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//===--- TokenConcatenation.h - Token Concatenation Avoidance ---*- C++ -*-===//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
// This file defines the TokenConcatenation class.
#include "clang/Basic/TokenKinds.h"
namespace clang {
class Preprocessor;
class Token;
/// TokenConcatenation class, which answers the question of
/// "Is it safe to emit two tokens without a whitespace between them, or
/// would that cause implicit concatenation of the tokens?"
/// For example, it emitting two identifiers "foo" and "bar" next to each
/// other would cause the lexer to produce one "foobar" token. Emitting "1"
/// and ")" next to each other is safe.
class TokenConcatenation {
const Preprocessor &PP;
enum AvoidConcatInfo {
/// By default, a token never needs to avoid concatenation. Most tokens
/// (e.g. ',', ')', etc) don't cause a problem when concatenated.
aci_never_avoid_concat = 0,
/// aci_custom_firstchar - AvoidConcat contains custom code to handle this
/// token's requirements, and it needs to know the first character of the
/// token.
aci_custom_firstchar = 1,
/// aci_custom - AvoidConcat contains custom code to handle this token's
/// requirements, but it doesn't need to know the first character of the
/// token.
aci_custom = 2,
/// aci_avoid_equal - Many tokens cannot be safely followed by an '='
/// character. For example, "<<" turns into "<<=" when followed by an =.
aci_avoid_equal = 4
/// TokenInfo - This array contains information for each token on what
/// action to take when avoiding concatenation of tokens in the AvoidConcat
/// method.
char TokenInfo[tok::NUM_TOKENS];
TokenConcatenation(const Preprocessor &PP);
bool AvoidConcat(const Token &PrevPrevTok,
const Token &PrevTok,
const Token &Tok) const;
/// IsIdentifierStringPrefix - Return true if the spelling of the token
/// is literally 'L', 'u', 'U', or 'u8'.
bool IsIdentifierStringPrefix(const Token &Tok) const;
} // end clang namespace