Updating readme for imminent v4 release

README.md

@@ -108,21 +108,18 @@ Supported by @rmescandon (https://launchpad.net/~rmescandon/+archive/ubuntu/yq)
 
 ## Features
 - Written in portable go, so you can download a lovely dependency free binary
+- Uses similar syntax as `jq` but works with YAML and JSON files
+- Fully supports multi document yaml files
 - Colorized yaml output
-- [Deep read a yaml file with a given path expression](https://mikefarah.gitbook.io/yq/v/v4.x/traverse)
-- [Return the lengths of arrays/object/scalars](https://mikefarah.gitbook.io/yq/commands/read#printing-length-of-the-results)
-- Update a yaml file given a [path expression](https://mikefarah.gitbook.io/yq/commands/write-update#basic) or [script file](https://mikefarah.gitbook.io/yq/commands/write-update#basic)
-- Update creates any missing entries in the path on the fly
-- Deeply [compare](https://mikefarah.gitbook.io/yq/commands/compare) yaml files
-- Keeps yaml formatting and comments when updating
-- [Validate a yaml file](https://mikefarah.gitbook.io/yq/commands/validate)
-- Create a yaml file given a [deep path and value](https://mikefarah.gitbook.io/yq/commands/create#creating-a-simple-yaml-file) or a [script file](https://mikefarah.gitbook.io/yq/commands/create#creating-using-a-create-script)
-- [Prefix a path to a yaml file](https://mikefarah.gitbook.io/yq/commands/prefix)
-- [Convert to/from json to yaml](https://mikefarah.gitbook.io/yq/usage/convert)
-- [Pipe data in by using '-'](https://mikefarah.gitbook.io/yq/commands/read#from-stdin)
-- [Merge](https://mikefarah.gitbook.io/yq/commands/merge) multiple yaml files with various options for [overriding](https://mikefarah.gitbook.io/yq/commands/merge#overwrite-values) and [appending](https://mikefarah.gitbook.io/yq/commands/merge#append-values-with-arrays)
-- Supports multiple documents in a single yaml file for [reading](https://mikefarah.gitbook.io/yq/commands/read#multiple-documents), [writing](https://mikefarah.gitbook.io/yq/commands/write-update#multiple-documents) and [merging](https://mikefarah.gitbook.io/yq/commands/merge#multiple-documents)
-- General shell completion scripts (bash/zsh/fish/powershell) (https://mikefarah.gitbook.io/yq/commands/shell-completion)
+- [Deeply traverse yaml](https://mikefarah.gitbook.io/yq/v/v4.x/traverse)
+- [Sort yaml by keys](https://mikefarah.gitbook.io/yq/v/v4.x/sort-keys)
+- Manipulate yaml [comments](https://app.gitbook.com/@mikefarah/s/yq/v/v4.x/comment-operators), [styling](https://app.gitbook.com/@mikefarah/s/yq/v/v4.x/style), [tags](https://app.gitbook.com/@mikefarah/s/yq/v/v4.x/tag) and [anchors](https://app.gitbook.com/@mikefarah/s/yq/v/v4.x/explode).
+- [Update yaml inplace](https://mikefarah.gitbook.io/yq/v/v4.x/commands/evaluate#flags)
+- [Complex expressions to select and update](https://mikefarah.gitbook.io/yq/v/v4.x/select#select-and-update-matching-values-in-map)
+- Keeps yaml formatting and comments when updating (though there are issues with whitespace)
+- [Convert to/from json to yaml](https://mikefarah.gitbook.io/yq/v/v4.x/usage/convert)
+- [Pipe data in by using '-'](https://mikefarah.gitbook.io/yq/v/v4.x/commands/evaluate)
+- General shell completion scripts (bash/zsh/fish/powershell) (https://mikefarah.gitbook.io/yq/v/v4.x/commands/shell-completion)
 
 ## [Usage](https://mikefarah.gitbook.io/yq/)
 
@@ -134,32 +131,35 @@ Usage:
   yq [command]
 
 Available Commands:
-  compare          yq x [--prettyPrint/-P] dataA.yaml dataB.yaml 'b.e(name==fr*).value'
-  delete           yq d [--inplace/-i] [--doc/-d index] sample.yaml 'b.e(name==fred)'
+  eval             Apply expression to each document in each yaml file given in sequence
+  eval-all         Loads _all_ yaml documents of _all_ yaml files and runs expression once
   help             Help about any command
-  merge            yq m [--inplace/-i] [--doc/-d index] [--overwrite/-x] [--append/-a] sample.yaml sample2.yaml
-  new              yq n [--script/-s script_file] a.b.c newValue
-  prefix           yq p [--inplace/-i] [--doc/-d index] sample.yaml a.b.c
-  read             yq r [--printMode/-p pv] sample.yaml 'b.e(name==fr*).value'
-  shell-completion Generates shell completion scripts
-  validate         yq v sample.yaml
-  write            yq w [--inplace/-i] [--script/-s script_file] [--doc/-d index] sample.yaml 'b.e(name==fr*).value' newValue
+  shell-completion Generate completion script
 
 Flags:
-  -C, --colors        print with colors
+  -C, --colors        force print with colors
+  -e, --exit-status   set exit status if there are no matches or null or false is returned
   -h, --help          help for yq
   -I, --indent int    sets indent level for output (default 2)
-  -P, --prettyPrint   pretty print
-  -j, --tojson        output as json. By default it prints a json document in one line, use the prettyPrint flag to print a formatted doc.
+  -i, --inplace       update the yaml file inplace of first yaml file given.
+  -M, --no-colors     force print with no colors
+  -N, --no-doc        Don't print document separators (---)
+  -n, --null-input    Don't read input, simply evaluate the expression given. Useful for creating yaml docs from scratch.
+  -j, --tojson        output as json. Set indent to 0 to print json in one line.
   -v, --verbose       verbose mode
   -V, --version       Print version information and quit
 
 Use "yq [command] --help" for more information about a command.
 ```
 
-## Upgrade from V2
-If you've been using v2 and want/need to upgrade, checkout the [upgrade guide](https://mikefarah.gitbook.io/yq/upgrading-from-v2).
+Simple Example:
+
+```bash
+yq e '.a.b | length' f1.yml f2.yml 
+```
+
+## Upgrade from V3
+If you've been using v3 and want/need to upgrade, checkout the [upgrade guide](https://mikefarah.gitbook.io/yq/v/v4.x/upgrading-from-v3).
 
 ## Known Issues / Missing Features
 - `yq` attempts to preserve comment positions and whitespace as much as possible, but it does not handle all scenarios (see https://github.com/go-yaml/yaml/tree/v3 for details)
-- You cannot (yet) select multiple paths/keys from the yaml to be printed out (https://github.com/mikefarah/yq/issues/287)

cmd/version.go

@@ -11,7 +11,7 @@ var (
 	GitDescribe string
 
 	// Version is main version number that is being run at the moment.
-	Version = "4.0.0-beta2"
+	Version = "4.0.0-beta1"
 
 	// VersionPrerelease is a pre-release marker for the version. If this is "" (empty string)
 	// then it means that it is a final release. Otherwise, this is a pre-release

pkg/yqlib/path_tokeniser.go

@@ -1,6 +1,7 @@
 package yqlib
 
 import (
+	"fmt"
 	"strconv"
 
 	lex "github.com/timtadh/lexmachine"
@@ -288,7 +289,7 @@ func (p *pathTokeniser) Tokenise(path string) ([]*Token, error) {
 	scanner, err := p.lexer.Scanner([]byte(path))
 
 	if err != nil {
-		return nil, err
+		return nil, fmt.Errorf("Parsing expression: %v", err)
 	}
 	var tokens []*Token
 	for tok, err, eof := scanner.Next(); !eof; tok, err, eof = scanner.Next() {
@@ -299,7 +300,7 @@ func (p *pathTokeniser) Tokenise(path string) ([]*Token, error) {
 			tokens = append(tokens, token)
 		}
 		if err != nil {
-			return nil, err
+			return nil, fmt.Errorf("Parsing expression: %v", err)
 		}
 	}
 	var postProcessedTokens = make([]*Token, 0)

pkg/yqlib/path_tree.go

@@ -1,6 +1,9 @@
 package yqlib
 
-import "fmt"
+import (
+	"fmt"
+	"strings"
+)
 
 var myPathTokeniser = NewPathTokeniser()
 var myPathPostfixer = NewPathPostFixer()
@@ -49,10 +52,16 @@ func (p *pathTreeCreator) CreatePathTree(postFixPath []*Operation) (*PathTreeNod
 		if Operation.OperationType.NumArgs > 0 {
 			numArgs := Operation.OperationType.NumArgs
 			if numArgs == 1 {
+				if len(stack) < 1 {
+					return nil, fmt.Errorf("'%v' expects 1 arg but received none", strings.TrimSpace(Operation.StringValue))
+				}
 				remaining, rhs := stack[:len(stack)-1], stack[len(stack)-1]
 				newNode.Rhs = rhs
 				stack = remaining
 			} else if numArgs == 2 {
+				if len(stack) < 2 {
+					return nil, fmt.Errorf("'%v' expects 2 args but there is %v", strings.TrimSpace(Operation.StringValue), len(stack))
+				}
 				remaining, lhs, rhs := stack[:len(stack)-2], stack[len(stack)-2], stack[len(stack)-1]
 				newNode.Lhs = lhs
 				newNode.Rhs = rhs
@@ -62,7 +71,7 @@ func (p *pathTreeCreator) CreatePathTree(postFixPath []*Operation) (*PathTreeNod
 		stack = append(stack, &newNode)
 	}
 	if len(stack) != 1 {
-		return nil, fmt.Errorf("expected stack to have 1 thing but its %v", stack)
+		return nil, fmt.Errorf("expected end of expression but found '%v', please check expression syntax", strings.TrimSpace(stack[1].Operation.StringValue))
 	}
 	return stack[0], nil
 }

pkg/yqlib/path_tree_test.go

@@ -0,0 +1,42 @@
+package yqlib
+
+import (
+	"testing"
+
+	"github.com/mikefarah/yq/v4/test"
+)
+
+func TestPathTreeNoArgsForTwoArgOp(t *testing.T) {
+	_, err := treeCreator.ParsePath("=")
+	test.AssertResultComplex(t, "'=' expects 2 args but there is 0", err.Error())
+}
+
+func TestPathTreeOneLhsArgsForTwoArgOp(t *testing.T) {
+	_, err := treeCreator.ParsePath(".a =")
+	test.AssertResultComplex(t, "'=' expects 2 args but there is 1", err.Error())
+}
+
+func TestPathTreeOneRhsArgsForTwoArgOp(t *testing.T) {
+	_, err := treeCreator.ParsePath("= .a")
+	test.AssertResultComplex(t, "'=' expects 2 args but there is 1", err.Error())
+}
+
+func TestPathTreeTwoArgsForTwoArgOp(t *testing.T) {
+	_, err := treeCreator.ParsePath(".a = .b")
+	test.AssertResultComplex(t, nil, err)
+}
+
+func TestPathTreeNoArgsForOneArgOp(t *testing.T) {
+	_, err := treeCreator.ParsePath("explode")
+	test.AssertResultComplex(t, "'explode' expects 1 arg but received none", err.Error())
+}
+
+func TestPathTreeOneArgForOneArgOp(t *testing.T) {
+	_, err := treeCreator.ParsePath("explode(.)")
+	test.AssertResultComplex(t, nil, err)
+}
+
+func TestPathTreeExtraArgs(t *testing.T) {
+	_, err := treeCreator.ParsePath("sortKeys(.) explode(.)")
+	test.AssertResultComplex(t, "expected end of expression but found 'explode', please check expression syntax", err.Error())
+}

pkg/yqlib/printer.go

@@ -22,6 +22,7 @@ type resultsPrinter struct {
 	writer             io.Writer
 	firstTimePrinting  bool
 	previousDocIndex   uint
+	previousFileIndex  int
 	printedMatches     bool
 }
 
@@ -89,19 +90,20 @@ func (p *resultsPrinter) PrintResults(matchingNodes *list.List) error {
 		return nil
 	}
 	if p.firstTimePrinting {
-		p.previousDocIndex = matchingNodes.Front().Value.(*CandidateNode).Document
+		node := matchingNodes.Front().Value.(*CandidateNode)
+		p.previousDocIndex = node.Document
+		p.previousFileIndex = node.FileIndex
 		p.firstTimePrinting = false
 	}
 
 	for el := matchingNodes.Front(); el != nil; el = el.Next() {
 		mappedDoc := el.Value.(*CandidateNode)
 		log.Debug("-- print sep logic: p.firstTimePrinting: %v, previousDocIndex: %v, mappedDoc.Document: %v, printDocSeparators: %v", p.firstTimePrinting, p.previousDocIndex, mappedDoc.Document, p.printDocSeparators)
-		if (p.previousDocIndex != mappedDoc.Document) && p.printDocSeparators {
+		if (p.previousDocIndex != mappedDoc.Document || p.previousFileIndex != mappedDoc.FileIndex) && p.printDocSeparators {
 			log.Debug("-- writing doc sep")
 			if err := p.writeString(bufferedWriter, "---\n"); err != nil {
 				return err
 			}
-
 		}
 
 		if err := p.printNode(mappedDoc.Node, bufferedWriter); err != nil {

pkg/yqlib/printer_test.go

@@ -52,7 +52,53 @@ func TestPrinterMultipleDocsInSequence(t *testing.T) {
 
 	writer.Flush()
 	test.AssertResult(t, multiDocSample, output.String())
+}
 
+func TestPrinterMultipleFilesInSequence(t *testing.T) {
+	var output bytes.Buffer
+	var writer = bufio.NewWriter(&output)
+	printer := NewPrinter(writer, false, true, false, 2, true)
+
+	inputs, err := readDocuments(strings.NewReader(multiDocSample), "sample.yml", 0)
+	if err != nil {
+		panic(err)
+	}
+
+	el := inputs.Front()
+	elNode := el.Value.(*CandidateNode)
+	elNode.Document = 0
+	elNode.FileIndex = 0
+	sample1 := nodeToMap(elNode)
+
+	el = el.Next()
+	elNode = el.Value.(*CandidateNode)
+	elNode.Document = 0
+	elNode.FileIndex = 1
+	sample2 := nodeToMap(elNode)
+
+	el = el.Next()
+	elNode = el.Value.(*CandidateNode)
+	elNode.Document = 0
+	elNode.FileIndex = 2
+	sample3 := nodeToMap(elNode)
+
+	err = printer.PrintResults(sample1)
+	if err != nil {
+		panic(err)
+	}
+
+	err = printer.PrintResults(sample2)
+	if err != nil {
+		panic(err)
+	}
+
+	err = printer.PrintResults(sample3)
+	if err != nil {
+		panic(err)
+	}
+
+	writer.Flush()
+	test.AssertResult(t, multiDocSample, output.String())
 }
 
 func TestPrinterMultipleDocsInSinglePrint(t *testing.T) {

snap/snapcraft.yaml

@@ -1,5 +1,5 @@
 name: yq
-version: '4.0.0-beta2'
+version: '4.0.0-beta1'
 summary: A lightweight and portable command-line YAML processor
 description: |
   The aim of the project is to be the jq or sed of yaml files.