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 CLANG_LEX_TOKEN_CONCATENATION_H 15 #define CLANG_LEX_TOKEN_CONCATENATION_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 /// 31 class TokenConcatenation { 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: 59 TokenConcatenation(Preprocessor &PP); 60 61 bool AvoidConcat(const Token &PrevPrevTok, 62 const Token &PrevTok, 63 const Token &Tok) const; 64 65 private: 66 /// StartsWithL - Return true if the spelling of this token starts with 'L'. 67 bool StartsWithL(const Token &Tok) const; 68 69 /// IsIdentifierL - Return true if the spelling of this token is literally 70 /// 'L'. 71 bool IsIdentifierL(const Token &Tok) const; 72 }; 73 } // end clang namespace 74 75 #endif 76
