Merge branch 'subtract'

pkg/yqlib/doc/Subtract.md

@@ -1,4 +1,43 @@
 
+## Array subtraction
+Running
+```bash
+yq eval --null-input '[1,2] - [2,3]'
+```
+will output
+```yaml
+- 1
+```
+
+## Array subtraction with nested array
+Running
+```bash
+yq eval --null-input '[[1], 1, 2] - [[1], 3]'
+```
+will output
+```yaml
+- 1
+- 2
+```
+
+## Array subtraction with nested object
+Note that order of the keys does not matter
+
+Given a sample.yml file of:
+```yaml
+- a: b
+  c: d
+- a: b
+```
+then
+```bash
+yq eval '. - [{"c": "d", "a": "b"}]' sample.yml
+```
+will output
+```yaml
+- a: b
+```
+
 ## Number subtraction - float
 If the lhs or rhs are floats then the expression will be calculated with floats.
 

pkg/yqlib/lib.go

@@ -121,6 +121,64 @@ type Operation struct {
 	UpdateAssign  bool // used for assign ops, when true it means we evaluate the rhs given the lhs
 }
 
+func recurseNodeArrayEqual(lhs *yaml.Node, rhs *yaml.Node) bool {
+	if len(lhs.Content) != len(rhs.Content) {
+		return false
+	}
+
+	for index := 0; index < len(lhs.Content); index = index + 1 {
+		if !recursiveNodeEqual(lhs.Content[index], rhs.Content[index]) {
+			return false
+		}
+	}
+	return true
+}
+
+func findInArray(array *yaml.Node, item *yaml.Node) int {
+
+	for index := 0; index < len(array.Content); index = index + 1 {
+		if recursiveNodeEqual(array.Content[index], item) {
+			return index
+		}
+	}
+	return -1
+}
+
+func recurseNodeObjectEqual(lhs *yaml.Node, rhs *yaml.Node) bool {
+	if len(lhs.Content) != len(rhs.Content) {
+		return false
+	}
+
+	for index := 0; index < len(lhs.Content); index = index + 2 {
+		key := lhs.Content[index]
+		value := lhs.Content[index+1]
+
+		indexInRhs := findInArray(rhs, key)
+
+		if indexInRhs == -1 || !recursiveNodeEqual(value, rhs.Content[indexInRhs+1]) {
+			return false
+		}
+	}
+	return true
+}
+
+func recursiveNodeEqual(lhs *yaml.Node, rhs *yaml.Node) bool {
+	if lhs.Kind != rhs.Kind || lhs.Tag != rhs.Tag {
+		return false
+	} else if lhs.Tag == "!!null" {
+		return true
+
+	} else if lhs.Kind == yaml.ScalarNode {
+		return lhs.Value == rhs.Value
+	} else if lhs.Kind == yaml.SequenceNode {
+		return recurseNodeArrayEqual(lhs, rhs)
+	} else if lhs.Kind == yaml.MappingNode {
+		return recurseNodeObjectEqual(lhs, rhs)
+	}
+	return false
+
+}
+
 // yaml numbers can be hex encoded...
 func parseInt(numberString string) (string, int64, error) {
 	if strings.HasPrefix(numberString, "0x") ||

pkg/yqlib/operator_subtract.go

@@ -5,7 +5,7 @@ import (
 
 	"strconv"
 
-	yaml "gopkg.in/yaml.v3"
+	"gopkg.in/yaml.v3"
 )
 
 func createSubtractOp(lhs *ExpressionNode, rhs *ExpressionNode) *ExpressionNode {
@@ -24,6 +24,24 @@ func subtractOperator(d *dataTreeNavigator, context Context, expressionNode *Exp
 	return crossFunction(d, context.ReadOnlyClone(), expressionNode, subtract, false)
 }
 
+func subtractArray(d *dataTreeNavigator, context Context, lhs *CandidateNode, rhs *CandidateNode) (*CandidateNode, error) {
+	newLhsArray := make([]*yaml.Node, 0)
+
+	for lindex := 0; lindex < len(lhs.Node.Content); lindex = lindex + 1 {
+		shouldInclude := true
+		for rindex := 0; rindex < len(rhs.Node.Content) && shouldInclude; rindex = rindex + 1 {
+			if recursiveNodeEqual(lhs.Node.Content[lindex], rhs.Node.Content[rindex]) {
+				shouldInclude = false
+			}
+		}
+		if shouldInclude {
+			newLhsArray = append(newLhsArray, lhs.Node.Content[lindex])
+		}
+	}
+	lhs.Node.Content = newLhsArray
+	return lhs, nil
+}
+
 func subtract(d *dataTreeNavigator, context Context, lhs *CandidateNode, rhs *CandidateNode) (*CandidateNode, error) {
 	lhs.Node = unwrapDoc(lhs.Node)
 	rhs.Node = unwrapDoc(rhs.Node)
@@ -40,14 +58,13 @@ func subtract(d *dataTreeNavigator, context Context, lhs *CandidateNode, rhs *Ca
 	case yaml.MappingNode:
 		return nil, fmt.Errorf("Maps not yet supported for subtraction")
 	case yaml.SequenceNode:
-		return nil, fmt.Errorf("Sequences not yet supported for subtraction")
-		// target.Node.Kind = yaml.SequenceNode
-		// target.Node.Style = lhsNode.Style
-		// target.Node.Tag = "!!seq"
-		// target.Node.Content = append(lhsNode.Content, toNodes(rhs)...)
+		if rhs.Node.Kind != yaml.SequenceNode {
+			return nil, fmt.Errorf("%v (%v) cannot be subtracted from %v", rhs.Node.Tag, rhs.Path, lhsNode.Tag)
+		}
+		return subtractArray(d, context, lhs, rhs)
 	case yaml.ScalarNode:
 		if rhs.Node.Kind != yaml.ScalarNode {
-			return nil, fmt.Errorf("%v (%v) cannot be added to a %v", rhs.Node.Tag, rhs.Path, lhsNode.Tag)
+			return nil, fmt.Errorf("%v (%v) cannot be subtracted from %v", rhs.Node.Tag, rhs.Path, lhsNode.Tag)
 		}
 		target.Node.Kind = yaml.ScalarNode
 		target.Node.Style = lhsNode.Style

pkg/yqlib/operator_subtract_test.go

@@ -13,6 +13,51 @@ var subtractOperatorScenarios = []expressionScenario{
 			"D0, P[], (doc)::{}\n",
 		},
 	},
+	{
+		description: "Array subtraction",
+		expression:  `[1,2] - [2,3]`,
+		expected: []string{
+			"D0, P[], (!!seq)::- 1\n",
+		},
+	},
+	{
+		skipDoc:    true,
+		expression: `[2,1,2,2] - [2,3]`,
+		expected: []string{
+			"D0, P[], (!!seq)::- 1\n",
+		},
+	},
+	{
+		description: "Array subtraction with nested array",
+		expression:  `[[1], 1, 2] - [[1], 3]`,
+		expected: []string{
+			"D0, P[], (!!seq)::- 1\n- 2\n",
+		},
+	},
+	{
+		skipDoc:    true,
+		expression: `[[1], 1, [[[2]]]] - [[1], [[[3]]]]`,
+		expected: []string{
+			"D0, P[], (!!seq)::- 1\n- - - - 2\n",
+		},
+	},
+	{
+		description:    "Array subtraction with nested object",
+		subdescription: `Note that order of the keys does not matter`,
+		document:       `[{a: b, c: d}, {a: b}]`,
+		expression:     `. - [{"c": "d", "a": "b"}]`,
+		expected: []string{
+			"D0, P[], (!!seq)::[{a: b}]\n",
+		},
+	},
+	{
+		skipDoc:    true,
+		document:   `[{a: [1], c: d}, {a: [2], c: d}, {a: b}]`,
+		expression: `. - [{"c": "d", "a": [1]}]`,
+		expected: []string{
+			"D0, P[], (!!seq)::[{a: [2], c: d}, {a: b}]\n",
+		},
+	},
 	{
 		description:    "Number subtraction - float",
 		subdescription: "If the lhs or rhs are floats then the expression will be calculated with floats.",