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Lorrie Cranor Programming Perl
|Jazyk:||Počet slov:||1 718|
|Referát vhodný pre:||Stredná odborná škola||Počet A4:||5.4|
|Priemerná známka:||2.96||Rýchle čítanie:||9m 0s|
|Pomalé čítanie:||13m 30s|
In Perl, special characters serve to disambiguate variable types. For example, variable names that begin with a $ refer to singular variables (scalars) while variable names that begin with a @ or a % refer to plural variables (arrays). As with English where a member of a group is described with singular words, an array element is referenced with the singular $. In addition, Wall has observed that unlike most computer languages, ``natural languages don't have any `theoretical axes' to grind.'' He adds, ``Natural languages typically don't have any shame in borrowing things from other languages, unless of course you're French.'' He pauses for a moment and looks through his notes for a statement he likes so much he has it written down: ``For most people the perceived usefulness of a computer language is inversely proportional to the number of theoretical axes the language intends to grind.''
But while Wall intends Perl to be useful, he does not intend it to replace other programming languages that are also useful for solving certain types of problems. ``I've tried not to reinvent any other language with Perl. So if you see some particular problem that C is good at, I've not tried to make Perl that good in that realm. For low level bit diddling, C is still going to be better. For very large, difficult to manage projects, C++ is going to better. For just starting and stopping processes, shells are going to be better. These are all sort of LegoLand type problems. The place where Perl excels is not where you want Legos, but where you want glue -- where you don't want Lincoln Logs so much as you want pipe cleaners. Its sort of officially a chewing gum and baling wire language.''
In fact, Wall says, ``The Perl slogan is, `There is more than one way to do it.' People have often taken that to mean that there is more than one way to do it within Perl. But I apply the same thing outside of Perl also. I know a lot of people use Perl for what it's useful for. But I don't expect them to take themselves off to a monastery and just write Perl scripts all day.''
Wall says Perl's biggest competitors -- REXX, Tcl, Python, and Scheme -- are useful for similar things that Perl is useful for. Although he prefers Perl because of it's efficiency, language structure, and lack of theoretical axes, Wall says he will not engage in language wars. ``I have a firm policy against making enemies,'' he states. Despite his training as a linguist, Wall turned to computer science because of its more lucrative job prospects.