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

. . . . . . . . . . . . . . . . . . . . . . . . . 12 3 Basic Programming 15 3.1 Evaluating Expressions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 3.2 Recursive Tactic Monad . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 5.2 Names and Expressions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34 5.3 Examples formal axiomatic framework in which one can define mathematical objects and reason about them. But expressions in Lean have a computational interpretation, which is to say, they can be evaluated. Any closed

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 3 Expressions 15 3.1 Errors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 3.9 Unit Expressions and Parenthesized Expressions . . . . . . . . . . . . . . . . . . . . . . . . 21 3.10 Arithmetic Sequences . . . . . . . . . . . . . . 21 3.12 Let Expressions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 3.13 Case Expressions . . . . . . . . . . . . . . . . . . . .

array constructor . . . . . . . . . . . . . . . . . . . . . . . . . . . 48 Dynamic array constant expressions . . . . . . . . . . . . . . . . . . . . . . 49 Packing and unpacking an array . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61 3.7.2 Variants in assignments and expressions . . . . . . . . . . . . . . . . . . . . 62 3.7.3 Variants and interfaces . . . . . . . . . . 10Enumeration in Objective-C classes . . . . . . . . . . . . . . . . . . . . . . . . . . 167 12 Expressions 169 12.1 Expression syntax . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69 4.1. Expressions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.1.3. Conditional Expressions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80 4.1.4. NULL in Expressions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 311 6.1.16. Common Table Expressions (“WITH … AS … SELECT”) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 312 6.2. INSERT

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50 4.1. Expressions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.1.3. Conditional Expressions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57 4.1.4. NULL in Expressions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 230 6.1.14. Common Table Expressions (“WITH … AS … SELECT”) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 231 6.2. INSERT

the language level. For example Jinja2 treats the non- breaking space as valid whitespace inside expressions which requires knowledge of the encoding or operating on an Unicode string. For more details about depending on if autoescaping is active or not. volatile True if the compiler cannot evaluate some expressions at compile time. At runtime this should always be False. 2.16 Custom Tests Tests work like filters even if you are not intercepting the call. Jinja2 might internally call the method to evaluate expressions. 43 44 CHAPTER 4 Native Python Types The default Environment renders templates to strings

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 130 8.8 Match Expressions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 131 8 procedures and decision procedures for specific languages and domains, such as linear or nonlinear expressions over the integers or the real numbers. Architectures like SMT (“satisfiability modulo theories”) example, we will discuss term rewriting, and Lean’s automated methods for simplifying terms and expressions automati- cally. Similarly, we will discuss methods of elaboration and type inference, which can

1960-01-15 # Herb 1950-05-05 # Grandma L. 1935-03-01 Combining filter expressions Peewee supports arbitrarily-nested expressions. Let’s get all the people whose birthday was either: • before 1940 (grandma) when an object is not found in the database. def get_object_or_404(model, *expressions): try: return model.get(*expressions) except model.DoesNotExist: abort(404) Note: To avoid having to frequently Contents: peewee Documentation, Release 3.6.0 We can also use the flags on the Post class to build expressions in queries: # Generates a WHERE clause that looks like: # WHERE (post.flags & 1 != 0) favorites