Pascal
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Pascal. 1130379007 Suhua Lei. NIKLAUS WIRTH. Known for Algol W, Euler,  Pascal , Modula,  Modula-2,Oberon,  Oberon-2,Oberon-07,  Oberon System. BORN February 15, 1934  (age 80) Winterthur, Switzerland Citizenship Switzerland.

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Pascal

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Pascal

Pascal

1130379007

Suhua Lei


Pascal

NIKLAUS WIRTH

Known for

Algol W, Euler, Pascal,Modula, Modula-2,Oberon, Oberon-2,Oberon-07, Oberon System

BORN

February 15, 1934 (age 80)Winterthur, Switzerland

Citizenship

Switzerland

Notable Awards SIGPLAN Programming Languages Achievement AwardFellow of the Computer History MuseumMarcel Benoist Prize (1989) Turing Award


A famous book

A Famous Book

Algorithms

Data Structures

Programs


Who influences its birth

Who influences its birth?

1958

ALGOL58

Algol Doesn’t Have Enough Data Types!

1960

ALGOL60

1966

ALGOL W

1970

PASCAL


Data types

Data Types


Data types1

Data Types

  • Complex types can be constructed from simple types:


Programming paradigm

Programming Paradigm

  • Imperative, procedural

    • the flow of control is structured into standard statements, usually without 'goto' commands.

  • Object Pascal support multiple paradigms

    • Programs written in Object Pascal can be purely procedural, or purely object-oriented, or contain elements of both paradigms


Type system

Type system

  • It’s statically typed

  • Its type system has been described as "too strong"

    • Eg: the size of an array or string is part of its type, making some programming tasks difficult

    • Java > Pascal > C

  • It’s safe except two conditions

    • Function as parameter

    • Using unsigned variant record type


Compilers

Compilers


Example hello world

Example: hello world


Example pi

Example: pi


Conclusion characteristic

Conclusion:characteristic

  • 严格的结构化形式;

  • 丰富完备的数据类型;

  • 运行效率高;

  • 查错能力强。


Conclusion disadvantages

Conclusion:disadvantages

  • 传统PASCAL的标准库中缺乏对网络编程的支持,并且仅通过自带的graph单元难以实现较好的图形界面(GUI),这些缺点大多需要嵌入汇编语言代码才能得到解决,缺乏与机器语言的接口。

  • 与面向对象的语言相比,不利于大型软件的开发。

  • 推广了C语言的Brian Kernighan在1981年《Why Pascal Is Not My Favourite Programming Language》对Pascal提出了严厉的抨击。


Applications

Applications

  • GCC,Gnu C编译器,最初是用Pascal的一种方言Pastel编写的

  • Pascal是Apple Lisa和早期Mac开发使用的高级语言

  • 流行的排版系统TeX是由高德纳使用基于DECPDP-10 Pascal的最初文学编程系统WEB编写的

  • Object Pascal仍然广泛用于开发像Skype这样的Windows应用

  • … …


Delphi

Delphi的没落

  • Object Pascal并没有像C/C++那样成为业内标准

  • 人才流失,与内部决策失误。Delphi之父AndersHejlsberg离开Borland去了微软,导致Delphi的编译器有三年的时间无人敢动,因为AndersHejlsberg完全使用汇编实现的编译器,无人能够看懂。

  • 市场转变开发市场现在更注重B/S结构的应用,桌面应用正在大幅减少,Delphi显然不是一个理想的WEB开发语言。


Thank you

Thank you !


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