From e092329bf31860d6172c6b924d402a77251e1b24 Mon Sep 17 00:00:00 2001
From: Mike Farah <mikefarah@gmail.com>
Date: Tue, 5 Mar 2024 14:10:12 +1100
Subject: [PATCH] String interpolation! #1149

---
 acceptance_tests/flags.sh                   |  21 ++
 cmd/root.go                                 |   2 +
 pkg/yqlib/doc/operators/string-operators.md |  34 ++++
 pkg/yqlib/lexer_participle.go               |   6 +-
 pkg/yqlib/lib.go                            | 190 -------------------
 pkg/yqlib/operation.go                      | 200 ++++++++++++++++++++
 pkg/yqlib/operator_strings.go               | 122 +++++++++++-
 pkg/yqlib/operator_strings_test.go          |  58 ++++++
 8 files changed, 435 insertions(+), 198 deletions(-)
 create mode 100755 acceptance_tests/flags.sh
 create mode 100644 pkg/yqlib/operation.go

diff --git a/acceptance_tests/flags.sh b/acceptance_tests/flags.sh
new file mode 100755
index 00000000..db702e3d
--- /dev/null
+++ b/acceptance_tests/flags.sh
@@ -0,0 +1,21 @@
+#!/bin/bash
+
+setUp() {
+  rm test*.yml || true
+  cat >test.yml <<EOL
+# comment
+EOL
+}
+
+testStringInterpolation() {
+    X=$(./yq -n '"Mike \(3 + 4)"')
+    assertEquals "Mike 7" "$X"
+}
+
+testNoStringInterpolation() {
+    X=$(./yq --string-interpolation=f -n '"Mike \(3 + 4)"')
+    assertEquals "Mike \(3 + 4)" "$X"
+}
+
+
+source ./scripts/shunit2
\ No newline at end of file
diff --git a/cmd/root.go b/cmd/root.go
index 84019bae..071c679e 100644
--- a/cmd/root.go
+++ b/cmd/root.go
@@ -158,6 +158,8 @@ yq -P -oy sample.json
 	rootCmd.PersistentFlags().StringVar(&yqlib.ConfiguredPropertiesPreferences.KeyValueSeparator, "properties-separator", yqlib.ConfiguredPropertiesPreferences.KeyValueSeparator, "separator to use between keys and values")
 	rootCmd.PersistentFlags().BoolVar(&yqlib.ConfiguredPropertiesPreferences.UseArrayBrackets, "properties-array-brackets", yqlib.ConfiguredPropertiesPreferences.UseArrayBrackets, "use [x] in array paths (e.g. for SpringBoot)")
 
+	rootCmd.PersistentFlags().BoolVar(&yqlib.StringInterpolationEnabled, "string-interpolation", yqlib.StringInterpolationEnabled, "Toggles strings interpolation of \\(exp)")
+
 	rootCmd.PersistentFlags().BoolVarP(&nullInput, "null-input", "n", false, "Don't read input, simply evaluate the expression given. Useful for creating docs from scratch.")
 	rootCmd.PersistentFlags().BoolVarP(&noDocSeparators, "no-doc", "N", false, "Don't print document separators (---)")
 
diff --git a/pkg/yqlib/doc/operators/string-operators.md b/pkg/yqlib/doc/operators/string-operators.md
index 6f7b8859..e76c8860 100644
--- a/pkg/yqlib/doc/operators/string-operators.md
+++ b/pkg/yqlib/doc/operators/string-operators.md
@@ -56,6 +56,40 @@ IFS= read -rd '' output < <(cat my_file)
 output=$output ./yq '.data.values = strenv(output)' first.yml
 ```
 
+## Interpolation
+Given a sample.yml file of:
+```yaml
+value: things
+another: stuff
+```
+then
+```bash
+yq '.message = "I like \(.value) and \(.another)"' sample.yml
+```
+will output
+```yaml
+value: things
+another: stuff
+message: I like things and stuff
+```
+
+## Interpolation - not a string
+Given a sample.yml file of:
+```yaml
+value:
+  an: apple
+```
+then
+```bash
+yq '.message = "I like \(.value)"' sample.yml
+```
+will output
+```yaml
+value:
+  an: apple
+message: 'I like an: apple'
+```
+
 ## To up (upper) case
 Works with unicode characters
 
diff --git a/pkg/yqlib/lexer_participle.go b/pkg/yqlib/lexer_participle.go
index c6488b4d..736fe305 100644
--- a/pkg/yqlib/lexer_participle.go
+++ b/pkg/yqlib/lexer_participle.go
@@ -374,7 +374,11 @@ func stringValue() yqAction {
 		value = strings.ReplaceAll(value, "\\\"", "\"")
 		value = strings.ReplaceAll(value, "\\n", "\n")
 		log.Debug("replaced: %v", value)
-		return &token{TokenType: operationToken, Operation: createValueOperation(value, value)}, nil
+		return &token{TokenType: operationToken, Operation: &Operation{
+			OperationType: stringInterpolationOpType,
+			StringValue:   value,
+			Value:         value,
+		}}, nil
 	}
 }
 
diff --git a/pkg/yqlib/lib.go b/pkg/yqlib/lib.go
index a3ff8f83..c917c254 100644
--- a/pkg/yqlib/lib.go
+++ b/pkg/yqlib/lib.go
@@ -28,169 +28,6 @@ func GetLogger() *logging.Logger {
 	return log
 }
 
-type operationType struct {
-	Type                 string
-	NumArgs              uint // number of arguments to the op
-	Precedence           uint
-	Handler              operatorHandler
-	CheckForPostTraverse bool
-}
-
-var orOpType = &operationType{Type: "OR", NumArgs: 2, Precedence: 20, Handler: orOperator}
-var andOpType = &operationType{Type: "AND", NumArgs: 2, Precedence: 20, Handler: andOperator}
-var reduceOpType = &operationType{Type: "REDUCE", NumArgs: 2, Precedence: 35, Handler: reduceOperator}
-
-var blockOpType = &operationType{Type: "BLOCK", Precedence: 10, NumArgs: 2, Handler: emptyOperator}
-
-var unionOpType = &operationType{Type: "UNION", NumArgs: 2, Precedence: 10, Handler: unionOperator}
-
-var pipeOpType = &operationType{Type: "PIPE", NumArgs: 2, Precedence: 30, Handler: pipeOperator}
-
-var assignOpType = &operationType{Type: "ASSIGN", NumArgs: 2, Precedence: 40, Handler: assignUpdateOperator}
-var addAssignOpType = &operationType{Type: "ADD_ASSIGN", NumArgs: 2, Precedence: 40, Handler: addAssignOperator}
-var subtractAssignOpType = &operationType{Type: "SUBTRACT_ASSIGN", NumArgs: 2, Precedence: 40, Handler: subtractAssignOperator}
-
-var assignAttributesOpType = &operationType{Type: "ASSIGN_ATTRIBUTES", NumArgs: 2, Precedence: 40, Handler: assignAttributesOperator}
-var assignStyleOpType = &operationType{Type: "ASSIGN_STYLE", NumArgs: 2, Precedence: 40, Handler: assignStyleOperator}
-var assignVariableOpType = &operationType{Type: "ASSIGN_VARIABLE", NumArgs: 2, Precedence: 40, Handler: useWithPipe}
-var assignTagOpType = &operationType{Type: "ASSIGN_TAG", NumArgs: 2, Precedence: 40, Handler: assignTagOperator}
-var assignCommentOpType = &operationType{Type: "ASSIGN_COMMENT", NumArgs: 2, Precedence: 40, Handler: assignCommentsOperator}
-var assignAnchorOpType = &operationType{Type: "ASSIGN_ANCHOR", NumArgs: 2, Precedence: 40, Handler: assignAnchorOperator}
-var assignAliasOpType = &operationType{Type: "ASSIGN_ALIAS", NumArgs: 2, Precedence: 40, Handler: assignAliasOperator}
-
-var multiplyOpType = &operationType{Type: "MULTIPLY", NumArgs: 2, Precedence: 42, Handler: multiplyOperator}
-var multiplyAssignOpType = &operationType{Type: "MULTIPLY_ASSIGN", NumArgs: 2, Precedence: 42, Handler: multiplyAssignOperator}
-
-var divideOpType = &operationType{Type: "DIVIDE", NumArgs: 2, Precedence: 42, Handler: divideOperator}
-
-var moduloOpType = &operationType{Type: "MODULO", NumArgs: 2, Precedence: 42, Handler: moduloOperator}
-
-var addOpType = &operationType{Type: "ADD", NumArgs: 2, Precedence: 42, Handler: addOperator}
-var subtractOpType = &operationType{Type: "SUBTRACT", NumArgs: 2, Precedence: 42, Handler: subtractOperator}
-var alternativeOpType = &operationType{Type: "ALTERNATIVE", NumArgs: 2, Precedence: 42, Handler: alternativeOperator}
-
-var equalsOpType = &operationType{Type: "EQUALS", NumArgs: 2, Precedence: 40, Handler: equalsOperator}
-var notEqualsOpType = &operationType{Type: "NOT_EQUALS", NumArgs: 2, Precedence: 40, Handler: notEqualsOperator}
-
-var compareOpType = &operationType{Type: "COMPARE", NumArgs: 2, Precedence: 40, Handler: compareOperator}
-
-// createmap needs to be above union, as we use union to build the components of the objects
-var createMapOpType = &operationType{Type: "CREATE_MAP", NumArgs: 2, Precedence: 15, Handler: createMapOperator}
-
-var shortPipeOpType = &operationType{Type: "SHORT_PIPE", NumArgs: 2, Precedence: 45, Handler: pipeOperator}
-
-var lengthOpType = &operationType{Type: "LENGTH", NumArgs: 0, Precedence: 50, Handler: lengthOperator}
-var lineOpType = &operationType{Type: "LINE", NumArgs: 0, Precedence: 50, Handler: lineOperator}
-var columnOpType = &operationType{Type: "LINE", NumArgs: 0, Precedence: 50, Handler: columnOperator}
-
-var expressionOpType = &operationType{Type: "EXP", NumArgs: 0, Precedence: 50, Handler: expressionOperator}
-
-var collectOpType = &operationType{Type: "COLLECT", NumArgs: 1, Precedence: 50, Handler: collectOperator}
-var mapOpType = &operationType{Type: "MAP", NumArgs: 1, Precedence: 50, Handler: mapOperator}
-var filterOpType = &operationType{Type: "FILTER", NumArgs: 1, Precedence: 50, Handler: filterOperator}
-var errorOpType = &operationType{Type: "ERROR", NumArgs: 1, Precedence: 50, Handler: errorOperator}
-var pickOpType = &operationType{Type: "PICK", NumArgs: 1, Precedence: 50, Handler: pickOperator}
-var evalOpType = &operationType{Type: "EVAL", NumArgs: 1, Precedence: 50, Handler: evalOperator}
-var mapValuesOpType = &operationType{Type: "MAP_VALUES", NumArgs: 1, Precedence: 50, Handler: mapValuesOperator}
-
-var formatDateTimeOpType = &operationType{Type: "FORMAT_DATE_TIME", NumArgs: 1, Precedence: 50, Handler: formatDateTime}
-var withDtFormatOpType = &operationType{Type: "WITH_DATE_TIME_FORMAT", NumArgs: 1, Precedence: 50, Handler: withDateTimeFormat}
-var nowOpType = &operationType{Type: "NOW", NumArgs: 0, Precedence: 50, Handler: nowOp}
-var tzOpType = &operationType{Type: "TIMEZONE", NumArgs: 1, Precedence: 50, Handler: tzOp}
-var fromUnixOpType = &operationType{Type: "FROM_UNIX", NumArgs: 0, Precedence: 50, Handler: fromUnixOp}
-var toUnixOpType = &operationType{Type: "TO_UNIX", NumArgs: 0, Precedence: 50, Handler: toUnixOp}
-
-var encodeOpType = &operationType{Type: "ENCODE", NumArgs: 0, Precedence: 50, Handler: encodeOperator}
-var decodeOpType = &operationType{Type: "DECODE", NumArgs: 0, Precedence: 50, Handler: decodeOperator}
-
-var anyOpType = &operationType{Type: "ANY", NumArgs: 0, Precedence: 50, Handler: anyOperator}
-var allOpType = &operationType{Type: "ALL", NumArgs: 0, Precedence: 50, Handler: allOperator}
-var containsOpType = &operationType{Type: "CONTAINS", NumArgs: 1, Precedence: 50, Handler: containsOperator}
-var anyConditionOpType = &operationType{Type: "ANY_CONDITION", NumArgs: 1, Precedence: 50, Handler: anyOperator}
-var allConditionOpType = &operationType{Type: "ALL_CONDITION", NumArgs: 1, Precedence: 50, Handler: allOperator}
-
-var toEntriesOpType = &operationType{Type: "TO_ENTRIES", NumArgs: 0, Precedence: 52, Handler: toEntriesOperator, CheckForPostTraverse: true}
-var fromEntriesOpType = &operationType{Type: "FROM_ENTRIES", NumArgs: 0, Precedence: 50, Handler: fromEntriesOperator}
-var withEntriesOpType = &operationType{Type: "WITH_ENTRIES", NumArgs: 1, Precedence: 50, Handler: withEntriesOperator}
-
-var withOpType = &operationType{Type: "WITH", NumArgs: 1, Precedence: 50, Handler: withOperator}
-
-var splitDocumentOpType = &operationType{Type: "SPLIT_DOC", NumArgs: 0, Precedence: 50, Handler: splitDocumentOperator}
-var getVariableOpType = &operationType{Type: "GET_VARIABLE", NumArgs: 0, Precedence: 55, Handler: getVariableOperator}
-var getStyleOpType = &operationType{Type: "GET_STYLE", NumArgs: 0, Precedence: 50, Handler: getStyleOperator}
-var getTagOpType = &operationType{Type: "GET_TAG", NumArgs: 0, Precedence: 50, Handler: getTagOperator}
-var getKindOpType = &operationType{Type: "GET_KIND", NumArgs: 0, Precedence: 50, Handler: getKindOperator}
-
-var getKeyOpType = &operationType{Type: "GET_KEY", NumArgs: 0, Precedence: 50, Handler: getKeyOperator}
-var isKeyOpType = &operationType{Type: "IS_KEY", NumArgs: 0, Precedence: 50, Handler: isKeyOperator}
-var getParentOpType = &operationType{Type: "GET_PARENT", NumArgs: 0, Precedence: 50, Handler: getParentOperator}
-
-var getCommentOpType = &operationType{Type: "GET_COMMENT", NumArgs: 0, Precedence: 50, Handler: getCommentsOperator}
-var getAnchorOpType = &operationType{Type: "GET_ANCHOR", NumArgs: 0, Precedence: 50, Handler: getAnchorOperator}
-var getAliasOpType = &operationType{Type: "GET_ALIAS", NumArgs: 0, Precedence: 50, Handler: getAliasOperator}
-var getDocumentIndexOpType = &operationType{Type: "GET_DOCUMENT_INDEX", NumArgs: 0, Precedence: 50, Handler: getDocumentIndexOperator}
-var getFilenameOpType = &operationType{Type: "GET_FILENAME", NumArgs: 0, Precedence: 50, Handler: getFilenameOperator}
-var getFileIndexOpType = &operationType{Type: "GET_FILE_INDEX", NumArgs: 0, Precedence: 50, Handler: getFileIndexOperator}
-
-var getPathOpType = &operationType{Type: "GET_PATH", NumArgs: 0, Precedence: 50, Handler: getPathOperator}
-var setPathOpType = &operationType{Type: "SET_PATH", NumArgs: 1, Precedence: 50, Handler: setPathOperator}
-var delPathsOpType = &operationType{Type: "DEL_PATHS", NumArgs: 1, Precedence: 50, Handler: delPathsOperator}
-
-var explodeOpType = &operationType{Type: "EXPLODE", NumArgs: 1, Precedence: 50, Handler: explodeOperator}
-var sortByOpType = &operationType{Type: "SORT_BY", NumArgs: 1, Precedence: 50, Handler: sortByOperator}
-var reverseOpType = &operationType{Type: "REVERSE", NumArgs: 0, Precedence: 50, Handler: reverseOperator}
-var sortOpType = &operationType{Type: "SORT", NumArgs: 0, Precedence: 50, Handler: sortOperator}
-var shuffleOpType = &operationType{Type: "SHUFFLE", NumArgs: 0, Precedence: 50, Handler: shuffleOperator}
-
-var sortKeysOpType = &operationType{Type: "SORT_KEYS", NumArgs: 1, Precedence: 50, Handler: sortKeysOperator}
-
-var joinStringOpType = &operationType{Type: "JOIN", NumArgs: 1, Precedence: 50, Handler: joinStringOperator}
-var subStringOpType = &operationType{Type: "SUBSTR", NumArgs: 1, Precedence: 50, Handler: substituteStringOperator}
-var matchOpType = &operationType{Type: "MATCH", NumArgs: 1, Precedence: 50, Handler: matchOperator}
-var captureOpType = &operationType{Type: "CAPTURE", NumArgs: 1, Precedence: 50, Handler: captureOperator}
-var testOpType = &operationType{Type: "TEST", NumArgs: 1, Precedence: 50, Handler: testOperator}
-var splitStringOpType = &operationType{Type: "SPLIT", NumArgs: 1, Precedence: 50, Handler: splitStringOperator}
-var changeCaseOpType = &operationType{Type: "CHANGE_CASE", NumArgs: 0, Precedence: 50, Handler: changeCaseOperator}
-var trimOpType = &operationType{Type: "TRIM", NumArgs: 0, Precedence: 50, Handler: trimSpaceOperator}
-var toStringOpType = &operationType{Type: "TO_STRING", NumArgs: 0, Precedence: 50, Handler: toStringOperator}
-
-var loadOpType = &operationType{Type: "LOAD", NumArgs: 1, Precedence: 52, Handler: loadYamlOperator}
-
-var keysOpType = &operationType{Type: "KEYS", NumArgs: 0, Precedence: 50, Handler: keysOperator}
-
-var collectObjectOpType = &operationType{Type: "COLLECT_OBJECT", NumArgs: 0, Precedence: 50, Handler: collectObjectOperator}
-var traversePathOpType = &operationType{Type: "TRAVERSE_PATH", NumArgs: 0, Precedence: 55, Handler: traversePathOperator}
-var traverseArrayOpType = &operationType{Type: "TRAVERSE_ARRAY", NumArgs: 2, Precedence: 50, Handler: traverseArrayOperator}
-
-var selfReferenceOpType = &operationType{Type: "SELF", NumArgs: 0, Precedence: 55, Handler: selfOperator}
-var valueOpType = &operationType{Type: "VALUE", NumArgs: 0, Precedence: 50, Handler: valueOperator}
-var referenceOpType = &operationType{Type: "REF", NumArgs: 0, Precedence: 50, Handler: referenceOperator}
-var envOpType = &operationType{Type: "ENV", NumArgs: 0, Precedence: 50, Handler: envOperator}
-var notOpType = &operationType{Type: "NOT", NumArgs: 0, Precedence: 50, Handler: notOperator}
-var toNumberOpType = &operationType{Type: "TO_NUMBER", NumArgs: 0, Precedence: 50, Handler: toNumberOperator}
-var emptyOpType = &operationType{Type: "EMPTY", Precedence: 50, Handler: emptyOperator}
-
-var envsubstOpType = &operationType{Type: "ENVSUBST", NumArgs: 0, Precedence: 50, Handler: envsubstOperator}
-
-var recursiveDescentOpType = &operationType{Type: "RECURSIVE_DESCENT", NumArgs: 0, Precedence: 50, Handler: recursiveDescentOperator}
-
-var selectOpType = &operationType{Type: "SELECT", NumArgs: 1, Precedence: 50, Handler: selectOperator}
-var hasOpType = &operationType{Type: "HAS", NumArgs: 1, Precedence: 50, Handler: hasOperator}
-var uniqueOpType = &operationType{Type: "UNIQUE", NumArgs: 0, Precedence: 50, Handler: unique}
-var uniqueByOpType = &operationType{Type: "UNIQUE_BY", NumArgs: 1, Precedence: 50, Handler: uniqueBy}
-var groupByOpType = &operationType{Type: "GROUP_BY", NumArgs: 1, Precedence: 50, Handler: groupBy}
-var flattenOpType = &operationType{Type: "FLATTEN_BY", NumArgs: 0, Precedence: 50, Handler: flattenOp}
-var deleteChildOpType = &operationType{Type: "DELETE", NumArgs: 1, Precedence: 40, Handler: deleteChildOperator}
-
-type Operation struct {
-	OperationType *operationType
-	Value         interface{}
-	StringValue   string
-	CandidateNode *CandidateNode // used for Value Path elements
-	Preferences   interface{}
-	UpdateAssign  bool // used for assign ops, when true it means we evaluate the rhs given the lhs
-}
-
 func recurseNodeArrayEqual(lhs *CandidateNode, rhs *CandidateNode) bool {
 	if len(lhs.Content) != len(rhs.Content) {
 		return false
@@ -335,33 +172,6 @@ func footComment(node *CandidateNode) string {
 	return strings.Replace(node.FootComment, "#", "", 1)
 }
 
-func createValueOperation(value interface{}, stringValue string) *Operation {
-	log.Debug("creating value op for string %v", stringValue)
-	var node = createScalarNode(value, stringValue)
-
-	return &Operation{
-		OperationType: valueOpType,
-		Value:         value,
-		StringValue:   stringValue,
-		CandidateNode: node,
-	}
-}
-
-// debugging purposes only
-func (p *Operation) toString() string {
-	if p == nil {
-		return "OP IS NIL"
-	}
-	if p.OperationType == traversePathOpType {
-		return fmt.Sprintf("%v", p.Value)
-	} else if p.OperationType == selfReferenceOpType {
-		return "SELF"
-	} else if p.OperationType == valueOpType {
-		return fmt.Sprintf("%v (%T)", p.Value, p.Value)
-	}
-	return fmt.Sprintf("%v", p.OperationType.Type)
-}
-
 // use for debugging only
 func NodesToString(collection *list.List) string {
 	if !log.IsEnabledFor(logging.DEBUG) {
diff --git a/pkg/yqlib/operation.go b/pkg/yqlib/operation.go
new file mode 100644
index 00000000..2350a4c1
--- /dev/null
+++ b/pkg/yqlib/operation.go
@@ -0,0 +1,200 @@
+package yqlib
+
+import "fmt"
+
+type Operation struct {
+	OperationType *operationType
+	Value         interface{}
+	StringValue   string
+	CandidateNode *CandidateNode // used for Value Path elements
+	Preferences   interface{}
+	UpdateAssign  bool // used for assign ops, when true it means we evaluate the rhs given the lhs
+}
+
+type operationType struct {
+	Type                 string
+	NumArgs              uint // number of arguments to the op
+	Precedence           uint
+	Handler              operatorHandler
+	CheckForPostTraverse bool
+	ToString             func(o *Operation) string
+}
+
+var valueToStringFunc = func(p *Operation) string {
+	return fmt.Sprintf("%v (%T)", p.Value, p.Value)
+}
+
+func createValueOperation(value interface{}, stringValue string) *Operation {
+	log.Debug("creating value op for string %v", stringValue)
+	var node = createScalarNode(value, stringValue)
+
+	return &Operation{
+		OperationType: valueOpType,
+		Value:         value,
+		StringValue:   stringValue,
+		CandidateNode: node,
+	}
+}
+
+var orOpType = &operationType{Type: "OR", NumArgs: 2, Precedence: 20, Handler: orOperator}
+var andOpType = &operationType{Type: "AND", NumArgs: 2, Precedence: 20, Handler: andOperator}
+var reduceOpType = &operationType{Type: "REDUCE", NumArgs: 2, Precedence: 35, Handler: reduceOperator}
+
+var blockOpType = &operationType{Type: "BLOCK", Precedence: 10, NumArgs: 2, Handler: emptyOperator}
+
+var unionOpType = &operationType{Type: "UNION", NumArgs: 2, Precedence: 10, Handler: unionOperator}
+
+var pipeOpType = &operationType{Type: "PIPE", NumArgs: 2, Precedence: 30, Handler: pipeOperator}
+
+var assignOpType = &operationType{Type: "ASSIGN", NumArgs: 2, Precedence: 40, Handler: assignUpdateOperator}
+var addAssignOpType = &operationType{Type: "ADD_ASSIGN", NumArgs: 2, Precedence: 40, Handler: addAssignOperator}
+var subtractAssignOpType = &operationType{Type: "SUBTRACT_ASSIGN", NumArgs: 2, Precedence: 40, Handler: subtractAssignOperator}
+
+var assignAttributesOpType = &operationType{Type: "ASSIGN_ATTRIBUTES", NumArgs: 2, Precedence: 40, Handler: assignAttributesOperator}
+var assignStyleOpType = &operationType{Type: "ASSIGN_STYLE", NumArgs: 2, Precedence: 40, Handler: assignStyleOperator}
+var assignVariableOpType = &operationType{Type: "ASSIGN_VARIABLE", NumArgs: 2, Precedence: 40, Handler: useWithPipe}
+var assignTagOpType = &operationType{Type: "ASSIGN_TAG", NumArgs: 2, Precedence: 40, Handler: assignTagOperator}
+var assignCommentOpType = &operationType{Type: "ASSIGN_COMMENT", NumArgs: 2, Precedence: 40, Handler: assignCommentsOperator}
+var assignAnchorOpType = &operationType{Type: "ASSIGN_ANCHOR", NumArgs: 2, Precedence: 40, Handler: assignAnchorOperator}
+var assignAliasOpType = &operationType{Type: "ASSIGN_ALIAS", NumArgs: 2, Precedence: 40, Handler: assignAliasOperator}
+
+var multiplyOpType = &operationType{Type: "MULTIPLY", NumArgs: 2, Precedence: 42, Handler: multiplyOperator}
+var multiplyAssignOpType = &operationType{Type: "MULTIPLY_ASSIGN", NumArgs: 2, Precedence: 42, Handler: multiplyAssignOperator}
+
+var divideOpType = &operationType{Type: "DIVIDE", NumArgs: 2, Precedence: 42, Handler: divideOperator}
+
+var moduloOpType = &operationType{Type: "MODULO", NumArgs: 2, Precedence: 42, Handler: moduloOperator}
+
+var addOpType = &operationType{Type: "ADD", NumArgs: 2, Precedence: 42, Handler: addOperator}
+var subtractOpType = &operationType{Type: "SUBTRACT", NumArgs: 2, Precedence: 42, Handler: subtractOperator}
+var alternativeOpType = &operationType{Type: "ALTERNATIVE", NumArgs: 2, Precedence: 42, Handler: alternativeOperator}
+
+var equalsOpType = &operationType{Type: "EQUALS", NumArgs: 2, Precedence: 40, Handler: equalsOperator}
+var notEqualsOpType = &operationType{Type: "NOT_EQUALS", NumArgs: 2, Precedence: 40, Handler: notEqualsOperator}
+
+var compareOpType = &operationType{Type: "COMPARE", NumArgs: 2, Precedence: 40, Handler: compareOperator}
+
+// createmap needs to be above union, as we use union to build the components of the objects
+var createMapOpType = &operationType{Type: "CREATE_MAP", NumArgs: 2, Precedence: 15, Handler: createMapOperator}
+
+var shortPipeOpType = &operationType{Type: "SHORT_PIPE", NumArgs: 2, Precedence: 45, Handler: pipeOperator}
+
+var lengthOpType = &operationType{Type: "LENGTH", NumArgs: 0, Precedence: 50, Handler: lengthOperator}
+var lineOpType = &operationType{Type: "LINE", NumArgs: 0, Precedence: 50, Handler: lineOperator}
+var columnOpType = &operationType{Type: "LINE", NumArgs: 0, Precedence: 50, Handler: columnOperator}
+
+var expressionOpType = &operationType{Type: "EXP", NumArgs: 0, Precedence: 50, Handler: expressionOperator}
+
+var collectOpType = &operationType{Type: "COLLECT", NumArgs: 1, Precedence: 50, Handler: collectOperator}
+var mapOpType = &operationType{Type: "MAP", NumArgs: 1, Precedence: 50, Handler: mapOperator}
+var filterOpType = &operationType{Type: "FILTER", NumArgs: 1, Precedence: 50, Handler: filterOperator}
+var errorOpType = &operationType{Type: "ERROR", NumArgs: 1, Precedence: 50, Handler: errorOperator}
+var pickOpType = &operationType{Type: "PICK", NumArgs: 1, Precedence: 50, Handler: pickOperator}
+var evalOpType = &operationType{Type: "EVAL", NumArgs: 1, Precedence: 50, Handler: evalOperator}
+var mapValuesOpType = &operationType{Type: "MAP_VALUES", NumArgs: 1, Precedence: 50, Handler: mapValuesOperator}
+
+var formatDateTimeOpType = &operationType{Type: "FORMAT_DATE_TIME", NumArgs: 1, Precedence: 50, Handler: formatDateTime}
+var withDtFormatOpType = &operationType{Type: "WITH_DATE_TIME_FORMAT", NumArgs: 1, Precedence: 50, Handler: withDateTimeFormat}
+var nowOpType = &operationType{Type: "NOW", NumArgs: 0, Precedence: 50, Handler: nowOp}
+var tzOpType = &operationType{Type: "TIMEZONE", NumArgs: 1, Precedence: 50, Handler: tzOp}
+var fromUnixOpType = &operationType{Type: "FROM_UNIX", NumArgs: 0, Precedence: 50, Handler: fromUnixOp}
+var toUnixOpType = &operationType{Type: "TO_UNIX", NumArgs: 0, Precedence: 50, Handler: toUnixOp}
+
+var encodeOpType = &operationType{Type: "ENCODE", NumArgs: 0, Precedence: 50, Handler: encodeOperator}
+var decodeOpType = &operationType{Type: "DECODE", NumArgs: 0, Precedence: 50, Handler: decodeOperator}
+
+var anyOpType = &operationType{Type: "ANY", NumArgs: 0, Precedence: 50, Handler: anyOperator}
+var allOpType = &operationType{Type: "ALL", NumArgs: 0, Precedence: 50, Handler: allOperator}
+var containsOpType = &operationType{Type: "CONTAINS", NumArgs: 1, Precedence: 50, Handler: containsOperator}
+var anyConditionOpType = &operationType{Type: "ANY_CONDITION", NumArgs: 1, Precedence: 50, Handler: anyOperator}
+var allConditionOpType = &operationType{Type: "ALL_CONDITION", NumArgs: 1, Precedence: 50, Handler: allOperator}
+
+var toEntriesOpType = &operationType{Type: "TO_ENTRIES", NumArgs: 0, Precedence: 52, Handler: toEntriesOperator, CheckForPostTraverse: true}
+var fromEntriesOpType = &operationType{Type: "FROM_ENTRIES", NumArgs: 0, Precedence: 50, Handler: fromEntriesOperator}
+var withEntriesOpType = &operationType{Type: "WITH_ENTRIES", NumArgs: 1, Precedence: 50, Handler: withEntriesOperator}
+
+var withOpType = &operationType{Type: "WITH", NumArgs: 1, Precedence: 50, Handler: withOperator}
+
+var splitDocumentOpType = &operationType{Type: "SPLIT_DOC", NumArgs: 0, Precedence: 50, Handler: splitDocumentOperator}
+var getVariableOpType = &operationType{Type: "GET_VARIABLE", NumArgs: 0, Precedence: 55, Handler: getVariableOperator}
+var getStyleOpType = &operationType{Type: "GET_STYLE", NumArgs: 0, Precedence: 50, Handler: getStyleOperator}
+var getTagOpType = &operationType{Type: "GET_TAG", NumArgs: 0, Precedence: 50, Handler: getTagOperator}
+var getKindOpType = &operationType{Type: "GET_KIND", NumArgs: 0, Precedence: 50, Handler: getKindOperator}
+
+var getKeyOpType = &operationType{Type: "GET_KEY", NumArgs: 0, Precedence: 50, Handler: getKeyOperator}
+var isKeyOpType = &operationType{Type: "IS_KEY", NumArgs: 0, Precedence: 50, Handler: isKeyOperator}
+var getParentOpType = &operationType{Type: "GET_PARENT", NumArgs: 0, Precedence: 50, Handler: getParentOperator}
+
+var getCommentOpType = &operationType{Type: "GET_COMMENT", NumArgs: 0, Precedence: 50, Handler: getCommentsOperator}
+var getAnchorOpType = &operationType{Type: "GET_ANCHOR", NumArgs: 0, Precedence: 50, Handler: getAnchorOperator}
+var getAliasOpType = &operationType{Type: "GET_ALIAS", NumArgs: 0, Precedence: 50, Handler: getAliasOperator}
+var getDocumentIndexOpType = &operationType{Type: "GET_DOCUMENT_INDEX", NumArgs: 0, Precedence: 50, Handler: getDocumentIndexOperator}
+var getFilenameOpType = &operationType{Type: "GET_FILENAME", NumArgs: 0, Precedence: 50, Handler: getFilenameOperator}
+var getFileIndexOpType = &operationType{Type: "GET_FILE_INDEX", NumArgs: 0, Precedence: 50, Handler: getFileIndexOperator}
+
+var getPathOpType = &operationType{Type: "GET_PATH", NumArgs: 0, Precedence: 50, Handler: getPathOperator}
+var setPathOpType = &operationType{Type: "SET_PATH", NumArgs: 1, Precedence: 50, Handler: setPathOperator}
+var delPathsOpType = &operationType{Type: "DEL_PATHS", NumArgs: 1, Precedence: 50, Handler: delPathsOperator}
+
+var explodeOpType = &operationType{Type: "EXPLODE", NumArgs: 1, Precedence: 50, Handler: explodeOperator}
+var sortByOpType = &operationType{Type: "SORT_BY", NumArgs: 1, Precedence: 50, Handler: sortByOperator}
+var reverseOpType = &operationType{Type: "REVERSE", NumArgs: 0, Precedence: 50, Handler: reverseOperator}
+var sortOpType = &operationType{Type: "SORT", NumArgs: 0, Precedence: 50, Handler: sortOperator}
+var shuffleOpType = &operationType{Type: "SHUFFLE", NumArgs: 0, Precedence: 50, Handler: shuffleOperator}
+
+var sortKeysOpType = &operationType{Type: "SORT_KEYS", NumArgs: 1, Precedence: 50, Handler: sortKeysOperator}
+
+var joinStringOpType = &operationType{Type: "JOIN", NumArgs: 1, Precedence: 50, Handler: joinStringOperator}
+var subStringOpType = &operationType{Type: "SUBSTR", NumArgs: 1, Precedence: 50, Handler: substituteStringOperator}
+var matchOpType = &operationType{Type: "MATCH", NumArgs: 1, Precedence: 50, Handler: matchOperator}
+var captureOpType = &operationType{Type: "CAPTURE", NumArgs: 1, Precedence: 50, Handler: captureOperator}
+var testOpType = &operationType{Type: "TEST", NumArgs: 1, Precedence: 50, Handler: testOperator}
+var splitStringOpType = &operationType{Type: "SPLIT", NumArgs: 1, Precedence: 50, Handler: splitStringOperator}
+var changeCaseOpType = &operationType{Type: "CHANGE_CASE", NumArgs: 0, Precedence: 50, Handler: changeCaseOperator}
+var trimOpType = &operationType{Type: "TRIM", NumArgs: 0, Precedence: 50, Handler: trimSpaceOperator}
+var toStringOpType = &operationType{Type: "TO_STRING", NumArgs: 0, Precedence: 50, Handler: toStringOperator}
+var stringInterpolationOpType = &operationType{Type: "STRING_INT", NumArgs: 0, Precedence: 50, Handler: stringInterpolationOperator, ToString: valueToStringFunc}
+
+var loadOpType = &operationType{Type: "LOAD", NumArgs: 1, Precedence: 52, Handler: loadYamlOperator}
+
+var keysOpType = &operationType{Type: "KEYS", NumArgs: 0, Precedence: 50, Handler: keysOperator}
+
+var collectObjectOpType = &operationType{Type: "COLLECT_OBJECT", NumArgs: 0, Precedence: 50, Handler: collectObjectOperator}
+
+var traversePathOpType = &operationType{Type: "TRAVERSE_PATH", NumArgs: 0, Precedence: 55, Handler: traversePathOperator,
+	ToString: func(p *Operation) string {
+		return fmt.Sprintf("%v", p.Value)
+	}}
+
+var traverseArrayOpType = &operationType{Type: "TRAVERSE_ARRAY", NumArgs: 2, Precedence: 50, Handler: traverseArrayOperator}
+
+var selfReferenceOpType = &operationType{Type: "SELF", NumArgs: 0, Precedence: 55, Handler: selfOperator}
+var valueOpType = &operationType{Type: "VALUE", NumArgs: 0, Precedence: 50, Handler: valueOperator, ToString: valueToStringFunc}
+var referenceOpType = &operationType{Type: "REF", NumArgs: 0, Precedence: 50, Handler: referenceOperator}
+var envOpType = &operationType{Type: "ENV", NumArgs: 0, Precedence: 50, Handler: envOperator}
+var notOpType = &operationType{Type: "NOT", NumArgs: 0, Precedence: 50, Handler: notOperator}
+var toNumberOpType = &operationType{Type: "TO_NUMBER", NumArgs: 0, Precedence: 50, Handler: toNumberOperator}
+var emptyOpType = &operationType{Type: "EMPTY", Precedence: 50, Handler: emptyOperator}
+
+var envsubstOpType = &operationType{Type: "ENVSUBST", NumArgs: 0, Precedence: 50, Handler: envsubstOperator}
+
+var recursiveDescentOpType = &operationType{Type: "RECURSIVE_DESCENT", NumArgs: 0, Precedence: 50, Handler: recursiveDescentOperator}
+
+var selectOpType = &operationType{Type: "SELECT", NumArgs: 1, Precedence: 50, Handler: selectOperator}
+var hasOpType = &operationType{Type: "HAS", NumArgs: 1, Precedence: 50, Handler: hasOperator}
+var uniqueOpType = &operationType{Type: "UNIQUE", NumArgs: 0, Precedence: 50, Handler: unique}
+var uniqueByOpType = &operationType{Type: "UNIQUE_BY", NumArgs: 1, Precedence: 50, Handler: uniqueBy}
+var groupByOpType = &operationType{Type: "GROUP_BY", NumArgs: 1, Precedence: 50, Handler: groupBy}
+var flattenOpType = &operationType{Type: "FLATTEN_BY", NumArgs: 0, Precedence: 50, Handler: flattenOp}
+var deleteChildOpType = &operationType{Type: "DELETE", NumArgs: 1, Precedence: 40, Handler: deleteChildOperator}
+
+// debugging purposes only
+func (p *Operation) toString() string {
+	if p == nil {
+		return "OP IS NIL"
+	}
+	if p.OperationType.ToString != nil {
+		return p.OperationType.ToString(p)
+	}
+	return fmt.Sprintf("%v", p.OperationType.Type)
+}
diff --git a/pkg/yqlib/operator_strings.go b/pkg/yqlib/operator_strings.go
index 7b18b61a..955975ed 100644
--- a/pkg/yqlib/operator_strings.go
+++ b/pkg/yqlib/operator_strings.go
@@ -7,10 +7,124 @@ import (
 	"strings"
 )
 
+var StringInterpolationEnabled = true
+
 type changeCasePrefs struct {
 	ToUpperCase bool
 }
 
+func encodeToYamlString(node *CandidateNode) (string, error) {
+	encoderPrefs := encoderPreferences{
+		format: YamlFormat,
+		indent: ConfiguredYamlPreferences.Indent,
+	}
+	result, err := encodeToString(node, encoderPrefs)
+
+	if err != nil {
+		return "", err
+	}
+	return chomper.ReplaceAllString(result, ""), nil
+}
+
+func evaluate(d *dataTreeNavigator, context Context, expStr string) (string, error) {
+	exp, err := ExpressionParser.ParseExpression(expStr)
+	if err != nil {
+		return "", err
+	}
+	result, err := d.GetMatchingNodes(context, exp)
+	if err != nil {
+		return "", err
+	}
+	if result.MatchingNodes.Len() == 0 {
+		return "", nil
+	}
+	node := result.MatchingNodes.Front().Value.(*CandidateNode)
+	if node.Kind != ScalarNode {
+		return encodeToYamlString(node)
+	}
+	return node.Value, nil
+}
+
+func interpolate(d *dataTreeNavigator, context Context, str string) (string, error) {
+	var sb strings.Builder
+	var expSb strings.Builder
+	inExpression := false
+	nestedBracketsCounter := 0
+	runes := []rune(str)
+	for i := 0; i < len(runes); i++ {
+		char := runes[i]
+		if !inExpression {
+			if char == '\\' && i != len(runes)-1 && runes[i+1] == '(' {
+				inExpression = true
+				i = i + 1 // skip over the next open bracket
+				continue
+			}
+			sb.WriteRune(char)
+		} else { // we are in an expression
+			if char == ')' && nestedBracketsCounter == 0 {
+				// finished the expression!
+				log.Debugf("Expression is :%v", expSb.String())
+				value, err := evaluate(d, context, expSb.String())
+				if err != nil {
+					return "", err
+				}
+
+				inExpression = false
+				expSb = strings.Builder{} // reset this
+
+				sb.WriteString(value)
+				continue
+			} else if char == '(' {
+				nestedBracketsCounter++
+			} else if char == '\\' && i != len(runes)-1 && runes[i+1] == ')' {
+				// close brackets is escaped, skip over it
+				expSb.WriteRune(char)
+				expSb.WriteRune(runes[i+1])
+				i = i + 1
+				continue
+			} else if char == ')' {
+				nestedBracketsCounter--
+			}
+			expSb.WriteRune(char)
+		}
+
+	}
+	if inExpression {
+		return "", fmt.Errorf("unclosed interpolation string \\(")
+	}
+	return sb.String(), nil
+}
+
+func stringInterpolationOperator(d *dataTreeNavigator, context Context, expressionNode *ExpressionNode) (Context, error) {
+	if !StringInterpolationEnabled {
+		return context.SingleChildContext(
+			createScalarNode(expressionNode.Operation.StringValue, expressionNode.Operation.StringValue),
+		), nil
+	}
+	if context.MatchingNodes.Len() == 0 {
+		value, err := interpolate(d, context, expressionNode.Operation.StringValue)
+		if err != nil {
+			return Context{}, err
+		}
+		node := createScalarNode(value, value)
+		return context.SingleChildContext(node), nil
+	}
+
+	var results = list.New()
+
+	for el := context.MatchingNodes.Front(); el != nil; el = el.Next() {
+		candidate := el.Value.(*CandidateNode)
+		value, err := interpolate(d, context.SingleChildContext(candidate), expressionNode.Operation.StringValue)
+		if err != nil {
+			return Context{}, err
+		}
+		node := createScalarNode(value, value)
+		results.PushBack(node)
+	}
+
+	return context.ChildContext(results), nil
+}
+
 func trimSpaceOperator(_ *dataTreeNavigator, context Context, _ *ExpressionNode) (Context, error) {
 	results := list.New()
 	for el := context.MatchingNodes.Front(); el != nil; el = el.Next() {
@@ -40,16 +154,10 @@ func toStringOperator(_ *dataTreeNavigator, context Context, _ *ExpressionNode)
 			newStringNode = node.CreateReplacement(ScalarNode, "!!str", node.Value)
 			newStringNode.Style = DoubleQuotedStyle
 		} else {
-			encoderPrefs := encoderPreferences{
-				format: YamlFormat,
-				indent: ConfiguredYamlPreferences.Indent,
-			}
-			result, err := encodeToString(node, encoderPrefs)
-
+			result, err := encodeToYamlString(node)
 			if err != nil {
 				return Context{}, err
 			}
-			result = chomper.ReplaceAllString(result, "")
 			newStringNode = node.CreateReplacement(ScalarNode, "!!str", result)
 			newStringNode.Style = DoubleQuotedStyle
 		}
diff --git a/pkg/yqlib/operator_strings_test.go b/pkg/yqlib/operator_strings_test.go
index 3b1fc536..1b0e56d4 100644
--- a/pkg/yqlib/operator_strings_test.go
+++ b/pkg/yqlib/operator_strings_test.go
@@ -5,6 +5,64 @@ import (
 )
 
 var stringsOperatorScenarios = []expressionScenario{
+	{
+		description: "Interpolation",
+		document:    "value: things\nanother: stuff",
+		expression:  `.message = "I like \(.value) and \(.another)"`,
+		expected: []string{
+			"D0, P[], (!!map)::value: things\nanother: stuff\nmessage: I like things and stuff\n",
+		},
+	},
+	{
+		description: "Interpolation - not a string",
+		document:    `value: {an: apple}`,
+		expression:  `.message = "I like \(.value)"`,
+		expected: []string{
+			"D0, P[], (!!map)::value: {an: apple}\nmessage: 'I like {an: apple}'\n",
+		},
+	},
+	{
+		skipDoc:     true,
+		description: "Interpolation - just escape",
+		expression:  `"\\"`,
+		expected: []string{
+			"D0, P[], (!!str)::\\\\\n",
+		},
+	},
+	{
+		skipDoc:     true,
+		description: "Interpolation - nested",
+		document:    `value: things`,
+		expression:  `"Hi \( (.value) )"`,
+		expected: []string{
+			"D0, P[], (!!str)::Hi things\n",
+		},
+	},
+	{
+		skipDoc:     true,
+		description: "Interpolation - don't",
+		document:    `value: things`,
+		expression:  `"Hi (.value)"`,
+		expected: []string{
+			"D0, P[], (!!str)::Hi (.value)\n",
+		},
+	},
+	{
+		skipDoc:     true,
+		description: "Interpolation - random close bracket",
+		document:    `value: things`,
+		expression:  `"Hi )"`,
+		expected: []string{
+			"D0, P[], (!!str)::Hi )\n",
+		},
+	},
+	{
+		skipDoc:       true,
+		description:   "Interpolation - unclosed interpolation string",
+		document:      `value: things`,
+		expression:    `"Hi \("`,
+		expectedError: "unclosed interpolation string \\(",
+	},
 	{
 		description:    "To up (upper) case",
 		subdescription: "Works with unicode characters",