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      1 //===--- Printable.h - Print function helpers -------------------*- 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 Printable struct.
     11 //
     12 //===----------------------------------------------------------------------===//
     13 
     14 #ifndef LLVM_SUPPORT_PRINTABLE_H
     15 #define LLVM_SUPPORT_PRINTABLE_H
     16 
     17 #include <functional>
     18 
     19 namespace llvm {
     20 
     21 class raw_ostream;
     22 
     23 /// Simple wrapper around std::function<void(raw_ostream&)>.
     24 /// This class is usefull to construct print helpers for raw_ostream.
     25 ///
     26 /// Example:
     27 ///     Printable PrintRegister(unsigned Register) {
     28 ///       return Printable([Register](raw_ostream &OS) {
     29 ///         OS << getRegisterName(Register);
     30 ///       }
     31 ///     }
     32 ///     ... OS << PrintRegister(Register); ...
     33 ///
     34 /// Implementation note: Ideally this would just be a typedef, but doing so
     35 /// leads to operator << being ambiguous as function has matching constructors
     36 /// in some STL versions. I have seen the problem on gcc 4.6 libstdc++ and
     37 /// microsoft STL.
     38 class Printable {
     39 public:
     40   std::function<void(raw_ostream &OS)> Print;
     41   Printable(const std::function<void(raw_ostream &OS)> Print)
     42     : Print(Print) {}
     43 };
     44 
     45 static inline raw_ostream &operator<<(raw_ostream &OS, const Printable &P) {
     46   P.Print(OS);
     47   return OS;
     48 }
     49 
     50 }
     51 
     52 #endif
     53