Skip to content

fix: Maintain onNewLine state on subsequent lookahead #2613

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
merged 2 commits into from
Jan 12, 2023
Merged

fix: Maintain onNewLine state on subsequent lookahead #2613

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
2 commits
Select commit Hold shift + click to select a range
db02c21
Maintain onNewLine state on subsequent lookahead
dcodeIO Jan 12, 2023
9c0d388
refactor and cache
dcodeIO Jan 12, 2023
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
40 changes: 20 additions & 20 deletions src/parser.ts
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -290,12 +290,12 @@ export class Parser extends DiagnosticEmitter {
tn.next();
let abstractStart = tn.tokenPos;
let abstractEnd = tn.pos;
let next = tn.peek(true);
if (tn.nextTokenOnNewLine) {
if (tn.peekOnNewLine()) {
tn.reset(state);
statement = this.parseStatement(tn, true);
break;
}
let next = tn.peek();
if (next != Token.Class) {
if (next == Token.Interface) {
this.error(
Expand All @@ -322,7 +322,7 @@ export class Parser extends DiagnosticEmitter {
case Token.Namespace: {
let state = tn.mark();
tn.next();
if (tn.peek(false, IdentifierHandling.Prefer) == Token.Identifier) {
if (tn.peek(IdentifierHandling.Prefer) == Token.Identifier) {
tn.discard(state);
statement = this.parseNamespace(tn, flags, decorators, startPos);
decorators = null;
Expand All @@ -345,7 +345,7 @@ export class Parser extends DiagnosticEmitter {
case Token.Type: { // also identifier
let state = tn.mark();
tn.next();
if (tn.peek(false, IdentifierHandling.Prefer) == Token.Identifier) {
if (tn.peek(IdentifierHandling.Prefer) == Token.Identifier) {
tn.discard(state);
statement = this.parseTypeDeclaration(tn, flags, decorators, startPos);
decorators = null;
Expand All @@ -358,7 +358,7 @@ export class Parser extends DiagnosticEmitter {
case Token.Module: { // also identifier
let state = tn.mark();
tn.next();
if (tn.peek(true) == Token.StringLiteral && !tn.nextTokenOnNewLine) {
if (tn.peek() == Token.StringLiteral && !tn.peekOnNewLine()) {
tn.discard(state);
statement = this.parseModuleDeclaration(tn, flags);
} else {
Expand Down Expand Up @@ -1113,10 +1113,11 @@ export class Parser extends DiagnosticEmitter {

let startPos = tn.tokenPos;
let expr: Expression | null = null;
let nextToken = tn.peek();
if (
tn.peek(true) != Token.Semicolon &&
tn.nextToken != Token.CloseBrace &&
!tn.nextTokenOnNewLine
nextToken != Token.Semicolon &&
nextToken != Token.CloseBrace &&
!tn.peekOnNewLine()
) {
if (!(expr = this.parseExpression(tn))) return null;
}
Expand Down Expand Up @@ -2042,7 +2043,7 @@ export class Parser extends DiagnosticEmitter {
let setEnd = 0;
if (!isInterface) {
if (tn.skip(Token.Get)) {
if (tn.peek(true, IdentifierHandling.Prefer) == Token.Identifier && !tn.nextTokenOnNewLine) {
if (tn.peek(IdentifierHandling.Prefer) == Token.Identifier && !tn.peekOnNewLine()) {
flags |= CommonFlags.Get;
isGetter = true;
getStart = tn.tokenPos;
Expand All @@ -2058,7 +2059,7 @@ export class Parser extends DiagnosticEmitter {
tn.reset(state);
}
} else if (tn.skip(Token.Set)) {
if (tn.peek(true, IdentifierHandling.Prefer) == Token.Identifier && !tn.nextTokenOnNewLine) {
if (tn.peek(IdentifierHandling.Prefer) == Token.Identifier && !tn.peekOnNewLine()) {
flags |= CommonFlags.Set;
isSetter = true;
setStart = tn.tokenPos;
Expand Down Expand Up @@ -2966,7 +2967,7 @@ export class Parser extends DiagnosticEmitter {
break;
}
case Token.Type: { // also identifier
if (tn.peek(false, IdentifierHandling.Prefer) == Token.Identifier) {
if (tn.peek(IdentifierHandling.Prefer) == Token.Identifier) {
statement = this.parseTypeDeclaration(tn, CommonFlags.None, null, tn.tokenPos);
break;
}
Expand Down Expand Up @@ -3020,7 +3021,7 @@ export class Parser extends DiagnosticEmitter {
// at 'break': Identifier? ';'?

let identifier: IdentifierExpression | null = null;
if (tn.peek(true) == Token.Identifier && !tn.nextTokenOnNewLine) {
if (tn.peek() == Token.Identifier && !tn.peekOnNewLine()) {
tn.next(IdentifierHandling.Prefer);
identifier = Node.createIdentifierExpression(tn.readIdentifier(), tn.range());
}
Expand All @@ -3036,7 +3037,7 @@ export class Parser extends DiagnosticEmitter {
// at 'continue': Identifier? ';'?

let identifier: IdentifierExpression | null = null;
if (tn.peek(true) == Token.Identifier && !tn.nextTokenOnNewLine) {
if (tn.peek() == Token.Identifier && !tn.peekOnNewLine()) {
tn.next(IdentifierHandling.Prefer);
identifier = Node.createIdentifierExpression(tn.readIdentifier(), tn.range());
}
Expand Down Expand Up @@ -3948,7 +3949,7 @@ export class Parser extends DiagnosticEmitter {
if (tn.skip(Token.TemplateLiteral)) {
return this.parseTemplateLiteral(tn, identifier);
}
if (tn.peek(true) == Token.Equals_GreaterThan && !tn.nextTokenOnNewLine) {
if (tn.peek() == Token.Equals_GreaterThan && !tn.peekOnNewLine()) {
return this.parseFunctionExpressionCommon(
tn,
Node.createEmptyIdentifierExpression(tn.range(startPos)),
Expand Down Expand Up @@ -4405,8 +4406,8 @@ export class Parser extends DiagnosticEmitter {
tn: Tokenizer
): void {
// see: https://tc39.es/ecma262/#sec-automatic-semicolon-insertion
let token = tn.peek(true);
if (tn.nextTokenOnNewLine || token == Token.EndOfFile || token == Token.CloseBrace) return;
let nextToken = tn.peek();
if (nextToken == Token.EndOfFile || nextToken == Token.CloseBrace || tn.peekOnNewLine()) return;
this.error(
DiagnosticCode.Unexpected_token,
tn.range(tn.nextTokenPos)
Expand All @@ -4415,18 +4416,17 @@ export class Parser extends DiagnosticEmitter {

/** Skips over a statement on errors in an attempt to reduce unnecessary diagnostic noise. */
skipStatement(tn: Tokenizer): void {
tn.peek(true);
if (tn.nextTokenOnNewLine) tn.next(); // if reset() to the previous line
if (tn.peekOnNewLine()) tn.next(); // if reset() to the previous line
do {
let nextToken = tn.peek(true);
let nextToken = tn.peek();
if (
nextToken == Token.EndOfFile || // next step should handle this
nextToken == Token.Semicolon // end of the statement for sure
) {
tn.next();
break;
}
if (tn.nextTokenOnNewLine) break; // end of the statement maybe
if (tn.peekOnNewLine()) break; // end of the statement maybe
switch (tn.next()) {
case Token.Identifier: {
tn.readIdentifier();
Expand Down
54 changes: 37 additions & 17 deletions src/tokenizer.ts
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -449,6 +449,13 @@ export function operatorTokenToString(token: Token): string {
/** Handler for intercepting comments while tokenizing. */
export type CommentHandler = (kind: CommentKind, text: string, range: Range) => void;

/** Whether a token begins on a new line, if known. */
enum OnNewLine {
No,
Yes,
Unknown
}

/** Tokenizes a source to individual {@link Token}s. */
export class Tokenizer extends DiagnosticEmitter {

Expand All @@ -461,7 +468,7 @@ export class Tokenizer extends DiagnosticEmitter {

nextToken: Token = -1;
nextTokenPos: i32 = 0;
nextTokenOnNewLine: bool = false;
nextTokenOnNewLine: OnNewLine = OnNewLine.Unknown;

onComment: CommentHandler | null = null;

Expand Down Expand Up @@ -504,7 +511,7 @@ export class Tokenizer extends DiagnosticEmitter {
}

next(identifierHandling: IdentifierHandling = IdentifierHandling.Default): Token {
this.nextToken = -1;
this.clearNextToken();
let token: Token;
do token = this.unsafeNext(identifierHandling);
while (token == Token.Invalid);
Expand Down Expand Up @@ -959,34 +966,41 @@ export class Tokenizer extends DiagnosticEmitter {
}

peek(
checkOnNewLine: bool = false,
identifierHandling: IdentifierHandling = IdentifierHandling.Default,
maxCompoundLength: i32 = i32.MAX_VALUE
): Token {
let text = this.source.text;
if (this.nextToken < 0) {
let nextToken = this.nextToken;
if (nextToken < 0) {
let posBefore = this.pos;
let tokenBefore = this.token;
let tokenPosBefore = this.tokenPos;
let nextToken: Token;
do nextToken = this.unsafeNext(identifierHandling, maxCompoundLength);
while (nextToken == Token.Invalid);
this.nextToken = nextToken;
this.nextTokenPos = this.tokenPos;
if (checkOnNewLine) {
this.nextTokenOnNewLine = false;
for (let pos = posBefore, end = this.nextTokenPos; pos < end; ++pos) {
if (isLineBreak(text.charCodeAt(pos))) {
this.nextTokenOnNewLine = true;
break;
}
}
}
this.nextTokenOnNewLine = OnNewLine.Unknown;
this.pos = posBefore;
this.token = tokenBefore;
this.tokenPos = tokenPosBefore;
}
return this.nextToken;
return nextToken;
}

peekOnNewLine(): bool {
switch (this.nextTokenOnNewLine) {
case OnNewLine.No: return false;
case OnNewLine.Yes: return true;
}
this.peek();
let text = this.source.text;
for (let pos = this.pos, end = this.nextTokenPos; pos < end; ++pos) {
if (isLineBreak(text.charCodeAt(pos))) {
this.nextTokenOnNewLine = OnNewLine.Yes;
return true;
}
}
this.nextTokenOnNewLine = OnNewLine.No;
return false;
}

skipIdentifier(identifierHandling: IdentifierHandling = IdentifierHandling.Prefer): bool {
Expand All @@ -1006,7 +1020,7 @@ export class Tokenizer extends DiagnosticEmitter {
while (nextToken == Token.Invalid);
if (nextToken == token) {
this.token = token;
this.nextToken = -1;
this.clearNextToken();
return true;
} else {
this.pos = posBefore;
Expand Down Expand Up @@ -1037,7 +1051,13 @@ export class Tokenizer extends DiagnosticEmitter {
this.pos = state.pos;
this.token = state.token;
this.tokenPos = state.tokenPos;
this.clearNextToken();
}

clearNextToken(): void {
this.nextToken = -1;
this.nextTokenPos = 0;
this.nextTokenOnNewLine = OnNewLine.Unknown;
}

range(start: i32 = -1, end: i32 = -1): Range {
Expand Down
8 changes: 7 additions & 1 deletion tests/parser/asi.ts
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -16,4 +16,10 @@ function successCloseBrace(): i32 {

function successCloseParen(): i32 {
return ( 123 )
}
}

function successAfterLet(): i32 {
// multiple tn.peeks
let a = 0
return a
}
4 changes: 4 additions & 0 deletions tests/parser/asi.ts.fixture.ts
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -17,6 +17,10 @@ function successCloseBrace(): i32 {
function successCloseParen(): i32 {
return (123);
}
function successAfterLet(): i32 {
let a = 0;
return a;
}
// ERROR 1012: "Unexpected token." in asi.ts(2,13+0)
// ERROR 1012: "Unexpected token." in asi.ts(7,14+0)
// ERROR 1012: "Unexpected token." in asi.ts(11,13+0)