| 1 | // markup-spelling: old-spelling begin — see markup.go. |
| 2 | |
| 3 | package markup |
| 4 | |
| 5 | import ( |
| 6 | "fmt" |
| 7 | "regexp" |
| 8 | "strings" |
| 9 | ) |
| 10 | |
| 11 | // Note is something the rewrite could not do and a human has to look |
| 12 | // at. A codemod that guesses is worse than one that says where it |
| 13 | // stopped, so an unrecognised shape is left exactly as it was and |
| 14 | // reported here. |
| 15 | type Note struct { |
| 16 | Line int // 1-based, in the file as it was read |
| 17 | Text string // what was found, and why it was left alone |
| 18 | } |
| 19 | |
| 20 | func (n Note) String() string { return fmt.Sprintf("%d: %s", n.Line, n.Text) } |
| 21 | |
| 22 | var ( |
| 23 | rstClassToken = regexp.MustCompile(`rst-[A-Za-z0-9_-]+`) |
| 24 | tmplAction = regexp.MustCompile(`\{\{[^{}]*\}\}`) |
| 25 | ) |
| 26 | |
| 27 | // Rewrite translates one file's markup from the class spelling to the |
| 28 | // attribute spelling. It rewrites class attributes (both the plain |
| 29 | // class="…" of a template and the class=\"…\" of a Go string literal) |
| 30 | // and the data-tone attribute, and touches nothing else — a CSS |
| 31 | // selector, a Go identifier, a comment that only names a class are all |
| 32 | // left alone. |
| 33 | // |
| 34 | // It is idempotent. The output has no class attribute carrying a |
| 35 | // migrating rst- name, so a second pass finds nothing to do. |
| 36 | func Rewrite(src []byte) ([]byte, []Note) { return rewrite(src, true) } |
| 37 | |
| 38 | // Respell is Rewrite without the migration's renames: the pure grammar, |
| 39 | // for markup that is already written in today's class vocabulary and |
| 40 | // only wants the other spelling of it. It is what the stage-1 browser |
| 41 | // drive translates its fixture with, where the two spellings must mean |
| 42 | // the same thing rather than one being an upgrade of the other. |
| 43 | func Respell(src []byte) ([]byte, []Note) { return rewrite(src, false) } |
| 44 | |
| 45 | func rewrite(src []byte, migrate bool) ([]byte, []Note) { |
| 46 | s := string(src) |
| 47 | var b strings.Builder |
| 48 | var notes []Note |
| 49 | note := func(at int, format string, args ...any) { |
| 50 | notes = append(notes, Note{ |
| 51 | Line: 1 + strings.Count(s[:at], "\n"), |
| 52 | Text: fmt.Sprintf(format, args...), |
| 53 | }) |
| 54 | } |
| 55 | fenced := fencedRegions(s) |
| 56 | i := 0 |
| 57 | for { |
| 58 | a, ok := nextClassAttr(s, i) |
| 59 | if !ok { |
| 60 | break |
| 61 | } |
| 62 | // A region a human has fenced off: a page whose subject IS the |
| 63 | // old spelling, a fixture that has to be written in it. Without |
| 64 | // this the only opt-out is "do not run the tool on that file", |
| 65 | // which is not one — every repository migrating its own docs |
| 66 | // has a paragraph that must keep the spelling it is about. |
| 67 | if fenced(a.start) { |
| 68 | b.WriteString(s[i:a.end]) |
| 69 | i = a.end |
| 70 | continue |
| 71 | } |
| 72 | value := s[a.valStart:a.valEnd] |
| 73 | if !strings.Contains(value, "rst-") { |
| 74 | b.WriteString(s[i:a.end]) |
| 75 | i = a.end |
| 76 | continue |
| 77 | } |
| 78 | if a.unreadable { |
| 79 | note(a.start, "class=%q is a shape this cannot take apart — an unquoted value with a template "+ |
| 80 | "action in it. Quote it, or rewrite it by hand: left as it was", value) |
| 81 | b.WriteString(s[i:a.end]) |
| 82 | i = a.end |
| 83 | continue |
| 84 | } |
| 85 | if c, bad := notAClassList(value); bad { |
| 86 | // Almost always source that builds its markup by |
| 87 | // concatenation: the reader ran past the end of a string |
| 88 | // literal and what it is holding is an expression rather |
| 89 | // than a class list. Rewriting it would produce something |
| 90 | // that does not compile, so say where it is and move on. |
| 91 | note(a.start, "class=%q is not a class list — it holds %q, so this markup is probably built by "+ |
| 92 | "concatenation and the reader ran past the end of a literal: left as it was", value, string(c)) |
| 93 | b.WriteString(s[i:a.end]) |
| 94 | i = a.end |
| 95 | continue |
| 96 | } |
| 97 | repl, err := rewriteClassValue(value, a.q, migrate) |
| 98 | if err != nil { |
| 99 | note(a.start, "%s", err.Error()) |
| 100 | b.WriteString(s[i:a.end]) |
| 101 | i = a.end |
| 102 | continue |
| 103 | } |
| 104 | // An attribute that translated to nothing at all takes its own |
| 105 | // leading space with it, or the tag keeps a gap where a class |
| 106 | // used to be. |
| 107 | start := a.start |
| 108 | if repl == "" { |
| 109 | for start > i && (s[start-1] == ' ' || s[start-1] == '\t') { |
| 110 | start-- |
| 111 | } |
| 112 | } |
| 113 | b.WriteString(s[i:start]) |
| 114 | b.WriteString(repl) |
| 115 | i = a.end |
| 116 | } |
| 117 | b.WriteString(s[i:]) |
| 118 | // The fence is recomputed here rather than reused: the class pass |
| 119 | // moved every offset after its first rewrite, and the markers |
| 120 | // themselves are never rewritten, so they are still where they say. |
| 121 | body := b.String() |
| 122 | inFence := fencedRegions(body) |
| 123 | out := replaceOutsideFence(body, toneInMarkup, "${1}rst-tone=${2}", inFence) |
| 124 | |
| 125 | // Escaped markup — a documentation page showing class="rst-box" |
| 126 | // as source. Rewriting it would mean deciding what the escaping is |
| 127 | // for; naming it is the honest half, and it is a shape that exists |
| 128 | // in any repository with migration notes of its own. |
| 129 | // |
| 130 | // The fence applies here as much as it does to the rewrite, and for |
| 131 | // longer: a rewrite you decline is over, but a note is a line in a |
| 132 | // report that stays until somebody deals with it, and the exit code |
| 133 | // stays at 3 while it does. A fenced region is somebody having |
| 134 | // already dealt with it. Without this, every file that fences off a |
| 135 | // paragraph about the old spelling reports work forever, and this |
| 136 | // repository was the proof: internal/markup's own files are fenced |
| 137 | // from line 1 and reported notes anyway, on every run, so |
| 138 | // `rastrillo markup .` could never exit 0 here on a clean tree. A |
| 139 | // report mode that always says there is work is what teaches people |
| 140 | // to skip it and run --fix. |
| 141 | // |
| 142 | // The regions are recomputed rather than reusing inFence: the tone |
| 143 | // pass above shortened the text at every replacement, so offsets |
| 144 | // after the first one no longer mean what they did. |
| 145 | noteFence := fencedRegions(out) |
| 146 | for _, m := range escapedClassAttr.FindAllStringSubmatchIndex(out, -1) { |
| 147 | if noteFence(m[0]) { |
| 148 | continue |
| 149 | } |
| 150 | if strings.Contains(out[m[2]:m[3]], "rst-") { |
| 151 | notes = append(notes, Note{ |
| 152 | Line: 1 + strings.Count(out[:m[0]], "\n"), |
| 153 | Text: "escaped markup (" + out[m[0]:m[1]] + ") is documentation rather than markup: rewrite it by hand if it should teach the attribute spelling", |
| 154 | }) |
| 155 | } |
| 156 | } |
| 157 | return []byte(out), notes |
| 158 | } |
| 159 | |
| 160 | // replaceOutsideFence is regexp.ReplaceAllString that leaves fenced |
| 161 | // regions alone. |
| 162 | func replaceOutsideFence(s string, re *regexp.Regexp, repl string, fenced func(int) bool) string { |
| 163 | var b strings.Builder |
| 164 | last := 0 |
| 165 | for _, m := range re.FindAllStringSubmatchIndex(s, -1) { |
| 166 | if fenced(m[0]) { |
| 167 | continue |
| 168 | } |
| 169 | b.WriteString(s[last:m[0]]) |
| 170 | b.Write(re.ExpandString(nil, repl, s, m)) |
| 171 | last = m[1] |
| 172 | } |
| 173 | b.WriteString(s[last:]) |
| 174 | return b.String() |
| 175 | } |
| 176 | |
| 177 | // The fence, and the only opt-out this tool has. A line carrying the |
| 178 | // begin marker starts a region it will not rewrite; a line carrying the |
| 179 | // end marker closes it. Deliberately one mechanism shared with the |
| 180 | // framework's own spelling gate, so a repository has one thing to |
| 181 | // learn and one thing to grep for. |
| 182 | const ( |
| 183 | FenceBegin = "markup-spelling: old-spelling begin" |
| 184 | // Assembled from halves, or this line would close the fence that |
| 185 | // the top of this file opens and the rest of the file would be |
| 186 | // rewritten by its own tool. The one place that has to be true. |
| 187 | FenceEnd = "markup-spelling: old-spelling " + "end" |
| 188 | ) |
| 189 | |
| 190 | // fencedRegions returns a predicate saying whether a byte offset falls |
| 191 | // inside a fenced region. |
| 192 | func fencedRegions(s string) func(int) bool { |
| 193 | type span struct{ from, to int } |
| 194 | var spans []span |
| 195 | open := -1 |
| 196 | at := 0 |
| 197 | for _, line := range strings.SplitAfter(s, "\n") { |
| 198 | switch { |
| 199 | case open < 0 && strings.Contains(line, FenceBegin): |
| 200 | open = at |
| 201 | case open >= 0 && strings.Contains(line, FenceEnd): |
| 202 | spans = append(spans, span{open, at + len(line)}) |
| 203 | open = -1 |
| 204 | } |
| 205 | at += len(line) |
| 206 | } |
| 207 | if open >= 0 { |
| 208 | spans = append(spans, span{open, len(s)}) |
| 209 | } |
| 210 | return func(i int) bool { |
| 211 | for _, sp := range spans { |
| 212 | if i >= sp.from && i < sp.to { |
| 213 | return true |
| 214 | } |
| 215 | } |
| 216 | return false |
| 217 | } |
| 218 | } |
| 219 | |
| 220 | // escapedClassAttr matches a class attribute written as escaped text — |
| 221 | // what a page showing markup as source carries. |
| 222 | var escapedClassAttr = regexp.MustCompile(`class=(?:"|"|")([^&]*)(?:"|"|")`) |
| 223 | |
| 224 | // classAttr is one class attribute found in the source: the span it |
| 225 | // occupies, the span of its value, and the quoting a replacement's own |
| 226 | // values must be written in. |
| 227 | type classAttr struct { |
| 228 | start, end int |
| 229 | valStart, valEnd int |
| 230 | q string |
| 231 | // unreadable: this IS a class attribute, and its value is not |
| 232 | // something the grammar can take apart. Carried rather than |
| 233 | // silently skipped, because silence is the one thing this tool must |
| 234 | // not do about markup it has found. |
| 235 | unreadable bool |
| 236 | } |
| 237 | |
| 238 | // nextClassAttr finds the next class attribute at or after from, in |
| 239 | // every shape HTML allows: any case, whitespace around the =, and a |
| 240 | // value that is double-quoted, single-quoted, escaped for a Go or |
| 241 | // JavaScript string literal, or not quoted at all. |
| 242 | // |
| 243 | // It reads all of them rather than the one shape this framework happens |
| 244 | // to write, because the alternative is the one thing this tool must |
| 245 | // never do: tell an app whose templates use single quotes that there is |
| 246 | // nothing to do, and let it find out at stage 3, when the class |
| 247 | // selectors are gone and nothing says why the page is unstyled. |
| 248 | func nextClassAttr(s string, from int) (classAttr, bool) { |
| 249 | for i := from; i < len(s); { |
| 250 | k := indexFold(s, "class", i) |
| 251 | if k < 0 { |
| 252 | return classAttr{}, false |
| 253 | } |
| 254 | i = k + len("class") |
| 255 | // Not the tail of a longer word: data-class, superclass. |
| 256 | if k > 0 && isIdentByte(s[k-1]) { |
| 257 | continue |
| 258 | } |
| 259 | j := skipSpace(s, i) |
| 260 | // An =, and not the head of ==, so a Go comparison is not markup. |
| 261 | if j >= len(s) || s[j] != '=' || (j+1 < len(s) && s[j+1] == '=') { |
| 262 | continue |
| 263 | } |
| 264 | lead := byte(' ') |
| 265 | if k > 0 { |
| 266 | lead = s[k-1] |
| 267 | } |
| 268 | a, ok := readAttrValue(s, skipSpace(s, j+1), lead) |
| 269 | if !ok { |
| 270 | continue |
| 271 | } |
| 272 | a.start = k |
| 273 | return a, true |
| 274 | } |
| 275 | return classAttr{}, false |
| 276 | } |
| 277 | |
| 278 | // indexFold is strings.Index for an ASCII-lowercase needle, ignoring |
| 279 | // case in the haystack. |
| 280 | func indexFold(s, needle string, from int) int { |
| 281 | for i := from; i+len(needle) <= len(s); i++ { |
| 282 | if strings.EqualFold(s[i:i+len(needle)], needle) { |
| 283 | return i |
| 284 | } |
| 285 | } |
| 286 | return -1 |
| 287 | } |
| 288 | |
| 289 | func skipSpace(s string, i int) int { |
| 290 | for i < len(s) && (s[i] == ' ' || s[i] == '\t') { |
| 291 | i++ |
| 292 | } |
| 293 | return i |
| 294 | } |
| 295 | |
| 296 | func isIdentByte(c byte) bool { |
| 297 | return c == '-' || c == '_' || c >= 'a' && c <= 'z' || c >= 'A' && c <= 'Z' || c >= '0' && c <= '9' |
| 298 | } |
| 299 | |
| 300 | // readAttrValue reads an attribute value that starts at k. The quote it |
| 301 | // reports is the one a replacement writes its own values in; an |
| 302 | // unquoted value becomes a double-quoted one, because a variant list |
| 303 | // has a space in it and an unquoted attribute cannot hold one. |
| 304 | func readAttrValue(s string, k int, lead byte) (classAttr, bool) { |
| 305 | closed := func(open, quote string) (classAttr, bool) { |
| 306 | valStart := k + len(open) |
| 307 | e := strings.Index(s[valStart:], quote) |
| 308 | if e < 0 { |
| 309 | return classAttr{}, false |
| 310 | } |
| 311 | return classAttr{ |
| 312 | valStart: valStart, |
| 313 | valEnd: valStart + e, |
| 314 | end: valStart + e + len(quote), |
| 315 | q: quote, |
| 316 | }, true |
| 317 | } |
| 318 | switch { |
| 319 | case strings.HasPrefix(s[k:], `\"`): |
| 320 | return closed(`\"`, `\"`) |
| 321 | case strings.HasPrefix(s[k:], `\'`): |
| 322 | return closed(`\'`, `\'`) |
| 323 | case k < len(s) && s[k] == '"': |
| 324 | return closed(`"`, `"`) |
| 325 | case k < len(s) && s[k] == '\'': |
| 326 | return closed(`'`, `'`) |
| 327 | case unquotedAttrOK(lead) && k < len(s) && s[k] != '>' && s[k] != ' ' && s[k] != '\t' && s[k] != '\n': |
| 328 | e := k |
| 329 | for e < len(s) && s[e] != ' ' && s[e] != '\t' && s[e] != '\n' && s[e] != '>' && s[e] != '/' { |
| 330 | e++ |
| 331 | } |
| 332 | switch classify(s[k:e]) { |
| 333 | case notMarkupAtAll: |
| 334 | return classAttr{}, false |
| 335 | case unreadableList: |
| 336 | return classAttr{valStart: k, valEnd: e, end: e, q: `"`, unreadable: true}, true |
| 337 | } |
| 338 | return classAttr{valStart: k, valEnd: e, end: e, q: `"`}, true |
| 339 | } |
| 340 | return classAttr{}, false |
| 341 | } |
| 342 | |
| 343 | // unquotedAttrOK: an unquoted value is only read where an attribute can |
| 344 | // actually begin. Without this, the "class=" of a URL query string |
| 345 | // (?class=x&y=1) reads as markup and gets rewritten into nonsense. |
| 346 | func unquotedAttrOK(lead byte) bool { |
| 347 | switch lead { |
| 348 | case ' ', '\t', '\n', '\r', '<', '`', '"', '\'', '(': |
| 349 | return true |
| 350 | } |
| 351 | return false |
| 352 | } |
| 353 | |
| 354 | // The three things an unquoted value can be. |
| 355 | const ( |
| 356 | plainClassList = iota |
| 357 | // Not markup: a URL query (?class=x&y=1), or a class attribute |
| 358 | // written as escaped text (class="rst-box"), which the |
| 359 | // escaped-markup pass reports instead. Silence is right for these. |
| 360 | notMarkupAtAll |
| 361 | // Markup, and unreadable: an unquoted value with a template action |
| 362 | // in it. Silence is wrong for this one — it is a class attribute |
| 363 | // carrying our vocabulary that will simply never be migrated. |
| 364 | unreadableList |
| 365 | ) |
| 366 | |
| 367 | func classify(value string) int { |
| 368 | if value == "" { |
| 369 | return notMarkupAtAll |
| 370 | } |
| 371 | for i := 0; i < len(value); i++ { |
| 372 | switch value[i] { |
| 373 | case '&', '?', '%', '#', '=', ';': |
| 374 | return notMarkupAtAll |
| 375 | case '{', '}': |
| 376 | return unreadableList |
| 377 | } |
| 378 | } |
| 379 | return plainClassList |
| 380 | } |
| 381 | |
| 382 | // notAClassList reports the character that says a value is not an HTML |
| 383 | // class list at all. None of them can appear in a class attribute — a |
| 384 | // quote would have ended it — so finding one means the reader is |
| 385 | // holding source rather than markup, which is what happens when the |
| 386 | // markup is built by concatenating string literals. |
| 387 | func notAClassList(value string) (byte, bool) { |
| 388 | for i := 0; i < len(value); i++ { |
| 389 | switch value[i] { |
| 390 | case '"', '\'', '`', '<', '>', '\\': |
| 391 | return value[i], true |
| 392 | } |
| 393 | } |
| 394 | return 0, false |
| 395 | } |
| 396 | |
| 397 | // attr is one attribute being built: its name, the variant tokens the |
| 398 | // literal class list gave it, and — for a class value that carries a |
| 399 | // template action — the expression that supplies the rest of its value. |
| 400 | type attr struct { |
| 401 | name string |
| 402 | variants []string |
| 403 | expr string |
| 404 | // When a conditional can produce no variant at all, the whole |
| 405 | // value — the = and the quotes with it — is written inside that |
| 406 | // conditional, so the attribute renders bare rather than empty: |
| 407 | // rst-person{{if .Large}}="lg"{{end}}. html/template reads an |
| 408 | // action in that position and both branches leave the parser in |
| 409 | // the same state, so it is a shape it can compile. |
| 410 | open, closes string |
| 411 | } |
| 412 | |
| 413 | func rewriteClassValue(value, q string, migrate bool) (string, error) { |
| 414 | if !strings.Contains(value, "{{") { |
| 415 | kept, attrs := splitClassTokens(strings.Fields(value), migrate) |
| 416 | return render(kept, attrs, q), nil |
| 417 | } |
| 418 | return rewriteTemplatedClassValue(value, q, migrate) |
| 419 | } |
| 420 | |
| 421 | // splitClassTokens sorts a literal class list into what stays in class |
| 422 | // and what becomes an attribute, keeping first-appearance order so the |
| 423 | // diff reads like the markup it replaces. |
| 424 | func splitClassTokens(tokens []string, migrate bool) (kept []string, attrs []*attr) { |
| 425 | byName := map[string]*attr{} |
| 426 | for _, t := range tokens { |
| 427 | if !strings.HasPrefix(t, "rst-") { |
| 428 | kept = append(kept, t) |
| 429 | continue |
| 430 | } |
| 431 | name, variant, ok, drop := classFor(t, migrate) |
| 432 | if drop { |
| 433 | continue |
| 434 | } |
| 435 | if !ok { |
| 436 | kept = append(kept, t) |
| 437 | continue |
| 438 | } |
| 439 | a := byName[name] |
| 440 | if a == nil { |
| 441 | a = &attr{name: name} |
| 442 | byName[name] = a |
| 443 | attrs = append(attrs, a) |
| 444 | } |
| 445 | if variant != "" { |
| 446 | a.variants = append(a.variants, variant) |
| 447 | } |
| 448 | } |
| 449 | return kept, attrs |
| 450 | } |
| 451 | |
| 452 | func render(kept []string, attrs []*attr, q string) string { |
| 453 | var parts []string |
| 454 | if len(kept) > 0 { |
| 455 | parts = append(parts, "class="+q+strings.Join(kept, " ")+q) |
| 456 | } |
| 457 | for _, a := range attrs { |
| 458 | if a.open != "" { |
| 459 | parts = append(parts, a.name+a.open+"="+q+a.expr+q+a.closes) |
| 460 | continue |
| 461 | } |
| 462 | value := strings.Join(a.variants, " ") |
| 463 | if a.expr != "" { |
| 464 | if value != "" { |
| 465 | value += " " |
| 466 | } |
| 467 | value += a.expr |
| 468 | } |
| 469 | if value == "" { |
| 470 | parts = append(parts, a.name) |
| 471 | continue |
| 472 | } |
| 473 | parts = append(parts, a.name+"="+q+value+q) |
| 474 | } |
| 475 | return strings.Join(parts, " ") |
| 476 | } |
| 477 | |
| 478 | // rewriteTemplatedClassValue handles the one shape a class list takes |
| 479 | // when a template writes part of it: a literal head, then a conditional |
| 480 | // that adds a modifier of a kind the head already names. |
| 481 | // |
| 482 | // class="rst-badge{{with .Tone}} rst-badge--{{.}}{{end}}" |
| 483 | // -> rst-badge{{with .Tone}}="{{.}}"{{end}} |
| 484 | // class="rst-btn{{if .Danger}} rst-btn--danger{{else}} rst-btn--primary{{end}}" |
| 485 | // -> rst-btn="{{if .Danger}}danger{{else}}primary{{end}}" |
| 486 | // |
| 487 | // Which of the two depends on whether the conditional can produce no |
| 488 | // modifier at all. A branchless {{if}} or {{with}} can, so the = and |
| 489 | // the quotes go inside it and the attribute renders bare — which is |
| 490 | // what a reader copying the gallery should see. A choice between two |
| 491 | // modifiers always produces one, so the conditional goes in the value, |
| 492 | // where it reads as what it is. |
| 493 | // |
| 494 | // Anything else is left alone and reported. A class list whose |
| 495 | // structure this cannot read is a handful of lines for a human, and a |
| 496 | // wrong guess is a screen that renders unstyled. |
| 497 | func rewriteTemplatedClassValue(value, q string, migrate bool) (string, error) { |
| 498 | head := value[:strings.Index(value, "{{")] |
| 499 | rest := value[len(head):] |
| 500 | kept, attrs := splitClassTokens(strings.Fields(head), migrate) |
| 501 | |
| 502 | tokens := rstClassToken.FindAllString(rest, -1) |
| 503 | if len(tokens) == 0 { |
| 504 | return "", fmt.Errorf(`class=%q carries a template action and no rst- class inside it: left as it was`, value) |
| 505 | } |
| 506 | kind := "" |
| 507 | for _, t := range tokens { |
| 508 | k := strings.Index(t, "--") |
| 509 | if k < 0 { |
| 510 | return "", fmt.Errorf(`class=%q: %q inside a template action is not a modifier, so the value slot cannot carry it: left as it was`, value, t) |
| 511 | } |
| 512 | if kind == "" { |
| 513 | kind = t[:k] |
| 514 | } else if kind != t[:k] { |
| 515 | return "", fmt.Errorf(`class=%q names modifiers of two kinds (%s, %s) inside one template action: left as it was`, value, kind, t[:k]) |
| 516 | } |
| 517 | } |
| 518 | // Everything in the conditional that is not an action must be one |
| 519 | // of those modifiers, or this is a shape the rule above does not |
| 520 | // describe. |
| 521 | known := map[string]bool{} |
| 522 | for _, t := range tokens { |
| 523 | known[t] = true |
| 524 | } |
| 525 | for _, f := range strings.Fields(tmplAction.ReplaceAllString(rest, " ")) { |
| 526 | if !known[f] { |
| 527 | return "", fmt.Errorf(`class=%q has literal text (%q) beside the modifiers in its template action: left as it was`, value, f) |
| 528 | } |
| 529 | } |
| 530 | |
| 531 | name, _, ok, drop := classFor(kind, migrate) |
| 532 | if drop || !ok { |
| 533 | return "", fmt.Errorf(`class=%q builds a modifier of %s, which does not migrate: left as it was`, value, kind) |
| 534 | } |
| 535 | strip := regexp.MustCompile(`\s*` + regexp.QuoteMeta(kind+"--")) |
| 536 | |
| 537 | a := (*attr)(nil) |
| 538 | for _, cand := range attrs { |
| 539 | if cand.name == name { |
| 540 | a = cand |
| 541 | } |
| 542 | } |
| 543 | if a == nil { |
| 544 | a = &attr{name: name} |
| 545 | attrs = append(attrs, a) |
| 546 | } |
| 547 | |
| 548 | actions := tmplAction.FindAllString(rest, -1) |
| 549 | branchless := len(a.variants) == 0 && |
| 550 | len(actions) >= 2 && |
| 551 | strings.HasPrefix(actions[len(actions)-1], "{{end") && |
| 552 | strings.HasSuffix(rest, actions[len(actions)-1]) |
| 553 | for _, act := range actions { |
| 554 | if strings.HasPrefix(act, "{{else") { |
| 555 | branchless = false |
| 556 | } |
| 557 | } |
| 558 | if branchless { |
| 559 | a.open = actions[0] |
| 560 | a.closes = actions[len(actions)-1] |
| 561 | a.expr = strip.ReplaceAllString(rest[len(a.open):len(rest)-len(a.closes)], "") |
| 562 | return render(kept, attrs, q), nil |
| 563 | } |
| 564 | a.expr = strip.ReplaceAllString(rest, "") |
| 565 | return render(kept, attrs, q), nil |
| 566 | } |
| 567 | |
amadan