
+				} else if isValidHCLIdentifier(valueNode.Value) && valueNode.Style == 0 {
+					// Could be unquoted identifier - but only if it came from HCL originally
+					// For safety, only use traversal if style is explicitly 0 (not set)
+					// This avoids treating strings from YAML as unquoted
+					traversal := hcl.Traversal{
+						hcl.TraverseRoot{Name: valueNode.Value},
+					}
+					body.SetAttributeTraversal(key, traversal)
+				} else {
+					// Regular quoted string - use cty.Value
+					ctyValue, err := nodeToCtyValue(valueNode)
+					if err != nil {
+						return err
+					}
+					body.SetAttributeValue(key, ctyValue)
+				}
+			} else {
+				// Non-string value - use cty.Value
+				ctyValue, err := nodeToCtyValue(valueNode)
+				if err != nil {
+					return err
+				}
+				body.SetAttributeValue(key, ctyValue)
 			}
-			body.SetAttributeValue(key, ctyValue)
 		}
 	}
 	return nil
@@ -96,11 +197,21 @@ func (he *hclEncoder) encodeNodeAttributes(body *hclwrite.Body, node *CandidateN
 		valueNode := node.Content[i+1]
 		key := keyNode.Value
 
-		ctyValue, err := nodeToCtyValue(valueNode)
-		if err != nil {
-			return err
+		// Check if this is an unquoted identifier (no DoubleQuotedStyle)
+		if valueNode.Kind == ScalarNode && valueNode.Tag == "!!str" && valueNode.Style&DoubleQuotedStyle == 0 {
+			// Unquoted identifier - use traversal
+			traversal := hcl.Traversal{
+				hcl.TraverseRoot{Name: valueNode.Value},
+			}
+			body.SetAttributeTraversal(key, traversal)
+		} else {
+			// Quoted value or non-string - use cty.Value
+			ctyValue, err := nodeToCtyValue(valueNode)
+			if err != nil {
+				return err
+			}
+			body.SetAttributeValue(key, ctyValue)
 		}
-		body.SetAttributeValue(key, ctyValue)
 	}
 	return nil
 }

pkg/yqlib/hcl_test.go

@@ -10,9 +10,33 @@ var hclFormatScenarios = []formatScenario{
 	{
 		description:  "Simple decode",
 		input:        `io_mode = "async"`,
+		expected:     "io_mode: \"async\"\n",
+		scenarioType: "decode",
+	},
+	{
+		description:  "Simple decode, no quotes",
+		input:        `io_mode = async`,
 		expected:     "io_mode: async\n",
 		scenarioType: "decode",
 	},
+	{
+		description:  "Simple roundtrip, no quotes",
+		input:        `io_mode = async`,
+		expected:     "io_mode = async\n",
+		scenarioType: "roundtrip",
+	},
+	{
+		description:  "Template decode",
+		input:        `message = "Hello, ${name}!"`,
+		expected:     "message: \"Hello, ${name}!\"\n",
+		scenarioType: "decode",
+	},
+	{
+		description:  "Template roundtrip",
+		input:        `message = "Hello, ${name}!"`,
+		expected:     "message = \"Hello, ${name}!\"\n",
+		scenarioType: "roundtrip",
+	},
 	{
 		description:  "number attribute",
 		input:        `port = 8080`,
@@ -34,13 +58,13 @@ var hclFormatScenarios = []formatScenario{
 	{
 		description:  "list of strings",
 		input:        `tags = ["a", "b"]`,
-		expected:     "tags:\n  - a\n  - b\n",
+		expected:     "tags:\n  - \"a\"\n  - \"b\"\n",
 		scenarioType: "decode",
 	},
 	{
 		description:  "object/map attribute",
 		input:        `obj = { a = 1, b = "two" }`,
-		expected:     "obj: {a: 1, b: two}\n",
+		expected:     "obj: {a: 1, b: \"two\"}\n",
 		scenarioType: "decode",
 	},
 	{
@@ -52,7 +76,7 @@ var hclFormatScenarios = []formatScenario{
 	{
 		description:  "multiple attributes",
 		input:        "name = \"app\"\nversion = 1\nenabled = true",
-		expected:     "name: app\nversion: 1\nenabled: true\n",
+		expected:     "name: \"app\"\nversion: 1\nenabled: true\n",
 		scenarioType: "decode",
 	},
 	{
@@ -76,19 +100,19 @@ var hclFormatScenarios = []formatScenario{
 	{
 		description:  "nested object",
 		input:        `config = { db = { host = "localhost", port = 5432 } }`,
-		expected:     "config: {db: {host: localhost, port: 5432}}\n",
+		expected:     "config: {db: {host: \"localhost\", port: 5432}}\n",
 		scenarioType: "decode",
 	},
 	{
 		description:  "mixed list",
 		input:        `values = [1, "two", true]`,
-		expected:     "values:\n  - 1\n  - two\n  - true\n",
+		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",
+		expected:     "resource aws_instance example:\n  ami: \"ami-12345\"\n",
 		scenarioType: "decode",
 	},
 	{

project-words.txt

@@ -189,8 +189,11 @@ risentveber
 rmescandon
 Rosey
 roundtrip
+roundtrips
 Roundtrip
 roundtripping
+Interp
+interp
 runningvms
 sadface
 selfupdate