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Perl    音标拼音: [p'ɚl]
A {high-level} programming language, started
by {Larry Wall} in 1987 and developed as an {open source}
project. It has an eclectic heritage, deriving from the
ubiquitous {C} programming language and to a lesser extent
from {sed}, {awk}, various {Unix} {shell} languages, {Lisp},
and at least a dozen other tools and languages. Originally
developed for {Unix}, it is now available for many
{platforms}.

Perl's elaborate support for {regular expression} matching and
substitution has made it the {language of choice} for tasks
involving {string manipulation}, whether for text or binary
data. It is particularly popular for writing {CGI scripts}.

The language's highly flexible syntax and concise regular
expression operators, make densely written Perl code
indecipherable to the uninitiated. The syntax is, however,
really quite simple and powerful and, once the basics have
been mastered, a joy to write.

Perl's only {primitive} data type is the "scalar", which can
hold a number, a string, the undefined value, or a typed
reference. Perl's {aggregate} data types are {arrays}, which
are ordered lists of {scalars} indexed by {natural numbers},
and hashes (or "{associative arrays}") which are unordered
lists of scalars indexed by strings. A reference can point to
a scalar, array, hash, {function}, or {filehandle}. {Objects}
are implemented as references "{blessed}" with a {class} name.
Strings in Perl are {eight-bit clean}, including {nulls}, and
so can contain {binary data}.

Unlike C but like most Lisp dialects, Perl internally and
dynamically handles all memory allocation, {garbage
collection}, and type {coercion}.

Perl supports {closures}, {recursive functions}, {symbols}
with either {lexical scope} or {dynamic scope}, nested {data
structures} of arbitrary content and complexity (as lists or
hashes of references), and packages (which can serve as
classes, optionally inheriting {methods} from one or more
other classes). There is ongoing work on {threads},
{Unicode}, {exceptions}, and {backtracking}. Perl program
files can contain embedded documentation in {POD} (Plain Old
Documentation), a simple markup language.

The normal Perl distribution contains documentation for the
language, as well as over a hundred modules (program
libraries). Hundreds more are available from The
{Comprehensive Perl Archive Network}. Modules are themselves
generally written in Perl, but can be implemented as
interfaces to code in other languages, typically compiled C.

The free availability of modules for almost any conceivable
task, as well as the fact that Perl offers direct access to
almost all {system calls} and places no arbitrary limits on
data structure size or complexity, has led some to describe
Perl, in a parody of a famous remark about {lex}, as the
"Swiss Army chainsaw" of programming.

The use of Perl has grown significantly since its adoption as
the language of choice of many {World-Wide Web} developers.
{CGI} interfaces and libraries for Perl exist for several
{platforms} and Perl's speed and flexibility make it well
suited for form processing and on-the-fly {web page} creation.

Perl programs are generally stored as {text} {source} files,
which are compiled into {virtual machine} code at run time;
this, in combination with its rich variety of data types and
its common use as a glue language, makes Perl somewhat hard to
classify as either a "{scripting language}" or an
"{applications language}" -- see {Ousterhout's dichotomy}.
Perl programs are usually called "Perl scripts", if only for
historical reasons.

Version 5 was a major rewrite and enhancement of version 4,
released sometime before November 1993. It added real {data
structures} by way of "references", un-adorned {subroutine}
calls, and {method} {inheritance}.

The spelling "Perl" is preferred over the older "PERL" (even
though some explain the language's name as originating in the
acronym for "Practical Extraction and Report Language"). The
program that interprets/compiles Perl code is called
"perl", typically "/usr/local/bin/perl" or "/usr/bin/perl".

Latest version: 5.005_03 stable, 5.005_62 in development, as
of 1999-12-04.

{(http://perl.com/)}.

{Usenet} newsgroups: {news:comp.lang.perl.announce},
{news:comp.lang.perl.misc}.

["Programming Perl", Larry Wall and Randal L. Schwartz,
O'Reilly & Associates, Inc. Sebastopol, CA. ISBN
0-93715-64-1].

["Learning Perl" by Randal L. Schwartz, O'Reilly & Associates,
Inc., Sebastopol, CA].

[{Jargon File}]

(1999-12-04)

Practical Extraction and Report Language (PERL)

Perl: /perl/, n. [Practical Extraction and Report Language, a.k.a. Pathologically
Eclectic Rubbish Lister] An interpreted language developed by Larry Wall,
author of
patch(1)
and
rn(1)).
Superficially resembles awk, but is much hairier,
including many facilities reminiscent of
sed(1)
and shells and a comprehensive Unix system-call interface. Unix sysadmins,
who are almost always incorrigible hackers, generally consider it one of
the languages of choice, and it is by far the most
widely used tool for makingliveweb pages via CGI. Perl has
been described, in a parody of a famous remark about
lex(1),
as the Swiss-Army chainsaw of Unix programming.
Though Perl is very useful, it would be a stretch to describe it as pretty
or elegant; people who like clean, spare design
generally prefer Python. See also Camel
Book, TMTOWTDI.


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英文字典中文字典相关资料:


  • operators - What does =~ do in Perl? - Stack Overflow
    51 I guess the tag is a variable, and it is checking for 9eaf - but does this exist in Perl? What is the "=~" sign doing here and what are the " " characters before and after 9eaf doing?
  • What is the meaning of @_ in Perl? - Stack Overflow
    128 perldoc perlvar is the first place to check for any special-named Perl variable info Quoting: @_: Within a subroutine the array @_ contains the parameters passed to that subroutine More details can be found in perldoc perlsub (Perl subroutines) linked from the perlvar: Any arguments passed in show up in the array @_
  • operators - What is the difference between || and or in Perl . . .
    53 From Perl documentation: OR List operators On the right side of a list operator, it has very low precedence, such that it controls all comma-separated expressions found there
  • Whats the use of lt; gt; in Perl? - Stack Overflow
    @pst, <> is not a file handle, "null" or otherwise It's an operator Specifically, the readline operator There's a reference to it as the "angle operator" in perlvar, although there isn't actually any such operator The angle brackets are used by two operators: readline or glob The operator depends on the contents of the brackets
  • Perl flags -pe, -pi, -p, -w, -d, -i, -t? - Stack Overflow
    Below are the flags that I encounter most often, and I don't have a clue what they mean: perl -pe perl -pi perl -p perl -w perl -d perl -i perl -t I will be very grateful if you tell me what each of those mean and some use cases for them, or at least tell me a way of finding out their meaning
  • [办公编程]Python不算啥,我已经有更好的选择——Perl (一文快速入门,附详细举例)
    骆驼书Learning Perl 《Learning Perl》骆驼书,全书加附录一共363页,很多对不对。买到书后我是如何翻这363页快速翻到Perl入门级? 我的答案是:不用每页都细读, 快速翻看目录找共同点和重点来看。我学习新语言的方式是找以往编程语言入门 共同点 和 重点,比如 基础变量, 控制循环,构建函数 共同
  • 如何从零开始学习 Perl? - 知乎
    注:笔者主要使用Perl做软件测试方面开发 按照笔者自己的经历,从对Perl一无所知到可以上手干活,可以从小骆驼书—— Learning Perl (豆瓣) 开始。快速浏览加实践下书上代码,两天就可以读个大概。 不过小骆驼书只覆盖了Perl Programming最基础的一部分知识,当你需要用Perl做面对对象或者大型程序编程
  • What does the - gt; arrow do in Perl? - Stack Overflow
    The outer part is a dereference - this implies is a reference to an array, so this operator deferences it to refer to the array directly, which is then copied to Chapter 8 of the ' Camel Book ' is a good place to learn about references, or the perlref section of the Perl documentation The arrow operator is an object dereference, in this case fetching the member of the object Similarly, later
  • How does double arrow (= gt;) operator work in Perl? - Stack Overflow
    The => operator in perl is basically the same as comma The only difference is that if there's an unquoted word on the left, it's treated like a quoted word So you could have written Martin => 28 which would be the same as 'Martin', 28 You can make a hash from any even-length list, which is all you're doing in your example Your Readonly example is taking advantage of Perl's flexibility with
  • terminology - What does ~~ mean in Perl? - Stack Overflow
    5 It is the smartmatch operator In general, when you want information about operators in Perl, see perldoc perlop





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