Added pipe and length docs, fix pipe precedence

pkg/yqlib/doc/Assign.md

@@ -8,7 +8,7 @@ This will do a similar thing to the plain form, however, the RHS expression is r
 ## Create yaml file
 Running
 ```bash
-yq eval --null-input '(.a.b = "cat") | (.x = "frog")'
+yq eval --null-input '.a.b = "cat" | .x = "frog"'
 ```
 will output
 ```yaml
@@ -112,7 +112,7 @@ a:
 ```
 then
 ```bash
-yq eval '.a.[] | select(. == "apple") |= "frog"' sample.yml
+yq eval '(.a.[] | select(. == "apple")) = "frog"' sample.yml
 ```
 will output
 ```yaml
@@ -130,7 +130,7 @@ Given a sample.yml file of:
 ```
 then
 ```bash
-yq eval '.[] | select(. == "*andy") |= "bogs"' sample.yml
+yq eval '(.[] | select(. == "*andy")) = "bogs"' sample.yml
 ```
 will output
 ```yaml

pkg/yqlib/doc/Length.md

@@ -0,0 +1,54 @@
+Returns the lengths of the nodes. Length is defined according to the type of the node.
+
+## String length
+returns length of string
+
+Given a sample.yml file of:
+```yaml
+a: cat
+```
+then
+```bash
+yq eval '.a | length' sample.yml
+```
+will output
+```yaml
+3
+```
+
+## Map length
+returns number of entries
+
+Given a sample.yml file of:
+```yaml
+a: cat
+c: dog
+```
+then
+```bash
+yq eval 'length' sample.yml
+```
+will output
+```yaml
+2
+```
+
+## Array length
+returns number of elements
+
+Given a sample.yml file of:
+```yaml
+- 2
+- 4
+- 6
+- 8
+```
+then
+```bash
+yq eval 'length' sample.yml
+```
+will output
+```yaml
+4
+```
+

pkg/yqlib/doc/Pipe.md

@@ -0,0 +1,35 @@
+Pipe the results of an expression into another. Like the bash operator.
+
+## Simple Pipe
+Given a sample.yml file of:
+```yaml
+a:
+  b: cat
+```
+then
+```bash
+yq eval '.a | .b' sample.yml
+```
+will output
+```yaml
+cat
+```
+
+## Multiple updates
+Given a sample.yml file of:
+```yaml
+a: cow
+b: sheep
+c: same
+```
+then
+```bash
+yq eval '.a = "cat" | .b = "dog"' sample.yml
+```
+will output
+```yaml
+a: cat
+b: dog
+c: same
+```
+

pkg/yqlib/doc/headers/Length.md

@@ -0,0 +1 @@
+Returns the lengths of the nodes. Length is defined according to the type of the node.

pkg/yqlib/doc/headers/Pipe.md

@@ -0,0 +1 @@
+Pipe the results of an expression into another. Like the bash operator.

pkg/yqlib/lib.go

@@ -29,6 +29,8 @@ var And = &OperationType{Type: "AND", NumArgs: 2, Precedence: 20, Handler: AndOp
 
 var Union = &OperationType{Type: "UNION", NumArgs: 2, Precedence: 10, Handler: UnionOperator}
 
+var Pipe = &OperationType{Type: "PIPE", NumArgs: 2, Precedence: 30, Handler: PipeOperator}
+
 var Assign = &OperationType{Type: "ASSIGN", NumArgs: 2, Precedence: 40, Handler: AssignUpdateOperator}
 var AddAssign = &OperationType{Type: "ADD_ASSIGN", NumArgs: 2, Precedence: 40, Handler: AddAssignOperator}
 
@@ -42,7 +44,8 @@ var Add = &OperationType{Type: "ADD", NumArgs: 2, Precedence: 45, Handler: AddOp
 
 var Equals = &OperationType{Type: "EQUALS", NumArgs: 2, Precedence: 40, Handler: EqualsOperator}
 var CreateMap = &OperationType{Type: "CREATE_MAP", NumArgs: 2, Precedence: 40, Handler: CreateMapOperator}
-var Pipe = &OperationType{Type: "PIPE", NumArgs: 2, Precedence: 45, Handler: PipeOperator}
+
+var ShortPipe = &OperationType{Type: "PIPE", NumArgs: 2, Precedence: 45, Handler: PipeOperator}
 
 var Length = &OperationType{Type: "LENGTH", NumArgs: 0, Precedence: 50, Handler: LengthOperator}
 var Collect = &OperationType{Type: "COLLECT", NumArgs: 0, Precedence: 50, Handler: CollectOperator}

pkg/yqlib/operator_assign_test.go

@@ -7,7 +7,7 @@ import (
 var assignOperatorScenarios = []expressionScenario{
 	{
 		description: "Create yaml file",
-		expression:  `(.a.b = "cat") | (.x = "frog")`,
+		expression:  `.a.b = "cat" | .x = "frog"`,
 		expected: []string{
 			"D0, P[], ()::a:\n    b: cat\nx: frog\n",
 		},
@@ -80,7 +80,7 @@ var assignOperatorScenarios = []expressionScenario{
 	{
 		description: "Update selected results",
 		document:    `{a: {b: apple, c: cactus}}`,
-		expression:  `.a.[] | select(. == "apple") |= "frog"`,
+		expression:  `(.a.[] | select(. == "apple")) = "frog"`,
 		expected: []string{
 			"D0, P[], (doc)::{a: {b: frog, c: cactus}}\n",
 		},
@@ -88,7 +88,7 @@ var assignOperatorScenarios = []expressionScenario{
 	{
 		description: "Update array values",
 		document:    `[candy, apple, sandy]`,
-		expression:  `.[] | select(. == "*andy") |= "bogs"`,
+		expression:  `(.[] | select(. == "*andy")) = "bogs"`,
 		expected: []string{
 			"D0, P[], (doc)::[bogs, apple, bogs]\n",
 		},

pkg/yqlib/operator_length.go

@@ -0,0 +1,35 @@
+package yqlib
+
+import (
+	"container/list"
+	"fmt"
+
+	yaml "gopkg.in/yaml.v3"
+)
+
+func LengthOperator(d *dataTreeNavigator, matchMap *list.List, pathNode *PathTreeNode) (*list.List, error) {
+	log.Debugf("-- lengthOperation")
+	var results = list.New()
+
+	for el := matchMap.Front(); el != nil; el = el.Next() {
+		candidate := el.Value.(*CandidateNode)
+		targetNode := UnwrapDoc(candidate.Node)
+		var length int
+		switch targetNode.Kind {
+		case yaml.ScalarNode:
+			length = len(targetNode.Value)
+		case yaml.MappingNode:
+			length = len(targetNode.Content) / 2
+		case yaml.SequenceNode:
+			length = len(targetNode.Content)
+		default:
+			length = 0
+		}
+
+		node := &yaml.Node{Kind: yaml.ScalarNode, Value: fmt.Sprintf("%v", length), Tag: "!!int"}
+		lengthCand := &CandidateNode{Node: node, Document: candidate.Document, Path: candidate.Path}
+		results.PushBack(lengthCand)
+	}
+
+	return results, nil
+}

pkg/yqlib/operator_length_test.go

@@ -0,0 +1,42 @@
+package yqlib
+
+import (
+	"testing"
+)
+
+var lengthOperatorScenarios = []expressionScenario{
+	{
+		description:    "String length",
+		subdescription: "returns length of string",
+		document:       `{a: cat}`,
+		expression:     `.a | length`,
+		expected: []string{
+			"D0, P[a], (!!int)::3\n",
+		},
+	},
+	{
+		description:    "Map length",
+		subdescription: "returns number of entries",
+		document:       `{a: cat, c: dog}`,
+		expression:     `length`,
+		expected: []string{
+			"D0, P[], (!!int)::2\n",
+		},
+	},
+	{
+		description:    "Array length",
+		subdescription: "returns number of elements",
+		document:       `[2,4,6,8]`,
+		expression:     `length`,
+		expected: []string{
+			"D0, P[], (!!int)::4\n",
+		},
+	},
+}
+
+func TestLengthOperatorScenarios(t *testing.T) {
+	for _, tt := range lengthOperatorScenarios {
+		testScenario(t, &tt)
+	}
+	documentScenarios(t, "Length", lengthOperatorScenarios)
+}

pkg/yqlib/operator_multiply.go

@@ -111,7 +111,7 @@ func createTraversalTree(path []interface{}) *PathTreeNode {
 		return &PathTreeNode{Operation: &Operation{OperationType: TraversePath, Value: path[0], StringValue: fmt.Sprintf("%v", path[0])}}
 	}
 	return &PathTreeNode{
-		Operation: &Operation{OperationType: Pipe},
+		Operation: &Operation{OperationType: ShortPipe},
 		Lhs:       createTraversalTree(path[0:1]),
 		Rhs:       createTraversalTree(path[1:])}
 

pkg/yqlib/operator_pipe.go

@@ -0,0 +1,11 @@
+package yqlib
+
+import "container/list"
+
+func PipeOperator(d *dataTreeNavigator, matchingNodes *list.List, pathNode *PathTreeNode) (*list.List, error) {
+	lhs, err := d.GetMatchingNodes(matchingNodes, pathNode.Lhs)
+	if err != nil {
+		return nil, err
+	}
+	return d.GetMatchingNodes(lhs, pathNode.Rhs)
+}

pkg/yqlib/operator_pipe_test.go

@@ -0,0 +1,31 @@
+package yqlib
+
+import (
+	"testing"
+)
+
+var pipeOperatorScenarios = []expressionScenario{
+	{
+		description: "Simple Pipe",
+		document:    `{a: {b: cat}}`,
+		expression:  `.a | .b`,
+		expected: []string{
+			"D0, P[a b], (!!str)::cat\n",
+		},
+	},
+	{
+		description: "Multiple updates",
+		document:    `{a: cow, b: sheep, c: same}`,
+		expression:  `.a = "cat" | .b = "dog"`,
+		expected: []string{
+			"D0, P[], (doc)::{a: cat, b: dog, c: same}\n",
+		},
+	},
+}
+
+func TestPipeOperatorScenarios(t *testing.T) {
+	for _, tt := range pipeOperatorScenarios {
+		testScenario(t, &tt)
+	}
+	documentScenarios(t, "Pipe", pipeOperatorScenarios)
+}

pkg/yqlib/operators.go

@@ -2,7 +2,6 @@ package yqlib
 
 import (
 	"container/list"
-	"fmt"
 
 	"gopkg.in/yaml.v3"
 )
@@ -20,14 +19,6 @@ func EmptyOperator(d *dataTreeNavigator, matchingNodes *list.List, pathNode *Pat
 	return list.New(), nil
 }
 
-func PipeOperator(d *dataTreeNavigator, matchingNodes *list.List, pathNode *PathTreeNode) (*list.List, error) {
-	lhs, err := d.GetMatchingNodes(matchingNodes, pathNode.Lhs)
-	if err != nil {
-		return nil, err
-	}
-	return d.GetMatchingNodes(lhs, pathNode.Rhs)
-}
-
 func createBooleanCandidate(owner *CandidateNode, value bool) *CandidateNode {
 	valString := "true"
 	if !value {
@@ -42,29 +33,3 @@ func nodeToMap(candidate *CandidateNode) *list.List {
 	elMap.PushBack(candidate)
 	return elMap
 }
-
-func LengthOperator(d *dataTreeNavigator, matchMap *list.List, pathNode *PathTreeNode) (*list.List, error) {
-	log.Debugf("-- lengthOperation")
-	var results = list.New()
-
-	for el := matchMap.Front(); el != nil; el = el.Next() {
-		candidate := el.Value.(*CandidateNode)
-		var length int
-		switch candidate.Node.Kind {
-		case yaml.ScalarNode:
-			length = len(candidate.Node.Value)
-		case yaml.MappingNode:
-			length = len(candidate.Node.Content) / 2
-		case yaml.SequenceNode:
-			length = len(candidate.Node.Content)
-		default:
-			length = 0
-		}
-
-		node := &yaml.Node{Kind: yaml.ScalarNode, Value: fmt.Sprintf("%v", length), Tag: "!!int"}
-		lengthCand := &CandidateNode{Node: node, Document: candidate.Document, Path: candidate.Path}
-		results.PushBack(lengthCand)
-	}
-
-	return results, nil
-}

pkg/yqlib/path_postfix.go

@@ -56,7 +56,7 @@ func (p *pathPostFixer) ConvertToPostfix(infixTokens []*Token) ([]*Operation, er
 			// now we should have [] as the last element on the opStack, get rid of it
 			opStack = opStack[0 : len(opStack)-1]
 			//and append a collect to the opStack
-			opStack = append(opStack, &Token{TokenType: OperationToken, Operation: &Operation{OperationType: Pipe}})
+			opStack = append(opStack, &Token{TokenType: OperationToken, Operation: &Operation{OperationType: ShortPipe}})
 			opStack = append(opStack, &Token{TokenType: OperationToken, Operation: &Operation{OperationType: collectOperator}})
 		case CloseBracket:
 			for len(opStack) > 0 && opStack[len(opStack)-1].TokenType != OpenBracket {

pkg/yqlib/path_tokeniser.go

@@ -318,7 +318,7 @@ func (p *pathTokeniser) Tokenise(path string) ([]*Token, error) {
 			if index != len(tokens)-1 && token.CheckForPostTraverse &&
 				tokens[index+1].TokenType == OperationToken &&
 				tokens[index+1].Operation.OperationType == TraversePath {
-				op := &Operation{OperationType: Pipe, Value: "PIPE"}
+				op := &Operation{OperationType: ShortPipe, Value: "PIPE"}
 				postProcessedTokens = append(postProcessedTokens, &Token{TokenType: OperationToken, Operation: op})
 			}
 		}