Files
carbon-lang/toolchain/lex/string_literal.h
T
Jon Ross-Perkins acbe6530c3 Move diagnostics into a namespace (#5173)
What this really does is avoids shadowing names, so that we can
comfortable have things like `Check::DiagnosticEmitter` or
`Check::DiagnosticLoc` without shadowing being a concern.

Note, down this path I'm also thinking about:

- Renaming misc DiagnosticConsumer/DiagnosticEmitter classes, possibly
just to DiagnosticConsumer/DiagnosticEmitter (so
`Check::DiagnosticEmitter` instead of `SemIRLocDiagnosticEmitter`).
- Dropping `Diagnostic` from `Emitter::DiagnosticBuilder`.
- But not for `Check::DiagnosticBuilder`, because `Check::Builder` would
be ambiguous.
- Renaming diagnostics/diagnostic_* to drop "diagnostic".

[Discussion about SemIRLoc ->
DiagnosticLoc](https://discord.com/channels/655572317891461132/655578254970716160/1353771570463768698)
reminded me of this (in particular the older [Check::DiagnosticBuilder
discussion](https://discord.com/channels/655572317891461132/655578254970716160/1344363562608627763)),
but I'd only do that rename if there's matching consensus about a path
forward where we keep SemIRLoc, and in a way that it's only ever used
for diagnostics (the divergence from which is at the root of current
LocId discussion).

I'm trying to keep that separate from a namespace addition for clarity.
2025-03-26 19:12:10 +00:00

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// Part of the Carbon Language project, under the Apache License v2.0 with LLVM
// Exceptions. See /LICENSE for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
#ifndef CARBON_TOOLCHAIN_LEX_STRING_LITERAL_H_
#define CARBON_TOOLCHAIN_LEX_STRING_LITERAL_H_
#include <optional>
#include "llvm/ADT/StringRef.h"
#include "llvm/Support/Allocator.h"
#include "toolchain/diagnostics/diagnostic_emitter.h"
namespace Carbon::Lex {
class StringLiteral {
public:
// Extract a string literal token from the given text, if it has a suitable
// form. Returning std::nullopt indicates no string literal was found;
// returning an invalid literal indicates a string prefix was found, but it's
// malformed and is returning a partial string literal to assist error
// construction.
static auto Lex(llvm::StringRef source_text) -> std::optional<StringLiteral>;
// Expand any escape sequences in the given string literal and compute the
// resulting value. This handles error recovery internally and cannot fail.
//
// When content_needs_validation_ is false and the string has no indent to
// deal with, this can return the content directly. Otherwise, the allocator
// will be used for the StringRef.
auto ComputeValue(llvm::BumpPtrAllocator& allocator,
Diagnostics::Emitter<const char*>& emitter) const
-> llvm::StringRef;
// Get the text corresponding to this literal.
auto text() const -> llvm::StringRef { return text_; }
// Determine whether this is a multi-line string literal.
auto is_multi_line() const -> bool { return multi_line_; }
// Returns true if the string has a valid terminator.
auto is_terminated() const -> bool { return is_terminated_; }
private:
enum MultiLineKind : int8_t {
NotMultiLine,
MultiLine,
MultiLineWithDoubleQuotes
};
struct Introducer;
explicit StringLiteral(llvm::StringRef text, llvm::StringRef content,
bool content_needs_validation, int hash_level,
MultiLineKind multi_line, bool is_terminated)
: text_(text),
content_(content),
content_needs_validation_(content_needs_validation),
hash_level_(hash_level),
multi_line_(multi_line),
is_terminated_(is_terminated) {}
// The complete text of the string literal.
llvm::StringRef text_;
// The content of the literal. For a multi-line literal, this begins
// immediately after the newline following the file type indicator, and ends
// at the start of the closing `"""`. Leading whitespace is not removed from
// either end.
llvm::StringRef content_;
// Whether content needs validation, in particular due to either an escape
// (which needs modifications) or a tab character (which may cause a warning).
bool content_needs_validation_;
// The number of `#`s preceding the opening `"` or `"""`.
int hash_level_;
// Whether this was a multi-line string literal.
MultiLineKind multi_line_;
// Whether the literal is valid, or should only be used for errors.
bool is_terminated_;
};
} // namespace Carbon::Lex
#endif // CARBON_TOOLCHAIN_LEX_STRING_LITERAL_H_