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{{Infobox programming language
| name = ALGOL W
| paradigm = [[编程范型|多范型]]：[[过程式编程|过程式]], [[指令式編程|指令式]], [[结构化编程|结构化]]
| family = [[ALGOL]]
| designers = [[Niklaus Wirth]], [[Tony Hoare]]
| released = {{Start date and age|1966}}
| typing = [[静态类型|静态]], [[强类型]]
| scope = [[作用域|词法]]
| programming language = [[PL360]]
| platform = [[IBM System/360]]
| influenced by = [[ALGOL 60]], [[ALGOL X]]
| influenced = [[Pascal語言|Pascal]], [[Modula-2]]
}}
'''ALGOL W'''，一種[[程式語言]]，為[[ALGOL]]家族的一份子。它基於[[尼克勞斯·維爾特]]與[[東尼·霍爾]]在{{le|IFIP Working Group 2.1}}針對[[ALGOL X]]所提出的草案而設計，希望能作為[[ALGOL 60]]的後繼者<ref name="Wirth">{{cite journal |last1=Wirth |first1=Niklaus |author1-link=Niklaus Wirth |last2=Hoare |first2=C. A. R. |author2-link=Tony Hoare |date=June 1966 |title=A contribution to the development of ALGOL |url=https://dl.acm.org/doi/10.1145/365696.365702 |journal=Communications of the ACM |volume=9 |issue=6 |pages=413–432 |doi=10.1145/365696.365702 |s2cid=11901135 |via=[[Association for Computing Machinery]] |access-date=2020-10-07|doi-access=free }}</ref>。經過小幅度的修改<ref>{{cite web|url=https://dl.acm.org/doi/10.5555/1061073.1061079|author= Niklaus Wirth|year=1966|title=Additional notes on "A Contribution to the Development of ALGOL|publisher=ALGOL Bulletin, Number 24 pp. 13 - 17}}</ref>，在[[史丹福大學]]，[[尼克勞斯·維爾特]]利用[[IBM System/360]]機器，以[[PL360]]實作出第一版的ALGOL W<ref name="Stanford">{{cite report |last1=Bauer |first1=Henry R. |last2=Becker |first2=Sheldon I. |last3=Graham |first3=Susan L. |last4=Forsythe |first4=George E. |last5=Satterthwaite |first5=Edwin H. |date=March 1968 |title=Technical Report Number: CS-TR-68-89 |url=http://www-db.stanford.edu/TR/CS-TR-68-89.html |website=Computer Science Department |publisher=Stanford University}} (Various documents for Stanford's 1972 implementation of ALGOL W; this report includes the ''ALGOL W Language Description''.</ref><ref name="TR71-230">{{cite web |last1=Sites |first1=Richard |title=ALGOL W Reference Manual |url=http://i.stanford.edu/pub/cstr/reports/cs/tr/71/230/CS-TR-71-230.pdf |website=i.stanford.edu |publisher=Stanford University |access-date=24 July 2022}}</ref>。

ALGOL W是原本ALGOL 60的相对简单的升级，它增加了[[字符串]]、位串、[[复数 (数学)|复数]]、到[[记录]][[数据类型]]的[[参照|引用]]，和[[求值策略#传复件-恢复调用|传结果调用]]的[[参数 (计算机科学)|参数]]传递，介入了<code>while</code>语句，将<code>switch</code>替代为<code>case</code>语句，并在总体上的紧实了这门语言。它的[[編譯器]]是用[[尼克勞斯·維爾特]]所設計的[[PL360]]組語所寫成<ref>{{Cite web |url=http://bitsavers.trailing-edge.com/pdf/stanford/cs_techReports/STAN-CS-71-215_PL360_Revised_A_Programming_Language_For_The_IBM_360_May71.pdf |title=PL360(REVISED) A PROGRAMMING LANGUAGE FOR THE IBM 360. |accessdate=2020-05-16 |archive-date=2016-03-04 |archive-url=https://web.archive.org/web/20160304073807/http://bitsavers.trailing-edge.com/pdf/stanford/cs_techReports/STAN-CS-71-215_PL360_Revised_A_Programming_Language_For_The_IBM_360_May71.pdf |dead-url=no }}</ref>。

== 语法和语义 ==
ALGOL W的{{le|语法 (编程语言)|Syntax (programming languages)|语法}}建造在[[EBCDIC]][[字符编码]]集的子集之上。在[[ALGOL 60]]中，保留字是独立的词法项目，但是在ALGOL W中它们只是字符序列，而不需要被{{le|索绕 (语法)|Stropping (syntax)|索绕}}起来。保留字和标识符由空格分隔<ref name="Stanford"/>。在这种方式下，ALGOL W的语法类似于[[Pascal语言|Pascal]]和后来的语言。

《ALGOL W语言描述》<ref name="description">{{cite report |last1=Bauer |first1=Henry R. |last2=Becker |first2=Sheldon I. |last3=Graham |first3=Susan L. |last4=Satterthwaite |first4=Edwin H. |last5=Sites |first5=Richard L. |date=June 1972 |title=ALGOL W Language Description |url=https://www.algol60.org/docsW/algolw.pdf}}</ref>，采用了类似于[[巴科斯范式|巴科斯-诺尔范式]]（BNF）的{{le|附缀文法|affix grammar}}定义了ALGOL W。这种[[形式文法]]是{{le|van Wijngaarden文法|Van Wijngaarden grammar}}的先驱<ref name="Wirth"/><ref>{{cite report |last=van Wijngaarden |first=Adriaan |author1-link=Adriaan van Wijngaarden |date=22 October 1965 |title=Orthogonal Design and Description of a Formal Language: MR76 |url=http://web.eah-jena.de/~kleine/history/languages/VanWijngaarden-MR76.pdf |publisher=Mathematical Centre |place=[[Amsterdam]], Netherlands |via=Ernst-Abbe-Hochschule [[Jena]], University of Applied Sciences, Germany |access-date=2020-10-07 |archive-date=29 October 2019 |archive-url=https://web.archive.org/web/20191029151436/http://web.eah-jena.de/%7Ekleine/history/languages/VanWijngaarden-MR76.pdf |url-status=dead }}</ref>。

大量的ALGOL W语义是在文法上定义的<ref name="description"/>：
* 标识符由它们在当前[[作用域]]内的定义来区分。例如，<code>⟨procedure identifier⟩</code>是由过程声明定义的标识符，<code>⟨label identifier⟩</code>是用作[[goto]]标签的标识符。
* [[变量 (计算机科学)|变量]]和{{le|表达式 (计算机科学)|Expression (computer science)|表达式}}的[[类型系统|类型]]通过附缀来的表示。例如，<code>⟨τ function identifier⟩</code>是针对返回类型<code>τ</code>的值的函数的一个语法实体，如果这个标识符已经在当前作用域内被声明为整数函数，那么它被展开为<code>⟨integer function identifier⟩</code>。
* 类型错误是文法错误。例如，<code>⟨integer expression⟩ / ⟨integer expression⟩</code>和<code>⟨real expression⟩ / ⟨real expression⟩</code>是表示表达式的有效而不同的语法实体，但是<code>⟨real expression⟩ DIV ⟨integer expression⟩</code>（即在浮点值上进行整数除法）是无效的语法实体。

== 例子 ==

下面例子展示ALGOL W的[[记录]]类型设施：

<syntaxhighlight lang="pascal">
RECORD PERSON (
STRING(20) NAME;
INTEGER AGE;
LOGICAL MALE;
REFERENCE(PERSON) FATHER, MOTHER, YOUNGESTOFFSPRING, ELDERSIBLING
);

REFERENCE(PERSON) PROCEDURE YOUNGESTUNCLE (REFERENCE(PERSON) R);
BEGIN
REFERENCE(PERSON) P, M;
P := YOUNGESTOFFSPRING(FATHER(FATHER(R)));
WHILE (P ¬= NULL) AND (¬ MALE(P)) OR (P = FATHER(R)) DO
P := ELDERSIBLING(P);
M := YOUNGESTOFFSPRING(MOTHER(MOTHER(R)));
WHILE (M ¬= NULL) AND (¬ MALE(M)) DO
M := ELDERSIBLING(M);
IF P = NULL THEN
M
ELSE IF M = NULL THEN
P
ELSE
IF AGE(P) < AGE(M) THEN P ELSE M
END
</syntaxhighlight>

== 引用 ==
{{Reflist|2}}

== 外部链接 ==
*[https://web.archive.org/web/20100523150449/http://www.jampan.co.nz/~glyn/ aw2c] – ALGOL W compiler for [[Linux]]
*[https://tiddly-pom.com/~glyn/ awe]{{Wayback|url=https://tiddly-pom.com/~glyn/ |date=20171004061610 }} – aw2c updated version
*[https://everything2.com/title/Algol+W?searchy=search ALGOL W @ Everything2] {{Wayback|url=https://everything2.com/title/Algol+W?searchy=search |date=20210224233423 }} – informal but detailed description of the language by a former user, with sidebars extolling ALGOL W over [[Pascal語言|Pascal]] as an educational programming language
*[http://bitsavers.org/pdf/stanford/listing/Algol_W_Listing_Nov69.pdf 1969 ALGOL W compiler listing]{{Wayback|url=http://bitsavers.org/pdf/stanford/listing/Algol_W_Listing_Nov69.pdf |date=20190926180336 }} at bitsavers.org
* The Michigan Terminal System Manuals, Volume 16: [http://bitsavers.org/pdf/univOfMichigan/mts/volumes/MTSVol16-ALGOLWInMTS-Sep1980.pdf ALGOL W in MTS]{{Wayback|url=http://bitsavers.org/pdf/univOfMichigan/mts/volumes/MTSVol16-ALGOLWInMTS-Sep1980.pdf |date=20110814225737 }}
*[http://www.algol60.org/15algolwlego.htm Algol W materials]{{Wayback|url=http://www.algol60.org/15algolwlego.htm |date=20200218175656 }} More than 200 Algol W programs and documentation

{{Authority control}}
{{ALGOL programming}}
[[Category:过程式编程语言]]
[[Category:ALGOL程式語言家族]]
[[Category:1966年建立的程式語言]]

ALGOL W - 版本历史

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