ladybird/Libraries/LibJS/ParserError.cpp
Timothy Flynn 00182a2405 LibJS: Port the JS lexer and parser to UTF-16
This ports the lexer to UTF-16 and deals with the immediate fallout up
to the AST. The AST will be dealt with in upcoming commits.

The lexer will still accept UTF-8 strings as input, and will transcode
them to UTF-16 for lexing. This doesn't actually incur a new allocation,
as we were already converting the input StringView to a ByteString for
each lexer.

One immediate logical benefit here is that we do not need to know off-
hand how many UTF-8 bytes some special code points occupy. They all
happen to be a single UTF-16 code unit. So instead of advancing the
lexer by 3 positions in some cases, we can just always advance by 1.
2025-08-13 09:56:13 -04:00

47 lines
1.6 KiB
C++

/*
* Copyright (c) 2020, Stephan Unverwerth <s.unverwerth@serenityos.org>
* Copyright (c) 2021-2022, David Tuin <davidot@serenityos.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <AK/StringView.h>
#include <AK/Vector.h>
#include <LibJS/ParserError.h>
#include <LibJS/Token.h>
namespace JS {
String ParserError::to_string() const
{
if (!position.has_value())
return message;
return MUST(String::formatted("{} (line: {}, column: {})", message, position.value().line, position.value().column));
}
ByteString ParserError::to_byte_string() const
{
if (!position.has_value())
return message.to_byte_string();
return ByteString::formatted("{} (line: {}, column: {})", message, position.value().line, position.value().column);
}
ByteString ParserError::source_location_hint(Utf16View const& source, char spacer, char indicator) const
{
if (!position.has_value())
return {};
// We need to modify the source to match what the lexer considers one line - normalizing
// line terminators to \n is easier than splitting using all different LT characters.
auto source_string = source.replace("\r\n"sv, "\n"sv, ReplaceMode::All).replace("\r"sv, "\n"sv, ReplaceMode::All).replace(LINE_SEPARATOR, "\n"sv, ReplaceMode::All).replace(PARAGRAPH_SEPARATOR, "\n"sv, ReplaceMode::All);
StringBuilder builder;
builder.append(source_string.split_view('\n', SplitBehavior::KeepEmpty)[position.value().line - 1]);
builder.append('\n');
for (size_t i = 0; i < position.value().column - 1; ++i)
builder.append(spacer);
builder.append(indicator);
return builder.to_byte_string();
}
}