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initial impl of like
This commit is contained in:
Jaden Weiss
parent
7f1b1f63ef
commit
9eb8fcb37f
2 changed files with 343 additions and 0 deletions
159
like.go
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159
like.go
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@ -0,0 +1,159 @@
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package pilosa
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import (
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"strings"
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"unicode/utf8"
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)
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func tokenizeLike(like string) []string {
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var tokens []string
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for like != "" {
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var token string
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i := strings.IndexAny(like, "%_")
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switch {
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case i == 0:
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j := 1
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for j < len(like) && (like[j] == '%' || like[j] == '_') {
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j++
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}
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token, like = like[:j], like[j:]
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case i < 0:
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token, like = like, ""
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default:
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token, like = like[:i], like[i:]
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}
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tokens = append(tokens, token)
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}
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return tokens
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}
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type filterStepKind uint8
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const (
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filterStepPrefix filterStepKind = iota
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filterStepSkipN
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filterStepSkipThrough
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filterStepMinLength
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)
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type filterStep struct {
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kind filterStepKind
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str string
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n int
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}
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func planLike(like string) []filterStep {
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tokens := tokenizeLike(like)
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steps := make([]filterStep, 0, len(tokens))
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var merged bool
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for i, t := range tokens {
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if merged {
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merged = false
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continue
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}
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var step filterStep
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hasPercent := strings.ContainsRune(t, '%')
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underscores := strings.Count(t, "_")
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switch {
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case hasPercent && i+1 < len(tokens):
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step = filterStep{
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kind: filterStepSkipThrough,
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str: tokens[i+1],
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n: underscores,
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}
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merged = true
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case hasPercent:
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step = filterStep{
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kind: filterStepMinLength,
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n: underscores,
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}
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case underscores > 0:
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step = filterStep{
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kind: filterStepSkipN,
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n: underscores,
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}
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default:
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step = filterStep{
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kind: filterStepPrefix,
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str: t,
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}
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}
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steps = append(steps, step)
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}
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return steps
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}
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func matchLike(key string, like ...filterStep) bool {
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for i, step := range like {
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switch step.kind {
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case filterStepPrefix:
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if !strings.HasPrefix(key, step.str) {
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return false
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}
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key = key[len(step.str):]
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case filterStepSkipN:
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n := step.n
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for j := 0; j < n; j++ {
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_, len := utf8.DecodeRuneInString(key)
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if len == 0 {
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return false
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}
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key = key[len:]
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}
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case filterStepSkipThrough:
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var skipped int
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for skipped < step.n {
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j := strings.Index(key, step.str)
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switch j {
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case -1:
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return false
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case 0:
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_, len := utf8.DecodeRuneInString(key)
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if len == 0 {
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return false
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}
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key = key[len:]
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skipped += len
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default:
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k := -1
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for k = range key[:j] {
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}
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skipped += k + 1
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key = key[j:]
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}
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}
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remaining := like[i+1:]
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for {
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j := strings.Index(key, step.str)
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switch {
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case j == -1:
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return false
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case j > 0:
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key = key[j:]
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}
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if matchLike(key[len(step.str):], remaining...) {
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return true
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}
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key = key[1:]
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}
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case filterStepMinLength:
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if len(key) < step.n {
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return false
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}
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j := -1
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for j = range key {
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}
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return j+1 >= step.n
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default:
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panic("invalid step")
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}
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}
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return key == ""
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}
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184
like_test.go
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184
like_test.go
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@ -0,0 +1,184 @@
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package pilosa
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import (
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"reflect"
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"testing"
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)
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func TestPlanLike(t *testing.T) {
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t.Parallel()
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cases := []struct {
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name string
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like string
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plan []filterStep
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match, nonmatch []string
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}{
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{
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name: "Empty",
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like: "",
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plan: []filterStep{},
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match: []string{""},
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nonmatch: []string{"a", " "},
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},
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{
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name: "Exact",
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like: "x",
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plan: []filterStep{
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{
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kind: filterStepPrefix,
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str: "x",
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},
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},
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match: []string{"x"},
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nonmatch: []string{"", "y", "z", "xy", "yx"},
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},
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{
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name: "Anything",
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like: "%",
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plan: []filterStep{
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{
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kind: filterStepMinLength,
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n: 0,
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},
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},
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match: []string{"", "a", "b", "ab"},
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},
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{
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name: "Prefix",
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like: "x%",
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plan: []filterStep{
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{
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kind: filterStepPrefix,
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str: "x",
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},
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{
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kind: filterStepMinLength,
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n: 0,
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},
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},
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match: []string{"xy", "xyz", "xyzzy"},
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nonmatch: []string{"plugh", "yx", ""},
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},
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{
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name: "Suffix",
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like: "%x",
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plan: []filterStep{
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{
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kind: filterStepSkipThrough,
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str: "x",
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},
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},
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match: []string{"x", "xx", "ax"},
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nonmatch: []string{"", "a", "x^"},
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},
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{
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name: "Sandwich",
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like: "x%y",
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plan: []filterStep{
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{
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kind: filterStepPrefix,
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str: "x",
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},
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{
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kind: filterStepSkipThrough,
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str: "y",
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},
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},
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match: []string{"xy", "xzy", "xyzzy"},
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nonmatch: []string{"plugh", ".xy.", ".x.y", "x.y."},
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},
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{
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name: "SingleRune",
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like: "_",
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plan: []filterStep{
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{
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kind: filterStepSkipN,
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n: 1,
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},
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},
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match: []string{"a", "á", "☺"},
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nonmatch: []string{"ab", "á", "h̷"},
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},
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{
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name: "DoubleRune",
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like: "__",
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plan: []filterStep{
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{
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kind: filterStepSkipN,
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n: 2,
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},
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},
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match: []string{"ab", "á", "h̷"},
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nonmatch: []string{"a", "á", "☺", "abc"},
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},
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{
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name: "MiddleBlank",
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like: "x_y",
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plan: []filterStep{
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{
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kind: filterStepPrefix,
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str: "x",
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},
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{
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kind: filterStepSkipN,
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n: 1,
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},
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{
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kind: filterStepPrefix,
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str: "y",
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},
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},
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match: []string{"x.y", "xay", "x y", "x⊕y"},
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nonmatch: []string{"x++y", "", "a"},
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},
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{
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name: "MinLength",
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like: "_%_",
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plan: []filterStep{
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{
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kind: filterStepMinLength,
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n: 2,
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},
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},
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match: []string{"ab", "á", "abc", "pilosa"},
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nonmatch: []string{"h", "á", ".", "☺"},
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},
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}
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t.Run("Plan", func(t *testing.T) {
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t.Parallel()
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for _, c := range cases {
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c := c
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t.Run(c.name, func(t *testing.T) {
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t.Parallel()
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plan := planLike(c.like)
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if !reflect.DeepEqual(plan, c.plan) {
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t.Errorf("incorrect plan: %v", plan)
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}
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})
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}
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})
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t.Run("Match", func(t *testing.T) {
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t.Parallel()
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for _, c := range cases {
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c := c
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t.Run(c.name, func(t *testing.T) {
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t.Parallel()
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for _, m := range c.match {
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if !matchLike(m, c.plan...) {
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t.Errorf("key %q was not matched", m)
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}
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}
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for _, nm := range c.nonmatch {
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if matchLike(nm, c.plan...) {
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t.Errorf("key %q was matched", nm)
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}
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}
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})
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}
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})
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}
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