clang  10.0.0svn
TokenConcatenation.h
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1 //===--- TokenConcatenation.h - Token Concatenation Avoidance ---*- C++ -*-===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 // This file defines the TokenConcatenation class.
10 //
11 //===----------------------------------------------------------------------===//
12 
13 #ifndef LLVM_CLANG_LEX_TOKENCONCATENATION_H
14 #define LLVM_CLANG_LEX_TOKENCONCATENATION_H
15 
16 #include "clang/Basic/TokenKinds.h"
17 
18 namespace clang {
19  class Preprocessor;
20  class Token;
21 
22  /// TokenConcatenation class, which answers the question of
23  /// "Is it safe to emit two tokens without a whitespace between them, or
24  /// would that cause implicit concatenation of the tokens?"
25  ///
26  /// For example, it emitting two identifiers "foo" and "bar" next to each
27  /// other would cause the lexer to produce one "foobar" token. Emitting "1"
28  /// and ")" next to each other is safe.
29  ///
31  const Preprocessor &PP;
32 
33  enum AvoidConcatInfo {
34  /// By default, a token never needs to avoid concatenation. Most tokens
35  /// (e.g. ',', ')', etc) don't cause a problem when concatenated.
36  aci_never_avoid_concat = 0,
37 
38  /// aci_custom_firstchar - AvoidConcat contains custom code to handle this
39  /// token's requirements, and it needs to know the first character of the
40  /// token.
41  aci_custom_firstchar = 1,
42 
43  /// aci_custom - AvoidConcat contains custom code to handle this token's
44  /// requirements, but it doesn't need to know the first character of the
45  /// token.
46  aci_custom = 2,
47 
48  /// aci_avoid_equal - Many tokens cannot be safely followed by an '='
49  /// character. For example, "<<" turns into "<<=" when followed by an =.
50  aci_avoid_equal = 4
51  };
52 
53  /// TokenInfo - This array contains information for each token on what
54  /// action to take when avoiding concatenation of tokens in the AvoidConcat
55  /// method.
56  char TokenInfo[tok::NUM_TOKENS];
57  public:
59 
60  bool AvoidConcat(const Token &PrevPrevTok,
61  const Token &PrevTok,
62  const Token &Tok) const;
63 
64  private:
65  /// IsIdentifierStringPrefix - Return true if the spelling of the token
66  /// is literally 'L', 'u', 'U', or 'u8'.
67  bool IsIdentifierStringPrefix(const Token &Tok) const;
68  };
69  } // end clang namespace
70 
71 #endif
TokenConcatenation class, which answers the question of "Is it safe to emit two tokens without a whit...
TokenConcatenation(const Preprocessor &PP)
Token - This structure provides full information about a lexed token.
Definition: Token.h:34
const FormatToken & Tok
Dataflow Directional Tag Classes.
bool AvoidConcat(const Token &PrevPrevTok, const Token &PrevTok, const Token &Tok) const
AvoidConcat - If printing PrevTok immediately followed by Tok would cause the two individual tokens t...
Defines the clang::TokenKind enum and support functions.
Engages in a tight little dance with the lexer to efficiently preprocess tokens.
Definition: Preprocessor.h:125