Back to Basics Lambda Expressions Barbara Geller & Ansel Sermersheim CppCon September 2020Introduction ● Prologue ● History ● Function Pointer ● Function Object ● Definition of a Lambda Expression slot library ○ CsLibGuarded ■ library for managing access to data shared between threadsLambda Expressions ● History ○ lambda calculus is a branch of mathematics ■ introduced in the 1930’s to prove memory ■ languages which were influenced by lambda calculus ● Haskell, LISP, and ML 5Lambda Expressions ● History ○ why do we use the terminology lambda expression ■ greek letter λ refers to an anonymous

About me 2 6 ways for implementing math expressions calculator, Amir Kirsh Lecturer Academic College of Tel-Aviv-Yaffo and Tel-Aviv University Developer Advocate at Member of the Israeli ISO C++ NB NB Co-Organizer of the CoreCpp conference and meetup group3 6 ways for implementing math expressions calculator, Amir Kirsh Suffering from slow builds? It’s not just waste of time It affects your dev implementing math expressions calculator, Amir KirshSuccess Stories 5 6 ways for implementing math expressions calculator, Amir KirshSuccess Stories 6 6 ways for implementing math expressions calculator, Amir

Object Parameters  if consteval  Multidimensional Subscript Operator  Attributes on Lambda-Expressions  Literal Suffix for size_t  auto(x): decay-copy in The Language  #elifdef, #elifndef, and Object Parameters  if consteval  Multidimensional Subscript Operator  Attributes on Lambda-Expressions  Literal Suffix for size_t  auto(x): decay-copy in The Language  #elifdef, #elifndef, and std::forward(self).m_name; }11 Explicit Object Parameters  Allows for recursive lambda expressions  this in a lambda accesses the object that contains the lambda, not the lambda instance itself

Machine 26 • Implementations must emulate the observable behavior of the abstract machine • Expressions with non-observable side effects may be ignoredCopyright © 2020 Bob Steagall K E W B C O M P Machine 28 • Implementations must emulate the observable behavior of the abstract machine • Expressions with non-observable side effects may be ignoredCopyright © 2020 Bob Steagall K E W B C O M P Machine 30 • Implementations must emulate the observable behavior of the abstract machine • Expressions with non-observable side effects may be ignoredCopyright © 2020 Bob Steagall K E W B C O M P

Variable Names . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 3.2 Assignment expressions and assignment versus mutation . . . . . . . . . . . . . . 9 3.3 Stylistic Conventions . . . Non-Standard String Literals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58 7.9 Regular Expressions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58 7.10 Byte Array Literals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88 9 Control Flow 89 9.1 Compound Expressions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89 9.2 Conditional Evaluation

Variable Names . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 3.2 Assignment expressions and assignment versus mutation . . . . . . . . . . . . . . 9 3.3 Stylistic Conventions . . . Non-Standard String Literals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58 7.9 Regular Expressions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58 7.10 Byte Array Literals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88 9 Control Flow 89 9.1 Compound Expressions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89 9.2 Conditional Evaluation

Variable Names . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 4.2 Assignment expressions and assignment versus mutation . . . . . . . . . . . . . . 12 4.3 Stylistic Conventions . . . Non-Standard String Literals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62 8.9 Regular Expressions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63 8.10 Byte Array Literals . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93 10 Control Flow 94 10.1 Compound Expressions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94 10.2 Conditional Evaluation

Variable Names . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 4.2 Assignment expressions and assignment versus mutation . . . . . . . . . . . . . . 12 4.3 Stylistic Conventions . . . Non-Standard String Literals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62 8.9 Regular Expressions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63 8.10 Byte Array Literals . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93 10 Control Flow 94 10.1 Compound Expressions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94 10.2 Conditional Evaluation

Variable Names . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 4.2 Assignment expressions and assignment versus mutation . . . . . . . . . . . . . . 12 4.3 Stylistic Conventions . . . Non-Standard String Literals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62 8.9 Regular Expressions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63 8.10 Byte Array Literals . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93 10 Control Flow 94 10.1 Compound Expressions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94 10.2 Conditional Evaluation

digits. However, your character class range `a--z` seems to be incorrectly typed. In regular expressions, a single `-` is used to represent a range, so this should be `a-z` instead: So the corrected the code should compile without issues. This kind of messages can help you debug your regular expressions in the future by helping you locate problematic parts of your regular expression. So when you digits. However, your character class range `a--z` seems to be incorrectly typed. In regular expressions, a single `-` is used to represent a range, so this should be `a-z` instead: So the corrected