04 Influences in Language Design

7/28/2019 04 Influences in Language Design

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INFLUENCES IN LANGUAGEDESIGN

Mr. Rico T. Teodoro


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COMPUTER ARCHITECTURE

VON NEUMANN ARCHITECTURE

A/LU Control Unit

Memory Stores both instructions and data

instructions and dataResults of operations

I/O devices

Central Processing Unit


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PROGRAMMING

METHODOLOGIES

STRUCTURED PROGRAMMING

also known as modular programming is a

subset of procedural programming thatenforces a logical structure on the program

being written to make it more efficient and

easier to understand and modify.

aimed on improving the clarity, quality, anddevelopment time of a computer program by

making extensive use of subroutines, block

structures and for and while loops


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PROGRAMMING

METHODOLOGIES


frequently employs a top-down design model, in

which developers map out the overall programstructure into separate subsections. A definedfunction or set of similar functions is coded in aseparate module or submodule, which meansthat code can be loaded into memory more

efficiently and that modules can be reused inother programs. After a module has been testedindividually, it is then integrated with othermodules into the overall program structure.


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PROGRAMMING

METHODOLOGIES


Program flow follows a simple hierarchical

model that employs looping constructs such as"for," "repeat," and "while." Use of the "Go To"

statement is discouraged.


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PROGRAMMING

METHODOLOGIES

TOP-DOWN DESIGN

in which design begins by specifying complex

pieces and then dividing them into successivelysmaller pieces

A way of developing a computer program byfirst describing general functions, then breakingeach function down into details which are

refined in successive steps until the wholeprogram is fully defined.

Also called STEPWISE REFINEMENT


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PROGRAMMING

METHODOLOGIES

Top-Down Design

in which design begins by specifying complex

pieces and then dividing them into successivelysmaller pieces

A way of developing a computer program byfirst describing general functions, then breakingeach function down into details which are

refined in successive steps until the wholeprogram is fully defined.

Also called STEPWISE REFINEMENT


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PROGRAMMING

METHODOLOGIES

OBJECT-ORIENTED PROGRAMMING

brought about due to shift from procedure-

oriented to data-oriented design methodologies

begins with data abstraction which

encapsulates processing with data objects and

controls access to data, and adds inheritance

and dynamic method binding.


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LANGUAGE DESIGN TRADE-

OFFS

Conflict on reliability and cost of execution

Conflict on expressivity and readability

Conflict on writability and reliability


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IMPLEMENTATION METHODS

COMPILATION

programs can be translated into machine

language which can be executed directly on thecomputer

Advantage : very fast execution once

translation process is complete


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COMPILATION

SOURCE

PROGRAM

Language that a

compiler translates

Sourceprogram

Lexicalanalyzer

Syntaxanalyzer

Intermediatecode

generator

Codegenerator

computer

Lexical units

Parse trees

Intermediate code

Machine language

results

optimizationSymbol table


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COMPILATION LEXICAL

ANALYZER Gathers the

characters of the

source programs

into lexical units

LEXICAL UNITS

Identifiers Special words

Operators

Punctuation

symbols

Sourceprogram

Lexicalanalyzer

Syntaxanalyzer

Intermediatecode

generator

Codegenerator

computer

Lexical units

Parse trees

Intermediate code

Machine language

results



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COMPILATION

SYNTAX

ANALYZER

Takes lexical units

to construct

structures called

PARSE TREES that

represents the

syntactic structure

of the program

Sourceprogram

Lexicalanalyzer

Syntaxanalyzer

Intermediatecode

generator

Codegenerator

computer

Lexical units

Parse trees

Intermediate code

Machine language

results



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COMPILATION

INTERMEDIATE

CODE

GENERATOR

Produces a

program in a

different language

at an intermediate

level between the

source program and

machine language

Sourceprogram

Lexicalanalyzer

Syntaxanalyzer

Intermediatecode

generator

Codegenerator

computer

Lexical units

Parse trees

Intermediate code

Machine language

results



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COMPILATION

OPTIMIZATION

Improves program

by making them

smaller or faster or

both

Sourceprogram

Lexicalanalyzer

Syntaxanalyzer

Intermediatecode

generator

Codegenerator

computer

Lexical units

Parse trees

Intermediate code

Machine language

results



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COMPILATION

CODE

GENERATOR

Translates the

optimized

intermediate code

version of the

program into an

equivalent machine

language program

Sourceprogram

Lexicalanalyzer

Syntaxanalyzer

Intermediatecode

generator

Codegenerator

computer

Lexical units

Parse trees

Intermediate code

Machine language

results



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COMPILATION

SYMBOL TABLE

Serves a database

containing type and

attribute information

of each user-

defined name in the

program

Sourceprogram

Lexicalanalyzer

Syntaxanalyzer

Intermediatecode

generator

Codegenerator

computer

Lexical units

Parse trees

Intermediate code

Machine language

results



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COMPILATION (Stages from Source to Executable)

Compilation: source code ==> relocatable object code (binaries) Linking: many relocatable binaries (modules plus libraries) ==>

one relocatable binary (with all external references satisfied)

Loading: relocatable ==> absolute binary (with all code and data

references bound to the addresses occupied in memory)

Execution: control is transferred to the first instruction of theprogram


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PURE INTERPRETATION Programs are interpreted with no translation

The INTEPRETER acts as a software simulation of a machine whosefetch-execute cycle deals with high-level language program

statements rather than machine instructions

Advantage : allows easy implementation of many source-level

debugging operations

Disadvatage :

slower in decoding Need for more space


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PURE

INTERPRETATION Source program

intepreter

result

Input data


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HYBRID IMPLEMENTATION Compromise between compilers and pure interpreters

Translate high-level programs to an intermediate language designedto allow easy interpretation

Advantage : faster than pure interpretation since source needs to be

decoded only once.


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HYBRIDSource

program

Lexicalanalyzer

Syntaxanalyzer

Intermediatecode

generator

Lexical units

Parse trees

results

interpreter

Intermediate codeInput data


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PREPROCESSOR

Program that processes a program immediately

before the program is compiled


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PROGRAMMING

ENVIRONMENT

Collection of tools used in the development of a

software

May consist of :

File system

Editor

Linker

Compiler

Documents

04 Influences in Language Design