Added split string operator

pkg/yqlib/doc/String Operators.md

@@ -1,3 +1,4 @@
+# String Operators
 
 ## Join strings
 Given a sample.yml file of:
@@ -17,3 +18,35 @@ will output
 cat; meow; 1; ; true
 ```
 
+## Split strings
+Given a sample.yml file of:
+```yaml
+cat; meow; 1; ; true
+```
+then
+```bash
+yq eval 'split("; ")' sample.yml
+```
+will output
+```yaml
+- cat
+- meow
+- "1"
+- ""
+- "true"
+```
+
+## Split strings one match
+Given a sample.yml file of:
+```yaml
+word
+```
+then
+```bash
+yq eval 'split("; ")' sample.yml
+```
+will output
+```yaml
+- word
+```
+

pkg/yqlib/doc/headers/String Operators.md

@@ -0,0 +1 @@
+# String Operators

pkg/yqlib/expression_tokeniser.go

@@ -244,6 +244,7 @@ func initLexer() (*lex.Lexer, error) {
 	lexer.Add([]byte(`splitDoc`), opToken(splitDocumentOpType))
 
 	lexer.Add([]byte(`join`), opToken(joinStringOpType))
+	lexer.Add([]byte(`split`), opToken(splitStringOpType))
 
 	lexer.Add([]byte(`style`), opAssignableToken(getStyleOpType, assignStyleOpType))
 

pkg/yqlib/lib.go

@@ -65,6 +65,7 @@ var getPathOpType = &operationType{Type: "GET_PATH", NumArgs: 0, Precedence: 50,
 var explodeOpType = &operationType{Type: "EXPLODE", NumArgs: 1, Precedence: 50, Handler: explodeOperator}
 var sortKeysOpType = &operationType{Type: "SORT_KEYS", NumArgs: 1, Precedence: 50, Handler: sortKeysOperator}
 var joinStringOpType = &operationType{Type: "JOIN", NumArgs: 1, Precedence: 50, Handler: joinStringOperator}
+var splitStringOpType = &operationType{Type: "SPLIT", NumArgs: 1, Precedence: 50, Handler: splitStringOperator}
 
 var collectObjectOpType = &operationType{Type: "COLLECT_OBJECT", NumArgs: 0, Precedence: 50, Handler: collectObjectOperator}
 var traversePathOpType = &operationType{Type: "TRAVERSE_PATH", NumArgs: 0, Precedence: 50, Handler: traversePathOperator}

pkg/yqlib/operator_strings.go

@@ -48,3 +48,49 @@ func join(content []*yaml.Node, joinStr string) *yaml.Node {
 
 	return &yaml.Node{Kind: yaml.ScalarNode, Value: strings.Join(stringsToJoin, joinStr), Tag: "!!str"}
 }
+
+func splitStringOperator(d *dataTreeNavigator, matchMap *list.List, expressionNode *ExpressionNode) (*list.List, error) {
+	log.Debugf("-- splitStringOperator")
+	splitStr := ""
+
+	rhs, err := d.GetMatchingNodes(matchMap, expressionNode.Rhs)
+	if err != nil {
+		return nil, err
+	}
+	if rhs.Front() != nil {
+		splitStr = rhs.Front().Value.(*CandidateNode).Node.Value
+	}
+
+	var results = list.New()
+
+	for el := matchMap.Front(); el != nil; el = el.Next() {
+		candidate := el.Value.(*CandidateNode)
+		node := unwrapDoc(candidate.Node)
+		if node.Tag == "!!null" {
+			continue
+		}
+		if node.Tag != "!!str" {
+			return nil, fmt.Errorf("Cannot split %v, can only split strings", node.Tag)
+		}
+		targetNode := split(node.Value, splitStr)
+		result := candidate.CreateChild(nil, targetNode)
+		results.PushBack(result)
+	}
+
+	return results, nil
+}
+
+func split(value string, spltStr string) *yaml.Node {
+	var contents []*yaml.Node
+
+	if value != "" {
+		var newStrings = strings.Split(value, spltStr)
+		contents = make([]*yaml.Node, len(newStrings))
+
+		for index, str := range newStrings {
+			contents[index] = &yaml.Node{Kind: yaml.ScalarNode, Tag: "!!str", Value: str}
+		}
+	}
+
+	return &yaml.Node{Kind: yaml.SequenceNode, Tag: "!!seq", Content: contents}
+}

pkg/yqlib/operator_strings_test.go

@@ -13,6 +13,35 @@ var stringsOperatorScenarios = []expressionScenario{
 			"D0, P[], (!!str)::cat; meow; 1; ; true\n",
 		},
 	},
+	{
+		description: "Split strings",
+		document:    `"cat; meow; 1; ; true"`,
+		expression:  `split("; ")`,
+		expected: []string{
+			"D0, P[], (!!seq)::- cat\n- meow\n- \"1\"\n- \"\"\n- \"true\"\n",
+		},
+	},
+	{
+		description: "Split strings one match",
+		document:    `"word"`,
+		expression:  `split("; ")`,
+		expected: []string{
+			"D0, P[], (!!seq)::- word\n",
+		},
+	},
+	{
+		skipDoc:    true,
+		document:   `""`,
+		expression: `split("; ")`,
+		expected: []string{
+			"D0, P[], (!!seq)::[]\n", // dont actually want this, just not to error
+		},
+	},
+	{
+		skipDoc:    true,
+		expression: `split("; ")`,
+		expected:   []string{},
+	},
 }
 
 func TestStringsOperatorScenarios(t *testing.T) {