Why does modern Perl avoid UTF-8 by default

Perl, a almighty and versatile scripting communication, has a agelong and typically analyzable relation with Unicode, particularly UTF-eight. Piece contemporary Perl variations are full susceptible of dealing with UTF-eight, it’s not the default encoding for inner operations. This tin beryllium complicated for newcomers and equal seasoned builders. Knowing wherefore Perl makes this prime is cardinal to penning sturdy and moveable Perl scripts, particularly once dealing with matter from divers sources. Truthful, wherefore does contemporary Perl debar UTF-eight by default, and what are the implications for builders?

Decoding Perl’s Default Encoding

Perl’s humanities discourse performs a important function successful its actual dealing with of quality encodings. Developed earlier Unicode’s general adoption, Perl initially centered connected byte-oriented processing. This meant treating characters arsenic azygous bytes, which labored fine for ASCII however not for languages with bigger quality units. Arsenic Unicode and UTF-eight gained prominence, Perl developed to activity them, however the center byte-oriented quality remained. This means that internally, Perl strings are not robotically assumed to beryllium UTF-eight.

This byte-oriented attack provides show benefits successful definite situations, particularly once dealing with ample records-data oregon information streams wherever quality encoding overhead tin beryllium important. Nevertheless, it besides locations the onus of encoding and decoding connected the developer. Failing to grip encodings appropriately tin pb to information corruption oregon surprising behaviour.

This nuanced attack permits for flexibility and ratio however requires cautious direction of encoding contexts. Knowing these subtleties is important for penning dependable Perl codification that handles matter appropriately.

The Value of Express Encoding Declarations

To guarantee accurate dealing with of UTF-eight information successful Perl, it’s indispensable to state the encoding explicitly. This tells Perl however to construe the bytes successful your strings. The about communal manner to bash this is utilizing the usage utf8; pragma. This tells Perl that your origin codification itself is encoded successful UTF-eight. It’s crucial to spot this pragma astatine the opening of your book.

For dealing with outer information, specified arsenic record enter oregon web streams, you’ll demand to usage features similar decode and encode. decode converts outer information into Perl’s inner cooperation, piece encode performs the reverse cognition once outputting information. Utilizing these features constantly is captious for avoiding encoding-associated points.

Present’s a elemental illustration demonstrating the usage of decode and encode:

usage Encode; my $utf8_data = decode('UTF-eight', $external_data); Procedure $utf8_data my $output_data = encode('UTF-eight', $utf8_data);

Champion Practices for UTF-eight successful Perl

Adopting accordant practices for dealing with UTF-eight is critical for penning sturdy Perl scripts. Ever state the encoding of your origin codification utilizing usage utf8;. Usage decode and encode once dealing with outer information, guaranteeing that you specify the accurate encoding.

State origin codification encoding: usage utf8;
Decode enter information: decode('UTF-eight', $input_data);

See utilizing modules similar Encode::Locale to mechanically grip locale-circumstantial encodings. Thorough investigating, together with with antithetic quality units and locales, is important for figuring out and resolving encoding-associated bugs.

Fit locale: setlocale(LC_ALL, 'en_US.UTF-eight');
Procedure information in accordance to locale.

By pursuing these champion practices, you tin guarantee that your Perl codification handles Unicode accurately, stopping information corruption and surprising behaviour.

Running with Outer Libraries and Modules

Once integrating with outer libraries oregon modules, it’s important to realize their encoding assumptions. Any libraries whitethorn anticipate UTF-eight enter, piece others whitethorn not. Seek the advice of the documentation for all room to find the accurate attack. If a room doesn’t explicitly activity UTF-eight, you whitethorn demand to encode oregon decode information accordingly earlier passing it to oregon receiving it from the room.

Being alert of these possible inconsistencies and dealing with them proactively volition forestall sudden points and guarantee creaseless interoperability betwixt antithetic parts of your Perl exertion. Appropriate encoding direction contributes importantly to the general stableness and reliability of your codification, particularly once dealing with divers information sources.

A large assets for Perl Unicode accusation is perluniintro.

“Appropriate encoding dealing with is not conscionable a method item; it’s cardinal to making certain information integrity and exertion reliability.” - Larry Partition (Perl creator, paraphrased).

FAQ

Q: What is the quality betwixt usage utf8; and usage encoding 'utf8';?

A: usage utf8; declares the origin codification encoding arsenic UTF-eight, piece usage encoding 'utf8'; units the default encoding for enter/output operations.

Knowing Perl’s attack to UTF-eight empowers builders to compose strong and moveable functions. By embracing express encoding declarations and implementing champion practices, we guarantee information integrity and debar communal pitfalls. Commencement incorporating these methods into your Perl initiatives present for much dependable and internationally suitable codification. Research associated matters similar quality encoding successful another programming languages and the past of Unicode for a deeper knowing. For deeper insights connected Unicode activity successful Perl, we urge checking retired Perl.com and MetaCPAN. Dive deeper into Perl’s intricacies by exploring the authoritative documentation disposable connected perldoc.perl.org and detect much astir effectual drawstring manipulation strategies successful Perl. Besides, cheque retired much astir Perl Unicode astatine this informative assets.

Question & Answer :
I wonderment wherefore about contemporary options constructed utilizing Perl don’t change UTF-eight by default.

I realize location are galore bequest issues for center Perl scripts, wherever it whitethorn interruption issues. However, from my component of position, successful the 21^st period, large fresh initiatives (oregon initiatives with a large position) ought to brand their package UTF-eight impervious from scratch. Inactive I don’t seat it taking place. For illustration, Moose allows strict and warnings, however not Unicode. Contemporary::Perl reduces boilerplate excessively, however nary UTF-eight dealing with.

Wherefore? Are location any causes to debar UTF-eight successful contemporary Perl tasks successful the twelvemonth 2011?

Commenting @tchrist bought excessively agelong, truthful I’m including it present.

It appears that I did not brand myself broad. Fto maine attempt to adhd any issues.

tchrist and I seat occupation beautiful likewise, however our conclusions are wholly successful other ends. I hold, the occupation with Unicode is complex, however this is wherefore we (Perl customers and coders) demand any bed (oregon pragma) which makes UTF-eight dealing with arsenic casual arsenic it essential beryllium these days.

tchrist pointed to galore points to screen, I volition publication and deliberation astir them for days oregon equal weeks. Inactive, this is not my component. tchrist tries to be that location is not 1 azygous manner “to change UTF-eight”. I person not truthful overmuch cognition to reason with that. Truthful, I implement to unrecorded examples.

I performed about with Rakudo and UTF-eight was conscionable location arsenic I wanted. I didn’t person immoderate issues, it conscionable labored. Possibly location are any regulation location deeper, however astatine commencement, each I examined labored arsenic I anticipated.

Shouldn’t that beryllium a end successful contemporary Perl 5 excessively? I emphasis it much: I’m not suggesting UTF-eight arsenic the default quality fit for center Perl, I propose the expectation to set off it with a catch for these who create fresh tasks.

Different illustration, however with a much antagonistic speech. Frameworks ought to brand improvement simpler. Any years agone, I tried internet frameworks, however conscionable threw them distant due to the fact that “enabling UTF-eight” was truthful obscure. I did not discovery however and wherever to hook Unicode activity. It was truthful clip-consuming that I recovered it simpler to spell the aged manner. Present I noticed present location was a bounty to woody with the aforesaid job with Mason 2: However to brand Mason2 UTF-eight cleanable?. Truthful, it is beautiful fresh model, however utilizing it with UTF-eight wants heavy cognition of its internals. It is similar a large reddish gesture: Halt, don’t usage maine!

I truly similar Perl. However dealing with Unicode is achy. I inactive discovery myself moving towards partitions. Any manner tchrist is correct and solutions my questions: fresh initiatives don’t pull UTF-eight due to the fact that it is excessively complex successful Perl 5.

𝙎𝙞𝙢𝙥𝙡𝙚𝙨𝙩 ℞: 𝟕 𝘿𝙞𝙨𝙘𝙧𝙚𝙩𝙚 𝙍𝙚𝙘𝙤𝙢𝙢𝙚𝙣𝙙𝙖𝙩𝙞𝙤𝙣𝙨

Fit your PERL_UNICODE envariable to Arsenic. This makes each Perl scripts decode @ARGV arsenic UTF‑eight strings, and units the encoding of each 3 of stdin, stdout, and stderr to UTF‑eight. Some these are planetary results, not lexical ones.
Astatine the apical of your origin record (programme, module, room, bashhickey), prominently asseverate that you are moving perl interpretation 5.12 oregon amended through:
```
usage v5.12; # minimal for unicode drawstring characteristic usage v5.14; # optimum for unicode drawstring characteristic 
```
Change warnings, since the former declaration lone permits strictures and options, not warnings. I besides propose selling Unicode warnings into exceptions, truthful usage some these strains, not conscionable 1 of them. Line nevertheless that nether v5.14, the utf8 informing people includes 3 another subwarnings which tin each beryllium individually enabled: nonchar, surrogate, and non_unicode. These you whitethorn want to exert better power complete.
```
usage warnings; usage warnings qw( Deadly utf8 ); 
```
State that this origin part is encoded arsenic UTF‑eight. Though erstwhile upon a clip this pragma did another issues, it present serves this 1 singular intent unsocial and nary another:
```
usage utf8; 
```
State that thing that opens a filehandle inside this lexical range however not elsewhere is to presume that that watercourse is encoded successful UTF‑eight until you archer it other. That manner you bash not impact another module’s oregon another programme’s codification.
```
usage unfastened qw( :encoding(UTF-eight) :std ); 
```

Change named characters through \N{CHARNAME}.

usage charnames qw( :afloat :abbreviated );

If you person a Information grip, you essential explicitly fit its encoding. If you privation this to beryllium UTF‑eight, past opportunity:
```
binmode(Information, ":encoding(UTF-eight)"); 
```

Location is of class nary extremity of another issues with which you whitethorn yet discovery your self afraid, however these volition suffice to approximate the government end to “brand every little thing conscionable activity with UTF‑eight”, albeit for a slightly weakened awareness of these status.

1 another pragma, though it is not Unicode associated, is:

usage autodie;

It is powerfully really useful.

🌴 🐪🐫🐪 🌞 𝕲𝖔 𝕿𝖍𝖔𝖚 𝖆𝖓𝖉 𝕯𝖔 𝕷𝖎𝖐𝖊𝖜𝖎𝖘𝖊 🌞 🐪🐫🐪 🐁

🎁 🐪 𝕭𝖔𝖎𝖑𝖊𝖗⸗𝖕𝖑𝖆𝖙𝖊 𝖋𝖔𝖗 𝖀𝖓𝖎𝖈𝖔𝖉𝖊⸗𝕬𝖜𝖆𝖗𝖊 𝕮𝖔𝖉𝖊 🐪 🎁

My ain boilerplate these days tends to expression similar this:

usage 5.014; usage utf8; usage strict; usage autodie; usage warnings; usage warnings qw< Deadly utf8 >; usage unfastened qw< :std :utf8 >; usage charnames qw< :afloat >; usage characteristic qw< unicode_strings >; usage Record::Basename qw< basename >; usage Carp qw< carp croak confess cluck >; usage Encode qw< encode decode >; usage Unicode::Normalize qw< NFD NFC >; Extremity { adjacent STDOUT } if (grep /\P{ASCII}/ => @ARGV) { @ARGV = representation { decode("UTF-eight", $_) } @ARGV; } $zero = basename($zero); # shorter messages $| = 1; binmode(Information, ":utf8"); # springiness a afloat stack dump connected immoderate untrapped exceptions section $SIG{__DIE__} = sub { confess "Uncaught objection: @_" except $^S; }; # present advance tally-clip warnings into stack-dumped # exceptions *except* we're successful an attempt artifact, successful # which lawsuit conscionable cluck the stack dump alternatively section $SIG{__WARN__} = sub { if ($^S) { cluck "Trapped informing: @_" } other { confess "Lethal informing: @_" } }; piece (<>) { chomp; $_ = NFD($_); ... } proceed { opportunity NFC($_); } __END__

🎅 𝕹 𝖔 𝕸 𝖆 𝖌 𝖎 𝖈 𝕭 𝖚 𝖑 𝖑 𝖊 𝖙 🎅

==========

Saying that “Perl ought to [someway!] change Unicode by default” doesn’t equal commencement to statesman to deliberation astir getting about to saying adequate to beryllium equal marginally utile successful any kind of uncommon and remoted lawsuit. Unicode is overmuch overmuch much than conscionable a bigger quality repertoire; it’s besides however these characters each work together successful galore, galore methods.

Equal the elemental-minded minimal measures that (any) group look to deliberation they privation are assured to miserably interruption thousands and thousands of strains of codification, codification that has nary accidental to “improve” to your spiffy fresh Courageous Fresh Planet modernity.

It is manner manner manner much complex than group unreal. I’ve idea astir this a immense, entire batch complete the ancient fewer years. I would emotion to beryllium proven that I americium incorrect. However I don’t deliberation I americium. Unicode is basically much analyzable than the exemplary that you would similar to enforce connected it, and location is complexity present that you tin ne\’er expanse nether the carpet. If you attempt, you’ll interruption both your ain codification oregon person other’s. Astatine any component, you merely person to interruption behind and larn what Unicode is astir. You can’t unreal it is thing it is not.

🐪 goes retired of its manner to brand Unicode casual, cold much than thing other I’ve always utilized. If you deliberation this is atrocious, attempt thing other for a piece. Past travel backmost to 🐪: both you volition person returned to a amended planet, oregon other you volition convey cognition of the aforesaid with you truthful that we tin brand usage of your fresh cognition to brand 🐪 amended astatine these issues.

💡 𝕴𝖉𝖊𝖆𝖘 𝖋𝖔𝖗 𝖆 𝖀𝖓𝖎𝖈𝖔𝖉𝖊 ⸗ 𝕬𝖜𝖆𝖗𝖊 🐪 𝕷𝖆𝖚𝖓𝖉𝖗𝖞 𝕷𝖎𝖘𝖙 💡

Astatine a minimal, present are any issues that would look to beryllium required for 🐪 to “change Unicode by default”, arsenic you option it:

Each 🐪 origin codification ought to beryllium successful UTF-eight by default. You tin acquire that with usage utf8 oregon export PERL5OPTS=-Mutf8.
The 🐪 Information grip ought to beryllium UTF-eight. You volition person to bash this connected a per-bundle ground, arsenic successful binmode(Information, ":encoding(UTF-eight)").
Programme arguments to 🐪 scripts ought to beryllium understood to beryllium UTF-eight by default. export PERL_UNICODE=A, oregon perl -CA, oregon export PERL5OPTS=-CA.
The modular enter, output, and mistake streams ought to default to UTF-eight. export PERL_UNICODE=S for each of them, oregon I, O, and/oregon E for conscionable any of them. This is similar perl -CS.
Immoderate another handles opened by 🐪 ought to beryllium thought-about UTF-eight except declared other; export PERL_UNICODE=D oregon with i and o for peculiar ones of these; export PERL5OPTS=-CD would activity. That makes -CSAD for each of them.
Screen some bases positive each the streams you unfastened with export PERL5OPTS=-Mopen=:utf8,:std. Seat uniquote.
You don’t privation to girl UTF-eight encoding errors. Attempt export PERL5OPTS=-Mwarnings=Deadly,utf8. And brand certain your enter streams are ever binmoded to :encoding(UTF-eight), not conscionable to :utf8.
Codification factors betwixt 128–255 ought to beryllium understood by 🐪 to beryllium the corresponding Unicode codification factors, not conscionable unpropertied binary values. usage characteristic "unicode_strings" oregon export PERL5OPTS=-Mfeature=unicode_strings. That volition brand uc("\xDF") eq "SS" and "\xE9" =~ /\w/. A elemental export PERL5OPTS=-Mv5.12 oregon amended volition besides acquire that.
Named Unicode characters are not by default enabled, truthful adhd export PERL5OPTS=-Mcharnames=:afloat,:abbreviated,italic,greek oregon any specified. Seat uninames and tcgrep.
You about ever demand entree to the capabilities from the modular Unicode::Normalize module assorted varieties of decompositions. export PERL5OPTS=-MUnicode::Normalize=NFD,NFKD,NFC,NFKD, and past ever tally incoming material done NFD and outbound material from NFC. Location’s nary I/O bed for these but that I’m alert of, however seat nfc, nfd, nfkd, and nfkc.
Drawstring comparisons successful 🐪 utilizing eq, ne, lc, cmp, kind, &c&cc are ever incorrect. Truthful alternatively of @a = kind @b, you demand @a = Unicode::Collate->fresh->kind(@b). Mightiness arsenic fine adhd that to your export PERL5OPTS=-MUnicode::Collate. You tin cache the cardinal for binary comparisons.
🐪 constructed-ins similar printf and compose bash the incorrect happening with Unicode information. You demand to usage the Unicode::GCString module for the erstwhile, and some that and besides the Unicode::LineBreak module arsenic fine for the second. Seat uwc and unifmt.
If you privation them to number arsenic integers, past you are going to person to tally your \d+ captures done the Unicode::UCD::num relation due to the fact that 🐪’s constructed-successful atoi(three) isn’t presently intelligent adequate.
You are going to person filesystem points connected 👽 filesystems. Any filesystems silently implement a conversion to NFC; others silently implement a conversion to NFD. And others bash thing other inactive. Any equal disregard the substance altogether, which leads to equal higher issues. Truthful you person to bash your ain NFC/NFD dealing with to support sane.
Each your 🐪 codification involving a-z oregon A-Z and specified Essential Beryllium Modified, together with m//, s///, and tr///. It ought to base retired arsenic a screaming reddish emblem that your codification is breached. However it is not broad however it essential alteration. Getting the correct properties, and knowing their casefolds, is more durable than you mightiness deliberation. I usage unichars and uniprops all azygous time.
Codification that makes use of \p{Lu} is about arsenic incorrect arsenic codification that makes use of [A-Za-z]. You demand to usage \p{High} alternatively, and cognize the ground wherefore. Sure, \p{Lowercase} and \p{Less} are antithetic from \p{Ll} and \p{Lowercase_Letter}.
Codification that makes use of [a-zA-Z] is equal worse. And it tin’t usage \pL oregon \p{Missive}; it wants to usage \p{Alphabetic}. Not each alphabetics are letters, you cognize!
If you are trying for 🐪 variables with /[\$\@\%]\w+/, past you person a job. You demand to expression for /[\$\@\%]\p{IDS}\p{IDC}*/, and equal that isn’t reasoning astir the punctuation variables oregon bundle variables.
If you are checking for whitespace, past you ought to take betwixt \h and \v, relying. And you ought to ne\’er usage \s, since it DOES NOT Average [\h\v], opposite to fashionable content.
If you are utilizing \n for a formation bound, oregon equal \r\n, past you are doing it incorrect. You person to usage \R, which is not the aforesaid!
If you don’t cognize once and whether or not to call Unicode::Stringprep, past you had amended larn.
Lawsuit-insensitive comparisons demand to cheque for whether or not 2 issues are the aforesaid letters nary substance their diacritics and specified. The best manner to bash that is with the modular Unicode::Collate module. Unicode::Collate->fresh(flat => 1)->cmp($a, $b). Location are besides eq strategies and specified, and you ought to most likely larn astir the lucifer and substr strategies, excessively. These are person chiseled advantages complete the 🐪 constructed-ins.
Generally that’s inactive not adequate, and you demand the Unicode::Collate::Locale module alternatively, arsenic successful Unicode::Collate::Locale->fresh(locale => "de__phonebook", flat => 1)->cmp($a, $b) alternatively. See that Unicode::Collate::->fresh(flat => 1)->eq("d", "ð") is actual, however Unicode::Collate::Locale->fresh(locale=>"is",flat => 1)->eq("d", "ð") is mendacious. Likewise, “ae” and “æ” are eq if you don’t usage locales, oregon if you usage the Nation 1, however they are antithetic successful the Icelandic locale. Present what? It’s pugnacious, I archer you. You tin drama with ucsort to trial any of these issues retired.
See however to lucifer the form CVCV (consonsant, vowel, consonant, vowel) successful the drawstring “niño”. Its NFD signifier — which you had darned fine amended person remembered to option it successful — turns into “nin\x{303}o”. Present what are you going to bash? Equal pretending that a vowel is [aeiou] (which is incorrect, by the manner), you received’t beryllium capable to bash thing similar (?=[aeiou])\X) both, due to the fact that equal successful NFD a codification component similar ‘ø’ does not decompose! Nevertheless, it volition trial close to an ‘o’ utilizing the UCA examination I conscionable confirmed you. You tin’t trust connected NFD, you person to trust connected UCA.

💩 𝔸 𝕤 𝕤 𝕦 𝕞 𝕖 𝔹 𝕣 𝕠 𝕜 𝕖 𝕟 𝕟 𝕖 𝕤 𝕤 💩

And that’s not each. Location are a cardinal breached assumptions that group brand astir Unicode. Till they realize these issues, their 🐪 codification volition beryllium breached.

Codification that assumes it tin unfastened a matter record with out specifying the encoding is breached.
Codification that assumes the default encoding is any kind of autochthonal level encoding is breached.
Codification that assumes that internet pages successful Nipponese oregon Island return ahead little abstraction successful UTF‑sixteen than successful UTF‑eight is incorrect.
Codification that assumes Perl makes use of UTF‑eight internally is incorrect.
Codification that assumes that encoding errors volition ever rise an objection is incorrect.
Codification that assumes Perl codification factors are constricted to 0x10_FFFF is incorrect.
Codification that assumes you tin fit $/ to thing that volition activity with immoderate legitimate formation separator is incorrect.
Codification that assumes roundtrip equality connected casefolding, similar lc(uc($s)) eq $s oregon uc(lc($s)) eq $s, is wholly breached and incorrect. See that the uc("σ") and uc("ς") are some "Σ", however lc("Σ") can not perchance instrument some of these.
Codification that assumes all lowercase codification component has a chiseled uppercase 1, oregon vice versa, is breached. For illustration, "ª" is a lowercase missive with nary uppercase; whereas some "ᵃ" and "ᴬ" are letters, however they are not lowercase letters; nevertheless, they are some lowercase codification factors with out corresponding uppercase variations. Acquired that? They are not \p{Lowercase_Letter}, contempt being some \p{Missive} and \p{Lowercase}.
Codification that assumes altering the lawsuit doesn’t alteration the dimension of the drawstring is breached.
Codification that assumes location are lone 2 instances is breached. Location’s besides titlecase.
Codification that assumes lone letters person lawsuit is breached. Past conscionable letters, it turns retired that numbers, symbols, and equal marks person lawsuit. Successful information, altering the lawsuit tin equal brand thing alteration its chief broad class, similar a \p{Grade} turning into a \p{Missive}. It tin besides brand it control from 1 book to different.
Codification that assumes that lawsuit is ne\’er locale-babelike is breached.
Codification that assumes Unicode provides a fig astir POSIX locales is breached.
Codification that assumes you tin distance diacritics to acquire astatine basal ASCII letters is evil, inactive, breached, encephalon-broken, incorrect, and justification for superior penalty.
Codification that assumes that diacritics \p{Diacritic} and marks \p{Grade} are the aforesaid happening is breached.
Codification that assumes \p{GC=Dash_Punctuation} covers arsenic overmuch arsenic \p{Sprint} is breached.
Codification that assumes sprint, hyphens, and minuses are the aforesaid happening arsenic all another, oregon that location is lone 1 of all, is breached and incorrect.
Codification that assumes all codification component takes ahead nary much than 1 mark file is breached.
Codification that assumes that each \p{Grade} characters return ahead zero mark columns is breached.
Codification that assumes that characters which expression alike are alike is breached.
Codification that assumes that characters which bash not expression alike are not alike is breached.
Codification that assumes location is a bounds to the figure of codification factors successful a line that conscionable 1 \X tin lucifer is incorrect.
Codification that assumes \X tin ne\’er commencement with a \p{Grade} quality is incorrect.
Codification that assumes that \X tin ne\’er clasp 2 non-\p{Grade} characters is incorrect.
Codification that assumes that it can’t usage "\x{FFFF}" is incorrect.
Codification that assumes a non-BMP codification component that requires 2 UTF-sixteen (surrogate) codification models volition encode to 2 abstracted UTF-eight characters, 1 per codification part, is incorrect. It doesn’t: it encodes to azygous codification component.
Codification that transcodes from UTF‐sixteen oregon UTF‐32 with starring BOMs into UTF‐eight is breached if it places a BOM astatine the commencement of the ensuing UTF-eight. This is truthful anserine the technologist ought to person their eyelids eliminated.
Codification that assumes the CESU-eight is a legitimate UTF encoding is incorrect. Likewise, codification that thinks encoding U+0000 arsenic "\xC0\x80" is UTF-eight is breached and incorrect. These guys besides merit the eyelid care.
Codification that assumes characters similar > ever factors to the correct and < ever factors to the near are incorrect — due to the fact that they successful information bash not.
Codification that assumes if you archetypal output quality X and past quality Y, that these volition entertainment ahead arsenic XY is incorrect. Generally they don’t.
Codification that assumes that ASCII is bully adequate for penning Nation decently is anserine, shortsighted, illiterate, breached, evil, and incorrect. Disconnected with their heads! If that appears excessively utmost, we tin compromise: henceforth they whitethorn kind lone with their large toed from 1 ft. (The remainder volition beryllium duct taped.)
Codification that assumes that each \p{Mathematics} codification factors are available characters is incorrect.
Codification that assumes \w accommodates lone letters, digits, and underscores is incorrect.
Codification that assumes that ^ and ~ are punctuation marks is incorrect.
Codification that assumes that ü has an umlaut is incorrect.
Codification that believes issues similar ₨ incorporate immoderate letters successful them is incorrect.
Codification that believes \p{InLatin} is the aforesaid arsenic \p{Italic} is heinously breached.
Codification that accept that \p{InLatin} is about always utile is about surely incorrect.
Codification that believes that fixed $FIRST_LETTER arsenic the archetypal missive successful any alphabet and $LAST_LETTER arsenic the past missive successful that aforesaid alphabet, that [${FIRST_LETTER}-${LAST_LETTER}] has immoderate which means in any respect is about ever absolute breached and incorrect and meaningless.
Codification that believes person’s sanction tin lone incorporate definite characters is anserine, violative, and incorrect.
Codification that tries to trim Unicode to ASCII is not simply incorrect, its perpetrator ought to ne\’er beryllium allowed to activity successful programming once more. Play. I’m not equal affirmative they ought to equal beryllium allowed to seat once more, since it evidently hasn’t accomplished them overmuch bully truthful cold.
Codification that believes location’s any manner to unreal textfile encodings don’t be is breached and unsafe. Mightiness arsenic fine poke the another oculus retired, excessively.
Codification that converts chartless characters to ? is breached, anserine, braindead, and runs opposite to the modular advice, which says NOT TO Bash THAT! RTFM for wherefore not.
Codification that believes it tin reliably conjecture the encoding of an unmarked textfile is blameworthy of a deadly mélange of hubris and naïveté that lone a lightning bolt from Zeus volition hole.
Codification that believes you tin usage 🐪 printf widths to pad and warrant Unicode information is breached and incorrect.
Codification that believes erstwhile you efficiently make a record by a fixed sanction, that once you tally ls oregon readdir connected its enclosing listing, you’ll really discovery that record with the sanction you created it nether is buggy, breached, and incorrect. Halt being amazed by this!
Codification that believes UTF-sixteen is a mounted-width encoding is anserine, breached, and incorrect. Revoke their programming licence.
Codification that treats codification factors from 1 flat 1 whit otherwise than these from immoderate another flat is ipso facto breached and incorrect. Spell backmost to schoolhouse.
Codification that believes that material similar /s/i tin lone lucifer "S" oregon "s" is breached and incorrect. You’d beryllium amazed.
Codification that makes use of \P.m.\p.m.* to discovery grapheme clusters alternatively of utilizing \X is breached and incorrect.
Group who privation to spell backmost to the ASCII planet ought to beryllium entire-heartedly inspired to bash truthful, and successful award of their superb improve they ought to beryllium offered free of charge with a pre-electrical guide typewriter for each their information-introduction wants. Messages dispatched to them ought to beryllium dispatched by way of an ᴀʟʟᴄᴀᴘs telegraph astatine forty characters per formation and manus-delivered by a courier. Halt.

😱 𝕾 𝖀 𝕸 𝕸 𝕬 𝕽 𝖄 😱

===

I don’t cognize however overmuch much “default Unicode successful 🐪” you tin acquire than what I’ve written. Fine, sure I bash: you ought to beryllium utilizing Unicode::Collate and Unicode::LineBreak, excessively. And most likely much.

Arsenic you seat, location are cold excessively galore Unicode issues that you truly bash person to concern astir for location to always be immoderate specified happening arsenic “default to Unicode”.

What you’re going to detect, conscionable arsenic we did backmost successful 🐪 5.eight, that it is merely intolerable to enforce each these issues connected codification that hasn’t been designed correct from the opening to relationship for them. Your fine-that means selfishness conscionable broke the full planet.

And equal erstwhile you bash, location are inactive captious points that necessitate a large woody of idea to acquire correct. Location is nary control you tin flip. Thing however encephalon, and I average existent encephalon, volition suffice present. Location’s a heck of a batch of material you person to larn. Modulo the retreat to the guide typewriter, you merely can not anticipation to sneak by successful ignorance. This is the 21ˢᵗ period, and you can’t want Unicode distant by willful ignorance.

You person to larn it. Play. It volition ne\’er beryllium truthful casual that “every little thing conscionable plant,” due to the fact that that volition warrant that a batch of issues don’t activity — which invalidates the presumption that location tin always beryllium a manner to “brand it each activity.”

You whitethorn beryllium capable to acquire a fewer tenable defaults for a precise fewer and precise constricted operations, however not with out reasoning astir issues a entire batch much than I deliberation you person.

Arsenic conscionable 1 illustration, canonical ordering is going to origin any existent complications. 😭"\x{F5}" ‘õ’, "o\x{303}" ‘õ’, "o\x{303}\x{304}" ‘ȭ’, and "o\x{304}\x{303}" ‘ō̃’ ought to each lucifer ‘õ’, however however successful the planet are you going to bash that? This is tougher than it appears to be like, however it’s thing you demand to relationship for. 💣

If location’s 1 happening I cognize astir Perl, it is what its Unicode bits bash and bash not bash, and this happening I commitment you: “ ̲ᴛ̲ʜ̲ᴇ̲ʀ̲ᴇ̲ ̲ɪ̲s̲ ̲ɴ̲ᴏ̲ ̲U̲ɴ̲ɪ̲ᴄ̲ᴏ̲ᴅ̲ᴇ̲ ̲ᴍ̲ᴀ̲ɢ̲ɪ̲ᴄ̲ ̲ʙ̲ᴜ̲ʟ̲ʟ̲ᴇ̲ᴛ̲ ̲ ” 😞

You can not conscionable alteration any defaults and acquire creaseless cruising. It’s actual that I tally 🐪 with PERL_UNICODE fit to "SA", however that’s each, and equal that is largely for bid-formation material. For existent activity, I spell done each the galore steps outlined supra, and I bash it precise, ** precise** cautiously.

😈 ¡ƨdləɥ ƨᴉɥʇ əbashɥ puɐ ʻλɐp əɔᴉu ɐ əʌɐɥ ʻʞɔnl poo⅁ 😈

Why does modern Perl avoid UTF-8 by default