Initial commit

.github/workflows/build.yaml

@@ -0,0 +1,42 @@
+on:
+  push:
+    tags:
+      - 'v*.*.*'
+name: Build
+jobs:
+  publish:
+    strategy:
+      matrix:
+        go-version: [1.15.x]
+        os:
+          - ubuntu-latest
+          - windows-latest
+          - macos-latest
+        include:
+          - os: ubuntu-latest
+            artifact_name: dasel
+            asset_name: dasel_linux_amd64
+          - os: windows-latest
+            artifact_name: dasel.exe
+            asset_name: dasel_windows_amd64.exe
+          - os: macos-latest
+            artifact_name: dasel
+            asset_name: dasel_macos_amd64
+    name: Publish for ${{ matrix.os }}
+    runs-on: ${{ matrix.os }}
+    steps:
+      - uses: actions/checkout@v2
+      - uses: actions/setup-go@v2-beta
+        with:
+          go-version: '^1.15.0' # The Go version to download (if necessary) and use.
+      - name: Set env
+        run: echo ::set-env name=RELEASE_VERSION::${GITHUB_REF:10}
+      - name: Build
+        run: go build -o target/release/${{ matrix.artifact_name }} -ldflags="-X 'github.com/tomwright/dasel/internal.Version=${{ env.RELEASE_VERSION }}'" ./cmd/dasel
+      - name: Upload binaries to release
+        uses: svenstaro/upload-release-action@v1-release
+        with:
+          repo_token: ${{ secrets.GITHUB_TOKEN }}
+          file: target/release/${{ matrix.artifact_name }}
+          asset_name: ${{ matrix.asset_name }}
+          tag: ${{ github.ref }}

.github/workflows/test.yaml

@@ -0,0 +1,24 @@
+on: [push, pull_request]
+name: Test
+jobs:
+  test:
+    strategy:
+      matrix:
+        go-version: [1.15.x]
+        platform: [ubuntu-latest]
+    runs-on: ${{ matrix.platform }}
+    steps:
+      - name: Install Go
+        uses: actions/setup-go@v1
+        with:
+          go-version: ${{ matrix.go-version }}
+      - name: Checkout code
+        uses: actions/checkout@v1
+      - uses: actions/cache@v1
+        with:
+          path: ~/go/pkg/mod
+          key: ${{ runner.os }}-go-${{ hashFiles('**/go.sum') }}
+          restore-keys: |
+            ${{ runner.os }}-go-
+      - name: Test
+        run: go test -race ./...

.gitignore

@@ -0,0 +1 @@
+.idea/

README.md

@@ -0,0 +1,47 @@
+# dasel
+
+Read and modify data structures using selectors.
+
+## Selectors
+The following YAML data structure will be used as a reference in the following examples.
+```
+name: Tom
+preferences:
+  favouriteColour: red
+colours:
+- red
+- green
+- blue
+colourCodes:
+- name: red
+  rgb: ff0000
+- name: green
+  rgb: 00ff00
+- name: blue
+  rgb: 0000ff
+```
+
+### Root Element
+Just use the root element name as a string.
+- `name` == `Tom`
+
+### Child Element
+Just separate the parent element from the parent element using a `.`:
+- `preferences.favouriteColour` == `red`
+
+#### Index
+When you have a list, you can use square brackets to access or modify a specific item.
+- `colours.[0]` == `red`
+- `colours.[1]` == `green`
+- `colours.[2]` == `blue`
+
+#### Next Available Index
+Next available index selector is used when adding to a list of items.
+- `colours.[]`
+
+#### Look up
+Look ups are defined in brackets and allow you to dynamically select an object to use.
+- `.colourCodes.(name=red).rgb` == `ff0000`
+- `.colourCodes.(name=green).rgb` == `00ff00`
+- `.colourCodes.(name=blue).rgb` == `0000ff`
+- `.colourCodes.(name=blue)(rgb=0000ff).rgb` == `0000ff`

cmd/dasel/main.go

@@ -0,0 +1,14 @@
+package main
+
+import (
+	"fmt"
+	"github.com/tomwright/dasel/internal/command"
+	"os"
+)
+
+func main() {
+	if err := command.RootCMD.Execute(); err != nil {
+		fmt.Println("Error: " + err.Error())
+		os.Exit(1)
+	}
+}

condition.go

@@ -0,0 +1,25 @@
+package dasel
+
+import "fmt"
+
+type EqualCondition struct {
+	Key   string
+	Value string
+}
+
+func (c EqualCondition) Check(other interface{}) (bool, error) {
+	switch o := other.(type) {
+	case map[string]string:
+		return o[c.Key] == c.Value, nil
+	case map[string]interface{}:
+		return fmt.Sprint(o[c.Key]) == c.Value, nil
+	case map[interface{}]interface{}:
+		return fmt.Sprint(o[c.Key]) == c.Value, nil
+	default:
+		return false, fmt.Errorf("unhandled check type: %T", other)
+	}
+}
+
+type Condition interface {
+	Check(other interface{}) (bool, error)
+}

error.go

@@ -0,0 +1,58 @@
+package dasel
+
+import (
+	"errors"
+	"fmt"
+)
+
+var ErrMissingPreviousNode = errors.New("missing previous node")
+
+type UnknownComparisonOperatorErr struct {
+	Operator string
+}
+
+func (e UnknownComparisonOperatorErr) Error() string {
+	return fmt.Sprintf("unknown comparison operator: %s", e.Operator)
+}
+
+type InvalidIndexErr struct {
+	Index string
+}
+
+func (e InvalidIndexErr) Error() string {
+	return fmt.Sprintf("invalid index: %s", e.Index)
+}
+
+type UnsupportedSelector struct {
+	Selector string
+}
+
+func (e UnsupportedSelector) Error() string {
+	return fmt.Sprintf("selector is not supported here: %s", e.Selector)
+}
+
+type UnsupportedTypeForSelector struct {
+	Selector Selector
+	Value    interface{}
+}
+
+func (e UnsupportedTypeForSelector) Error() string {
+	return fmt.Sprintf("selector [%s] does not support value: %T: %v", e.Selector.Type, e.Value, e.Value)
+}
+
+type NotFound struct {
+	Selector string
+	Node     *Node
+}
+
+func (e NotFound) Error() string {
+	return fmt.Sprintf("nothing found for selector: %s", e.Selector)
+}
+
+type UnexpectedPreviousNilValue struct {
+	Selector string
+}
+
+func (e UnexpectedPreviousNilValue) Error() string {
+	return fmt.Sprintf("previous value is nil: %s", e.Selector)
+}

go.mod

@@ -0,0 +1,9 @@
+module github.com/tomwright/dasel
+
+go 1.15
+
+require (
+	github.com/google/go-cmp v0.2.0
+	github.com/spf13/cobra v1.0.0
+	gopkg.in/yaml.v2 v2.2.2
+)

go.sum

@@ -0,0 +1,129 @@
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+golang.org/x/crypto v0.0.0-20180904163835-0709b304e793/go.mod h1:6SG95UA2DQfeDnfUPMdvaQW0Q7yPrPDi9nlGo2tz2b4=
+golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
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+golang.org/x/lint v0.0.0-20190313153728-d0100b6bd8b3/go.mod h1:6SW0HCj/g11FgYtHlgUYUwCkIfeOF89ocIRzGO/8vkc=
+golang.org/x/net v0.0.0-20180826012351-8a410e7b638d/go.mod h1:mL1N/T3taQHkDXs73rZJwtUhF3w3ftmwwsq0BUmARs4=
+golang.org/x/net v0.0.0-20181114220301-adae6a3d119a/go.mod h1:mL1N/T3taQHkDXs73rZJwtUhF3w3ftmwwsq0BUmARs4=
+golang.org/x/net v0.0.0-20181220203305-927f97764cc3/go.mod h1:mL1N/T3taQHkDXs73rZJwtUhF3w3ftmwwsq0BUmARs4=
+golang.org/x/net v0.0.0-20190311183353-d8887717615a/go.mod h1:t9HGtf8HONx5eT2rtn7q6eTqICYqUVnKs3thJo3Qplg=
+golang.org/x/net v0.0.0-20190522155817-f3200d17e092/go.mod h1:HSz+uSET+XFnRR8LxR5pz3Of3rY3CfYBVs4xY44aLks=
+golang.org/x/oauth2 v0.0.0-20180821212333-d2e6202438be/go.mod h1:N/0e6XlmueqKjAGxoOufVs8QHGRruUQn6yWY3a++T0U=
+golang.org/x/sync v0.0.0-20180314180146-1d60e4601c6f/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
+golang.org/x/sync v0.0.0-20181108010431-42b317875d0f/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
+golang.org/x/sync v0.0.0-20181221193216-37e7f081c4d4/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
+golang.org/x/sys v0.0.0-20180830151530-49385e6e1522/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
+golang.org/x/sys v0.0.0-20180905080454-ebe1bf3edb33/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
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+golang.org/x/sys v0.0.0-20181116152217-5ac8a444bdc5/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
+golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
+golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
+golang.org/x/time v0.0.0-20190308202827-9d24e82272b4/go.mod h1:tRJNPiyCQ0inRvYxbN9jk5I+vvW/OXSQhTDSoE431IQ=
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+google.golang.org/appengine v1.1.0/go.mod h1:EbEs0AVv82hx2wNQdGPgUI5lhzA/G0D9YwlJXL52JkM=
+google.golang.org/genproto v0.0.0-20180817151627-c66870c02cf8/go.mod h1:JiN7NxoALGmiZfu7CAH4rXhgtRTLTxftemlI0sWmxmc=
+google.golang.org/grpc v1.19.0/go.mod h1:mqu4LbDTu4XGKhr4mRzUsmM4RtVoemTSY81AxZiDr8c=
+google.golang.org/grpc v1.21.0/go.mod h1:oYelfM1adQP15Ek0mdvEgi9Df8B9CZIaU1084ijfRaM=
+gopkg.in/alecthomas/kingpin.v2 v2.2.6/go.mod h1:FMv+mEhP44yOT+4EoQTLFTRgOQ1FBLkstjWtayDeSgw=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+gopkg.in/check.v1 v1.0.0-20180628173108-788fd7840127/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+gopkg.in/resty.v1 v1.12.0/go.mod h1:mDo4pnntr5jdWRML875a/NmxYqAlA73dVijT2AXvQQo=
+gopkg.in/yaml.v2 v2.0.0-20170812160011-eb3733d160e7/go.mod h1:JAlM8MvJe8wmxCU4Bli9HhUf9+ttbYbLASfIpnQbh74=
+gopkg.in/yaml.v2 v2.2.1/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
+gopkg.in/yaml.v2 v2.2.2 h1:ZCJp+EgiOT7lHqUV2J862kp8Qj64Jo6az82+3Td9dZw=
+gopkg.in/yaml.v2 v2.2.2/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
+honnef.co/go/tools v0.0.0-20190102054323-c2f93a96b099/go.mod h1:rf3lG4BRIbNafJWhAfAdb/ePZxsR/4RtNHQocxwk9r4=

internal/command/root.go

@@ -0,0 +1,19 @@
+package command
+
+import (
+	"github.com/spf13/cobra"
+)
+
+var RootCMD = &cobra.Command{
+	Use:        "dasel",
+	Aliases:    nil,
+	SuggestFor: nil,
+	Short:      "A small helper to manage kubernetes configurations.",
+}
+
+func init() {
+	RootCMD.AddCommand(
+		selectCommand(),
+		versionCommand(),
+	)
+}

internal/command/select.go

@@ -0,0 +1,43 @@
+package command
+
+import (
+	"fmt"
+	"github.com/spf13/cobra"
+	dasel "github.com/tomwright/dasel"
+	"github.com/tomwright/dasel/internal/storage"
+)
+
+func selectCommand() *cobra.Command {
+	var file, selector, parser string
+
+	cmd := &cobra.Command{
+		Use:   "select -f <file> -s <selector>",
+		Short: "Select properties from the given files.",
+		Args:  cobra.ExactArgs(0),
+		RunE: func(cmd *cobra.Command, args []string) error {
+			parser, err := storage.FromString(parser)
+			if err != nil {
+				return err
+			}
+			value, err := parser.LoadFromFile(file)
+			if err != nil {
+				return fmt.Errorf("could not load file: %w", err)
+			}
+			rootNode := dasel.New(value)
+			res, err := rootNode.Query(selector)
+			if err != nil {
+				return fmt.Errorf("could not query node: %w", err)
+			}
+
+			fmt.Printf("%v\n", res.Value)
+
+			return nil
+		},
+	}
+
+	cmd.Flags().StringVarP(&file, "file", "f", "", "The file to query.")
+	cmd.Flags().StringVarP(&selector, "selector", "s", "", "The selector to use when querying.")
+	cmd.Flags().StringVarP(&parser, "parser", "p", "yaml", "The parser to use with the given file.")
+
+	return cmd
+}

internal/command/version.go

@@ -0,0 +1,20 @@
+package command
+
+import (
+	"fmt"
+	"github.com/spf13/cobra"
+	"github.com/tomwright/dasel/internal"
+)
+
+func versionCommand() *cobra.Command {
+	cmd := &cobra.Command{
+		Use:   "version",
+		Short: "Prints the dasel version.",
+		Args:  cobra.ExactArgs(0),
+		Run: func(cmd *cobra.Command, args []string) {
+			fmt.Println(internal.Version)
+		},
+	}
+
+	return cmd
+}

internal/oflag/flags.go

@@ -0,0 +1,111 @@
+package oflag
+
+import (
+	"fmt"
+	"strings"
+)
+
+// Override represents a single override.
+type Override struct {
+	// Path is a string that may have dot separators within it.
+	Path string
+	// Value is the value to set in the config file.
+	Value interface{}
+}
+
+// String returns a string representation of the override.
+func (o Override) String() string {
+	return fmt.Sprintf("%s=%v", o.Path, o.Value)
+}
+
+// NewOverrideFlag returns an OverrideFlag with the given parse func.
+func NewOverrideFlag(parse ParseOverrideValueFn) *OverrideFlag {
+	return &OverrideFlag{
+		overrides: make([]*Override, 0),
+		Parse:     parse,
+	}
+}
+
+// Combine returns a combined list of overrides from all given OverrideFlag's.
+func Combine(flags ...*OverrideFlag) []*Override {
+	res := make([]*Override, 0)
+	for _, f := range flags {
+		res = append(res, f.Overrides()...)
+	}
+	return res
+}
+
+// OverrideFlag allows us to collect a list of overrides from command line flags.
+type OverrideFlag struct {
+	overrides []*Override
+	// Parse allows us to parse override values into specific types.
+	Parse ParseOverrideValueFn
+}
+
+// Overrides returns the collected overrides.
+func (of *OverrideFlag) Overrides() []*Override {
+	return of.overrides
+}
+
+// Type returns the type of flag.
+// As far as I can tell this isn't used...
+// todo : figure out what this is supposed to return.
+func (of *OverrideFlag) Type() string {
+	panic("implement me")
+}
+
+// String returns a string representation of all Override's within the OverrideFlag.
+func (of *OverrideFlag) String() string {
+	val := make([]string, len(of.overrides))
+	for k, o := range of.overrides {
+		val[k] = o.String()
+	}
+	return strings.Join(val, " ")
+}
+
+// Set is used to add a new value to the OverrideFlag.
+func (of *OverrideFlag) Set(value string) error {
+	if value == "" {
+		return nil
+	}
+	args := strings.Split(value, "=")
+
+	var override *Override
+	switch len(args) {
+	case 0:
+		// No value was given.
+		return nil
+	case 1:
+		// A blank value was given.
+		override = &Override{
+			Path:  args[0],
+			Value: "",
+		}
+	case 2:
+		// A single value was given.
+		override = &Override{
+			Path:  args[0],
+			Value: args[1],
+		}
+	default:
+		// The value contained more than 1 = sign.
+		// Assume the extra = values are within the value.
+		override = &Override{
+			Path:  args[0],
+			Value: strings.Join(args[1:], "="),
+		}
+	}
+
+	if of.Parse != nil {
+		var err error
+		// We know that override.Value will be a string here.
+		override.Value, err = of.Parse(override.Value.(string))
+		if err != nil {
+			return fmt.Errorf("invalid value for path `%s`: %w", override.Path, err)
+		}
+	}
+
+	of.overrides = append(of.overrides, override)
+
+	return nil
+}

internal/oflag/flags_test.go

@@ -0,0 +1,69 @@
+package oflag_test
+
+import (
+	"github.com/google/go-cmp/cmp"
+	"github.com/tomwright/dasel/internal/oflag"
+	"testing"
+)
+
+func TestOverrideFlag_Set(t *testing.T) {
+	overrides := oflag.NewOverrideFlag(oflag.StringParser)
+	if err := overrides.Set("a=asd"); err != nil {
+		t.Errorf("unexpected error: %s", err)
+	}
+	if err := overrides.Set("b="); err != nil {
+		t.Errorf("unexpected error: %s", err)
+	}
+	if err := overrides.Set("c=a=b"); err != nil {
+		t.Errorf("unexpected error: %s", err)
+	}
+	if err := overrides.Set("a.b.c=d.e.f"); err != nil {
+		t.Errorf("unexpected error: %s", err)
+	}
+	if err := overrides.Set(""); err != nil {
+		t.Errorf("unexpected error: %s", err)
+	}
+
+	exp := []*oflag.Override{
+		{
+			Path:  "a",
+			Value: "asd",
+		},
+		{
+			Path:  "b",
+			Value: "",
+		},
+		{
+			Path:  "c",
+			Value: "a=b",
+		},
+		{
+			Path:  "a.b.c",
+			Value: "d.e.f",
+		},
+	}
+
+	got := overrides.Overrides()
+
+	if !cmp.Equal(exp, got) {
+		t.Errorf("unexpected data:\n%s\n", cmp.Diff(exp, got))
+	}
+}
+
+func TestCombine(t *testing.T) {
+	a := oflag.NewOverrideFlag(nil)
+	b := oflag.NewOverrideFlag(nil)
+	c := oflag.NewOverrideFlag(nil)
+	_ = a.Set("a=1")
+	_ = b.Set("b=2")
+	_ = c.Set("c=3")
+	got := oflag.Combine(a, b, c)
+	exp := []*oflag.Override{
+		{Path: "a", Value: "1"},
+		{Path: "b", Value: "2"},
+		{Path: "c", Value: "3"},
+	}
+	if !cmp.Equal(exp, got) {
+		t.Errorf("unexpected combined result:\n%s\n", cmp.Diff(exp, got))
+	}
+}

internal/oflag/parser.go

@@ -0,0 +1,39 @@
+package oflag
+
+import (
+	"errors"
+	"strconv"
+	"strings"
+)
+
+// ParseOverrideValueFn defines a function used to parse config values passed in through command line arguments.
+type ParseOverrideValueFn func(value string) (interface{}, error)
+
+// StringParser parses string config values.
+func StringParser(value string) (interface{}, error) {
+	return value, nil
+}
+
+// IntParser parses int config values.
+func IntParser(value string) (interface{}, error) {
+	i, err := strconv.ParseInt(value, 10, 64)
+	if err != nil {
+		return 0, err
+	}
+	return int(i), nil
+}
+
+// ErrInvalidBool is returned if the given value does not match an expected bool value.
+var ErrInvalidBool = errors.New("unexpected bool value")
+
+// BoolParser parses int config values.
+func BoolParser(value string) (interface{}, error) {
+	switch strings.ToLower(value) {
+	case "yes", "y", "true", "t", "1":
+		return true, nil
+	case "no", "n", "false", "f", "0":
+		return false, nil
+	default:
+		return false, ErrInvalidBool
+	}
+}

internal/oflag/parser_test.go

@@ -0,0 +1,92 @@
+package oflag_test
+
+import (
+	"errors"
+	"github.com/google/go-cmp/cmp"
+	"github.com/tomwright/dasel/internal/oflag"
+	"strconv"
+	"testing"
+)
+
+type testCase struct {
+	In  string
+	Exp interface{}
+	Err error
+}
+
+func runTestCase(tc testCase, fn oflag.ParseOverrideValueFn) func(t *testing.T) {
+	return func(t *testing.T) {
+		got, err := fn(tc.In)
+		if tc.Exp == nil && got != nil {
+			t.Errorf("unexpected error: %v", got)
+		} else if tc.Exp != nil && got == nil {
+			t.Errorf("expected error `%v`, got none", tc.Exp)
+		} else if !errors.Is(err, tc.Err) {
+			t.Errorf("expected error `%v`, got `%v`", tc.Err, err)
+		}
+		if !cmp.Equal(tc.Exp, got) {
+			t.Errorf("unexpected output\n%s", cmp.Diff(tc.Exp, got))
+		}
+	}
+}
+
+func TestStringParser(t *testing.T) {
+	tests := []testCase{
+		{In: "", Exp: "", Err: nil},
+		{In: "a", Exp: "a", Err: nil},
+		{In: "true", Exp: "true", Err: nil},
+		{In: "123", Exp: "123", Err: nil},
+	}
+
+	for _, testCase := range tests {
+		tc := testCase
+		t.Run(tc.In, runTestCase(tc, oflag.StringParser))
+	}
+}
+
+func TestBoolParser(t *testing.T) {
+	tests := []testCase{
+		{In: "", Exp: false, Err: oflag.ErrInvalidBool},
+		{In: "asd", Exp: false, Err: oflag.ErrInvalidBool},
+		{In: "yes", Exp: true, Err: nil},
+		{In: "YES", Exp: true, Err: nil},
+		{In: "y", Exp: true, Err: nil},
+		{In: "Y", Exp: true, Err: nil},
+		{In: "true", Exp: true, Err: nil},
+		{In: "TRUE", Exp: true, Err: nil},
+		{In: "t", Exp: true, Err: nil},
+		{In: "T", Exp: true, Err: nil},
+		{In: "1", Exp: true, Err: nil},
+		{In: "no", Exp: false, Err: nil},
+		{In: "NO", Exp: false, Err: nil},
+		{In: "n", Exp: false, Err: nil},
+		{In: "N", Exp: false, Err: nil},
+		{In: "false", Exp: false, Err: nil},
+		{In: "FALSE", Exp: false, Err: nil},
+		{In: "f", Exp: false, Err: nil},
+		{In: "F", Exp: false, Err: nil},
+		{In: "0", Exp: false, Err: nil},
+	}
+
+	for _, testCase := range tests {
+		tc := testCase
+		t.Run(tc.In, runTestCase(tc, oflag.BoolParser))
+	}
+}
+
+func TestIntParser(t *testing.T) {
+	tests := []testCase{
+		{In: "", Exp: 0, Err: strconv.ErrSyntax},
+		{In: "asd", Exp: 0, Err: strconv.ErrSyntax},
+		{In: "1.0", Exp: 0, Err: strconv.ErrSyntax},
+		{In: "0", Exp: 0, Err: nil},
+		{In: "12", Exp: 12, Err: nil},
+		{In: "-1", Exp: -1, Err: nil},
+		{In: "12345678", Exp: 12345678, Err: nil},
+	}
+
+	for _, testCase := range tests {
+		tc := testCase
+		t.Run(tc.In, runTestCase(tc, oflag.IntParser))
+	}
+}

internal/storage/parser.go

@@ -0,0 +1,50 @@
+package storage
+
+import (
+	"fmt"
+	"gopkg.in/yaml.v2"
+	"io/ioutil"
+)
+
+type unknownParserErr struct {
+	parser string
+}
+
+func (e unknownParserErr) Error() string {
+	return fmt.Sprintf("unknown parser: %s", e.parser)
+}
+
+type Parser interface {
+	FromBytes(byteData []byte) (interface{}, error)
+	LoadFromFile(filename string) (interface{}, error)
+}
+
+func FromString(parser string) (Parser, error) {
+	switch parser {
+	case "yaml":
+		return &YAMLParser{}, nil
+	default:
+		return nil, &unknownParserErr{parser: parser}
+	}
+}
+
+type YAMLParser struct {
+}
+
+// FromBytes returns some Data that is represented by the given bytes.
+func (p *YAMLParser) FromBytes(byteData []byte) (interface{}, error) {
+	var data interface{}
+	if err := yaml.Unmarshal(byteData, &data); err != nil {
+		return data, fmt.Errorf("could not unmarshal config data: %w", err)
+	}
+	return data, nil
+}
+
+// LoadFromFile loads Data from the given file.
+func (p *YAMLParser) LoadFromFile(filename string) (interface{}, error) {
+	byteData, err := ioutil.ReadFile(filename)
+	if err != nil {
+		return nil, fmt.Errorf("could not read config file: %w", err)
+	}
+	return p.FromBytes(byteData)
+}

internal/version.go

@@ -0,0 +1,5 @@
+package internal
+
+// Version represents the current version of dasel.
+// The real version number is injected at build time using ldflags.
+var Version = "development"

node.go

@@ -0,0 +1,346 @@
+package dasel
+
+import (
+	"encoding/json"
+	"fmt"
+	"regexp"
+	"strconv"
+	"strings"
+)
+
+// Selector represents the selector for a node.
+type Selector struct {
+	// Raw is the full selector.
+	Raw string `json:"raw"`
+	// Current is the selector to be used with the current node.
+	Current string `json:"current"`
+	// Remaining is the remaining parts of the Raw selector.
+	Remaining string `json:"remaining"`
+	// Type is the type of the selector.
+	Type string `json:"type"`
+	// Property is the name of the property this selector targets, if applicable.
+	Property string `json:"property,omitempty"`
+	// Index is the index to use if applicable.
+	Index int64 `json:"index,omitempty"`
+	// Conditions contains a set of conditions to optionally match a target.
+	Conditions []Condition `json:"conditions,omitempty"`
+}
+
+// Node represents a single node in the chain of nodes for a selector.
+type Node struct {
+	// Previous is the previous node in the chain.
+	Previous *Node `json:"-"`
+	// Next is the next node in the chain.
+	Next *Node `json:"next,omitempty"`
+
+	// Value is the value of the current node.
+	Value interface{} `json:"value"`
+	// Selector is the selector for the current node.
+	Selector Selector `json:"selector"`
+}
+
+func (n *Node) String() string {
+	b, err := json.MarshalIndent(n, "", "  ")
+	if err != nil {
+		panic(err)
+	}
+	return string(b)
+}
+
+const (
+	propertySelector = `(?P<property>[a-zA-Z\-_]+)`
+	indexSelector    = `\[(?P<index>[0-9]*?)\]`
+	dynamicSelector  = `\((?P<name>[a-zA-Z\-_]+)(?P<comparison>=)(?P<name>.*?)\)`
+)
+
+var (
+	// firstNodeRegexp = regexp.MustCompile(`(.+\.?)*?`)
+	propertyRegexp        = regexp.MustCompile(fmt.Sprintf("^\\.?%s", propertySelector))
+	indexRegexp           = regexp.MustCompile(fmt.Sprintf("^\\.?%s", indexSelector))
+	dynamicRegexp         = regexp.MustCompile(fmt.Sprintf("^\\.?(?:%s)+", dynamicSelector))
+	multipleDynamicRegexp = regexp.MustCompile(fmt.Sprintf("%s+", dynamicSelector))
+)
+
+// ParseSelector parses the given selector string and returns a Selector.
+func ParseSelector(selector string) (Selector, error) {
+	sel := Selector{
+		Raw:        selector,
+		Current:    "",
+		Remaining:  "",
+		Type:       "",
+		Property:   "",
+		Conditions: make([]Condition, 0),
+	}
+
+	if match := propertyRegexp.FindStringSubmatch(selector); len(match) != 0 {
+		sel.Type = "PROPERTY"
+		sel.Current = match[0]
+		sel.Property = match[1]
+	} else if match := indexRegexp.FindStringSubmatch(selector); len(match) != 0 {
+		sel.Current = match[0]
+		if match[1] == "" {
+			sel.Type = "NEXT_AVAILABLE_INDEX"
+		} else {
+			sel.Type = "INDEX"
+			var err error
+			sel.Index, err = strconv.ParseInt(match[1], 10, 64)
+			if err != nil {
+				return sel, &InvalidIndexErr{Index: match[1]}
+			}
+		}
+	} else if match := dynamicRegexp.FindString(selector); match != "" {
+		sel.Current = match
+		matches := multipleDynamicRegexp.FindAllStringSubmatch(match, -1)
+		for _, m := range matches {
+			var cond Condition
+			switch m[2] {
+			case "=":
+				cond = &EqualCondition{
+					Key:   m[1],
+					Value: m[3],
+				}
+			default:
+				return sel, &UnknownComparisonOperatorErr{Operator: m[2]}
+			}
+
+			sel.Conditions = append(sel.Conditions, cond)
+		}
+		sel.Type = "DYNAMIC"
+	}
+
+	sel.Remaining = strings.TrimPrefix(sel.Raw, sel.Current)
+
+	return sel, nil
+}
+
+func New(value interface{}) *Node {
+	rootNode := &Node{
+		Previous: nil,
+		Next:     nil,
+		Value:    value,
+		Selector: Selector{
+			Raw:       ".",
+			Current:   ".",
+			Remaining: "",
+			Type:      "ROOT",
+			Property:  "",
+		},
+	}
+	return rootNode
+}
+
+func (n Node) Query(selector string) (*Node, error) {
+	n.Selector.Remaining = selector
+	rootNode := &n
+	var previousNode = rootNode
+	var nextNode *Node
+	var err error
+
+	for {
+		if previousNode == nil {
+			break
+		}
+		if previousNode.Selector.Remaining == "" {
+			break
+		}
+
+		nextNode = &Node{}
+
+		// Parse the selector.
+		nextNode.Selector, err = ParseSelector(previousNode.Selector.Remaining)
+		if err != nil {
+			return nil, fmt.Errorf("failed to parse selector: %w", err)
+		}
+
+		// Link the nodes.
+		previousNode.Next = nextNode
+		nextNode.Previous = previousNode
+
+		nextNode.Value, err = FindValue(nextNode)
+		// Populate the value for the new node.
+		if err != nil {
+			return nil, &NotFound{Selector: nextNode.Selector.Current, Node: nextNode}
+		}
+
+		previousNode = nextNode
+	}
+
+	return previousNode, nil
+}
+
+// findValueProperty finds the value for the given node using the property selector
+// information.
+func findValueProperty(n *Node) (interface{}, error) {
+	switch p := n.Previous.Value.(type) {
+	case nil:
+		return nil, &UnexpectedPreviousNilValue{Selector: n.Previous.Selector.Current}
+	case map[string]interface{}:
+		v, ok := p[n.Selector.Property]
+		if ok {
+			return v, nil
+		} else {
+			return nil, &NotFound{Selector: n.Selector.Current, Node: n}
+		}
+	case map[interface{}]interface{}:
+		v, ok := p[n.Selector.Property]
+		if ok {
+			return v, nil
+		} else {
+			return nil, &NotFound{Selector: n.Selector.Current, Node: n}
+		}
+	default:
+		return nil, &UnsupportedTypeForSelector{Selector: n.Selector, Value: n.Previous.Value}
+	}
+}
+
+// findValueIndex finds the value for the given node using the index selector
+// information.
+func findValueIndex(n *Node) (interface{}, error) {
+	switch p := n.Previous.Value.(type) {
+	case nil:
+		return nil, &UnexpectedPreviousNilValue{Selector: n.Previous.Selector.Current}
+	case []map[interface{}]interface{}:
+		l := int64(len(p))
+		if n.Selector.Index >= 0 && n.Selector.Index < l {
+			return p[n.Selector.Index], nil
+		} else {
+			return nil, &NotFound{Selector: n.Selector.Current, Node: n}
+		}
+	case []map[string]interface{}:
+		l := int64(len(p))
+		if n.Selector.Index >= 0 && n.Selector.Index < l {
+			return p[n.Selector.Index], nil
+		} else {
+			return nil, &NotFound{Selector: n.Selector.Current, Node: n}
+		}
+	case map[interface{}]interface{}:
+		l := int64(len(p))
+		if n.Selector.Index >= 0 && n.Selector.Index < l {
+			return p[n.Selector.Index], nil
+		} else {
+			return nil, &NotFound{Selector: n.Selector.Current, Node: n}
+		}
+	case map[int]interface{}:
+		l := int64(len(p))
+		if n.Selector.Index >= 0 && n.Selector.Index < l {
+			return p[int(n.Selector.Index)], nil
+		} else {
+			return nil, &NotFound{Selector: n.Selector.Current, Node: n}
+		}
+	case []interface{}:
+		l := int64(len(p))
+		if n.Selector.Index >= 0 && n.Selector.Index < l {
+			return p[n.Selector.Index], nil
+		} else {
+			return nil, &NotFound{Selector: n.Selector.Current, Node: n}
+		}
+	case []string:
+		l := int64(len(p))
+		if n.Selector.Index >= 0 && n.Selector.Index < l {
+			return p[n.Selector.Index], nil
+		} else {
+			return nil, &NotFound{Selector: n.Selector.Current, Node: n}
+		}
+	case []int:
+		l := int64(len(p))
+		if n.Selector.Index >= 0 && n.Selector.Index < l {
+			return p[n.Selector.Index], nil
+		} else {
+			return nil, &NotFound{Selector: n.Selector.Current, Node: n}
+		}
+	default:
+		return nil, &UnsupportedTypeForSelector{Selector: n.Selector, Value: n.Previous.Value}
+	}
+}
+
+// findValueDynamic finds the value for the given node using the dynamic selector
+// information.
+func findValueDynamic(n *Node) (interface{}, error) {
+	switch p := n.Previous.Value.(type) {
+	case nil:
+		return nil, &UnexpectedPreviousNilValue{Selector: n.Previous.Selector.Current}
+	case []map[interface{}]interface{}:
+		for _, v := range p {
+			// Loop through each condition.
+			allConditionsMatched := true
+			for _, c := range n.Selector.Conditions {
+				// If the object doesn't match any checks, return a NotFound.
+				found, err := c.Check(v)
+				if err != nil {
+					return nil, err
+				}
+				if !found {
+					allConditionsMatched = false
+					break
+				}
+			}
+			if allConditionsMatched {
+				return v, nil
+			}
+		}
+		return nil, &NotFound{Selector: n.Selector.Current, Node: n}
+	case []map[string]interface{}:
+		for _, v := range p {
+			// Loop through each condition.
+			allConditionsMatched := true
+			for _, c := range n.Selector.Conditions {
+				// If the object doesn't match any checks, return a NotFound.
+				found, err := c.Check(v)
+				if err != nil {
+					return nil, err
+				}
+				if !found {
+					allConditionsMatched = false
+					break
+				}
+			}
+			if allConditionsMatched {
+				return v, nil
+			}
+		}
+		return nil, &NotFound{Selector: n.Selector.Current, Node: n}
+	case []map[string]string:
+		for _, v := range p {
+			// Loop through each condition.
+			allConditionsMatched := true
+			for _, c := range n.Selector.Conditions {
+				// If the object doesn't match any checks, return a NotFound.
+				found, err := c.Check(v)
+				if err != nil {
+					return nil, err
+				}
+				if !found {
+					allConditionsMatched = false
+					break
+				}
+			}
+			if allConditionsMatched {
+				return v, nil
+			}
+		}
+		return nil, &NotFound{Selector: n.Selector.Current, Node: n}
+	default:
+		return nil, &UnsupportedTypeForSelector{Selector: n.Selector, Value: n.Previous.Value}
+	}
+}
+
+// FindValue finds the value for the given node.
+// The value is essentially pulled from the previous node, using the (already parsed) selector
+// information stored on the current node.
+func FindValue(n *Node) (interface{}, error) {
+	if n.Previous == nil {
+		// previous node is required to get it's value.
+		return nil, ErrMissingPreviousNode
+	}
+
+	switch n.Selector.Type {
+	case "PROPERTY":
+		return findValueProperty(n)
+	case "INDEX":
+		return findValueIndex(n)
+	case "DYNAMIC":
+		return findValueDynamic(n)
+	default:
+		return nil, &UnsupportedSelector{Selector: n.Selector.Type}
+	}
+}

node_test.go

@@ -0,0 +1,254 @@
+package dasel_test
+
+import (
+	"errors"
+	"github.com/tomwright/dasel"
+	"reflect"
+	"testing"
+)
+
+var (
+	tom = map[string]interface{}{
+		"name": "Tom",
+		"age":  28,
+	}
+	amelia = map[string]interface{}{
+		"name": "Amelia",
+		"age":  26,
+	}
+	people = []map[string]interface{}{tom, amelia}
+	mapC   = map[string]interface{}{
+		"thing": "1",
+	}
+	mapB = map[string]interface{}{
+		"c":      mapC,
+		"people": people,
+	}
+	mapA = map[string]interface{}{
+		"b": mapB,
+	}
+	mapRoot = map[string]interface{}{
+		"a": mapA,
+	}
+)
+
+type processFn func(t *testing.T, n *dasel.Node) (*dasel.Node, bool)
+type checkFn func(t *testing.T, n *dasel.Node) bool
+
+type parseTest struct {
+	Selector   string
+	Input      interface{}
+	ProcessFns []processFn
+	CheckFns   []checkFn
+	Names      []string
+	Err        error
+}
+
+func (pt parseTest) Add(name string, p processFn, c checkFn) parseTest {
+	if pt.ProcessFns == nil {
+		pt.ProcessFns = make([]processFn, 0)
+	}
+	if pt.CheckFns == nil {
+		pt.CheckFns = make([]checkFn, 0)
+	}
+	if pt.Names == nil {
+		pt.Names = make([]string, 0)
+	}
+	pt.Names = append(pt.Names, name)
+	pt.ProcessFns = append(pt.ProcessFns, p)
+	pt.CheckFns = append(pt.CheckFns, c)
+	return pt
+}
+
+func TestNode_Query(t *testing.T) {
+	t.Run("ParentChildPathToProperty", func(t *testing.T) {
+		rootNode := dasel.New(mapRoot)
+
+		got, err := rootNode.Query(".a.b.c.thing")
+		if err != nil {
+			t.Errorf("unexpected error: %v", err)
+			return
+		}
+
+		if exp, got := "1", got.Value.(string); exp != got {
+			t.Errorf("expected %s, got %s", exp, got)
+		}
+	})
+	t.Run("ParentChildPathToIndexProperty", func(t *testing.T) {
+		rootNode := dasel.New(mapRoot)
+
+		got, err := rootNode.Query(".a.b.people.[1].name")
+		if err != nil {
+			t.Errorf("unexpected error: %v", err)
+			return
+		}
+
+		if exp, got := "Amelia", got.Value.(string); exp != got {
+			t.Errorf("expected %s, got %s", exp, got)
+		}
+	})
+	t.Run("ParentChildPathToDynamicProperty", func(t *testing.T) {
+		rootNode := dasel.New(mapRoot)
+
+		got, err := rootNode.Query(".a.b.people.(name=Tom).name")
+		if err != nil {
+			t.Errorf("unexpected error: %v", err)
+			return
+		}
+
+		if exp, got := "Tom", got.Value.(string); exp != got {
+			t.Errorf("expected %s, got %s", exp, got)
+		}
+	})
+	t.Run("ParentChildPathToMultipleDynamicProperty", func(t *testing.T) {
+		rootNode := dasel.New(mapRoot)
+
+		got, err := rootNode.Query(".a.b.people.(name=Tom)(age=28).name")
+		if err != nil {
+			t.Errorf("unexpected error: %v", err)
+			return
+		}
+
+		if exp, got := "Tom", got.Value.(string); exp != got {
+			t.Errorf("expected %s, got %s", exp, got)
+		}
+	})
+
+	t.Run("Traversal", func(t *testing.T) {
+		tests := parseTest{
+			Selector: ".a.b.c.thing",
+			Input:    mapRoot,
+		}.Add(
+			"StartsAtEndElement",
+			func(t *testing.T, n *dasel.Node) (*dasel.Node, bool) { return n, true },
+			func(t *testing.T, n *dasel.Node) bool {
+				if exp, got := ".thing", n.Selector.Current; exp != got {
+					t.Errorf("expected selector of `%s`, got `%s`", exp, got)
+					return false
+				}
+				if !reflect.DeepEqual("1", n.Value) {
+					t.Errorf("expected value of\n%s\ngot\n%s", "1", n.Value)
+					return false
+				}
+				return true
+			},
+		).Add(
+			"Previous1",
+			func(t *testing.T, n *dasel.Node) (*dasel.Node, bool) { return n.Previous, true },
+			func(t *testing.T, n *dasel.Node) bool {
+				if exp, got := ".c", n.Selector.Current; exp != got {
+					t.Errorf("expected selector of `%s`, got `%s`", exp, got)
+					return false
+				}
+				if !reflect.DeepEqual(mapC, n.Value) {
+					t.Errorf("expected value of\n%s\ngot\n%s", mapC, n.Value)
+					return false
+				}
+				return true
+			},
+		).Add(
+			"Previous2",
+			func(t *testing.T, n *dasel.Node) (*dasel.Node, bool) { return n.Previous, true },
+			func(t *testing.T, n *dasel.Node) bool {
+				if exp, got := ".b", n.Selector.Current; exp != got {
+					t.Errorf("expected selector of `%s`, got `%s`", exp, got)
+					return false
+				}
+				if !reflect.DeepEqual(mapB, n.Value) {
+					t.Errorf("expected value of\n%s\ngot\n%s", mapB, n.Value)
+					return false
+				}
+				return true
+			},
+		).Add(
+			"Previous3",
+			func(t *testing.T, n *dasel.Node) (*dasel.Node, bool) { return n.Previous, true },
+			func(t *testing.T, n *dasel.Node) bool {
+				if exp, got := ".a", n.Selector.Current; exp != got {
+					t.Errorf("expected selector of `%s`, got `%s`", exp, got)
+					return false
+				}
+				if !reflect.DeepEqual(mapA, n.Value) {
+					t.Errorf("expected value of\n%s\ngot\n%s", mapA, n.Value)
+					return false
+				}
+				return true
+			},
+		).Add(
+			"Next",
+			func(t *testing.T, n *dasel.Node) (*dasel.Node, bool) { return n.Next, true },
+			func(t *testing.T, n *dasel.Node) bool {
+				if exp, got := ".b", n.Selector.Current; exp != got {
+					t.Errorf("expected selector of `%s`, got `%s`", exp, got)
+					return false
+				}
+
+				if !reflect.DeepEqual(mapB, n.Value) {
+					t.Errorf("expected value of\n%s\ngot\n%s", mapB, n.Value)
+					return false
+				}
+				return true
+			},
+		).Add(
+			"Previous4",
+			func(t *testing.T, n *dasel.Node) (*dasel.Node, bool) { return n.Previous, true },
+			func(t *testing.T, n *dasel.Node) bool {
+				if exp, got := ".a", n.Selector.Current; exp != got {
+					t.Errorf("expected selector of `%s`, got `%s`", exp, got)
+					return false
+				}
+				if !reflect.DeepEqual(mapA, n.Value) {
+					t.Errorf("expected value of\n%s\ngot\n%s", mapA, n.Value)
+					return false
+				}
+				return true
+			},
+		).Add(
+			"Previous5",
+			func(t *testing.T, n *dasel.Node) (*dasel.Node, bool) { return n.Previous, true },
+			func(t *testing.T, n *dasel.Node) bool {
+				if exp, got := ".", n.Selector.Current; exp != got {
+					t.Errorf("expected selector of `%s`, got `%s`", exp, got)
+					return false
+				}
+				if !reflect.DeepEqual(mapRoot, n.Value) {
+					t.Errorf("expected value of\n%s\ngot\n%s", mapRoot, n.Value)
+					return false
+				}
+				return true
+			},
+		)
+
+		rootNode := dasel.New(tests.Input)
+		got, err := rootNode.Query(tests.Selector)
+		switch {
+		case err == nil && tests.Err != nil:
+			t.Errorf("expected err `%v`, got `%v`", tests.Err, err)
+			return
+		case err != nil && tests.Err == nil:
+			t.Errorf("unexpected err `%v`", err)
+			return
+		case err != nil && tests.Err != nil && !errors.Is(err, tests.Err):
+			t.Errorf("expected err `%v`, got `%v`", tests.Err, err)
+			return
+		}
+
+		ok := true
+
+		for i := 0; i < len(tests.ProcessFns); i++ {
+			if !ok {
+				break
+			}
+			t.Run(tests.Names[i], func(t *testing.T) {
+				got, ok = tests.ProcessFns[i](t, got)
+				if !ok {
+					return
+				}
+				ok = tests.CheckFns[i](t, got)
+				if !ok {
+					return
+				}
+			})
+		}
+	})
+}

tests/assets/example.yaml

@@ -0,0 +1,14 @@
+name: Tom
+preferences:
+  favouriteColour: red
+colours:
+  - red
+  - green
+  - blue
+colourCodes:
+  - name: red
+    rgb: ff0000
+  - name: green
+    rgb: 00ff00
+  - name: blue
+    rgb: 0000ff