Think of string_view as a non-owning pointer to a known-size array. If the array is moved or destroyed, then string_view is left dangling... just like a pointer.
something similar was initiated by herb-sutter as well in his 'guru of the week' (gotw) columns. which then became books in their own right aka 'exceptional c++' series.
Tip #1 appears on the surface to be about C++17's std::string_view, but many shops had something similar to string_view for a decade or more before C++ made it official. The tips are not presented in their original form; edits have been made (as per the linked page). I think Google had something like string_view by 2009 at the latest, using C++03 compilers.
> Yes. It is a small step from the well-worn convention to pass each char* around with its length.
kind of surprising to note that implicit 'string_view' conversions are now regarded as a good thing?
on a side note, the language is _complicated_, and shows no signs of stopping ! 3 articles on move/copy ctor's and only one that applies to programming in general.
And they also claim string_views can be constructed from a std::string. That's true of their implementation and it's true of the TS string_view but it was removed from the c++17 string_view.
Both series have been created over many years, so I'm not sure which one is more modern. Herb Sutter says that all GotW articles are being revised to reflect changes in C++14.
Herb Sutter's recent tips are more modern (and the backlog is being updated).
Scott Meyers' Effective Modern C++ is a great successor to his Effective C++ book which spawned the whole "Effective *" snowclone books and covers C++14, though not 17, of course.
Actually, this blog post's content looks like a watered-down version of a tip from either or both of the above authors, though I'm too lazy to chase down a verification.
No amount of 'tips' can save this language now. C++ never had a clear goal. The features of C++ were added almost at random. Stroustrup's original idea was essentially "C is cool and OOP is cool so let's bolt OOP onto C". Retrospectively, OOP was massively overhyped and is the wrong tool for the job for most of the people most of the time. Half of the GoF design patterns just emulate idioms from functional programming. Real OOP languages like Smalltalk and IO express many useful things that C++ cannot. The feature that C needed most was perhaps parametric polymorphism (aka generics in Java and C#, first seen in ML in the late 1970s) but instead of that C++ got templates that weren't designed to solve any particular problem but rather to kind of solve several completely unrelated problems (e.g. generics and metaprogramming). Someone actually discovered by accident that C++ templates are Turing complete and they wrote and published a program that computed prime numbers at compile time. Wow. A remarkable observation that led to decades of template abuse where people used templates to solve problems much better solved by other pre-existing solutions such Lisp macros and ML polymorphism. Worse, this abuse led to even more language features being piled on top, like template partial specialization.
The massive incidental complexity in C++ made it almost impossible to write a working compiler. For example, it remains extremely difficult to write a parser for the C++ language. The syntax also has horrible aspects like List<Set<int>> being interpreted as logical shift right. None of the original C++ compilers were reliable. Only after two decades did we start to see solid C++ compilers (by which time C++ was in decline in industry due to Java and C#).
C++ is said to be fast but the reality is that C++ is essentially only fast when you write C-like code and even then it is only fast for certain kinds of programs. Due to the "you don't pay for what you don't use" attitude, C++ is generally inefficient. RAII injects lots of unnecessary function calls at the end of scope, sometimes even expensive virtual calls. These calls often require data that would otherwise be dead so the data are kept alive, increasing register pressure and spilling and decreasing performance. The C++ exception mechanism is very inefficient (~6x slower than OCaml) because it unwinds the stack frame by frame calling destructors rather than long jumping. Allocation with new and delete is slow compared to a modern garbage collector so people are encouraged to use STL collections but these pre-allocate huge blocks of memory in comparison so you've lost the memory-efficiency of C and then you are advised to write your own STL allocator which is no better than using C in the first place. One of the main long-standing advantages of C over modern languages is the unpredictable latency incurred by garbage collectors. C++ offers the worst of both worlds by not having a garbage collector (making it impossible to leverage useful concepts like purely functional data structures properly) but it encourages all destructors to avalanche so you get unbounded pause times (worse than any production GC). Although templates are abused for metaprogramming they are very poor at it and C++ has no real support for metaprogramming. For example, you cannot write an efficient portable regular expression library in C++ because there is no way to do run-time code generation and compilation as you can in Java, C# and languages dating back to Lisp (1960). So while Java and C# have had regular expressions in their standard libraries for well over 10 years, C++ only just got them and they are slow.
C++ is so complicated that even world experts make rookie mistakes with it. Herb Sutter works for Microsoft and sits on the C++ standards committee where he influences the future of C++. In a lecture he gave his favorite 10-line C++ program, a thread-safe object cache.
My personal feeling is that the new Rust programming language is what C++ should have been. It has useful known features like generics, discriminated unions and pattern matching and useful new features like memory safety without garbage collection.
> We’ve decided to expose most of these tips to the Abseil development community, and the C++ community at large. Over the coming months, we’ll be posting new tips as we review and refine them for publication. Not all the entries we’ve written are relevant to the outside world; some were specific to our internal tools and abstractions, and some have become obsolete as the language has changed.
> Consisting of the foundational C++ and Python code at Google, Abseil includes libraries that will grow to underpin other Google-backed open source projects like gRPC, Protobuf and TensorFlow.
This library already seems like it is suffering from scope-creep. Tensorflow, gRPC, and Protobuf are hardly related to improving the C++ standard. Why are these even in the same library at all?
Published every weekday!
https://g.co/kgs/Gyvg69
https://docs.quantifiedcode.com/python-anti-patterns
Hopefully whatever stopped the project has been resolved and they’ll be consistent now.
Edit: the indexing is explained in a note on the site.
are these tips more 'modernish' ?
kind of surprising to note that implicit 'string_view' conversions are now regarded as a good thing?
on a side note, the language is _complicated_, and shows no signs of stopping ! 3 articles on move/copy ctor's and only one that applies to programming in general.
https://github.com/boostorg/utility/blob/develop/include/boo...
This proposal references Google and LLVM implementations:
http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2012/n344...
Looks like the LLVM implementation goes back to at least 2009:
https://github.com/llvm-mirror/llvm/blob/master/include/llvm...
Yeah, StringPiece
http://google.github.io/google-api-cpp-client/latest/doxygen...
Scott Meyers' Effective Modern C++ is a great successor to his Effective C++ book which spawned the whole "Effective *" snowclone books and covers C++14, though not 17, of course.
Actually, this blog post's content looks like a watered-down version of a tip from either or both of the above authors, though I'm too lazy to chase down a verification.
The massive incidental complexity in C++ made it almost impossible to write a working compiler. For example, it remains extremely difficult to write a parser for the C++ language. The syntax also has horrible aspects like List<Set<int>> being interpreted as logical shift right. None of the original C++ compilers were reliable. Only after two decades did we start to see solid C++ compilers (by which time C++ was in decline in industry due to Java and C#).
C++ is said to be fast but the reality is that C++ is essentially only fast when you write C-like code and even then it is only fast for certain kinds of programs. Due to the "you don't pay for what you don't use" attitude, C++ is generally inefficient. RAII injects lots of unnecessary function calls at the end of scope, sometimes even expensive virtual calls. These calls often require data that would otherwise be dead so the data are kept alive, increasing register pressure and spilling and decreasing performance. The C++ exception mechanism is very inefficient (~6x slower than OCaml) because it unwinds the stack frame by frame calling destructors rather than long jumping. Allocation with new and delete is slow compared to a modern garbage collector so people are encouraged to use STL collections but these pre-allocate huge blocks of memory in comparison so you've lost the memory-efficiency of C and then you are advised to write your own STL allocator which is no better than using C in the first place. One of the main long-standing advantages of C over modern languages is the unpredictable latency incurred by garbage collectors. C++ offers the worst of both worlds by not having a garbage collector (making it impossible to leverage useful concepts like purely functional data structures properly) but it encourages all destructors to avalanche so you get unbounded pause times (worse than any production GC). Although templates are abused for metaprogramming they are very poor at it and C++ has no real support for metaprogramming. For example, you cannot write an efficient portable regular expression library in C++ because there is no way to do run-time code generation and compilation as you can in Java, C# and languages dating back to Lisp (1960). So while Java and C# have had regular expressions in their standard libraries for well over 10 years, C++ only just got them and they are slow.
C++ is so complicated that even world experts make rookie mistakes with it. Herb Sutter works for Microsoft and sits on the C++ standards committee where he influences the future of C++. In a lecture he gave his favorite 10-line C++ program, a thread-safe object cache.
My personal feeling is that the new Rust programming language is what C++ should have been. It has useful known features like generics, discriminated unions and pattern matching and useful new features like memory safety without garbage collection.
> Consisting of the foundational C++ and Python code at Google, Abseil includes libraries that will grow to underpin other Google-backed open source projects like gRPC, Protobuf and TensorFlow.
This library already seems like it is suffering from scope-creep. Tensorflow, gRPC, and Protobuf are hardly related to improving the C++ standard. Why are these even in the same library at all?