Why Perl?
Phillip Thorne
Rev 0, 2000-03-06

Point one: programmers are lazy. They don't seek extra work if
there's a simpler, faster, pre-existing way. If there isn't, they'll
create it themselves, then re-use it later. Any facility in a
language that encourages/assists this (libraries, functions, complex
data types) is appreciated. Point two: they're anarchic. They don't
enjoy being told how to perform a task, especially if they perceive
the directive as less efficient/ideal than their own solution.

It's possible to perform essentially any task in any language, but
some are specialized. But how many hoops will you have to jump? A
fundamental ability of most languages is to create subroutines (aka
functions) that encapsulate some complex, oft-repeated task inside a
simple shell. This encourages code re-use (you needn't type the same
sequence of statements in multiple places) and maintainability (any
changes are made in only one place).

Most modern languages are hybrids, and/or have had portions of other
flavors grafted on (with new releases). Fortran-77 is exclusively
procedural. C is procedural, but its structs are rudimentary OO; C++
extended them and added features for full OO. Java looks like C++ but
is OO from the ground up. Smalltalk, everything is an object.
Javascript and VBscript aren't often used to create new objects, but
more often to access/manipulate pre-existing arrays (such as the
browser DOM). Javascript has some functional notes. SQL-89 is
exclusively declarative, but -92 (???) added a few procedural control
structures.

Procedural languages use primitive data types (integers, decimals,
characters) and process them with functions and intermediary
variables. Object-oriented languages are procedural in character, but
combine (encapsulate) primitives and functions into abstract data
types (aka objects) that more adequately resemble the real-world
entities they're modelling. Declarative languages (Prolog, SQL)
describe what the results should look like, without bothering with
flow-of-control. programs in functional languages (LISP, APL) strive
to be a single huge nested function in which data flows from one to
another without intermediate storage. Most commonly used in
artificial intelligence research.

Most programs are hybrids of multiple languages. C links to
Assembler, Java links to C, a web application is split between
client-side Javascript, server-side Perl, and database-side stored
SQL procedures. It's simply a matter of assigning subtasks to the
language most suited, rather than contorting a single solution into
unsuited/unfitting/suboptimal/subpar performance for "purity."

As with anything else, programmer can grow attached to a favorite
language and may rely on it overmuch when another one might be better
suited.

Applications, system, scripting, code generation, platforms
supported.  Primitive types, facilities for roll-your-own, variable
typing.

Why do so many web coders swear by the programming language Perl,
rather than C, C++, Java, Javascript or Visual Basic?

Perl is interpreted. Broadly speaking, there are two types of
languages: interpreted and compiled. For either, the "development
cycle" involves repeated stages of edit-test-debug. With an
interpreted language, you can immediately run a program and analyze
the results (and any bugs). A compiled language includes an extra
step: edit-compile-test. You first have to repair any compile-phase
(syntax) bugs before the program itself runs and produces execution-
phase (logic) bugs.

Perl has regular expressions. When analyzing or processing text, it's
useful to describe its "shape" in general terms. For instance, if a
question demands a yes/no answer (also valid: y/n, YES/NO), the shape
is a y (followed by anything), regardless of capitalization. When
generating a document, the components are in a certain order. ...
Regular expressions (aka regexps or regexes) offer a powerful way to
describe these shapes. They're a small language in themselves, a
grammar, for describing structure.

Perl is concise. Perl, C++, Java and JavaScript all inherited certain
syntax from C. For instance,

  x++;           x = x + 1
  x && y;        x and y
  x ? y : z;     if x then y else z
  msg .= "xyz";  msg = msg & "xyz"

Perl offers alternatives. A fundamental construct in any programming
language is the "branch," whereby the program embarks upon
alternative courses of action based on some input. In Perl, a branch
is written in one of the following five ways:

  if(somecondition){
    dosomething;
  }else{
    dosemethingelse;
  }

  dosomething if somecondition;

  dosomething unless !somecondition;

  somecondition || dosomething;

  somecondition ? dosomething : dosomethingelse;

In Visual Basic, there's only one way:

  if somecondition then
    dosomething
  else
    dosomethingelse
  endif

Perl makes file I/O easy.

Perl is loosely-typed. JS variables are untyped, but there are
different types. VB has typed variables plus a "variant" that can
hold any type.

Perl has useful data structures. Arrays and hashes. In JavaScript,
these are one structure.

Perl ignores formatting. Since statements are terminated with a
semicolon, the interpreter doesn't care how much whitespace (spaces,
tabs, carriage returns) are in the middle. VB inherits an ancient
Fortran requirement that statements fit on a single line, and if not,
a line-continuation character (underscore "_") must be used. (Java
resource bundles use a backslash "\").

Perl has libraries of utilities, and the CPAN repository.

Perl is free, although advanced IDEs customized for it aren't.