Flashcards
Organization of Programming Languages Chapter 1
Cards in this deck (71)
- 1Reasons for studying concepts of programming LanguagesIncreased ability to express ideas
Improved background for choosing appropriate languages
Increased ability to learn new languages
Better understanding of significance of implementation
Better use of languages that are already known
Overall advancement of computing - 2(Programming Domains) Scientific ApplicationsLarge number of floating point computations; use of arrays
Fortran - 3(Programming Domains) Business applicationsProduce reports, use decimal numbers and characters
COBOL - 4(Programming Domains) Artificial IntelligenceSymbols rather than numbers manipulated; use of linked lists
LISP - 5(Programming Domains) Systems ProgrammingNeed efficiency because of continuous use
C - 6(Programming Domains) Web SoftwareEclectic collection of languages: markup (e.g., HTML), scripting (e.g., PHP), general-purpose (e.g., Java)
- 7Readabilitythe ease with which programs can be read and understood
- 8Writabilitythe ease with which a language can be used to create programs
- 9Reliabilityconformance to specifications (i.e., performs to its specifications)
- 10Costthe ultimate total cost
- 11Evaluation Criteria: Readability Overall simplicitymanageable set of features and constructs
Minimal feature multiplicity
Minimal feature multiplicity
Minimal operator overloading - 12Evaluation Criteria: Readability OrthogonalityA relatively small set of primitive constructs can be combined in a relatively small number of ways
Every possible combination is legal - 13Evaluation Criteria: Readability Data typesAdequate predefined data types
- 14Evaluation Criteria: Readability Syntax ConsiderationsIdentifier forms: flexible composition
Special words and methods of forming compound statements
form and meaning: self-descriptive constructs, meaningful keywords - 15Evaluation Criteria: Writability Simplicity and orthogonalityFew constructs, a small number of primitives, a small set of rules for combining them
- 16Evaluation Criteria: Writability Support for abstractionThe ability to define and use complex structures or operations in ways that allow details to be ignored
- 17Evaluation Criteria: Writability ExpressivityA set of relatively covenient ways of specifying operations
Strength and number of operators and predefined functions - 18Orthogonalitya relatively small set of primitive constructs
a small set of rules for combining them to build the control and data structures of the language
Every possible combination is legal and meaningful
the more orthogonal the design, the fewer the exceptions (hence the simpler the lang)
the meaning of an orthogonal feature is independent of context (eg., a pointer in C)
IBM Mainframe
VAX - 19Evaluation Criteria: Reliability Type checkingtesting for type errors
- 20Evaluation Criteria: Reliability Exception handlingintercept run-time errors and take corrective measures
- 21Evaluation Criteria: Reliability AliasingPresence of two or more distinct referencing methods for the same memory location
- 22Evaluation Criteria: Reliability Readability and Writabilitya language that does not support "natural" ways of expressing an algorithm will require the use of "unnatural" approaches, and hence reduce reliability
- 23Evaluation Criteria: CostTraining programmers to use the language
Writing programs (closeness to particular applications)
Compiling programs
Executing Programs
Language implementation system: availability of free compilers and run times
Reliability: poor reliability leads to high costs
Maintaining programs (Most Cost) - 24PortabilityFeature that made Java popular
the ease with which programs can be moved from one implementation to another
(Compare Java with Swift on portability) - 25GeneralityThe applicability to a wide range of applications
- 26Well-definednessThe completeness and precision of the language's official definition
WORA -> write once, run anywhere - 27Influences on Language Design (Von Neuman)Computer Architecture- Most languages were developed around the this prevalent computer architecture
- 28Influences on language Design (Program Design)New software development methodologies (.eg., object-oriented software development) led to new programming paradigms and by extension, new programming languages
- 29Von NeumanVery well known computer architecture
Imperative languages, most dominant because of Von Neuman computers
Data and programs stored in memory and separated from the CPU
Instuctions and data are piped from memory to CPU - 30Imperative languagesVariables model memory cells
assignment statements model piping
iteration is efficient - 31—Von Neuman Architecture
- 32initialize the program counter repeat forever fetch the instruction pointed by the counter increment the counter decode the instruction execute the instruction end repeatFetch-execute-cycle (On an Von Neumann architecture computer)
- 33Programming Methodologies Influences 1950s and early 1960sSimple applications; worry about machine efficiency
- 34Programming Methodologies Influences Late 1960sPeople efficiency became important: readability, better control structures
structures programming (got rid of "goto" statement)
top-down design and step-wise refinement (Break problem down from abstracted idea) - 35Programming Methodologies Influences Late 1970sProcess-oriented to data-oriented
data abstraction - 36Programming Methodologies Influences Middle 1980sObject-oriented programming
Data abstraction + inheritance + polymorphism
OOP is the most used approach to writing applications - 37Language CategoriesImperative
functional
logic
Markup/programming hybrid - 38Imperative languageCentral features are variables, assignment statements, and iteration
include languages that support object-oriented programming
Include scripting languages
include the visual languages
EX: C, Java, Perl, JavaScript, Visual BASIC, .NET, C++ - 39Functional LanguagesMain means of making computations is by applying functions to given parameters
Ex: LISP, Scheme, ML, F# - 40Logic LanguagesRule-based(rules are specified in no particular order)
Ex: Prolog - 41Markup/Programming hybridMarkup languages extend to support some programming
HTML -> helps you write programming langs
Ex: JSTL, XSLT - 42Reactive ProgrammingBased on observation, "we will do better if we listen to each other"
let each component of the program listen
Model, view, controller - 43Design Trade-Offs Reliability vs. cost of executionEx: java demands all references to array elements be checked for proper indexing, which leads to increased execution costs
- 44Programming Methodologies Influences Readability vs. WritabilityEx: APL provides many powerful operators (and a large number of new symbols), allowing complex computations to be written in compact program but at the cost of poor readability
- 45Writability (flexibility) vs. reliabilityEx: C++ pointers are powerful and very flexible but are unreliable
- 46Implementation MethodsCompilation
Pure Interpretation
Hybrid Implementation Systems - 47Implementation Methods CompilationPrograms are translated into machine language; includes JIT systems
use: Large commercial applications - 48Implementation Methods Pure InterpretationPrograms are interpreted by another program known as an interpreter
use: Small programs or when efficiency is not an issue - 49Implementation Methods Hybrid Implementation SystemsA compromise between compilers and pure interpreters
use: Small and medium systems when efficiency is not the first concern - 50—Layered View of Computer
the operating system and language implementation are layered over machine interface of a computer
- 51CompilationTranslate high-level program(source language) into machine code (machine language)
slow translation, fast execution - 52Compilation processPhases:
lexical analysis
Syntax analysis
Semantics analysis
Code generation - 53Lexical analysis:Compilation phase that converts characters in the source program into lexical units
- 54Syntax analysis phaseCompilation phase that transforms lexical units into parse trees which represent the syntactic structure of programs
- 55Semantic Analysis phaseCompilation phase that generates intermediate code
- 56Code generation phaseCompilation phase where machine code is generated
- 57—Compilation process
- 58Compilation Terms: Load module(executable image): the user and the system code together
- 59Compilation terms: Linking and Loadingthe process of collection system program units and linking them to a user program
- 60Von Neumann Bottleneckthe connection speed between the computer's memory and it's processor determines the speed of the computer
the program instructions often can be executed much faster than the speed of the connection
the primary limiting factor in the speed of computers - 61Pure interpretationNo translation
Easier implementation f programs (run-time errors can easily and immediately be displayed)
slower execution (10 to 100 times slower than compiled programs)
often requires more space
Now rare for traditional high- level languages
Significant comeback with some Web scripting languages (e.g., JavaScript, PHP) - 62—Pure interpretation Process
- 63Hybrid Implementation SystemA compromise between compilers and pure interpreters
a high-level language program is translated to an intermediate language that allows easy interpretation
ex: Perl programs are partially compiled to detect errors before interpretation
ex: initial implementations of java were hybrid; the intermediate form, byte code, provides portability to any machine that has byte code interpreter and a run-time system(together, these are called Java Virtual Machine) - 64Java Virtual Machine vs. Java Run time environmentMore libraries in run time environment
Interpreted as the same - 65—Hybrid implementation Process
- 66Just-in-Time Implementation SystemsInitially translated programs to an intermediate language
then compile the intermediate language of the subprograms int machine code when they are called
Machine code version is kept for subsequent calls
JIT systems are widely used for Java programs
.NET languages are implemented with a JIT system
In essence, JIT systems are delayed compilers - 67PreprocessorsMicro substitution mechanisms
Preprocessors macros (instructions) are commonly used to specify that code from another file is to be included
A preprocessor processes a program immediately before the program immediately expand emmbedded preprocessor macros
A well-known example: C preprocessor
expands #include, #define, and similar macros - 68Programming EnvironmentsA colletion of tools used in software development
Unix
Microsoft Visual Studio.NET
NetBeans - 69Programming Environments Unixan older operating system and tool collection
Nowadays often used through a GUI (eg., CDE, KDE, or GNOME) that runs on top of UNIX - 70Programming Environments Microsoft Visual Studio.NETa large, complex visual environment
used to build Web applications and non-Web applications in any .NET language - 71Programming Environments NetBeansRelated to Visual Studio .Net, expect for applications in Java
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- 2 Computer Science Flashcards on Organization of Programming Languages Chapter 1, created by James Herd on 17/02/2019.
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