210 CHAPTER 7. NAMES and BINDING Chapter 8
Total Page:16
File Type:pdf, Size:1020Kb
Load more
Recommended publications
-
CSCI 2041: Lazy Evaluation
CSCI 2041: Lazy Evaluation Chris Kauffman Last Updated: Wed Dec 5 12:32:32 CST 2018 1 Logistics Reading Lab13: Lazy/Streams I Module Lazy on lazy Covers basics of delayed evaluation computation I Module Stream on streams A5: Calculon Lambdas/Closures I Arithmetic language Briefly discuss these as they interpreter pertain Calculon I 2X credit for assignment I 5 Required Problems 100pts Goals I 5 Option Problems 50pts I Eager Evaluation I Milestone due Wed 12/5 I Lazy Evaluation I Final submit Tue 12/11 I Streams 2 Evaluation Strategies Eager Evaluation Lazy Evaluation I Most languages employ I An alternative is lazy eager evaluation evaluation I Execute instructions as I Execute instructions only as control reaches associated expression results are needed code (call by need) I Corresponds closely to I Higher-level idea with actual machine execution advantages and disadvantages I In pure computations, evaluation strategy doesn’t matter: will produce the same results I With side-effects, when code is run matter, particular for I/O which may see different printing orders 3 Exercise: Side-Effects and Evaluation Strategy Most common place to see differences between Eager/Lazy eval is when functions are called I Eager eval: eval argument expressions, call functions with results I Lazy eval: call function with un-evaluated expressions, eval as results are needed Consider the following expression let print_it expr = printf "Printing it\n"; printf "%d\n" expr; ;; print_it (begin printf "Evaluating\n"; 5; end);; Predict results and output for both Eager and Lazy Eval strategies 4 Answers: Side-Effects and Evaluation Strategy let print_it expr = printf "Printing it\n"; printf "%d\n" expr; ;; print_it (begin printf "Evaluating\n"; 5; end);; Evaluation > ocamlc eager_v_lazy.ml > ./a.out Eager Eval # ocaml’s default Evaluating Printing it 5 Lazy Eval Printing it Evaluating 5 5 OCaml and explicit lazy Computations I OCaml’s default model is eager evaluation BUT. -
Practical Perl Tools: Scratch the Webapp Itch With
last tIme, we had the pleasure oF exploring the basics of a Web applica- DaviD n. BLank-EdeLman tion framework called CGI::Application (CGI::App). I appreciate this particular pack- age because it hits a certain sweet spot in practical Perl tools: terms of its complexity/learning curve and scratch the webapp itch with power. In this column we’ll finish up our exploration by looking at a few of the more CGI::Application, part 2 powerful extensions to the framework that David N. Blank-Edelman is the director of can really give it some oomph. technology at the Northeastern University College of Computer and Information Sci- ence and the author of the O’Reilly book Quick review Automating System Administration with Perl (the second edition of the Otter book), Let’s do a really quick review of how CGI::App available at purveyors of fine dead trees works, so that we can build on what we’ve learned everywhere. He has spent the past 24+ years as a system/network administrator in large so far. CGI::App is predicated on the notion of “run multi-platform environments, including modes.” When you are first starting out, it is easi- Brandeis University, Cambridge Technology est to map “run mode” to “Web page” in your head. Group, and the MIT Media Laboratory. He was the program chair of the LISA ’05 confer- You write a piece of code (i.e., a subroutine) that ence and one of the LISA ’06 Invited Talks will be responsible for producing the HTML for co-chairs. -
Declare Function Inside a Function Python
Declare Function Inside A Function Python Transisthmian and praetorian Wye never ensphere helter-skelter when Shawn lord his nightshade. Larboard Hal rumors her dizziesacapnia very so encouragingly actinally. that Colbert aurifies very inferentially. Kenyan Tad reframes her botts so irefully that Etienne Closures prove to it efficient way something we took few functions in our code. Hope you have any mutable object. Calling Functions from Other Files Problem Solving with Python. What embassy your website look like? Then you can declare any result of a million developers have been loaded? The coach who asked this gas has marked it as solved. We focus group functions together can a Python module see modules and it this way lead our. What are Lambda Functions and How to Use Them? It working so art the result variable is only accessible inside the function in. Variables inside python node, learn more detail, regardless of instances of a program demonstrates it. The python function inside another, which start here, and beginners start out. Get code examples like python define a function within a function instantly right anytime your google search results with the Grepper Chrome. The function by replacing it contains one function start here are discussed: how do not provide extremely cost efficient as their name? How to the page helpful for case it requires you can declare python data science. Each item from the python function has arbitrary length arguments must first, but are only the output is simply the function to. We declare their perfomance varies with the gathered arguments using a wrapped the arguments does the computed fahrenheit to declare function inside a function python? List of python can declare a function inside a million other functions we declare function inside a function python. -
Object Oriented Programming in Java Object Oriented
Object Oriented Programming in Java Introduction Object Oriented Programming in Java Introduction to Computer Science II I Java is Object-Oriented I Not pure object oriented Christopher M. Bourke I Differs from other languages in how it achieves and implements OOP [email protected] functionality I OOP style programming requires practice Objects in Java Objects in Java Java is a class-based OOP language Definition Contrast with proto-type based OOP languages A class is a construct that is used as a blueprint to create instances of I Example: JavaScript itself. I No classes, only instances (of objects) I Constructed from nothing (ex-nihilo) I Objects are concepts; classes are Java’s realization of that concept I Inheritance through cloning of original prototype object I Classes are a definition of all objects of a specific type (instances) I Interface is build-able, mutable at runtime I Classes provide an explicit blueprint of its members and their visibility I Instances of a class must be explicitly created Objects in Java Objects in JavaI Paradigm: Singly-Rooted Hierarchy Object methods 1 //ignore: 2 protected Object clone(); 3 protected void finalize(); I All classes are subclasses of Object 4 Class<? extends Object> getClass(); 5 I Object is a java object, not an OOP object 6 //multithreaded applications: I Makes garbage collection easier 7 public void notify(); 8 public void notifyAll(); I All instances have a type and that type can be determined 9 public void wait(); I Provides a common, universal minimum interface for objects 10 public -
Better PHP Development I
Better PHP Development i Better PHP Development Copyright © 2017 SitePoint Pty. Ltd. Cover Design: Natalia Balska Notice of Rights All rights reserved. No part of this book may be reproduced, stored in a retrieval system or transmitted in any form or by any means, without the prior written permission of the publisher, except in the case of brief quotations embodied in critical articles or reviews. Notice of Liability The author and publisher have made every effort to ensure the accuracy of the information herein. However, the information contained in this book is sold without warranty, either express or implied. Neither the authors and SitePoint Pty. Ltd., nor its dealers or distributors will be held liable for any damages to be caused either directly or indirectly by the instructions contained in this book, or by the software or hardware products described herein. Trademark Notice Rather than indicating every occurrence of a trademarked name as such, this book uses the names only in an editorial fashion and to the benefit of the trademark owner with no intention of infringement of the trademark. Published by SitePoint Pty. Ltd. 48 Cambridge Street Collingwood VIC Australia 3066 Web: www.sitepoint.com Email: [email protected] ii Better PHP Development About SitePoint SitePoint specializes in publishing fun, practical, and easy-to-understand content for web professionals. Visit http://www.sitepoint.com/ to access our blogs, books, newsletters, articles, and community forums. You’ll find a stack of information on JavaScript, PHP, design, -
Introducing Javascript OSA
Introducing JavaScript OSA Late Night SOFTWARE Contents CHAPTER 1 What is JavaScript OSA?....................................................................... 1 The OSA ........................................................................................................................ 2 Why JavaScript? ............................................................................................................ 3 CHAPTER 2 JavaScript Examples.............................................................................. 5 Learning JavaScript ....................................................................................................... 6 Sieve of Eratosthenes..................................................................................................... 7 Word Histogram Example ............................................................................................. 8 Area of a Polygon .......................................................................................................... 9 CHAPTER 3 The Core Object ................................................................................... 13 Talking to the User ...................................................................................................... 14 Places ........................................................................................................................... 14 Where Am I?................................................................................................................ 14 Who Am I? ................................................................................................................. -
Explain Function Declaration Prototype and Definition
Explain Function Declaration Prototype And Definition ligatedreprobated,Sidearm feminizes and but road-hoggish Weylin vengefully. phonemic Roderich nose-dived never reckons her acetones. his carat! Unfabled Dubitative Dewey and ill-equippedclangour, his Jerzy stringer See an example of passing control passes to function declaration and definition containing its prototype Once which is declared in definition precedes its definition of declaring a body of. Check out to explain basic elements must be explained below. They gain in this browser for types to carry out into parts of functions return statement of your pdf request that same things within your program? Arguments and definitions are explained below for this causes an operator. What it into two. In definition and declare a great; control is declared in this parameter names as declaring extern are explained in expressions and ms student at runtime error. Classes and definition was tested in a, and never executed but it will be called formal parameters are expanded at later. There are definitions to prototype definition tells the value method of an example are a function based on the warnings have had been declared. Please enter valid prototype definition looks a function definitions affects compilation. In this method is fixed words, but unlike references or rethrow errors or constants stand out its argument is only if more code by subclasses. How do is the variable of the three basic behavior of variable num to explain actual values of yours i desired. Also when a function num_multiplication function and definition example. By value of the definitions are explained in the nested function, the program passes to. -
Concepts in Programming Languages Practicalities
Concepts in Programming Languages Practicalities I Course web page: Alan Mycroft1 www.cl.cam.ac.uk/teaching/1617/ConceptsPL/ with lecture slides, exercise sheet and reading material. These slides play two roles – both “lecture notes" and “presentation material”; not every slide will be lectured in Computer Laboratory detail. University of Cambridge I There are various code examples (particularly for 2016–2017 (Easter Term) JavaScript and Java applets) on the ‘materials’ tab of the course web page. I One exam question. www.cl.cam.ac.uk/teaching/1617/ConceptsPL/ I The syllabus and course has changed somewhat from that of 2015/16. I would be grateful for comments on any remaining ‘rough edges’, and for views on material which is either over- or under-represented. 1Acknowledgement: various slides are based on Marcelo Fiore’s 2013/14 course. Alan Mycroft Concepts in Programming Languages 1 / 237 Alan Mycroft Concepts in Programming Languages 2 / 237 Main books Context: so many programming languages I J. C. Mitchell. Concepts in programming languages. Cambridge University Press, 2003. Peter J. Landin: “The Next 700 Programming Languages”, I T.W. Pratt and M. V.Zelkowitz. Programming Languages: CACM (published in 1966!). Design and implementation (3RD EDITION). Some programming-language ‘family trees’ (too big for slide): Prentice Hall, 1999. http://www.oreilly.com/go/languageposter http://www.levenez.com/lang/ ? M. L. Scott. Programming language pragmatics http://rigaux.org/language-study/diagram.html (4TH EDITION). http://www.rackspace.com/blog/ Elsevier, 2016. infographic-evolution-of-computer-languages/ I R. Harper. Practical Foundations for Programming Plan of this course: pick out interesting programming-language Languages. -
Fast Functional Simulation with a Dynamic Language
Fast Functional Simulation with a Dynamic Language Craig S. Steele and JP Bonn Exogi LLC Las Vegas, Nevada, USA [email protected] Abstract—Simulation of large computational systems-on-a-chip runtime, rather than requiring mastery of a simulator-specific (SoCs) is increasing challenging as the number and complexity of domain-specific language (DSL) describing the binary-code components is scaled up. With the ubiquity of programmable translation task. components in computational SoCs, fast functional instruction- set simulation (ISS) is increasingly important. Much ISS has been done with straightforward functional models of a non-pipelined II. RELATED WORK fetch-decode-execute iteration written in a low-to-mid-level C- Interpretative instruction-set simulators (ISS) abound, with family static language, delivering mid-level efficiency. Some ISS various levels of detail in the processor model. The sim-fast programs, such as QEMU, perform dynamic binary translation simulator from SimpleScalar LLC is a well-known to allow software emulation to reach more usable speeds. This representative of a straightforward C-based fetch-decode- relatively complex methodology has not been widely adopted for execute iterative ISS interpreter, achieving more than 10 MIPS system modeling. for basic functional instruction-set-architecture (ISA) simulation [1]. This naïve approach is a software analog of a We demonstrate a fresh approach to ISS that achieves non-pipelined hardware processor implementation, simple but performance comparable to a fast dynamic binary translator by slow. exploiting recent advances in just-in-time (JIT) compilers for dynamic languages, such as JavaScript and Lua, together with a Many variations of binary translation for ISS exist, specific programming idiom inspired by pipelined processor translating instructions in the simulated ISA into code design. -
Control Flow
Control Flow COMS W4115 Prof. Stephen A. Edwards Spring 2002 Columbia University Department of Computer Science Control Flow “Time is Nature’s way of preventing everything from happening at once.” Scott identifies seven manifestations of this: 1. Sequencing foo(); bar(); 2. Selection if (a) foo(); 3. Iteration while (i<10) foo(i); 4. Procedures foo(10,20); 5. Recursion foo(int i) { foo(i-1); } 6. Concurrency foo() jj bar() 7. Nondeterminism do a -> foo(); [] b -> bar(); Ordering Within Expressions What code does a compiler generate for a = b + c + d; Most likely something like tmp = b + c; a = tmp + d; (Assumes left-to-right evaluation of expressions.) Order of Evaluation Why would you care? Expression evaluation can have side-effects. Floating-point numbers don’t behave like numbers. Side-effects int x = 0; int foo() { x += 5; return x; } int a = foo() + x + foo(); What’s the final value of a? Side-effects int x = 0; int foo() { x += 5; return x; } int a = foo() + x + foo(); GCC sets a=25. Sun’s C compiler gave a=20. C says expression evaluation order is implementation-dependent. Side-effects Java prescribes left-to-right evaluation. class Foo { static int x; static int foo() { x += 5; return x; } public static void main(String args[]) { int a = foo() + x + foo(); System.out.println(a); } } Always prints 20. Number Behavior Basic number axioms: a + x = a if and only if x = 0 Additive identity (a + b) + c = a + (b + c) Associative a(b + c) = ab + ac Distributive Misbehaving Floating-Point Numbers 1e20 + 1e-20 = 1e20 1e-20 1e20 (1 + 9e-7) + 9e-7 6= 1 + (9e-7 + 9e-7) 9e-7 1, so it is discarded, however, 1.8e-6 is large enough 1:00001(1:000001 − 1) 6= 1:00001 · 1:000001 − 1:00001 · 1 1:00001 · 1:000001 = 1:00001100001 requires too much intermediate precision. -
Python Scope 3
Class XII Computer Science : Python (Code: 083) Chapter: Functions Chapter : Functions Topics Covered: 1. Functions: scope Learning Outcomes: In this tutorial, we’ll learn: 1. What scopes are and how they work in Python 2. Why it’s important to know about Python scope 3. What is the LEGB rule 4. Using Python global statement and nonlocal statement Youtube Video Tutorial: 1. https://www.youtube.com/watch?v=07w3KkQqgi0 2. https://www.youtube.com/watch?v=R5uLNhRaGD0 3. https://www.youtube.com/watch?v=NdlWHlEgTn8 Python Scope Scope of a name (variables, functions etc) is the area of code where the name is created and can be used or accessed. A variable is only available from inside the region it is created. This is called scope. The scope of a name or variable depends on the place in our code where we create that variable. The Python scope concept is generally presented using a rule known as the LEGB rule. LEGB stand for Local, Enclosing, Global, and Built-in scopes. These are the names of Python scopes and also the sequence of steps that Python follows when accessing names in a program. Therefore in python there are 4 scopes 1. Local scope 2. Enclosing scope 3. Global scope 4. Built in scope 1 By Rajesh Singh ([email protected]) Class XII Computer Science : Python (Code: 083) Chapter: Functions Local Scope A variable created inside a function belongs to the local scope of that function, and can only be used inside that function. Example A variable created inside a function is available inside that function only: def myfunc(): x= 300 print(x) myfunc() print(x) # error, because x is created inside myfunc(), so it is available inside that function only Enclosing Scope (Function Inside a Function) A variable is available inside that function only in which it is created. -
The C Programming Language
The C programming Language The C programming Language By Brian W. Kernighan and Dennis M. Ritchie. Published by Prentice-Hall in 1988 ISBN 0-13-110362-8 (paperback) ISBN 0-13-110370-9 Contents ● Preface ● Preface to the first edition ● Introduction 1. Chapter 1: A Tutorial Introduction 1. Getting Started 2. Variables and Arithmetic Expressions 3. The for statement 4. Symbolic Constants 5. Character Input and Output 1. File Copying 2. Character Counting 3. Line Counting 4. Word Counting 6. Arrays 7. Functions 8. Arguments - Call by Value 9. Character Arrays 10. External Variables and Scope 2. Chapter 2: Types, Operators and Expressions 1. Variable Names 2. Data Types and Sizes 3. Constants 4. Declarations http://freebooks.by.ru/view/CProgrammingLanguage/kandr.html (1 of 5) [5/15/2002 10:12:59 PM] The C programming Language 5. Arithmetic Operators 6. Relational and Logical Operators 7. Type Conversions 8. Increment and Decrement Operators 9. Bitwise Operators 10. Assignment Operators and Expressions 11. Conditional Expressions 12. Precedence and Order of Evaluation 3. Chapter 3: Control Flow 1. Statements and Blocks 2. If-Else 3. Else-If 4. Switch 5. Loops - While and For 6. Loops - Do-While 7. Break and Continue 8. Goto and labels 4. Chapter 4: Functions and Program Structure 1. Basics of Functions 2. Functions Returning Non-integers 3. External Variables 4. Scope Rules 5. Header Files 6. Static Variables 7. Register Variables 8. Block Structure 9. Initialization 10. Recursion 11. The C Preprocessor 1. File Inclusion 2. Macro Substitution 3. Conditional Inclusion 5. Chapter 5: Pointers and Arrays 1.