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fix(parser): reduced branching and simplified for parenthesized arrow…
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… head & async arrow
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@KFlash
KFlash committed May 8, 2019
1 parent 09683b4 commit 25a5bff
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Showing 2 changed files with 55 additions and 78 deletions.
126 changes: 51 additions & 75 deletions src/parser.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -4048,27 +4048,23 @@ export function parseParenthesizedExpression(parser: ParserState, context: Conte
let expr: any;
let expressions: ESTree.Expression[] = [];
let toplevelComma: 0 | 1 = 0;
let isComplex: 0 | 1 = 0;

parser.assignable = AssignmentKind.Assignable;

while (parser.token !== Token.RightParen) {
if (parser.token & (Token.IsIdentifier | Token.Keyword)) {
const token = parser.token;
if ((token & Token.IsEvalOrArguments) === Token.IsEvalOrArguments) parser.flags |= Flags.SimpleParameterList;
if ((token & Token.FutureReserved) === Token.FutureReserved) parser.flags |= Flags.SimpleParameterList;
expr = parsePrimaryExpressionExtended(
parser,
context,
BindingType.None,
/* inNewExpression */ 0,
/* assignable */ 1
);
const { token } = parser;
if ((token & Token.IsEvalOrArguments) === Token.IsEvalOrArguments) isComplex = 1;
if ((token & Token.FutureReserved) === Token.FutureReserved) isComplex = 1;

expr = parsePrimaryExpressionExtended(parser, context, BindingType.None, 0, 1);

if (consumeOpt(parser, context | Context.AllowRegExp, Token.Assign)) {
parser.flags |= Flags.SimpleParameterList;
isComplex = 1;
validateIdentifier(parser, context, BindingType.None, token);
const right = parseExpression(parser, context, /* assignable */ 1);
parser.assignable = destructible = AssignmentKind.NotAssignable;
parser.assignable = AssignmentKind.NotAssignable;
expr = {
type: 'AssignmentExpression',
left: expr,
Expand All @@ -4077,18 +4073,15 @@ export function parseParenthesizedExpression(parser: ParserState, context: Conte
};
} else {
destructible |=
parser.token === Token.Comma || parser.token === Token.RightParen
(parser.token & Token.IsCommaOrRightParen) === Token.IsCommaOrRightParen
? parser.assignable & AssignmentKind.NotAssignable
? DestructuringKind.NotDestructible
: 0
: DestructuringKind.NotDestructible;

expr = parseAssignmentExpression(
parser,
context,
parseMemberOrUpdateExpression(parser, context, expr, /* assignable */ 0)
);
destructible |= parser.assignable;
expr = parseMemberOrUpdateExpression(parser, context, expr, /* assignable */ 0);

expr = parseAssignmentExpression(parser, context, expr);
}
} else if (parser.token & Token.IsPatternStart) {
expr =
Expand All @@ -4098,31 +4091,31 @@ export function parseParenthesizedExpression(parser: ParserState, context: Conte

destructible |= parser.destructible;

parser.flags |= Flags.SimpleParameterList;
isComplex = 1;

parser.assignable = AssignmentKind.NotAssignable;

if ((parser.token & Token.IsCommaOrRightParen) !== Token.IsCommaOrRightParen) {
if (destructible & DestructuringKind.Required) report(parser, Errors.InvalidPatternTail);

if (parser.token !== Token.Comma && parser.token !== Token.RightParen) {
if (destructible & DestructuringKind.Required) {
report(parser, Errors.InvalidPatternTail);
}
parser.assignable = AssignmentKind.NotAssignable;
expr = parseMemberOrUpdateExpression(parser, context, expr, /* assignable */ 0);

destructible |= DestructuringKind.NotDestructible;
if (parser.token !== Token.Comma && parser.token !== Token.RightParen) {

if ((parser.token & Token.IsCommaOrRightParen) !== Token.IsCommaOrRightParen) {
expr = parseAssignmentExpression(parser, context, expr);
}
} else {
parser.assignable = AssignmentKind.NotAssignable;
}
} else if (parser.token === Token.Ellipsis) {
expr = parseRestOrSpreadElement(parser, context, Token.RightParen, BindingType.ArgumentList, /* isAsync */ 0);

parser.flags |= Flags.SimpleParameterList;

if (parser.destructible & DestructuringKind.NotDestructible) report(parser, Errors.InvalidRestArg);

isComplex = 1;

destructible |= parser.destructible;

if (toplevelComma && (parser.token === Token.Comma || parser.token === Token.RightParen)) {
if (toplevelComma && (parser.token & Token.IsCommaOrRightParen) === Token.IsCommaOrRightParen) {
expressions.push(expr);
}
destructible |= DestructuringKind.Required;
Expand All @@ -4131,9 +4124,8 @@ export function parseParenthesizedExpression(parser: ParserState, context: Conte
destructible |= DestructuringKind.NotDestructible;

expr = parseExpression(parser, context, /* assignable */ 1);
destructible = parser.assignable;

if (toplevelComma && (parser.token === Token.Comma || parser.token === Token.RightParen)) {
if (toplevelComma && (parser.token & Token.IsCommaOrRightParen) === Token.IsCommaOrRightParen) {
expressions.push(expr);
}

Expand All @@ -4143,6 +4135,7 @@ export function parseParenthesizedExpression(parser: ParserState, context: Conte
expressions = [expr];
}
}

if (toplevelComma) {
while (consumeOpt(parser, context | Context.AllowRegExp, Token.Comma)) {
expressions.push(parseExpression(parser, context, /* assignable */ 1));
Expand All @@ -4156,20 +4149,14 @@ export function parseParenthesizedExpression(parser: ParserState, context: Conte
};
}

destructible |= parser.assignable;

if (toplevelComma) {
parser.assignable = AssignmentKind.NotAssignable;
}

consume(parser, context, Token.RightParen);

parser.destructible = destructible;

return expr;
}

if (toplevelComma && (parser.token === Token.Comma || parser.token === Token.RightParen)) {
if (toplevelComma && (parser.token & Token.IsCommaOrRightParen) === Token.IsCommaOrRightParen) {
expressions.push(expr);
}

Expand All @@ -4190,24 +4177,25 @@ export function parseParenthesizedExpression(parser: ParserState, context: Conte

if (toplevelComma) {
parser.assignable = AssignmentKind.NotAssignable;

expr = {
type: 'SequenceExpression',
expressions
};
}

if (destructible & DestructuringKind.NotDestructible && destructible & DestructuringKind.Required) {
report(parser, Errors.UnexpectedToken);
}
if (destructible & DestructuringKind.NotDestructible && destructible & DestructuringKind.Required)
report(parser, Errors.Unexpected);

if (parser.token === Token.Arrow) {
if (isComplex) parser.flags |= Flags.SimpleParameterList;
if (!assignable) report(parser, Errors.IllegalArrowFunctionParams);
if (destructible & DestructuringKind.NotDestructible) report(parser, Errors.InvalidLHSInAsyncArrow);
if (destructible & DestructuringKind.Assignable) report(parser, Errors.InvalidArrowDestructLHS);
if (context & (Context.Module | Context.InAwaitContext) && parser.flags & Flags.SeenAwait)
report(parser, Errors.IllegalArrowFunctionParams);
// if (context & (Context.Strict | Context.InYieldContext) && parser.destructible & DestructuringKind.HasYield)
// report(parser, Errors.YieldInParameter);
if (context & (Context.Strict | Context.InYieldContext) && parser.destructible & DestructuringKind.HasYield)
report(parser, Errors.YieldInParameter);
if (parser.destructible & DestructuringKind.HasAWait) report(parser, Errors.InvalidArrowDefaultYield);
return parseArrowFunctionExpression(parser, context, toplevelComma ? expressions : [expr], /* isAsync */ 0);
} else if (destructible & DestructuringKind.Required) {
Expand Down Expand Up @@ -4565,22 +4553,17 @@ export function parseAsyncArrowOrCallExpression(
let destructible: AssignmentKind | DestructuringKind = 0;
let expr: any;
let params: ESTree.Expression[] = [];
let isComplex: 0 | 1 = 0;

while (parser.token !== Token.RightParen) {
if (parser.token & (Token.IsIdentifier | Token.Keyword)) {
if ((parser.token & Token.IsEvalOrArguments) === Token.IsEvalOrArguments)
parser.flags |= Flags.SimpleParameterList;
if ((parser.token & Token.FutureReserved) === Token.FutureReserved) parser.flags |= Flags.SimpleParameterList;
expr = parsePrimaryExpressionExtended(
parser,
context,
BindingType.None,
/* inNewExpression */ 0,
/* assignable */ 1
);
if ((parser.token & Token.IsEvalOrArguments) === Token.IsEvalOrArguments) isComplex = 1;
if ((parser.token & Token.FutureReserved) === Token.FutureReserved) isComplex = 1;

expr = parsePrimaryExpressionExtended(parser, context, BindingType.None, 0, 1);

if (consumeOpt(parser, context | Context.AllowRegExp, Token.Assign)) {
parser.flags |= Flags.SimpleParameterList;
isComplex = 1;

expr = {
type: 'AssignmentExpression',
Expand All @@ -4590,17 +4573,15 @@ export function parseAsyncArrowOrCallExpression(
};
} else {
destructible |=
parser.token === Token.Comma || parser.token === Token.RightParen
(parser.token & Token.IsCommaOrRightParen) === Token.IsCommaOrRightParen
? parser.assignable & AssignmentKind.NotAssignable
? DestructuringKind.NotDestructible
: 0
: DestructuringKind.NotDestructible;

expr = parseAssignmentExpression(
parser,
context,
parseMemberOrUpdateExpression(parser, context, expr, /* assignable */ 0)
);
expr = parseMemberOrUpdateExpression(parser, context, expr, /* assignable */ 0);

expr = parseAssignmentExpression(parser, context, expr);

destructible |= parser.assignable;
}
Expand All @@ -4612,30 +4593,26 @@ export function parseAsyncArrowOrCallExpression(

destructible |= parser.destructible;

parser.flags |= Flags.SimpleParameterList;
isComplex = 1;

if (parser.token !== Token.Comma && parser.token !== Token.RightParen) {
if (destructible & DestructuringKind.Required) {
report(parser, Errors.InvalidPatternTail);
}
parser.assignable = AssignmentKind.NotAssignable;

if ((parser.token & Token.IsCommaOrRightParen) !== Token.IsCommaOrRightParen) {
if (destructible & DestructuringKind.Required) report(parser, Errors.InvalidPatternTail);

expr = parseMemberOrUpdateExpression(parser, context, expr, /* assignable */ 0);

destructible |= DestructuringKind.NotDestructible;

if (parser.token !== Token.Comma && parser.token !== Token.RightParen) {
if ((parser.token & Token.IsCommaOrRightParen) !== Token.IsCommaOrRightParen)
expr = parseAssignmentExpression(parser, context, expr);
}
} else {
parser.assignable = AssignmentKind.NotAssignable;
}
} else if (parser.token === Token.Ellipsis) {
expr = parseRestOrSpreadElement(parser, context, Token.RightParen, BindingType.ArgumentList, /* isAsync */ 1);

destructible |= parser.destructible;

parser.flags |= Flags.SimpleParameterList;

isComplex = 1;
if (parser.token !== Token.RightParen) parser.destructible |= DestructuringKind.NotDestructible;
} else {
expr = parseExpression(parser, context, /* assignable */ 1);
Expand Down Expand Up @@ -4669,9 +4646,8 @@ export function parseAsyncArrowOrCallExpression(

consume(parser, context, Token.RightParen);

// TODO: Simplify and clean up!

if (parser.token === Token.Arrow) {
if (isComplex) parser.flags |= Flags.SimpleParameterList;
if (!assignable) report(parser, Errors.IllegalArrowFunctionParams);
if (destructible & DestructuringKind.NotDestructible) report(parser, Errors.InvalidLHSInAsyncArrow);
if (destructible & DestructuringKind.Assignable) report(parser, Errors.InvalidArrowDestructLHS);
Expand Down
7 changes: 4 additions & 3 deletions src/token.ts
View file
Original file line number Diff line number Diff line change
Expand Up @@ -25,7 +25,8 @@ export const enum Token {
IsMemberOrCallExpression = 1 << 26,
IsStringOrNumber = 1 << 27,
VarDecl = 1 << 28,
IsEvalOrArguments = 1 << 29 | IsExpressionStart | IsIdentifier,
IsEvalOrArguments = 1 << 29 | IsExpressionStart | IsIdentifier,
IsCommaOrRightParen = 1 << 30,


/* Node types */
Expand All @@ -51,9 +52,9 @@ export const enum Token {
Period = 13 | IsMemberOrCallExpression, // .
Ellipsis = 14, // ...
RightBrace = 15 | IsAutoSemicolon, // }
RightParen = 16, // )
RightParen = 16 | IsCommaOrRightParen, // )
Semicolon = 17 | IsAutoSemicolon, // ;
Comma = 18, // ,
Comma = 18 | IsCommaOrRightParen, // ,
LeftBracket = 19 | IsExpressionStart | IsPatternStart | IsMemberOrCallExpression, // [
RightBracket = 20, // ]
Colon = 21, // :
Expand Down

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