Colin Cross | d9c6b80 | 2019-03-19 21:10:31 -0700 | [diff] [blame] | 1 | // Copyright 2013 The Go Authors. All rights reserved. |
| 2 | // Use of this source code is governed by a BSD-style |
| 3 | // license that can be found in the LICENSE file. |
| 4 | |
| 5 | package astutil |
| 6 | |
| 7 | // This file defines utilities for working with source positions. |
| 8 | |
| 9 | import ( |
| 10 | "fmt" |
| 11 | "go/ast" |
| 12 | "go/token" |
| 13 | "sort" |
Dan Willemsen | bc60c3c | 2021-12-15 01:09:00 -0800 | [diff] [blame] | 14 | |
| 15 | "golang.org/x/tools/internal/typeparams" |
Colin Cross | d9c6b80 | 2019-03-19 21:10:31 -0700 | [diff] [blame] | 16 | ) |
| 17 | |
| 18 | // PathEnclosingInterval returns the node that encloses the source |
| 19 | // interval [start, end), and all its ancestors up to the AST root. |
| 20 | // |
| 21 | // The definition of "enclosing" used by this function considers |
| 22 | // additional whitespace abutting a node to be enclosed by it. |
| 23 | // In this example: |
| 24 | // |
| 25 | // z := x + y // add them |
| 26 | // <-A-> |
| 27 | // <----B-----> |
| 28 | // |
| 29 | // the ast.BinaryExpr(+) node is considered to enclose interval B |
| 30 | // even though its [Pos()..End()) is actually only interval A. |
| 31 | // This behaviour makes user interfaces more tolerant of imperfect |
| 32 | // input. |
| 33 | // |
| 34 | // This function treats tokens as nodes, though they are not included |
| 35 | // in the result. e.g. PathEnclosingInterval("+") returns the |
| 36 | // enclosing ast.BinaryExpr("x + y"). |
| 37 | // |
| 38 | // If start==end, the 1-char interval following start is used instead. |
| 39 | // |
| 40 | // The 'exact' result is true if the interval contains only path[0] |
| 41 | // and perhaps some adjacent whitespace. It is false if the interval |
| 42 | // overlaps multiple children of path[0], or if it contains only |
| 43 | // interior whitespace of path[0]. |
| 44 | // In this example: |
| 45 | // |
| 46 | // z := x + y // add them |
| 47 | // <--C--> <---E--> |
| 48 | // ^ |
| 49 | // D |
| 50 | // |
| 51 | // intervals C, D and E are inexact. C is contained by the |
| 52 | // z-assignment statement, because it spans three of its children (:=, |
| 53 | // x, +). So too is the 1-char interval D, because it contains only |
| 54 | // interior whitespace of the assignment. E is considered interior |
| 55 | // whitespace of the BlockStmt containing the assignment. |
| 56 | // |
| 57 | // Precondition: [start, end) both lie within the same file as root. |
| 58 | // TODO(adonovan): return (nil, false) in this case and remove precond. |
| 59 | // Requires FileSet; see loader.tokenFileContainsPos. |
| 60 | // |
| 61 | // Postcondition: path is never nil; it always contains at least 'root'. |
| 62 | // |
| 63 | func PathEnclosingInterval(root *ast.File, start, end token.Pos) (path []ast.Node, exact bool) { |
| 64 | // fmt.Printf("EnclosingInterval %d %d\n", start, end) // debugging |
| 65 | |
| 66 | // Precondition: node.[Pos..End) and adjoining whitespace contain [start, end). |
| 67 | var visit func(node ast.Node) bool |
| 68 | visit = func(node ast.Node) bool { |
| 69 | path = append(path, node) |
| 70 | |
| 71 | nodePos := node.Pos() |
| 72 | nodeEnd := node.End() |
| 73 | |
| 74 | // fmt.Printf("visit(%T, %d, %d)\n", node, nodePos, nodeEnd) // debugging |
| 75 | |
| 76 | // Intersect [start, end) with interval of node. |
| 77 | if start < nodePos { |
| 78 | start = nodePos |
| 79 | } |
| 80 | if end > nodeEnd { |
| 81 | end = nodeEnd |
| 82 | } |
| 83 | |
| 84 | // Find sole child that contains [start, end). |
| 85 | children := childrenOf(node) |
| 86 | l := len(children) |
| 87 | for i, child := range children { |
| 88 | // [childPos, childEnd) is unaugmented interval of child. |
| 89 | childPos := child.Pos() |
| 90 | childEnd := child.End() |
| 91 | |
| 92 | // [augPos, augEnd) is whitespace-augmented interval of child. |
| 93 | augPos := childPos |
| 94 | augEnd := childEnd |
| 95 | if i > 0 { |
| 96 | augPos = children[i-1].End() // start of preceding whitespace |
| 97 | } |
| 98 | if i < l-1 { |
| 99 | nextChildPos := children[i+1].Pos() |
| 100 | // Does [start, end) lie between child and next child? |
| 101 | if start >= augEnd && end <= nextChildPos { |
| 102 | return false // inexact match |
| 103 | } |
| 104 | augEnd = nextChildPos // end of following whitespace |
| 105 | } |
| 106 | |
| 107 | // fmt.Printf("\tchild %d: [%d..%d)\tcontains interval [%d..%d)?\n", |
| 108 | // i, augPos, augEnd, start, end) // debugging |
| 109 | |
| 110 | // Does augmented child strictly contain [start, end)? |
| 111 | if augPos <= start && end <= augEnd { |
| 112 | _, isToken := child.(tokenNode) |
| 113 | return isToken || visit(child) |
| 114 | } |
| 115 | |
| 116 | // Does [start, end) overlap multiple children? |
| 117 | // i.e. left-augmented child contains start |
| 118 | // but LR-augmented child does not contain end. |
| 119 | if start < childEnd && end > augEnd { |
| 120 | break |
| 121 | } |
| 122 | } |
| 123 | |
| 124 | // No single child contained [start, end), |
| 125 | // so node is the result. Is it exact? |
| 126 | |
| 127 | // (It's tempting to put this condition before the |
| 128 | // child loop, but it gives the wrong result in the |
| 129 | // case where a node (e.g. ExprStmt) and its sole |
| 130 | // child have equal intervals.) |
| 131 | if start == nodePos && end == nodeEnd { |
| 132 | return true // exact match |
| 133 | } |
| 134 | |
| 135 | return false // inexact: overlaps multiple children |
| 136 | } |
| 137 | |
| 138 | if start > end { |
| 139 | start, end = end, start |
| 140 | } |
| 141 | |
| 142 | if start < root.End() && end > root.Pos() { |
| 143 | if start == end { |
| 144 | end = start + 1 // empty interval => interval of size 1 |
| 145 | } |
| 146 | exact = visit(root) |
| 147 | |
| 148 | // Reverse the path: |
| 149 | for i, l := 0, len(path); i < l/2; i++ { |
| 150 | path[i], path[l-1-i] = path[l-1-i], path[i] |
| 151 | } |
| 152 | } else { |
| 153 | // Selection lies within whitespace preceding the |
| 154 | // first (or following the last) declaration in the file. |
| 155 | // The result nonetheless always includes the ast.File. |
| 156 | path = append(path, root) |
| 157 | } |
| 158 | |
| 159 | return |
| 160 | } |
| 161 | |
| 162 | // tokenNode is a dummy implementation of ast.Node for a single token. |
| 163 | // They are used transiently by PathEnclosingInterval but never escape |
| 164 | // this package. |
| 165 | // |
| 166 | type tokenNode struct { |
| 167 | pos token.Pos |
| 168 | end token.Pos |
| 169 | } |
| 170 | |
| 171 | func (n tokenNode) Pos() token.Pos { |
| 172 | return n.pos |
| 173 | } |
| 174 | |
| 175 | func (n tokenNode) End() token.Pos { |
| 176 | return n.end |
| 177 | } |
| 178 | |
| 179 | func tok(pos token.Pos, len int) ast.Node { |
| 180 | return tokenNode{pos, pos + token.Pos(len)} |
| 181 | } |
| 182 | |
| 183 | // childrenOf returns the direct non-nil children of ast.Node n. |
| 184 | // It may include fake ast.Node implementations for bare tokens. |
| 185 | // it is not safe to call (e.g.) ast.Walk on such nodes. |
| 186 | // |
| 187 | func childrenOf(n ast.Node) []ast.Node { |
| 188 | var children []ast.Node |
| 189 | |
| 190 | // First add nodes for all true subtrees. |
| 191 | ast.Inspect(n, func(node ast.Node) bool { |
| 192 | if node == n { // push n |
| 193 | return true // recur |
| 194 | } |
| 195 | if node != nil { // push child |
| 196 | children = append(children, node) |
| 197 | } |
| 198 | return false // no recursion |
| 199 | }) |
| 200 | |
| 201 | // Then add fake Nodes for bare tokens. |
| 202 | switch n := n.(type) { |
| 203 | case *ast.ArrayType: |
| 204 | children = append(children, |
| 205 | tok(n.Lbrack, len("[")), |
| 206 | tok(n.Elt.End(), len("]"))) |
| 207 | |
| 208 | case *ast.AssignStmt: |
| 209 | children = append(children, |
| 210 | tok(n.TokPos, len(n.Tok.String()))) |
| 211 | |
| 212 | case *ast.BasicLit: |
| 213 | children = append(children, |
| 214 | tok(n.ValuePos, len(n.Value))) |
| 215 | |
| 216 | case *ast.BinaryExpr: |
| 217 | children = append(children, tok(n.OpPos, len(n.Op.String()))) |
| 218 | |
| 219 | case *ast.BlockStmt: |
| 220 | children = append(children, |
| 221 | tok(n.Lbrace, len("{")), |
| 222 | tok(n.Rbrace, len("}"))) |
| 223 | |
| 224 | case *ast.BranchStmt: |
| 225 | children = append(children, |
| 226 | tok(n.TokPos, len(n.Tok.String()))) |
| 227 | |
| 228 | case *ast.CallExpr: |
| 229 | children = append(children, |
| 230 | tok(n.Lparen, len("(")), |
| 231 | tok(n.Rparen, len(")"))) |
| 232 | if n.Ellipsis != 0 { |
| 233 | children = append(children, tok(n.Ellipsis, len("..."))) |
| 234 | } |
| 235 | |
| 236 | case *ast.CaseClause: |
| 237 | if n.List == nil { |
| 238 | children = append(children, |
| 239 | tok(n.Case, len("default"))) |
| 240 | } else { |
| 241 | children = append(children, |
| 242 | tok(n.Case, len("case"))) |
| 243 | } |
| 244 | children = append(children, tok(n.Colon, len(":"))) |
| 245 | |
| 246 | case *ast.ChanType: |
| 247 | switch n.Dir { |
| 248 | case ast.RECV: |
| 249 | children = append(children, tok(n.Begin, len("<-chan"))) |
| 250 | case ast.SEND: |
| 251 | children = append(children, tok(n.Begin, len("chan<-"))) |
| 252 | case ast.RECV | ast.SEND: |
| 253 | children = append(children, tok(n.Begin, len("chan"))) |
| 254 | } |
| 255 | |
| 256 | case *ast.CommClause: |
| 257 | if n.Comm == nil { |
| 258 | children = append(children, |
| 259 | tok(n.Case, len("default"))) |
| 260 | } else { |
| 261 | children = append(children, |
| 262 | tok(n.Case, len("case"))) |
| 263 | } |
| 264 | children = append(children, tok(n.Colon, len(":"))) |
| 265 | |
| 266 | case *ast.Comment: |
| 267 | // nop |
| 268 | |
| 269 | case *ast.CommentGroup: |
| 270 | // nop |
| 271 | |
| 272 | case *ast.CompositeLit: |
| 273 | children = append(children, |
| 274 | tok(n.Lbrace, len("{")), |
| 275 | tok(n.Rbrace, len("{"))) |
| 276 | |
| 277 | case *ast.DeclStmt: |
| 278 | // nop |
| 279 | |
| 280 | case *ast.DeferStmt: |
| 281 | children = append(children, |
| 282 | tok(n.Defer, len("defer"))) |
| 283 | |
| 284 | case *ast.Ellipsis: |
| 285 | children = append(children, |
| 286 | tok(n.Ellipsis, len("..."))) |
| 287 | |
| 288 | case *ast.EmptyStmt: |
| 289 | // nop |
| 290 | |
| 291 | case *ast.ExprStmt: |
| 292 | // nop |
| 293 | |
| 294 | case *ast.Field: |
| 295 | // TODO(adonovan): Field.{Doc,Comment,Tag}? |
| 296 | |
| 297 | case *ast.FieldList: |
| 298 | children = append(children, |
Dan Willemsen | bc60c3c | 2021-12-15 01:09:00 -0800 | [diff] [blame] | 299 | tok(n.Opening, len("(")), // or len("[") |
| 300 | tok(n.Closing, len(")"))) // or len("]") |
Colin Cross | d9c6b80 | 2019-03-19 21:10:31 -0700 | [diff] [blame] | 301 | |
| 302 | case *ast.File: |
| 303 | // TODO test: Doc |
| 304 | children = append(children, |
| 305 | tok(n.Package, len("package"))) |
| 306 | |
| 307 | case *ast.ForStmt: |
| 308 | children = append(children, |
| 309 | tok(n.For, len("for"))) |
| 310 | |
| 311 | case *ast.FuncDecl: |
| 312 | // TODO(adonovan): FuncDecl.Comment? |
| 313 | |
| 314 | // Uniquely, FuncDecl breaks the invariant that |
| 315 | // preorder traversal yields tokens in lexical order: |
| 316 | // in fact, FuncDecl.Recv precedes FuncDecl.Type.Func. |
| 317 | // |
| 318 | // As a workaround, we inline the case for FuncType |
| 319 | // here and order things correctly. |
| 320 | // |
| 321 | children = nil // discard ast.Walk(FuncDecl) info subtrees |
| 322 | children = append(children, tok(n.Type.Func, len("func"))) |
| 323 | if n.Recv != nil { |
| 324 | children = append(children, n.Recv) |
| 325 | } |
| 326 | children = append(children, n.Name) |
Dan Willemsen | bc60c3c | 2021-12-15 01:09:00 -0800 | [diff] [blame] | 327 | if tparams := typeparams.ForFuncType(n.Type); tparams != nil { |
| 328 | children = append(children, tparams) |
| 329 | } |
Colin Cross | d9c6b80 | 2019-03-19 21:10:31 -0700 | [diff] [blame] | 330 | if n.Type.Params != nil { |
| 331 | children = append(children, n.Type.Params) |
| 332 | } |
| 333 | if n.Type.Results != nil { |
| 334 | children = append(children, n.Type.Results) |
| 335 | } |
| 336 | if n.Body != nil { |
| 337 | children = append(children, n.Body) |
| 338 | } |
| 339 | |
| 340 | case *ast.FuncLit: |
| 341 | // nop |
| 342 | |
| 343 | case *ast.FuncType: |
| 344 | if n.Func != 0 { |
| 345 | children = append(children, |
| 346 | tok(n.Func, len("func"))) |
| 347 | } |
| 348 | |
| 349 | case *ast.GenDecl: |
| 350 | children = append(children, |
| 351 | tok(n.TokPos, len(n.Tok.String()))) |
| 352 | if n.Lparen != 0 { |
| 353 | children = append(children, |
| 354 | tok(n.Lparen, len("(")), |
| 355 | tok(n.Rparen, len(")"))) |
| 356 | } |
| 357 | |
| 358 | case *ast.GoStmt: |
| 359 | children = append(children, |
| 360 | tok(n.Go, len("go"))) |
| 361 | |
| 362 | case *ast.Ident: |
| 363 | children = append(children, |
| 364 | tok(n.NamePos, len(n.Name))) |
| 365 | |
| 366 | case *ast.IfStmt: |
| 367 | children = append(children, |
| 368 | tok(n.If, len("if"))) |
| 369 | |
| 370 | case *ast.ImportSpec: |
| 371 | // TODO(adonovan): ImportSpec.{Doc,EndPos}? |
| 372 | |
| 373 | case *ast.IncDecStmt: |
| 374 | children = append(children, |
| 375 | tok(n.TokPos, len(n.Tok.String()))) |
| 376 | |
| 377 | case *ast.IndexExpr: |
| 378 | children = append(children, |
Dan Willemsen | bc60c3c | 2021-12-15 01:09:00 -0800 | [diff] [blame] | 379 | tok(n.Lbrack, len("[")), |
| 380 | tok(n.Rbrack, len("]"))) |
| 381 | |
| 382 | case *typeparams.IndexListExpr: |
| 383 | children = append(children, |
| 384 | tok(n.Lbrack, len("[")), |
| 385 | tok(n.Rbrack, len("]"))) |
Colin Cross | d9c6b80 | 2019-03-19 21:10:31 -0700 | [diff] [blame] | 386 | |
| 387 | case *ast.InterfaceType: |
| 388 | children = append(children, |
| 389 | tok(n.Interface, len("interface"))) |
| 390 | |
| 391 | case *ast.KeyValueExpr: |
| 392 | children = append(children, |
| 393 | tok(n.Colon, len(":"))) |
| 394 | |
| 395 | case *ast.LabeledStmt: |
| 396 | children = append(children, |
| 397 | tok(n.Colon, len(":"))) |
| 398 | |
| 399 | case *ast.MapType: |
| 400 | children = append(children, |
| 401 | tok(n.Map, len("map"))) |
| 402 | |
| 403 | case *ast.ParenExpr: |
| 404 | children = append(children, |
| 405 | tok(n.Lparen, len("(")), |
| 406 | tok(n.Rparen, len(")"))) |
| 407 | |
| 408 | case *ast.RangeStmt: |
| 409 | children = append(children, |
| 410 | tok(n.For, len("for")), |
| 411 | tok(n.TokPos, len(n.Tok.String()))) |
| 412 | |
| 413 | case *ast.ReturnStmt: |
| 414 | children = append(children, |
| 415 | tok(n.Return, len("return"))) |
| 416 | |
| 417 | case *ast.SelectStmt: |
| 418 | children = append(children, |
| 419 | tok(n.Select, len("select"))) |
| 420 | |
| 421 | case *ast.SelectorExpr: |
| 422 | // nop |
| 423 | |
| 424 | case *ast.SendStmt: |
| 425 | children = append(children, |
| 426 | tok(n.Arrow, len("<-"))) |
| 427 | |
| 428 | case *ast.SliceExpr: |
| 429 | children = append(children, |
| 430 | tok(n.Lbrack, len("[")), |
| 431 | tok(n.Rbrack, len("]"))) |
| 432 | |
| 433 | case *ast.StarExpr: |
| 434 | children = append(children, tok(n.Star, len("*"))) |
| 435 | |
| 436 | case *ast.StructType: |
| 437 | children = append(children, tok(n.Struct, len("struct"))) |
| 438 | |
| 439 | case *ast.SwitchStmt: |
| 440 | children = append(children, tok(n.Switch, len("switch"))) |
| 441 | |
| 442 | case *ast.TypeAssertExpr: |
| 443 | children = append(children, |
| 444 | tok(n.Lparen-1, len(".")), |
| 445 | tok(n.Lparen, len("(")), |
| 446 | tok(n.Rparen, len(")"))) |
| 447 | |
| 448 | case *ast.TypeSpec: |
| 449 | // TODO(adonovan): TypeSpec.{Doc,Comment}? |
| 450 | |
| 451 | case *ast.TypeSwitchStmt: |
| 452 | children = append(children, tok(n.Switch, len("switch"))) |
| 453 | |
| 454 | case *ast.UnaryExpr: |
| 455 | children = append(children, tok(n.OpPos, len(n.Op.String()))) |
| 456 | |
| 457 | case *ast.ValueSpec: |
| 458 | // TODO(adonovan): ValueSpec.{Doc,Comment}? |
| 459 | |
| 460 | case *ast.BadDecl, *ast.BadExpr, *ast.BadStmt: |
| 461 | // nop |
| 462 | } |
| 463 | |
| 464 | // TODO(adonovan): opt: merge the logic of ast.Inspect() into |
| 465 | // the switch above so we can make interleaved callbacks for |
| 466 | // both Nodes and Tokens in the right order and avoid the need |
| 467 | // to sort. |
| 468 | sort.Sort(byPos(children)) |
| 469 | |
| 470 | return children |
| 471 | } |
| 472 | |
| 473 | type byPos []ast.Node |
| 474 | |
| 475 | func (sl byPos) Len() int { |
| 476 | return len(sl) |
| 477 | } |
| 478 | func (sl byPos) Less(i, j int) bool { |
| 479 | return sl[i].Pos() < sl[j].Pos() |
| 480 | } |
| 481 | func (sl byPos) Swap(i, j int) { |
| 482 | sl[i], sl[j] = sl[j], sl[i] |
| 483 | } |
| 484 | |
| 485 | // NodeDescription returns a description of the concrete type of n suitable |
| 486 | // for a user interface. |
| 487 | // |
| 488 | // TODO(adonovan): in some cases (e.g. Field, FieldList, Ident, |
| 489 | // StarExpr) we could be much more specific given the path to the AST |
| 490 | // root. Perhaps we should do that. |
| 491 | // |
| 492 | func NodeDescription(n ast.Node) string { |
| 493 | switch n := n.(type) { |
| 494 | case *ast.ArrayType: |
| 495 | return "array type" |
| 496 | case *ast.AssignStmt: |
| 497 | return "assignment" |
| 498 | case *ast.BadDecl: |
| 499 | return "bad declaration" |
| 500 | case *ast.BadExpr: |
| 501 | return "bad expression" |
| 502 | case *ast.BadStmt: |
| 503 | return "bad statement" |
| 504 | case *ast.BasicLit: |
| 505 | return "basic literal" |
| 506 | case *ast.BinaryExpr: |
| 507 | return fmt.Sprintf("binary %s operation", n.Op) |
| 508 | case *ast.BlockStmt: |
| 509 | return "block" |
| 510 | case *ast.BranchStmt: |
| 511 | switch n.Tok { |
| 512 | case token.BREAK: |
| 513 | return "break statement" |
| 514 | case token.CONTINUE: |
| 515 | return "continue statement" |
| 516 | case token.GOTO: |
| 517 | return "goto statement" |
| 518 | case token.FALLTHROUGH: |
| 519 | return "fall-through statement" |
| 520 | } |
| 521 | case *ast.CallExpr: |
| 522 | if len(n.Args) == 1 && !n.Ellipsis.IsValid() { |
| 523 | return "function call (or conversion)" |
| 524 | } |
| 525 | return "function call" |
| 526 | case *ast.CaseClause: |
| 527 | return "case clause" |
| 528 | case *ast.ChanType: |
| 529 | return "channel type" |
| 530 | case *ast.CommClause: |
| 531 | return "communication clause" |
| 532 | case *ast.Comment: |
| 533 | return "comment" |
| 534 | case *ast.CommentGroup: |
| 535 | return "comment group" |
| 536 | case *ast.CompositeLit: |
| 537 | return "composite literal" |
| 538 | case *ast.DeclStmt: |
| 539 | return NodeDescription(n.Decl) + " statement" |
| 540 | case *ast.DeferStmt: |
| 541 | return "defer statement" |
| 542 | case *ast.Ellipsis: |
| 543 | return "ellipsis" |
| 544 | case *ast.EmptyStmt: |
| 545 | return "empty statement" |
| 546 | case *ast.ExprStmt: |
| 547 | return "expression statement" |
| 548 | case *ast.Field: |
| 549 | // Can be any of these: |
| 550 | // struct {x, y int} -- struct field(s) |
| 551 | // struct {T} -- anon struct field |
| 552 | // interface {I} -- interface embedding |
| 553 | // interface {f()} -- interface method |
| 554 | // func (A) func(B) C -- receiver, param(s), result(s) |
| 555 | return "field/method/parameter" |
| 556 | case *ast.FieldList: |
| 557 | return "field/method/parameter list" |
| 558 | case *ast.File: |
| 559 | return "source file" |
| 560 | case *ast.ForStmt: |
| 561 | return "for loop" |
| 562 | case *ast.FuncDecl: |
| 563 | return "function declaration" |
| 564 | case *ast.FuncLit: |
| 565 | return "function literal" |
| 566 | case *ast.FuncType: |
| 567 | return "function type" |
| 568 | case *ast.GenDecl: |
| 569 | switch n.Tok { |
| 570 | case token.IMPORT: |
| 571 | return "import declaration" |
| 572 | case token.CONST: |
| 573 | return "constant declaration" |
| 574 | case token.TYPE: |
| 575 | return "type declaration" |
| 576 | case token.VAR: |
| 577 | return "variable declaration" |
| 578 | } |
| 579 | case *ast.GoStmt: |
| 580 | return "go statement" |
| 581 | case *ast.Ident: |
| 582 | return "identifier" |
| 583 | case *ast.IfStmt: |
| 584 | return "if statement" |
| 585 | case *ast.ImportSpec: |
| 586 | return "import specification" |
| 587 | case *ast.IncDecStmt: |
| 588 | if n.Tok == token.INC { |
| 589 | return "increment statement" |
| 590 | } |
| 591 | return "decrement statement" |
| 592 | case *ast.IndexExpr: |
| 593 | return "index expression" |
Dan Willemsen | bc60c3c | 2021-12-15 01:09:00 -0800 | [diff] [blame] | 594 | case *typeparams.IndexListExpr: |
| 595 | return "index list expression" |
Colin Cross | d9c6b80 | 2019-03-19 21:10:31 -0700 | [diff] [blame] | 596 | case *ast.InterfaceType: |
| 597 | return "interface type" |
| 598 | case *ast.KeyValueExpr: |
| 599 | return "key/value association" |
| 600 | case *ast.LabeledStmt: |
| 601 | return "statement label" |
| 602 | case *ast.MapType: |
| 603 | return "map type" |
| 604 | case *ast.Package: |
| 605 | return "package" |
| 606 | case *ast.ParenExpr: |
| 607 | return "parenthesized " + NodeDescription(n.X) |
| 608 | case *ast.RangeStmt: |
| 609 | return "range loop" |
| 610 | case *ast.ReturnStmt: |
| 611 | return "return statement" |
| 612 | case *ast.SelectStmt: |
| 613 | return "select statement" |
| 614 | case *ast.SelectorExpr: |
| 615 | return "selector" |
| 616 | case *ast.SendStmt: |
| 617 | return "channel send" |
| 618 | case *ast.SliceExpr: |
| 619 | return "slice expression" |
| 620 | case *ast.StarExpr: |
| 621 | return "*-operation" // load/store expr or pointer type |
| 622 | case *ast.StructType: |
| 623 | return "struct type" |
| 624 | case *ast.SwitchStmt: |
| 625 | return "switch statement" |
| 626 | case *ast.TypeAssertExpr: |
| 627 | return "type assertion" |
| 628 | case *ast.TypeSpec: |
| 629 | return "type specification" |
| 630 | case *ast.TypeSwitchStmt: |
| 631 | return "type switch" |
| 632 | case *ast.UnaryExpr: |
| 633 | return fmt.Sprintf("unary %s operation", n.Op) |
| 634 | case *ast.ValueSpec: |
| 635 | return "value specification" |
| 636 | |
| 637 | } |
| 638 | panic(fmt.Sprintf("unexpected node type: %T", n)) |
| 639 | } |