clang  6.0.0svn
TokenConcatenation.h
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1 //===--- TokenConcatenation.h - Token Concatenation Avoidance ---*- C++ -*-===//
2 //
3 // The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 // This file defines the TokenConcatenation class.
11 //
12 //===----------------------------------------------------------------------===//
13 
14 #ifndef LLVM_CLANG_LEX_TOKENCONCATENATION_H
15 #define LLVM_CLANG_LEX_TOKENCONCATENATION_H
16 
17 #include "clang/Basic/TokenKinds.h"
18 
19 namespace clang {
20  class Preprocessor;
21  class Token;
22 
23  /// TokenConcatenation class, which answers the question of
24  /// "Is it safe to emit two tokens without a whitespace between them, or
25  /// would that cause implicit concatenation of the tokens?"
26  ///
27  /// For example, it emitting two identifiers "foo" and "bar" next to each
28  /// other would cause the lexer to produce one "foobar" token. Emitting "1"
29  /// and ")" next to each other is safe.
30  ///
32  Preprocessor &PP;
33 
34  enum AvoidConcatInfo {
35  /// By default, a token never needs to avoid concatenation. Most tokens
36  /// (e.g. ',', ')', etc) don't cause a problem when concatenated.
37  aci_never_avoid_concat = 0,
38 
39  /// aci_custom_firstchar - AvoidConcat contains custom code to handle this
40  /// token's requirements, and it needs to know the first character of the
41  /// token.
42  aci_custom_firstchar = 1,
43 
44  /// aci_custom - AvoidConcat contains custom code to handle this token's
45  /// requirements, but it doesn't need to know the first character of the
46  /// token.
47  aci_custom = 2,
48 
49  /// aci_avoid_equal - Many tokens cannot be safely followed by an '='
50  /// character. For example, "<<" turns into "<<=" when followed by an =.
51  aci_avoid_equal = 4
52  };
53 
54  /// TokenInfo - This array contains information for each token on what
55  /// action to take when avoiding concatenation of tokens in the AvoidConcat
56  /// method.
57  char TokenInfo[tok::NUM_TOKENS];
58  public:
60 
61  bool AvoidConcat(const Token &PrevPrevTok,
62  const Token &PrevTok,
63  const Token &Tok) const;
64 
65  private:
66  /// IsIdentifierStringPrefix - Return true if the spelling of the token
67  /// is literally 'L', 'u', 'U', or 'u8'.
68  bool IsIdentifierStringPrefix(const Token &Tok) const;
69  };
70  } // end clang namespace
71 
72 #endif
TokenConcatenation class, which answers the question of "Is it safe to emit two tokens without a whit...
Token - This structure provides full information about a lexed token.
Definition: Token.h:35
const FormatToken & Tok
TokenConcatenation(Preprocessor &PP)
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:127