Meta tags:
Headings (most frequently used words):
perl, and, history, america, contents, name, logos, design, ports, performance, applications, community, see, also, references, further, reading, external, links, early, versions, 1990s, 2000, 2020, raku, philosophy, features, syntax, implementation, yet, another, conference, reception, locations, north, europe, israel, russia, ukraine, australia, south, asia, brazil,
Text of the page (most frequently used words):
the (603), perl (598), and (215), from (147), retrieved (128), archived (118), for (114), yapc (107), original (97), 2011 (86), that (86), language (79), june (73), was (72), programming (66), with (64), 2013 (59), january (58), org (54), may (49), 2012 (43), 2020 (40), are (39), version (39), july (38), 2014 (38), software (36), edit (36), new (36), code (35), wall (34), august (34), this (33), machine (33), conference (33), has (33), december (32), 2006 (32), 2010 (31), 2015 (31), reilly (30), interpreter (30), february (29), october (29), languages (28), isbn (28), 2009 (28), march (28), september (27), 978 (27), 2007 (27), 2008 (27), can (27), its (27), source (26), time (26), run (25), april (24), 2005 (24), first (24), released (24), use (23), com (23), used (23), but (23), modules (23), also (23), wayback (22), which (22), 2016 (21), data (21), development (21), larry (21), 2004 (21), what (21), perldoc (21), programs (21), japan (21), other (20), november (20), 2017 (20), media (20), 2000 (20), not (20), phase (20), most (20), unsupported (20), articles (19), project (19), all (19), 2003 (19), documentation (19), usa (19), linux (18), community (18), raku (18), 2021 (18), 2019 (18), compile (18), such (18), free (17), only (17), been (17), russia (17), 2022 (16), open (16), 2023 (16), features (16), using (15), 2025 (15), history (15), more (15), license (14), statements (14), core (14), support (14), 2018 (14), have (14), release (14), were (14), one (14), citation (14), needed (14), many (14), links (13), web (13), design (13), cpan (13), modern (13), 2002 (13), database (13), name (13), implementation (13), asia (13), brazil (13), text (12), 2026 (12), object (12), schwartz (12), rakudo (12), edition (12), there (12), large (12), called (12), line (12), tokyo (12), into (12), include (12), example (11), randal (11), 2001 (11), book (11), 1999 (11), written (11), virtual (11), syntax (11), 2024 (11), held (11), brasil (11), these (11), foundation (10), inc (10), page (10), short (10), unix (10), scripting (10), high (10), israel (10), general (10), dbi (10), practical (10), culture (10), another (10), computer (10), parsing (10), versions (10), wikipedia (9), tools (9), specification (9), sql (9), type (9), processing (9), link (9), metacpan (9), work (9), often (9), write (9), than (9), included (9), different (9), because (9), system (9), regular (9), search (8), cs1 (8), gnu (8), module (8), just (8), archive (8), journal (8), usenet (8), some (8), www (8), execution (8), scripts (8), both (8), during (8), releases (8), variables (8), expressions (8), added (8), available (7), under (7), external (7), 1987 (7), management (7), applications (7), english (7), based (7), shell (7), java (7), brian (7), learning (7), functional (7), 596 (7), europe (7), internet (7), tom (7), lines (7), onion (7), performance (7), efficient (7), over (7), queries (7), compiler (7), update (7), camel (7), built (7), document (7), part (7), several (7), made (7), program (7), even (7), provides (7), cgi (7), however (7), would (7), noise (7), major (7), about (6), pages (6), dead (6), maint (6), unsourced (6), artistic (6), python (6), systems (6), foy (6), class (6), projects (6), reference (6), cite (6), developer (6), golf (6), functions (6), api (6), benchmarks (6), activestate (6), windows (6), distributions (6), without (6), plan (6), will (6), tests (6), perl5 (6), amsterdam (6), pittsburgh (6), canada (6), yet (6), interfaces (6), important (6), compiled (6), known (6), number (6), given (6), developed (6), his (6), including (6), while (6), hashes (6), memory (6), article (6), supported (6), changes (6), 000 (6), main (6), unicode (6), add (5), toggle (5), terms (5), you (5), non (5), commons (5), containing (5), potentially (5), dated (5), oriented (5), level (5), dynamic (5), php (5), states (5), databases (5), security (5), definition (5), comparison (5), events (5), commercial (5), long (5), standard (5), chromatic (5), parrot (5), things (5), writing (5), describes (5), introduction (5), tim (5), 4493 (5), power (5), professional (5), orwant (5), jon (5), perlmonks (5), pdf (5), who (5), state (5), mod_perl (5), their (5), faq (5), game (5), tool (5), 1998 (5), online (5), parse (5), see (5), cloud (5), github (5), talk (5), dev (5), ponie (5), logo (5), sometimes (5), since (5), process (5), any (5), own (5), file (5), references (5), list (5), taipei (5), porto (5), alegre (5), america (5), moscow (5), due (5), ukraine (5), pennsylvania (5), when (5), they (5), had (5), user (5), around (5), world (5), possible (5), pastime (5), programmers (5), similar (5), common (5), each (5), arrays (5), designed (5), distribution (5), every (5), complete (5), like (5), case (5), parser (5), string (5), remaining (5), should (5), documents (5), notable (5), began (5), contents (4), developers (4), additional (4), trademark (4), sister (4), wikidata (4), failed (4), deprecated (4), archival (4), service (4), description (4), conferences (4), cross (4), family (4), portal (4), hardware (4), related (4), proprietary (4), public (4), debian (4), licenses (4), apache (4), movement (4), operating (4), facilities (4), javascript (4), haskell (4), net (4), visual (4), audrey (4), tang (4), books (4), moarvm (4), official (4), mark (4), addison (4), wesley (4), beginner (4), those (4), further (4), christiansen (4), obfuscated (4), hacker (4), browser (4), extensively (4), duckduckgo (4), uses (4), start (4), activeperl (4), ports (4), 1997 (4), ieee (4), doi (4), big (4), porters (4), months (4), nntp (4), announced (4), future (4), years (4), pugs (4), second (4), information (4), extraction (4), report (4), later (4), ability (4), team (4), significant (4), fukuoka (4), kyoto (4), são (4), paulo (4), australia (4), kyiv (4), became (4), houston (4), through (4), network (4), being (4), collection (4), various (4), itself (4), idea (4), series (4), 1990s (4), much (4), same (4), print (4), published (4), implemented (4), interface (4), automatic (4), make (4), easy (4), structures (4), early (4), maintenance (4), together (4), makes (4), popular (4), overhead (4), typical (4), engine (4), sed (4), awk (4), package (4), platforms (4), compatible (4), lexer (4), tree (4), then (4), could (4), regex (4), stated (4), sigils (4), apocalypses (4), stable (4), originally (4), latest (4), 1994 (4), symbol (4), pearl (4), hide (4), move (4), sidebar (4), view (3), legal (3), site (3), profit (3), creative (3), categories (3), template (3), archives (3), verification (3), image (3), created (3), paradigm (3), platform (3), https (3), republic (3), international (3), category (3), shared (3), initiative (3), microsoft (3), topics (3), drivers (3), packages (3), timeline (3), outline (3), term (3), alternative (3), ruby (3), lisp (3), basic (3), patterns (3), best (3), order (3), advanced (3), website (3), wikibooks (3), examples (3), 2nd (3), european (3), university (3), 2146 (3), unmatched (3), better (3), poetry (3), adam (3), rsa (3), newsgroup (3), value (3), japh (3), simple (3), bunce (3), blog (3), html (3), handles (3), library (3), traffic (3), doug (3), phoenix (3), bytecode (3), louis (3), alioth (3), ppm (3), hello (3), binary (3), kennedy (3), giving (3), found (3), particularly (3), compilers (3), 1995 (3), technology (3), nature (3), how (3), become (3), guru (3), steering (3), after (3), feature (3), thesis (3), porting (3), kuhn (3), rperl (3), perl11 (3), little (3), stevan (3), texas (3), enlightened (3), out (3), implement (3), britannica (3), 004 (3), chicago (3), third (3), although (3), point (3), always (3), powerful (3), hard (3), now (3), osdc (3), toronto (3), salt (3), lake (3), city (3), florida (3), north (3), locations (3), yacc (3), three (3), 250 (3), organized (3), mongers (3), submitted (3), well (3), 1996 (3), signature (3), style (3), few (3), phrase (3), enough (3), includes (3), end (3), yearly (3), life (3), introduced (3), via (3), single (3), handling (3), mechanism (3), done (3), executable (3), here (3), commonly (3), purpose (3), command (3), complex (3), improvements (3), unlike (3), implementations (3), interpreted (3), exceptions (3), halting (3), problem (3), cannot (3), parsed (3), resolve (3), ambiguities (3), begin (3), according (3), create (3), current (3), total (3), referred (3), continue (3), improved (3), programmer (3), scalar (3), conversions (3), typing (3), takes (3), sigil (3), expression (3), array (3), strings (3), function (3), hash (3), philosophy (3), active (3), runtime (3), next (3), rfcs (3), operator (3), change (3), switch (3), effort (3), logos (3), ago (3), subsection (3), topic (2), table (2), statement (2), contact (2), privacy (2), policy (2), organization (2), wikimedia (2), last (2), hidden (2), default (2), publisher (2), location (2), url (2), webarchive (2), errors (2), ignored (2), multiple (2), auto (2), procedural (2), multi (2), title (2), spain (2), france (2), control (2), model (2), promise (2), types (2), india (2), formerly (2), apps (2), games (2), bioinformatics (2), closed (2), lists (2), pascal (2), julia (2), fortran (2), forth (2), classic (2), apl (2), jesse (2), vincent (2), people (2), intermediate (2), cookbook (2), higher (2), effective (2), rules (2), twiki (2), request (2), movable (2), bugzilla (2), psgi (2), dbix (2), catalyst (2), frameworks (2), wikiversity (2), wikiquote (2), techniques (2), onyx (2), neon (2), tutorial (2), beginning (2), reading (2), worldcat (2), frankfurt (2), magazine (2), press (2), minimal (2), 201 (2), legacy (2), dictionary (2), 754 (2), building (2), contest (2), comp (2), lang (2), misc (2), slice (2), canonical (2), rose (2), relational (2), mysql (2), bekman (2), stas (2), descartes (2), alligator (2), sites (2), principles (2), 56592 (2), portable (2), munging (2), 700 (2), duck (2), architecture (2), imdb (2), inline (2), backend (2), leroy (2), jean (2), timely (2), mac (2), aix (2), solaris (2), macperl (2), kegler (2), jeffrey (2), undecidability (2), undecidable (2), fall (2), review (2), ppi (2), abuin (2), jose (2), pichel (2), juan (2), pena (2), tomas (2), gamallo (2), pablo (2), garcia (2), marcos (2), perldoop (2), hadoop (2), clusters (2), 771 (2), 4799 (2), 5666 (2), 1109 (2), bigdata (2), 7004303 (2), 766 (2), 3rd (2), chapter (2), confused (2), perlstyle (2), perlintro (2), 1993 (2), art (2), 221 (2), s2cid (2), issn (2), behavior (2), methods (2), richardson (2), marjorie (2), council (2), blogs (2), remains (2), rename (2), worthington (2), jonathan (2), 6guts (2), plus (2), thread (2), prototypes (2), bradley (2), perl6 (2), nathan (2), goccy (2), gperl (2), moe (2), austin (2), modernperlbooks (2), preface (2), renaissance (2), announcement (2), put (2), oscon (2), bridge (2), apocalypse (2), good (2), facts (2), perl56delta (2), 005 (2), perlhist (2), records (2), help (2), 00027 (2), universal (2), students (2), usage (2), pathologically (2), eclectic (2), rubbish (2), lister (2), among (2), actually (2), backronym (2), acronym (2), expansion (2), isn (2), sheppard (2), task (2), pattern (2), everything2 (2), taken (2), path (2), separate (2), man (2), designers (2), licensing (2), repository (2), old (2), environment (2), hakodate (2), hiroshima (2), okinawa (2), kansai (2), hokkaido (2), taiwan (2), permanent (2), south (2), place (2), mova (2), herzliya (2), helsinki (2), riga (2), glasgow (2), netherlands (2), germany (2), corporate (2), portugal (2), england (2), 159 (2), london (2), tprc (2), greenville (2), las (2), vegas (2), tpcih (2), planned (2), utah (2), orlando (2), illinois (2), ontario (2), participants (2), despite (2), parallel (2), low (2), expense (2), company (2), reception (2), calling (2), cost (2), quickly (2), 155 (2), 153 (2), group (2), schedule (2), 151 (2), practice (2), poems (2), 150 (2), late (2), syntactic (2), flexibility (2), four (2), fit (2), characters (2), block (2), way (2), between (2), meant (2), likely (2), signatures (2), postings (2), performed (2), widespread (2), subsequent (2), email (2), message (2), derives (2), linguistic (2), background (2), occasionally (2), growth (2), handle (2), application (2), improve (2), slashdot (2), dbd (2), generating (2), programmatically (2), resulting (2), amounts (2), variable (2), graphical (2), simplify (2), build (2), off (2), tasks (2), creating (2), combination (2), entered (2), glue (2), varied (2), once (2), typically (2), present (2), counting (2), reasons (2), small (2), invoked (2), took (2), longer (2), expected (2), spent (2), experimental (2), therefore (2), very (2), toward (2), give (2), posix (2), variant (2), carries (2), comprehensive (2), unusual (2), special (2), independently (2), ensure (2), users (2), bugs (2), instead (2), constructs (2), turing (2), full (2), executed (2), straight (2), coordinate (2), modified (2), bison (2), lex (2), grammar (2), executes (2), optimization (2), before (2), context (2), happens (2), compilation (2), execute (2), points (2), blocks (2), eval (2), broadly (2), scalars (2), structs (2), defined (2), uninitiated (2), follow (2), consistent (2), scheme (2), nearly (2), plans (2), along (2), started (2), facto (2), txt (2), bob (2), robert (2), files (2), counter (2), named (2), strict (2), critics (2), punctuation (2), actual (2), unless (2), consistency (2), 101 (2), metamodel (2), 100 (2), looks (2), coding (2), proper (2), look (2), requirements (2), storage (2), them (2), manual (2), automatically (2), rather (2), pragma (2), implicit (2), leading (2), denoted (2), arrayname (2), structure (2), subroutines (2), broad (2), consequence (2), want (2), come (2), concise (2), limits (2), costs (2), two (2), brought (2), backward (2), upgrade (2), successor (2), boilerplate (2), get (2), primarily (2), centered (2), allowing (2), decided (2), presented (2), numbered (2), correspond (2), developing (2), synopses (2), led (2), decision (2), recent (2), random (2), dtrace (2), hooks (2), lexical (2), subs (2), still (2), updates (2), enhancements (2), intended (2), yada (2), monthly (2), existed (2), rewrite (2), numbers (2), preview (2), popularity (2), established (2), authors (2), allowed (2), 1991 (2), cover (2), existing (2), owns (2), highly (2), capitalized (2), changed (2), sixth (2), influenced (2), appearance (2), upload (2), read (2), norsk (2), bahasa (2), log (2), account (2), donate (2), menu (2), mobile, cookie, statistics, conduct, safety, contacts, disclaimers, apply, agree, registered, attribution, sharealike, rendered, parsoid, edited, utc, namespace, mismatch, permanently, unfit, periodical, scaled, images, mdy, dates, matches, programmed, interpreters, dynamically, typed, american, inventions, index, oldid, 1376416048, yale, lux, elmcip, czech, bnf, united, national, gnd, authority, revolution, cathedral, bazaar, manifesto, forking, trusted, computing, tivoization, patents, sco, controversies, firmware, device, mozilla, rebranding, proliferation, digital, rights, challenges, domain, permissive, cultural, works, guidelines, copyleft, contributor, agreement, standards, zlib, wtfpl, unlicense, sleepycat, mpl, mit, isc, lgpl, agpl, gpl, epl, cddl, bsd, beerware, apsl, afl, organisations, advocacy, ios, android, commerce, video, television, routing, office, suites, mathematics, health, wireless, graphics, configuration, codecs, audio, directories, hosting, generational, categorical, alphabetical, swift, smalltalk, scratch, sas, rust, prolog, ocaml, caml, matlab, lua, kotlin, elixir, erlang, cobol, assembly, simula, algol, ada, sean, burke, allison, damian, conway, practices, webmin, w3perl, foswiki, spamassassin, tracker, otrs, munin, makepp, ikiwiki, dada, mail, bricolage, backuppc, awstats, ssp, argus, amavis, toolkit, plack, moose, mojolicious, lwp, dancer, bioperl, resources, textbooks, quotations, wiktionary, definitions, dominus, jason, morgan, kaufmann, 55860, 701, 00313, guide, idiomatic, 4th, definitive, 1st, wrox, 6th, proceedings, fourteenth, hemel, armijn, samenscholing, leblanc, oxford, 292, 530589, exploring, dna, maher, greenwich, conn, manning, 440, 932394, scott, peter, boston, 288, 79526, 287, medic, electronic, resource, transforming, pierce, clinton, indianapolis, ind, sams, 672, 32067, arlow, jim, 1327, 0253, enterprise, mda, archetype, uml, gallo, felix, diversions, zeroth, 29degrees, back, bacon, greg, 7imnti, mjh, info2, uah, edu, incrementing, m1hfpvh2jq, fsf, halfdome, holdit, church, aka, pdfpremiumfree, querying, extensible, mapper, orm, abstraction, pachev, sasha, 55280, understanding, internals, discovering, improving, great, 1536, google, beijing, 699, perlport, quite, unstable, mar, 20101231135106, http, gabrielweinberg, amount, million, per, day, congress, movie, helpdesk, gilmore, apress, 4302, 3114, 484, novice, fourth, ingerson, cholet, eric, 00227, stein, lincoln, maceachern, 567, 0358, beattie, malcolm, enache, adrian, fastest, info, crane, dana, goodbye, prime, freeware, hietaniemi, jarkko, rice, theorem, summer, analyze, manipulate, seem, absolutely, nothing, nobody, ever, able, show, downside, parseable, perlguts, 467, carefully, distinguishes, versus, associates, 1993lepe, bibcode, miller, freeman, dobb, unknown, 199705101952, maa00756, nagpal, chand, 8121927635, perlfunc, builtin, wherefore, thou, myhrvold, conor, fastcompany, promising, gilbert, james, 38728402, 1087, 0156, 1038, nbt0302, biotechnology, tadpole, alan, 609, 61028367, 0743, 3808, 3758, bf03209477, 605, research, instruments, computers, psychologically, reformatting, linuxjournal, happened, leanpub, preparing, clark, nicholas, bump, immediately, don, think, deliver, meeting, 019, announcing, perlfoundation, lwn, nqp, jvm, news, pragmatic, bookshelf, 68050, 088, cincinnati, considerations, samples, torkington, transcription, potion, clarification, yapcna, onyxneon, milestones, perl5200delta, perl5180delta, perl5160delta, perl5140delta, perl5120delta, perlsyn, perl5100delta, pasture, broadwell, geoff, onlamp, inside, ten, perl58delta, ugly, bad, perl5005delta, patwardhan, siever, ellen, spainhour, stephen, 00241, nutshell, perl5004delta, holloway, ruth, opensource, turns, continues, thrive, docstore, mik, kalita, jugal, publishers, 58112, 550, professionals, advent, calendar, gillmore, dan, tribune, 00132, expansions, creator, came, why, caps, arguing, correct, endorses, 1449313142, wired, lido, deck, leonard, andrew, salon, joy, smith, roderick, 77423, 594, networking, unparalleled, importance, involves, matching, input, strongest, extremely, directed, textual, formats, unsurpassed, evaluations, measured, steps, effectuate, existence, impact, continuing, die, lapworth, leo, questions, occasional, idiosyncracies, let, git, ashton, elaine, 0_0505, plain, taubaté, soluções, tecnológicas, para, gestão, pública, itapema, universo, científico, hacking, curitiba, revolução, dos, dados, rio, janeiro, solução, integração, negócios, fortaleza, niterói, conjunction, conisli, jointly, thereafter, melbourne, petersburg, event, taking, netanya, haifa, koha, cancelled, coronavirus, pandemic, con, perlcon, cluj, napoca, romania, engineering, granada, sofia, bulgaria, 160, latvia, pisa, italy, lisbon, beautiful, copenhagen, denmark, social, vienna, austria, birmingham, everywhere, braga, belfast, northern, ireland, paris, munich, wednesday, 24th, friday, 26th, replaces, tuesday, saturday, 27th, covid, alexandria, virginia, madison, wisconsin, asheville, carolina, columbus, ohio, buffalo, york, boca, raton, ottawa, saint, missouri, montréal, québec, 19100, homage, dutch, reviewed, consternation, organisers, revealed, listening, unencrypted, passwords, theme, year, speech, sessions, listed, scene, priced, grassroots, benefit, either, afford, elaborately, staged, prefer, geeks, recommended, 2000s, 158, 157, rebranded, former, reflect, renaming, convention, 757, 156, spread, members, continents, never, hosted, antarctica, africa, origins, assembled, speakers, 154, kevin, lenzo, carnegie, mellon, discussing, usually, auspices, corporation, advancement, collaborative, efforts, sciences, society, tpc, 152, piece, words, regularly, black, competitions, competition, arch, virtue, awards, space, 149, reducing, key, strokes, bare, minimum, players, seek, take, shots, round, emphasized, difference, pedestrian, teach, newcomer, terse, hacks, amuse, experienced, latter, japhs, already, elsewhere, stunts, unnamed, previous, decades, encryption, prompted, interest, applied, monterey, california, 148, 147, 146, board, trend, originated, earliest, trainers, parlance, hackers, spirit, concept, moderately, comma, omitted, 145, sic, 144, summaries, progress, characterized, hallmark, humor, employing, wider, christian, eventually, 143, keynote, alongside, venue, course, evolution, shaped, broadening, services, wide, surrounds, fact, 142, especially, indirectly, generate, transparently, author, 141, 140, 139, mappers, caching, greatly, lived, environments, helping, volume, avert, load, spikes, 138, effect, 137, presents, independent, driver, details, accessing, 136, ansi, capabilities, collect, returned, arguments, thus, customize, hold, query, allows, post, subprogram, relinking, sufficiently, difficult, widely, restricted, 135, client, side, 134, sets, interpolation, wxperl, across, suppliers, cots, bespoke, packaging, deployment, 133, shelf, tying, specifically, interoperate, converting, reports, strengths, linked, intimately, liner, administrators, 132, chiefly, websites, optional, component, stack, lieu, 131, lamp, ticketmaster, 130, 129, livejournal, 128, 127, craigslist, priceline, slash, cpanel, compounded, availability, party, critical, routines, connected, flexible, 126, interpretation, checking, 125, situation, sought, address, rapidly, 124, isapi, slowly, runs, finding, within, pre, compiling, pay, penalty, startup, substantial, measure, times, skewed, 123, amortized, 122, 121, compares, problems, perform
Text of the page (random words):
ll files ending with txt in the current directory to robert perl i bak lp e s bob robert g txt implementation edit no written specification or standard for the perl language exists for perl versions through perl 5 and there are no plans to create one for the current version of perl there has been only one implementation of the interpreter and the language has evolved along with it that interpreter together with its functional tests stands as a de facto specification of the language perl 6 however started with a specification 102 and several projects 103 aim to implement some or all of the specification citation needed perl is implemented as a core interpreter written in c together with a large collection of modules written in perl and c as of 2010 update the interpreter is 150 000 lines of c code and compiles to a 1 mb executable on typical machine architectures alternatively the interpreter can be compiled to a link library and embedded in other programs there are nearly 500 modules in the distribution comprising 200 000 lines of perl and an additional 350 000 lines of c code much of the c code in the modules consists of character encoding tables citation needed the interpreter has an object oriented architecture all of the elements of the perl language scalars arrays hashes coderefs file handles are represented in the interpreter by c structs operations on these structs are defined by a large collection of macros typedefs and functions these constitute the perl c api the perl api can be bewildering to the uninitiated but its entry points follow a consistent naming scheme which provides guidance to those who use it citation needed the life of a perl interpreter divides broadly into a compile phase and a run phase 104 according to aluín et al perl cannot be parsed by a straight lex yacc lexer parser combination instead the interpreter implements its own lexer which coordinates with a modified gnu bison parser to resolve ambiguities in the language 105 most of what happens in perl s compile phase is compilation and most of what happens in perl s run phase is execution but there are significant exceptions perl makes important use of its capability to execute perl code during the compile phase perl will also delay compilation into the run phase the terms that indicate the kind of processing that is actually occurring at any moment are compile time and run time perl is in compile time at most points during the compile phase but compile time may also be entered during the run phase the compile time for code in a string argument passed to the eval built in occurs during the run phase perl is often in run time during the compile phase and spends most of the run phase in run time code in begin blocks executes at run time but in the compile phase at compile time the interpreter parses perl code into a syntax tree at run time it executes the program by walking the tree text is parsed only once and the syntax tree is subject to optimization before it is executed so that execution is relatively efficient compile time optimizations on the syntax tree include constant folding and context propagation but peephole optimization is also performed 106 perl has a turing complete grammar because parsing can be affected by run time code executed during the compile phase 107 the code cannot be parsed by a straight lex yacc lexer parser to resolve ambiguities in the language the interpreter must implement its own lexer to coordinate with a modified gnu bison parser 108 it is often said that only perl can parse perl 109 meaning that only the perl interpreter perl can parse the perl language perl but even this is not in general true because the perl interpreter can simulate a turing machine during its compile phase it would need to decide the halting problem in order to complete parsing in every case it is a longstanding result that the halting problem is undecidable and therefore not even perl can always parse perl perl makes the unusual choice of giving the user access to its full programming power in its own compile phase the cost in terms of theoretical purity is high but practical inconvenience seems to be rare 110 other programs that undertake to parse perl such as source code analyzers and auto indenters have to contend not only with ambiguous syntactic constructs but also with the undecidability of perl parsing in the general case adam kennedy s ppi project focused on parsing perl code as a document retaining its integrity as a document instead of parsing perl as executable code that not even perl itself can always do it was kennedy who first conjectured that parsing perl suffers from the halting problem 111 which was later proved 112 perl is distributed with over 250 000 functional tests for core perl language and over 250 000 functional tests for core modules these run as part of the normal build process and extensively exercise the interpreter and its core modules perl developers rely on the functional tests to ensure that changes to the interpreter do not introduce software bugs further perl users who see that the interpreter passes its functional tests on their system can have a high degree of confidence that it is working properly citation needed ports edit perl is dual licensed under both the artistic license 1 0 4 5 and the gnu general public license 6 distributions are available for most operating systems it is particularly prevalent on unix and unix like systems but it has been ported to most modern and many obsolete platforms with only six citation needed reported exceptions perl can be compiled from source code on all posix compliant or otherwise unix compatible platforms 113 because of unusual changes required for the classic mac os environment a special port called macperl was shipped independently 114 the comprehensive perl archive network carries a complete list of supported platforms with links to the distributions available on each 115 cpan is also the source for publicly available perl modules that are not part of the core perl distribution citation needed activeperl is a closed source distribution from activestate that has regular releases that track the core perl releases 116 the distribution previously included the perl package manager ppm 117 a popular tool for installing removing upgrading and managing the use of common perl modules however this tool was discontinued as of activeperl 5 28 118 included also is perlscript a windows script host wsh engine implementing the perl language visual perl is an activestate tool that adds perl to the visual studio net development suite a vbscript to perl converter a perl compiler for windows and converters of awk and sed to perl have also been produced by this company and included on the activestate cd for windows which includes all of their distributions plus the komodo ide and all but the first on the unix linux posix variant thereof in 2002 and afterward citation needed performance edit the computer language benchmarks game compares the performance of implementations of typical programming problems in several programming languages 119 the submitted perl implementations typically perform toward the high end of the memory usage spectrum and give varied speed results perl s performance in the benchmarks game is typical for interpreted languages 120 large perl programs start more slowly than similar programs in compiled languages because perl has to compile the source every time it runs in a talk at the yapc europe 2005 conference and subsequent article a timely start jean louis leroy found that his perl programs took much longer to run than expected because the perl interpreter spent significant time finding modules within his over large include path 121 unlike java python and ruby perl has only experimental support for pre compiling 122 therefore perl programs pay this overhead penalty on every execution the run phase of typical programs is long enough that amortized startup time is not substantial but benchmarks that measure very short execution times are likely to be skewed due to this overhead 123 a number of tools have been introduced to improve this situation the first such tool was apache s mod_perl which sought to address one of the most common reasons that small perl programs were invoked rapidly cgi web development activeperl via microsoft isapi provides similar performance improvements 124 once perl code is compiled there is additional overhead during the execution phase that typically isn t present for programs written in compiled languages such as c or c examples of such overhead include bytecode interpretation reference counting memory management and dynamic type checking 125 the most critical routines can be written in other languages such as c which can be connected to perl via simple inline modules or the more complex but flexible xs mechanism 126 applications edit perl has many and varied applications compounded by the availability of many standard and third party modules perl has chiefly been used to write cgi scripts large projects written in perl include cpanel slash bugzilla rt twiki and movable type high traffic websites that use perl extensively include priceline com craigslist 127 imdb 128 livejournal duckduckgo 129 130 slashdot and ticketmaster it is also an optional component of the popular lamp technology stack for web development in lieu of php or python perl is used extensively as a system programming language in the debian linux distribution 131 perl is often used as a glue language tying together systems and interfaces that were not specifically designed to interoperate and for data munging 132 that is converting or processing large amounts of data for tasks such as creating reports these strengths are linked intimately the combination makes perl a popular all purpose language for system administrators particularly because short programs often called one liner programs can be entered and run on a single command line citation needed perl code can be made portable across windows and unix such code is often used by suppliers of software both commercial off the shelf cots and bespoke to simplify packaging and maintenance of software build and deployment scripts 133 perl tk and wxperl are commonly used to add graphical user interfaces to perl scripts perl s text handling capabilities can be used for generating sql queries arrays hashes and automatic memory management make it easy to collect and process the returned data for example in tim bunce s perl dbi application programming interface api the arguments to the api can be the text of sql queries thus it is possible to program in multiple languages at the same time e g for generating a web page using html javascript and sql in a here document the use of perl variable interpolation to programmatically customize each of the sql queries and the specification of perl arrays or hashes as the structures to programmatically hold the resulting data sets from each sql query allows a high level mechanism for handling large amounts of data for post processing by a perl subprogram 134 in early versions of perl database interfaces were created by relinking the interpreter with a client side database library this was sufficiently difficult that it was done for only a few of the most important and most widely used databases and it restricted the resulting perl executable to using just one database interface at a time 135 in perl 5 database interfaces are implemented by perl dbi modules the dbi database interface module presents a single database independent interface to perl applications while the dbd database driver modules handle the details of accessing some 50 different databases there are dbd drivers for most ansi sql databases 136 dbi provides caching for database handles and queries which can greatly improve performance in long lived execution environments such as mod_perl 137 helping high volume systems avert load spikes as in the slashdot effect 138 in modern perl applications especially those written using web frameworks such as catalyst the dbi module is often used indirectly via object relational mappers such as dbix class class dbi 139 or rose db object 140 that generate sql queries and handle data transparently to the application author 141 community edit perl s culture and community has developed alongside the language itself usenet was the first public venue in which perl was introduced but over the course of its evolution perl s community was shaped by the growth of broadening internet based services including the introduction of the world wide web the community that surrounds perl was in fact the topic of wall s first state of the onion talk 142 state of the onion is the name for wall s yearly keynote style summaries on the progress of perl and its community they are characterized by his hallmark humor employing references to perl s culture the wider hacker culture wall s linguistic background sometimes his family life and occasionally even his christian background 143 each talk is first given at various perl conferences and is eventually also published online in email usenet and message board postings just another perl hacker japh programs are a common trend originated by randal l schwartz one of the earliest professional perl trainers 144 in the parlance of perl culture perl programmers are known as perl hackers and from this derives the practice of writing short programs to print out the phrase just another perl hacker sic in the spirit of the original concept these programs are moderately obfuscated and short enough to fit into the signature of an email or usenet message the canonical japh as developed by schwartz includes the comma at the end although this is often omitted 145 perl golf is the pastime of reducing the number of characters key strokes used in a perl program to the bare minimum much in the same way that golf players seek to take as few shots as possible in a round the phrase s first use 146 emphasized the difference between pedestrian code meant to teach a newcomer and terse hacks likely to amuse experienced perl programmers an example of the latter being japhs that were already used in signatures in usenet postings and elsewhere similar stunts had been an unnamed pastime in the language apl in previous decades the use of perl to write a program that performed rsa encryption prompted a widespread and practical interest in this pastime 147 in subsequent years the term code golf has been applied to the pastime in other languages 148 a perl golf apocalypse was held at perl conference 4 0 in monterey california in july 2000 as with c obfuscated code competitions were a well known pastime in the late 1990s the obfuscated perl contest was a competition held by the perl journal from 1996 to 2000 that made an arch virtue of perl s syntactic flexibility awards were given for categories such as most powerful programs that made efficient use of space and best four line signature...
|
