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fix(parser): simplified arrow parsing
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@KFlash
KFlash committed Aug 7, 2019
1 parent b1c387f commit db388db
Showing 1 changed file with 93 additions and 44 deletions.
137 changes: 93 additions & 44 deletions src/parser.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -1071,14 +1071,8 @@ export function parseAsyncArrowOrAsyncFunctionDeclaration(
);
} else {
if (parser.token === Token.Arrow) {
let scope: ScopeState | undefined = void 0;

if (context & Context.OptionsLexical) {
scope = addChildScope(createScope(), ScopeKind.FunctionBody);
addBlockName(parser, context, scope, parser.tokenValue, BindingKind.ArgumentList, Origin.None);
}

expr = parseArrowFunctionExpression(parser, context, scope, [expr], 0, start, line, column);
classifyIdentifier(parser, context, token, /* isArrow */ 1, /* shouldBanEscaped */ 1);
expr = parseArrowFromIdentifier(parser, context, parser.tokenValue, expr, 0, 1, 0, start, line, column);
}

parser.assignable = AssignmentKind.Assignable;
Expand Down Expand Up @@ -3159,18 +3153,18 @@ export function parseSequenceExpression(
*
* @param parser Parser object
* @param context Context masks
* @param assignable
* @param allowAssign
*/
export function parseExpressions(
parser: ParserState,
context: Context,
inGroup: 0 | 1,
assignable: 0 | 1,
allowAssign: 0 | 1,
start: number,
line: number,
column: number
): ESTree.SequenceExpression | ESTree.Expression {
const expr = parseExpression(parser, context, assignable, 0, inGroup, start, line, column);
const expr = parseExpression(parser, context, allowAssign, 0, inGroup, start, line, column);
return parser.token === Token.Comma
? parseSequenceExpression(parser, context, inGroup, start, line, column, expr)
: expr;
Expand Down Expand Up @@ -3717,6 +3711,9 @@ export function parseSuperExpression(
* @param parser Parser object
* @param context Context masks
* @param allowAssign
* @param start
* @param line
* @param column
*/
export function parseLeftHandSideExpression(
parser: ParserState,
Expand Down Expand Up @@ -3746,13 +3743,49 @@ export function parseLeftHandSideExpression(
return parseMemberOrUpdateExpression(parser, context, expression, inGroup, 0, 0, start, line, column);
}

/**
* Parse update expression
*
* @param parser Parser object
* @param context Context masks
* @param inNewExpression
* @param start
* @param line
* @param column
*/
function parseUpdateExpression(
parser: ParserState,
context: Context,
expr: ESTree.Expression,
start: number,
line: number,
column: number
) {
if (parser.assignable & AssignmentKind.CannotAssign) report(parser, Errors.InvalidIncDecTarget);

const { token } = parser;

nextToken(parser, context);

parser.assignable = AssignmentKind.CannotAssign;

return finishNode(parser, context, start, line, column, {
type: 'UpdateExpression',
argument: expr,
operator: KeywordDescTable[token & Token.Type] as ESTree.UpdateOperator,
prefix: false
});
}
/**
* Parses member or update expression
*
* @param parser Parser object
* @param context Context masks
* @param expr ESTree AST node
* @param inNewExpression
* @param inGroup
* @param start
* @param line
* @param column
*/
export function parseMemberOrUpdateExpression(
parser: ParserState,
Expand All @@ -3765,22 +3798,8 @@ export function parseMemberOrUpdateExpression(
line: number,
column: number
): any {
// Update + Member expression
if ((parser.token & Token.IsUpdateOp) === Token.IsUpdateOp && (parser.flags & Flags.NewLine) < 1) {
if (parser.assignable & AssignmentKind.CannotAssign) report(parser, Errors.InvalidIncDecTarget);

const { token } = parser;

nextToken(parser, context);

parser.assignable = AssignmentKind.CannotAssign;

return finishNode(parser, context, start, line, column, {
type: 'UpdateExpression',
argument: expr,
operator: KeywordDescTable[token & Token.Type] as ESTree.UpdateOperator,
prefix: false
});
return parseUpdateExpression(parser, context, expr, start, line, column);
}

if ((parser.token & Token.IsMemberOrCallExpression) === Token.IsMemberOrCallExpression || isOptional) {
Expand Down Expand Up @@ -3966,7 +3985,7 @@ export function parsePropertyOrPrivatePropertyName(parser: ParserState, context:
* @param line
* @param column
*/
export function parseUpdateExpression(
export function parseUpdateExpressionPrefixed(
parser: ParserState,
context: Context,
inNewExpression: 0 | 1,
Expand Down Expand Up @@ -4125,15 +4144,14 @@ export function parsePrimaryExpressionExtended(
switch (parser.token) {
case Token.Increment:
case Token.Decrement:
return parseUpdateExpression(parser, context, inNewExpression, start, line, column);
return parseUpdateExpressionPrefixed(parser, context, inNewExpression, start, line, column);
case Token.DeleteKeyword:
case Token.Negate:
case Token.Complement:
case Token.Add:
case Token.Subtract:
case Token.TypeofKeyword:
case Token.VoidKeyword:
if (inNewExpression) report(parser, Errors.InvalidNewUnary, KeywordDescTable[parser.token & Token.Type]);
return parseUnaryExpression(parser, context, start, line, column, inGroup);
case Token.FunctionKeyword:
return parseFunctionExpression(parser, context, /* isAsync */ 0, inGroup, start, line, column);
Expand Down Expand Up @@ -6516,7 +6534,7 @@ export function parseComputedPropertyName(parser: ParserState, context: Context,
export function parseParenthesizedExpression(
parser: ParserState,
context: Context,
assignable: 0 | 1,
allowAssign: 0 | 1,
kind: BindingKind,
origin: Origin,
start: number,
Expand All @@ -6528,12 +6546,13 @@ export function parseParenthesizedExpression(
nextToken(parser, context | Context.AllowRegExp);

const scope = context & Context.OptionsLexical ? addChildScope(createScope(), ScopeKind.ArrowParams) : void 0;

context = (context | Context.DisallowIn) ^ Context.DisallowIn;

if (consumeOpt(parser, context, Token.RightParen)) {
// Not valid expression syntax, but this is valid in an arrow function
// with no params: `() => body`.
if (!assignable) report(parser, Errors.UnexpectedToken, KeywordDescTable[parser.token & Token.Type]);
return parseArrowFunctionExpression(parser, context, scope, [], /* isAsync */ 0, start, line, column);
return parseParenthesizedArrow(parser, context, scope, [], allowAssign, 0, start, line, column);
}

let destructible: AssignmentKind | DestructuringKind = 0;
Expand Down Expand Up @@ -6702,7 +6721,6 @@ export function parseParenthesizedExpression(
: 0;

if (parser.token === Token.Arrow) {
if (!assignable) report(parser, Errors.IllegalArrowFunctionParams);
if (destructible & (DestructuringKind.Assignable | DestructuringKind.CannotDestruct))
report(parser, Errors.InvalidArrowDestructLHS);
if (context & (Context.InAwaitContext | Context.Module) && destructible & DestructuringKind.Await)
Expand All @@ -6711,11 +6729,12 @@ export function parseParenthesizedExpression(
report(parser, Errors.YieldInParameter);
}
if (isSimpleParameterList) parser.flags |= Flags.SimpleParameterList;
return parseArrowFunctionExpression(
return parseParenthesizedArrow(
parser,
context,
scope,
isSequence ? expressions : [expr],
allowAssign,
0,
start,
line,
Expand Down Expand Up @@ -6799,6 +6818,35 @@ function parseArrowFromIdentifier(
return parseArrowFunctionExpression(parser, context, scope, [expr], isAsync, start, line, column);
}

/**
* Parse arrow function expression
*
* @param parser Parser object
* @param context Context masks
* @param params
* @param isAsync
* @param start Start index
* @param line Start line
* @param column Start of column
*/
function parseParenthesizedArrow(
parser: ParserState,
context: Context,
scope: ScopeState | undefined,
params: any,
allowAssign: 0 | 1,
isAsync: 0 | 1,
start: number,
line: number,
column: number
): ESTree.ArrowFunctionExpression {
if (!allowAssign) report(parser, Errors.InvalidAssignmentTarget);

for (let i = 0; i < params.length; ++i) reinterpretToPattern(parser, params[i]);

return parseArrowFunctionExpression(parser, context, scope, params, isAsync, start, line, column);
}

/**
* Parse arrow function expression
*
Expand Down Expand Up @@ -6844,8 +6892,6 @@ export function parseArrowFunctionExpression(

consume(parser, context | Context.AllowRegExp, Token.Arrow);

for (let i = 0; i < params.length; ++i) reinterpretToPattern(parser, params[i]);

context = ((context | 0b0000000111100000000_0000_00000000) ^ 0b0000000111100000000_0000_00000000) | (isAsync << 22);

const expression = parser.token !== Token.LeftBrace;
Expand Down Expand Up @@ -7195,6 +7241,10 @@ export function parseNewExpression(

parser.assignable = AssignmentKind.CannotAssign;

if ((parser.token & Token.IsUnaryOp) === Token.IsUnaryOp) {
report(parser, Errors.InvalidNewUnary, KeywordDescTable[parser.token & Token.Type]);
}

const expr = parsePrimaryExpressionExtended(
parser,
context,
Expand Down Expand Up @@ -7269,7 +7319,7 @@ export function parseMetaProperty(
function parseAsyncArrowAfterIdent(
parser: ParserState,
context: Context,
assignable: 0 | 1,
allowAssign: 0 | 1,
start: number,
line: number,
column: number
Expand All @@ -7290,7 +7340,7 @@ function parseAsyncArrowAfterIdent(
parser.tokenValue,
parseIdentifier(parser, context, 0),
0,
assignable,
allowAssign,
1,
start,
line,
Expand All @@ -7317,7 +7367,7 @@ export function parseAsyncArrowOrCallExpression(
parser: ParserState,
context: Context,
callee: ESTree.Identifier | void,
assignable: 0 | 1,
allowAssign: 0 | 1,
kind: BindingKind,
origin: Origin,
flags: Flags,
Expand All @@ -7334,8 +7384,7 @@ export function parseAsyncArrowOrCallExpression(
if (consumeOpt(parser, context, Token.RightParen)) {
if (parser.token === Token.Arrow) {
if (flags & Flags.NewLine) report(parser, Errors.InvalidLineBreak);
if (!assignable) report(parser, Errors.InvalidAsyncParamList);
return parseArrowFunctionExpression(parser, context, scope, [], /* isAsync */ 1, start, line, column);
return parseParenthesizedArrow(parser, context, scope, [], allowAssign, 1, start, line, column);
}

return finishNode(
Expand Down Expand Up @@ -7505,15 +7554,15 @@ export function parseAsyncArrowOrCallExpression(
: 0;

if (parser.token === Token.Arrow) {
if (!assignable) report(parser, Errors.IllegalArrowFunctionParams);
if (destructible & (DestructuringKind.Assignable | DestructuringKind.CannotDestruct))
report(parser, Errors.InvalidLHSAsyncArrow);
if (parser.flags & Flags.NewLine || flags & Flags.NewLine) report(parser, Errors.InvalidLineBreak);
if (destructible & DestructuringKind.Await) report(parser, Errors.AwaitInParameter);
if (context & (Context.Strict | Context.InYieldContext) && destructible & DestructuringKind.Yield)
report(parser, Errors.YieldInParameter);
if (isSimpleParameterList) parser.flags |= Flags.SimpleParameterList;
return parseArrowFunctionExpression(parser, context, scope, params, /* isAsync */ 1, start, line, column);

return parseParenthesizedArrow(parser, context, scope, params, allowAssign, 1, start, line, column);
} else if (destructible & DestructuringKind.HasToDestruct) {
report(parser, Errors.InvalidShorthandPropInit);
}
Expand Down

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