Skip to content

Lexer: use standard JS functions to handle Unicode #3322

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 1 commit into from
Oct 20, 2021
Merged

Lexer: use standard JS functions to handle Unicode #3322

Changes from all commits
Commits
Show all changes
1 commit
Select commit
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
47 changes: 12 additions & 35 deletions src/language/lexer.ts
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -144,17 +144,6 @@ function isTrailingSurrogate(code: number): boolean {
return code >= 0xdc00 && code <= 0xdfff;
}

function encodeSurrogatePair(point: number): string {
return String.fromCharCode(
0xd800 | ((point - 0x10000) >> 10), // Leading Surrogate
0xdc00 | ((point - 0x10000) & 0x3ff), // Trailing Surrogate
);
}

function decodeSurrogatePair(leading: number, trailing: number): number {
return 0x10000 + (((leading & 0x03ff) << 10) | (trailing & 0x03ff));
}

/**
* Prints the code point (or end of file reference) at a given location in a
* source for use in error messages.
Expand All @@ -163,22 +152,18 @@ function decodeSurrogatePair(leading: number, trailing: number): number {
* code point form (ie. U+1234).
*/
function printCodePointAt(lexer: Lexer, location: number): string {
const body = lexer.source.body;
if (location >= body.length) {
const code = lexer.source.body.codePointAt(location);

if (code === undefined) {
return TokenKind.EOF;
} else if (code >= 0x0020 && code <= 0x007e) {
// Printable ASCII
const char = String.fromCodePoint(code);
return char === '"' ? "'\"'" : `"${char}"`;
}
const code = body.charCodeAt(location);
// Printable ASCII
if (code >= 0x0020 && code <= 0x007e) {
return code === 0x0022 ? "'\"'" : `"${body[location]}"`;
}

// Unicode code point
const point = isSupplementaryCodePoint(body, location)
? decodeSurrogatePair(code, body.charCodeAt(location + 1))
: code;
const zeroPad =
point > 0xfff ? '' : point > 0xff ? '0' : point > 0xf ? '00' : '000';
return `U+${zeroPad}${point.toString(16).toUpperCase()}`;
return 'U+' + code.toString(16).toUpperCase().padStart(4, '0');
}

/**
Expand Down Expand Up @@ -596,15 +581,7 @@ function readEscapedUnicodeVariableWidth(
if (size < 5 || !isUnicodeScalarValue(point)) {
break;
}
// JavaScript defines strings as a sequence of UTF-16 code units and
// encodes Unicode code points above U+FFFF using a surrogate pair.
return {
value:
point <= 0xffff
? String.fromCharCode(point)
: encodeSurrogatePair(point),
size,
};
return { value: String.fromCodePoint(point), size };
}
// Append this hex digit to the code point.
point = (point << 4) | readHexDigit(code);
Expand All @@ -631,7 +608,7 @@ function readEscapedUnicodeFixedWidth(
const code = read16BitHexCode(body, position + 2);

if (isUnicodeScalarValue(code)) {
return { value: String.fromCharCode(code), size: 6 };
return { value: String.fromCodePoint(code), size: 6 };
}

// GraphQL allows JSON-style surrogate pair escape sequences, but only when
Expand All @@ -650,7 +627,7 @@ function readEscapedUnicodeFixedWidth(
// include both codes into the JavaScript string value. Had JavaScript
// not been internally based on UTF-16, then this surrogate pair would
// be decoded to retrieve the supplementary code point.
return { value: String.fromCharCode(code, trailingCode), size: 12 };
return { value: String.fromCodePoint(code, trailingCode), size: 12 };
}
}
}
Expand Down