Lingua::Romana::Perligata(3p)

NOMEN
Lingua::Romana::Perligata -- Perl in Latin

EDITIO
This document describes version 0.605 of Lingua::Romana::Perligata released May 3, 2001.

SUMMARIUM
    use Lingua::Romana::Perligata;

    adnota Illud Cribrum Eratosthenis

    maximum tum val inquementum tum biguttam tum stadium egresso scribe.
    da meo maximo vestibulo perlegementum.

    maximum comementum tum novumversum egresso scribe.
    meis listis conscribementa II tum maximum da.
    dum damentum nexto listis decapitamentum fac
        sic
            lista sic hoc tum nextum recidementum cis vannementa listis da.
            dictum sic deinde cis tum biguttam tum stadium tum cum nextum
            comementum tum novumversum scribe egresso.
        cis

DESCRIPTIO
The Lingua::Romana::Perligata makes it possible to write Perl programs in Latin. (If you have to ask "Why?", then the answer probably won't make any sense to you either.)

The linguistic principles behind Perligata are described in:

    http://www.csse.monash.edu.au/~damian/papers/HTML/Perligata.html

The module is "use"d at the start of the program, and installs a filter which allows the rest of the program to be written in (modified) Latin, as described in the following sections.

GRAMMATICA PERLIGATA

  Variables
To simplify the mind-numbingly complex rules of declension and conjugation that govern inflexions in Latin, Perligata treats all user-defined scalar and array variables as neuter nouns of the second declension -- singular for scalars, plural for arrays.

Hashes represent something of a difficulty in Perligata, as Latin lacks an obvious way of distinguishing these "plural" variables from arrays. The solution that has been adopted is to depart from the second declension and represent hashes as masculine plural nouns of the fourth declension.

Hence, the type and role of all types variables are specified by their number and case.

When elements of arrays and hashes are referred to directly in Perl, the prefix of the container changes from "@" or "%" to "$". So it should not be surprising that Perligata also makes use of a different inflexion to distinguish these cases.

Indexing operations such as $array[$elem] or $hash{$key} might be translated as "elem of array" or "key of hash". This suggests that when arrays or hashes are indexed, their names should be rendered in the genitive (or possessive) case. Multi-level indexing operations ("$array[$row][$column]") mean "column of row of array", and hence the first indexing variable must also be rendered in the genitive.

Note that the current release of Perligata only supports homogeneous multi-level indexing. That is: "$lol[$row][$column]" or "$hoh{key}{subkey}{subsubkey}", but not "$lohol[$index1]{key}[$index2]".

The rules for specifying variables may be summarized as follows:

    Perligata    Number, Case, and Declension    Perl         Role
    =========    ============================    ====         ====
    nextum       accusative singular 2nd         $next        scalar rvalue
    nexta        accusative plural 2nd           @next        array rvalue
    nextus       accusative plural 4th           %next        hash rvalue
    nexto        dative singular 2nd             $next        scalar lvalue
    nextis       dative plural 2nd               @next        array lvalue
    nextibus     dative plural 4th               %next        hash lvalue
    nexti        genitive singular 2nd           [$next]...   scalar index
    nextorum     genitive plural 2nd             $next[...]   array element
    nextuum      genitive plural 4th             $next{...}   hash entry

In other words, scalars are always singular nouns, arrays and hashes are always plural (but of different declensions), and the case of the noun specifies its syntactic role in a statement: accusative for an rvalue, dative for an lvalue, genitive when being an index. Of course, because the inflection determines the syntactic role, the various components of a statement can be given in any order. For example, the Perl statement:

    $last = $next;

could be expressed in Perligata as any of the following ("da" is the Perligata assignment operator -- see "Built-in functions and operators"):

    lasto da nextum.
    lasto nextum da.
    nextum da lasto.
    nextum lasto da.
    da lasto nextum.
    da nextum lasto.

The special form $#array is rendered via the Perligata verb admeta ("measure out"). See "Subroutines, operators, and functions".

The common punctuation variables $_ and @_ are special cases. $_ is often the value under implicit consideration (e.g. in pattern matches, or "for" loops) and so it is rendered as "this thing": hoc as an rvalue, huic as an lvalue, huius used as an intermediate index.

Similarly, @_ is implicitly the list of things passed into a subroutine, and so is rendered as "these things": haec as an rvalue, his as an lvalue, horum when indexed.

Other punctuation variables take the Latin forms of their English.pm equivalents (see "THESAURUS PERLIGATUS"), often with a large measure of poetic licence. For example, in Perligata, $/ is rendered as ianitorem or "gatekeeper".

The "numeral" variables -- $1, $2, etc. -- are rendered as synthetic compounds: parprimum ("the equal of the first"), parsecundum ("the equal of the second"), etc. When used as interim indices, they take their genitive forms: parprimi, parsecundi, etc. Since they cannot be used as an lvalue, they have no dative forms.

The one exception is $0 (the variable storing the name of the current program), which is programma in the accusative and programmati in the dative. It also has a genitive form (programmatis), though it's hard to imagine ever needing that.

The parameter variable (@ARGV) is rendered as parametra in the accusative, parametris in the dative, and parametrorum in the genetive. Its related filehandle (*ARGV) is always dative singular: parametro

  "my", "our", and "local"
In Perligata, the "my" modifier is rendered -- not surprisingly -- by the first person possessive pronouns: meo (conferring a scalar context) and meis (for a list context). Note that the modifier is always applied to a dative (lvalue), and hence is itself declined in that case. Thus:

        meo varo haec da.                # my $var = @_;
        meis varo haec da.               # my ($var) = @_;
        meis varis haec da.              # my @var = @_;

Similarly the "our" modifier is rendered as nostro or nostris, depending on the desired context.

The Perl "local" modifier is loco or locis in Perligata:

        loco varo haec da.               # local $var = @_;
        locis varo haec da.              # local ($var) = @_;
        locis varis haec da.             # local @var = @_;

This is particularly felicitous: not only is loco the Latin term from which the word "local" derives, it also means "in place of" (as in: in loco parentis). This meaning is much closer to the actual behaviour of the "local" modifier, namely to temporarily install a new symbol table entry in place of the current one.

  Subroutines, operators, and functions
Functions, operators, and user-defined subroutines are represented as verbs or, in some situations, verbal nouns. The inflexion of the verb determines not only its syntactic role, but also its call context.

User-defined subroutines are the simplest group. To avoid ambiguities, they are all treated as verbs of the third conjugation. For example, here are the various conjugations for different usages for a user-defined subroutine count():

    Perligata       Number, Mood, etc       Perl        Role    Context
    =========       =================       ====        ====    =======
    countere        infinitive              sub count   defn    -
    counte          imperative sing.        count()     call    void
    countementum    acc. sing. resultant    count()     call    scalar
    countementa     acc. plur. resultant    count()     call    list
    countemento     dat. sing. resultant    count()     call    scalar lvalue
    countementis    dat. plur. resultant    count()     call    list lvalue

The use of the infinitive as a subroutine definition is obvious: accipere would tell Perligata how "to accept"; spernere, how "to reject". So countere specifies how "to count".

The use of the imperative for void context is also straightforward: accipe commands Perligata to "accept!", sperne tells it to "reject!", and counte bids it "count!". In each case, an instruction is being given (and in a void context too, so no backchat is expected).

Handling scalar and list contexts is a little more challenging. The corresponding Latin must still have verbal properties, since an action is being performed upon objects. But it must also have the characteristics of a noun, since the result of the call will itself be used as the object (i.e. target or data) of some other verb. Fortunately, Latin has a rich assortment of verbal nouns -- far more than English -- that could fill this role.

Since it is the result of the subroutine call that is of interest here, the chosen solution was to use the -ementum suffix, which specifies the (singular, accusative) outcome of an action. This corresponds to the result of a subroutine called in a scalar context and used as data. For a list data context, the plural suffix -ementa is used, and for targets, the dative forms are used: -emento and -ementis. Of course, Perl does not (yet) support lvalue subroutines that return a list/array, so the -mentis suffix currently triggers an error.

Note that these resultative endings are completely consistent with those for variables.

  Built-in functions and operators
Built-in operators and functions could have followed the same "dog-latin" pattern as subroutines. For example "shift" might have been shifte in a void context, shiftementa when used as data in an array context, shiftemento when used as a target in a scalar context, etc.

However, Latin already has a perfectly good verb with the same meaning as "shift": decapitare ("to behead"). Unfortunately, this verb is of the first conjugation, not the second, and hence has the imperative form decapita, which makes it look like a Perligata array in a data role.

Orthogonality has never been Perl's highest design criterion, so Perligata follows suit by eschewing bland consistency in favour of aesthetics. All Perligata keywords -- including function and operator names -- are therefore specified as correct Latin verbs, of whatever conjugation is required. For example:

    Operator/  Literal        In void     When used as      When used as
    function   meaning        context     scalar rvalue     list rvalue
    ========   =======        =======     =============     ============
    +          "add"          adde        addementum        addementa
    =          "give"         da          damentum          damenta
    .          "conjoin"      sere        serementum        serementa
    ..         "enlist"       conscribe   conscribementum   conscribementa

    shift      "behead"       decapita    decapitamentum    decapitamenta

    push       "stack"        cumula      cumulamentum      cumulamenta
    pop        "unstack"      decumula    decumulamentum    decumulamenta

    grep       "winnow"       vanne       vannementum       vannementa
    print      "write"        scribe      scribementum      scribementa
    write      "write below"  subscribe   subscribementum   subscribementa

    die        "die"          mori        morimentum        morimenta

The full list of Perligata keywords is provided in "THESAURUS PERLIGATUS".

Note, however, that consistency has not been entirely forsaken. The back-formations of inflexions for scalar and list context are entirely regular, and consistent with those for user-defined subroutines (described above).

A few Perl built-in functions -- "pos", "substr", "keys" -- can be used as lvalues. That is, they can be the target of some other action (typically of an assignment). In Perligata such cases are written in the dative singular (since the lvalues are always scalar). Note too that, because an assignment to an lvalue function modifies its first argument, that argument must be a target too, and hence must be written in the dative as well.

Thus:

        nexto stringum reperimentum da.     # $next = pos $string;
        nextum stringo reperimento da.      # pos $string = $next;

        inserto stringum tum unum tum duo excerpementum da.
                                            # $insert = substr($string,1,2);
        insertum stringo unum tum duo excerpemento da.
                                            # substr($string,1,2) = $insert;

        clavis hashus nominamentum da.      # @keys = keys %hash;
        clava hashibus nominamento da.      # keys %hash = @keys;

An interesting special case is the $#array construction, which in Perligata is rendered via the verb admeta:

    counto da arraya admetamentum.      # $count = $#array;

  Comments
In Perligata, comments are rendered by the verb adnota ("annotate") and extend until the end of the line. For example:

    nexto da prevum.    adnota mensuram antiquam reserva

means:

    $next = $prev;      # remember old amount

  Imposing precedence on argument lists
The order-independence of argument lists and subroutine calls largely makes up for the lack of bracketing in Perligata. For example, the Perl statement:

    $res = foo(bar($xray,$yell),$zip);

can be written:

     reso da xrayum tum yellum barmentum tum zipum foomentum.

Note that the lack of argument list brackets in Perligata means that if it were written:

    reso da foomentum barmentum xrayum tum yellum tum zipum.

it would be equivalent to:

    $res = foo(bar($xray,$yell,$zip));

instead.

Likewise, it is possible to translate:

    $res = foo($xray,bar($yell,$zip));

like so:

    reso da xrayum tum barmentum yellum tum zipum foomentum.

But translating:

    $res = foo($weld,bar($xray,$yell),$zip);

presents a difficulty.

In the first example above (xrayum tum yellum barmentum tum zipum foomentum), the verb barmentum was used as a suffix on xrayum tum yellum -- to keep the variable zipum out of the argument list of the call to "bar". In the second example (xrayum tum barmentum yellum tum zipum foomentum), the verb barmentum was used as a prefix on yellum tum zipum -- to keep the variable xrayum out of the argument list.

But in this third example, it's necessary to keep both weldum and zipum out of "bar"'s argument list. Unfortunately, barmentum can't be both a prefix (to isolate weldum) and a suffix (to isolate zipum) simultaneously.

The solution is to use the preposition cum (meaning "with...") at the start of "bar"'s argument list, with barmentum as a suffix at the end of the list:

        reso da foomentum weldum tum cum xrayum tum yellum barmentum tum zipum.

It is always permissible to specify the start of a nested argument list with a cum, so long as the governing verb is used as a suffix.

  Blocks and control structures
Natural languages generally use some parenthetical device -- such as parentheses, commas, or (as here) dashes -- to group and separate collections of phrases or statements.

Some such mechanism would be an obvious choice for denoting Perligata code blocks, but there is a more aesthetically pleasing solution. Perl's block delimiters ("{".."}") have two particularly desirable properties: they are individually short, and collectively symmetrical. It was considered important to retain those characteristics in Perligata.

In Latin, the word sic has a sense that means "as follows". Happily, its heteropalindrome, cis, has the meaning (among others) "to here", making these two words perfect heteroantigrams (just like "{" and "}"). The allure of this kind of wordplay being impossible to resist, Perligata delimits blocks of statements with these two words. For example:

        sic                                     # {
            loco ianitori.                      #   local $/;
            dato nuntio perlegementum da.       #   $data = <DATA>;
        cis                                     # }

Control structures in Perligata are rendered as conditional clauses, as they are in Latin, English, and Perl. And as in those other languages, they may precede or follow the code blocks they control.

Perligata provides the following control structures:

    Perligata                        Perl
    =========                        ====
    si ... fac                       if ...
    nisi ... fac                     unless ...
    dum ... fac                      while ...
    donec ... fac                    until ...
    per (quisque) ... in ... fac     for(each) ...
    posterus                         next
    ultimus                          last
    reconatus                        redo
    confectus                        continue

The trailing fac is the imperative form of facere ("to do") and is used as a delimiter on the control statement's condition. It is required, regardless of whether the control statement precedes or follows its block.

The choice of dum and donec is completely arbitrary, since Latin does not distinguish "while" and "until" as abstractions in the way English does. Dum and donec each mean both "while" and "until", and Latin relies on context (i.e. semantics) to distinguish them. This is impractical for Perligata, so it always treats dum as "while" and donec as "until". This choice was made in order to favour the shorter term for the more common type of loop.

The choice of confectus for "continue" seeks to convey the function of the control structure, not the literal meaning of the English word. That is, a "continue" block specifies how to complete (conficere) an iteration.

Perligata only supports the pure iterative form of for(each), not the C-like three-part syntax.

Because:

        foreach $var (@list) {...}

means "for each variable in the list...", the scalar variable must be in the accusative (as it is governed by the preposition "for"), and the list must be in the ablative (denoting inclusion). Fortunately, in the second declension, the inflexion for ablatives is exactly the same as for datives, giving:

        per quisque varum in listis sic ... cis

This means that no extra inflexions have to be learned just to use the per loop. Better still, the list (listis) looks like a Perligata array variable in a target role, which it clearly is, since its contents may be modified within the loop.

Note that you can also omit the accusative variable completely:

        per quisque in listis sic ... cis

and leave hoc ($_) implied, as in regular Perl.

  Data
The "__END__" and "__DATA__" markers in Perligata are finis ("boundary") and nuntius ("information") respectively. Data specified after either of these markers is available via the input stream nuntio. For example:

        dum perlege nuntio fac sic              # while (<DATA>) {
                scribe egresso hoc.             #       print $_;
        cis                                     # }
                                                #
        finis                                   # __END__
        post                                    # post
        hoc                                     # hoc
        ergo                                    # ergo
        propter                                 # propter
        hoc                                     # hoc

  Numbers
Numeric literals in Perligata are rendered by Roman numerals -- I, II, III, IV...XV...XLII, etc, up to (((((((I)))))))((((((((I))))))))((((((I))))))(((((((I)))))))(((((I)))))((((((I))))))((((I))))(((((I)))))(((I)))((((I))))((I))(((I)))M((I))CMXCIX (that is: 9,999,999,999)

The digits are:

           Roman            Arabic
           =====            ======
             I                       1
             V                       5
             X                      10
             L                      50
             C                     100
             D                     500
             M                   1,000
             I))                 5,000
           ((I))                10,000
             I)))               50,000
          (((I)))              100,000
             I))))             500,000
         ((((I))))           1,000,000
             I)))))          5,000,000
        (((((I)))))         10,000,000
             I))))))       500,000,000
       ((((((I))))))     1,000,000,000
             I)))))))    5,000,000,000
      (((((((I)))))))   10,000,000,000

The value ((I)) is 10,000 and every additional pair of apostrophi (rendered as parentheses in ASCII) multiply that value by 10.

Notice that those wacky Romans literally used "half" of each big number (e.g. I)), I))), etc.) to represent half of each big numbers (i.e. 5000, 50000, etc.)

The first 10 numbers may also be referred to by name: unum/unam, duo/duas, tres, quattuor, quinque, sex, septem, octo, novem, decem. Zero, for which there is no Latin numeral, is rendered by nullum ("no-one"). Nihil ("nothing") might have been a closer rendering, but it is indeclinable and hence indistinguishable in the accusative and genitive.

When a numeric literal is used in an indexing operation, it must be an ordinal: "zeroth (element)", "first (element)", "second (element)", etc.

The first ten ordinals are named (in the accusative): primum/primam, secundum/secundam, tertium/tertiam, quartum/quartam, quintum/quintam, sextum/sextam, septimum/septimam, octavum/octavam, nonum/nonam, decimum/decimam. Ordinals greater than ten are represented by their corresponding numeral with the suffix -imum: XVimum ("15th"), XLIIimum ("42nd"), etc. By analogy, ordinal zero is rendered by the invented form nullimum.

If the element being indexed is used as an lvalue, then the ordinal must of course be in the dative instead: nullimo, primo, secundo, tertio, quarto, quinto, sexto, septimo, octavo, nono, decimo, XIimo, etc. Note that the feminine dative forms are not available in Perligata, as they are ambiguous with the feminine genitive singular forms.

In a multi-level indexing operation, ordinals may need to be specified in the genitive: nulli/nullae, primi/primae, secundi/secundae, tertii/tertiae...XVimi/XVimae, etc.

For example:

        $unimatrix[1][3][9][7];

would be:

        septimum noni tertii primi unimatrixorum

which is literally:

        seventh of ninth of third of first of unimatrix

Note that the order of the genitives is significant here, and is the reverse of that required in Perl.

As mentioned in "Variables", Perligata currently only supports homogeneous multi-level indexing. If the final genitive indicates an array (e.g. unimatrixorum in the previous example), then the preceding index is assumed to be an array index. If the final genitive indicates a hash, every preceding genitive, and the original ordinal are presumed to be keys. For example:

        septimum noni tertii primi unimatrixorum   # $unimatrix[1][3][9][7];
        septimum noni tertii primi unimatrixuum    # $unimatrix{1}{3}{9}{7};

Floating point numbers are expressed in Perligata as Latin fractions:

        unum quartum                  # 0.25
        MMMCXLI Mimos                 # 3.141

Note that the numerator is always a cardinal and the denominator a (singular or plural) ordinal ("one fourth", "3141 1000ths"). The plural of a Latin accusative ordinal is formed by replacing the -um suffix by -os. This nicety can be ignored, as Perligata will accept fractions in the form MMMCXLI Mimum ("3141 1000th")

Technically, both numerator and denominator should also be in the feminine gender -- una quartam, MMMCXLI Mimas. This Latin rule is not enforced in Perligata (to help minimize the number of suffixes that must be remembered), but Perligata does accept the feminine forms.

Perligata outputs numbers in Arabic, but the verb come ("beautify") may be used to convert numbers to proper Roman numerals:

        per quisque in I tum C conscribementum sic
                hoc tum duos multiplicamentum comementum egresso scribe.
        cis

  Strings
Classical Latin does not use punctuation to denote direct quotation. Instead the verb inquit ("said") is used to report a direct utterance. Hence in Perligata, a literal character string is constructed, not with quotation marks, but by invoking the verbal noun inquementum ("the result of saying"), with a data list of literals to be interpolated. For example:

        print STDOUT 'Enter next word:';

becomes:

        Enter tum next tum word inquementum tum biguttam egresso scribe.

Note that the arguments to inquementum are special, in that they are treated as literals. Punctuation strings have special names, such as lacunam ("a hole") for space, stadium ("a stride") for tabspace, novumversum ("new verse") for newline, comma ("comma") for comma, guttam ("a spot") for period, or biguttam ("two spots") for colon.

It is also possible to directly quote a series of characters (as if they were inside a "q{...}". The Perligata equivalent is a dictum sic...cis:

        sic Enter next word : cis dictum egresso scribe.

or:

        dictum sic Enter next word : cis egresso scribe.

"dictum" is, of course, a contraction of "dicementum" ("the result of saying"), and Perligata allows this older form as well.

Perligata does not provide an interpolated quotation mechanism. Instead, variables must be concatenated into a string. So:

        print STDERR "You entered $word\n";
        $mesg = "You entered $word";

becomes:

        You tum entered inquementum tum wordum tum novumversum oraculo scribe.
        mesgo da You tum entered inquementum tum wordum serementum.

  Regular expressions
[Perligata's regular expression mechanism is not yet implemented. This section outlines how it will work in a future release.]

In Perligata, patterns will be specified in a constructive syntax (as opposed to Perl's declarative approach). Literals will be regular strings and other components of a pattern will be adjectives, verbs, nouns, or a connective:

    Perl        Perligata       Meaning
    ====        =========       =======
    ...+?       multum          "many"
    ...+        plurissimum     "most"
    ...??       potis           "possible"
    ...?        potissimum      "most possible"
    (...)       captivum        "captured"
    (?=...)     excuba          "keep watch"
    [...]       opta            "choose between"
    .           quidlibet       "anything"
    \d          digitum         "a finger"
    \s          lacunam albam   "a white space"
    \w          litteram        "a character"
    |           an              interrogative "or"

The final pattern will be produced using the supine desideratum. For example:

        pato da desideratum                         # $pat = qr/(?x)
            C tum plurissimum A tum O opta tum T    #          C[AO]+T
            an DOG tum potissimum GY.               #          |DOG(?:GY)?/;

Actual matching against a pattern will be done via the compara ("match") and substitue ("substitute") verbs:

        si stringum patum comparamentum fac sic   # if ($string =~ /$pat/) {
                scribe egresso par inquementum    #    print "match"
        cis                                       #

        huic substitue patum tum valum            # s/$pat/$val/
                per quisque in listis.            #    foreach @list;

Note that the string being modified by substitue will have to be dative.

  References
To create a reference to a variable, the variable is written in the ablative (which looks exactly like the dative in Perligata's restricted Latin syntax) and prefaced with the preposition ad ("to"). To create a reference to a subroutine, the associated verb is inflected with the accusative suffix -torem ("one who...") to produce the corresponding noun-of-agency.

For example:

        val inquemento hashuum ad dato da.       # $hash{'val'} = \$dat;
        arg inquemento hashuum ad argis da.      # $hash{'arg'} = \@arg;
        act inquemento hashuum functorem da.     # $hash{'act'} = \&func;

        ad val inquemento hashuum dato da.       # $dat   = \$hash{'val'};
        ad inquemento arg hashuum argis da.      # @arg   = \$hash{'arg'};
        funcemento da ad inquemento act hashuum. # func() = \$hash{'act'};

A special case of this construction is the anonymous subroutine constructor factorem ("one who does..."), which is the equivalent of "sub {...}" in Perl:

        anonymo da factorem sic haec mori cis.    # $anon = sub { die @_ };

As in Perl, such subroutines may be invoked by concatenating a call specifier to the name of the variable holding the reference:

        anonymume nos tum morituri inquementum.   # &$anon('Nos morituri');

Note that the variable holding the reference (anonymum) is being used as data, so it is named in the accusative.

In the few cases where a subroutine reference can be the target of an action, the dative suffix (-tori) is used instead:

        benedictum functori classum.              # bless \&func, $class;
        benedictum factori sic mori cis classum.  # bless sub{die}, $class;

To dereference other types of references, a resultative of the verb arcesse ("fetch") is used:

        Ref type        Perligata               Perl            Context
        ========        =========               ====            =======
        scalar          arcessementum varum     $$var           rvalue
        scalar          arcessemento varum      $$var           lvalue
        array           arcessementi varum      ...[$$var]      rvalue

        array           arcessementa varum      @$var           rvalue
        array           arcessementis varum     @$var           lvalue
        array           arcessementorum varum   $var->[...]     either

        hash            arcessementus varum     %$var           rvalue
        hash            arcessementibus varum   %$var           lvalue
        array           arcessementuum varum    $var->{...}     either

Note that the first six forms are just the standard resultatives (in accusative, dative, and genitive) for the regular Perligata verb arcesse. The last three forms are ungrammatical inflections (-mentum is 2nd declension, not 4th), but are plausible extensions of the resultative to denote a hash return value.

Multiple levels of dereferencing are also possible:

        valo da arcessementa arcessementum varum    # $val = @$$var;

as is appropriate indexing (using the genitive forms):

        valo da primum varum arcessementorum        # $val = $var->[1];
        valo da primum varum arcessementuum         # $val = $var->{1};
        valo da primum varum arcessementi arrorum   # $val = $arr[$$var][1];

  Boolean logic
Perl's logical conjunctive and disjunctive operators come in two precedences, and curiously, so do those of Latin. The higher precedence Perl operators -- "&&" and "||" -- are represented in Perligata by the emphatic Latin conjunctions atque and vel respectively. The lower precedence operators -- "and" and "or" -- are represented by the unemphatic conjunctive suffixes -que and -ve. Hence:

        reso damentum foundum atque runementum.   # $res = $found && run();
        reso damentum foundum runementumque.      # $res = $found and run();
        reso damentum foundum vel runementum.     # $res = $found || run();
        reso damentum foundum runementumve.       # $res = $found or run();

Note that, as in Latin, the suffix of the unemphatic conjunction is always appended to the first word after the point at which the conjunction would appear in English. Thus:

        $result = $val or max($1,$2);

is rendered as:

        resulto damentum valum parprimumve tum parsecundum maxementum.

or:

        resulto damentum valum maxementumve parprimum tum parsecundum.

Proper Latinate comparisons would be odious in Perligata, because they require their first argument to be expressed in the nominative and would themselves have to be indicative. This would, of course, improve the positional independence of the language even further, allowing:

        si valus praecedit datum...              # if $val < $dat...
        si praecedit datum valus...              # if $val < $dat...
        si datum valus praecedit...              # if $val < $dat...

Unfortunately, it also introduces another set of case inflexions and another verbal suffix. Worse, it would mean that noun suffixes are no longer unambiguous. In the 2nd declension, the nominative plural ends in the same -i as the genitive singular, and the nominative singular ending (-us) is the same as the accusative plural suffix for the fourth declension. So if nominatives were used, scalars could no longer always be distinguished from arrays or from hashes, except by context.

To avoid these problems, Perligata represents the equality and simple inequality operators by three pairs of verbal nouns:

    Perligata       Meaning                     Perl
    =========       =======                     ====
    aequalitam      "equality (of...)"          ==
    aequalitas      "equalities (of...)"        eq
    praestantiam    "precedence (of...)"        <
    praestantias    "precedences (of...)"       lt
    comparitiam     "comparison (of...)"        <=>
    comparitias     "comparisons (of...)"       cmp

Each operator takes two data arguments, which it compares:

        si valum tum datum aequalitam           # si $val == $dat
        si valum tum datum praestantias         # si $val lt $dat
        si aum tum bum comparitiam              # si $a <=> $b

The effects of the other comparison operators -- ">", "<=", "!=", "ne", "ge", etc. -- are all achieved by appropriate ordering of the two arguments and combination with the the logical negation operator non:

        si valum tum datum non aequalitam     # if $val != $dat
        si datum tum valum praestantiam       # if $val > $dat
        si valum non praestantias datum       # if $val ge $dat

  Packages, classes, and modules
The Perligata keyword to declare a package is domus, literally "the house of". In this context, the name of the class follows the keyword and is treated as a literal; as if it were the data argument of an inquementum.

To explicitly specify a variable or subroutine as belonging to a package, the preposition intra ("within") is used. To call a subroutine as a method of a particular package (or of an object), the preposition apud ("of the house of") is used. Thus intra is Perligata's "::" and apud is its "->".

Inheritance is specified by the legatarius statement, within a "domus". The name of the base class follows the keyword and is treated as a literal. This is equivalent to Perl's "use base" pragma.

The Perl "bless" function is benedice in Perligata, but almost invariably used in the scalar accusative form benedicementum. Perligata also understands the correct (contracted) Latin form of this verb: benedictum.

Thus:

        domus Exemplar intra Simplicio.             # package Simplicio::Exemplar;

        printere                                    # sub print
        sic                                         # {
            modus tum indefinitus inquementum mori. #   die 'method undefined';
        cis                                         # }

        domus Specimen.                             # package Specimen;
        legatarius Exemplar intra Simplicio.        # use base 'Simplicio::Exemplar';

        newere                                      # sub new
        sic                                         # {
            meis datibus.                           #   my %data;
            counto intra Specimen postincresce.     #   $Specimen::count++;
            datibus primum horum benedictum.        #   bless \%data, $_[0];
        cis                                         # }

        printere                                    # sub print
        sic                                         # {
            meo selfo his decapitamentum da.        #     my $self = shift @_;
            haec inquementum carpe.                 #     carp "@_";
        cis                                         # }

        domus princeps.                             # package main;

        meo objecto da                              # my $object =
                newementum apud Specimen.           #       Specimen->new;

        printe apud objectum;                       # $object->print;

To import semantics from external modules, the Perl "use" function is ute ("use") in Perligata. Note that many module name components end in character patterns that match Perligata syntactic suffixes; e.g. the "Type" in "File::Type" ends with an "e", and "e" is used as a suffix to represent a subroutine call in void context. To prevent Perligata from misinterpreting such name components, the keyword sicut ("as it certainly is") is used to tell Perligata to not interpret the suffix as being syntactically significant.

For example:

        strict ute.                                 # use strict;
        warnings ute.                               # use warnings;

        Type sicut intra File ute.                  # use File::Type;

        meo specio da                               # my $type =
            newementum apud Type intra File.        #     File::Type->new();

Without the sicut keyword in the ute line, the "e" in "Type" would be interpreted as being syntactically significant, and an error would be reported on that line. (Note that the "e" in "File" on the ute line and those in "Type" and "File" on the da line do not require their own sicut keywords, since there is no ambiguity as to whether they might represent subroutine calls in void context.)

  ERA (Expositio Rustica Antiqua)
Perligata supports almost the same set of documentation blocks as Perl. (See perlpod for details).

However, whereas POD blocks are introduced by an "=" sign, ERA blocks are prefixed with the interjection: "Ecce" ("Behold!")

Just as with POD, each ERA documentation block must be the first thing on a line, and opens a documentation section that continues until the next "Ecce seco" ("Behold! I cut") command.

ERA also recognizes two unheralded block types: verbatim blocks, which are lines of text starting on the left margin; and code blocks, which are lines of text that are indented. All the standard Perl formatting codes — "B<>", "I<>", "C<>", "E<>", etc. — are also supported.

The following table lists the available ERA documentation blocks:

    Perligata                    Perl equivalent

    ecce explico                 =pod
    ecce prosum                  =for
    ecce incipio                 =begin
    ecce finio                   =end
    ecce intitulo primum         =head1
    ecce intitulo secundum       =head2
    ecce intitulo tertium        =head3
    ecce intitulo quartum        =head4
    ecce intitulo quintum        =head5
    ecce intitulo sextum         =head6
    ecce ad dextram              =over
    ecce ad sinistram            =back
    ecce facio punctum           =item *
    ecce numero punctum          =item 1.
    ecce definio <TERM>          =item <TERM>
    ecce seco                    =cut

The module also ships with a script (bin/explica) which can convert ERA to POD and pass it to "perldoc" for display.

THESAURUS PERLIGATUS
This section lists the complete Perligata vocabulary, except for Roman numerals (I, II, III, etc.)

In each of the following tables, the three columns are always the same: "Perl construct", "Perligata equivalent", "Literal meaning of Perligata equivalent".

Generally, only the accusative form is shown for nouns and adjectives, and only the imperative for verbs.

  Values and variables
        0            nullum           "no-one"
        1            unum             "one"
        2            duo              "two"
        3            tres             "three"
        4            quattuor         "four"
        5            quinque          "five"
        6            sex              "six"
        7            septem           "seven"
        8            octo             "eight"
        9            novem            "nine"
        10           decem            "ten"
        [0]          nullimum         "zeroth"
        [1]          primum           "first"
        [2]          secundum         "second"
        [3]          tertium          "third"
        [4]          quartum          "fourth"
        [5]          quintum          "fifth"
        [6]          sextum           "sixth"
        [7]          septimum         "seventh"
        [8]          octavum          "eighth"
        [9]          nonum            "ninth"
        [10]         decimum          "tenth"
        $0           programma        "the program"
        $1           parprimum        "equal of the first"
        $2           parsecundum      "equal of the first"
        $3           partertium       "equal of the third"
        $4           parquartum       "equal of the fourth"
        $5           parquintum       "equal of the fifth"
        $6           parsextum        "equal of the sixth"
        $7           parseptimum      "equal of the seventh"
        $8           paroctavum       "equal of the eighth"
        $9           parnonum         "equal of the ninth"
        $10          pardecimum       "equal of the tenth"
        $/           ianitorem        "gatekeeper"
        $#var        admeta varum     "measure out"
        $_           hoc/huic         "this thing"
        @_           his/horum        "these things"
        $<           nomen            "a name"
        @ARGV        parametra        "parameters"
        ","          comma            "a comma"
        "."          guttam           "a spot"
        ":"          biguttam         "two spots"
        ";"          semicolon        "semicolon"
        " "          lacunam          "a gap"
        "\t"         stadium          "a stride"
        "\n"         novumversum      "new line"
        local        loco             "in place of"
        my           meo              "my"
        our          nostro           "our"
        main         princeps         "principal"

  Quotelike operators
        '...'        inque        "say"
        q//          inque        "say"
        m//          compara      "match"
        s///         substitue    "substitute"
        tr///        converte     "translate"

  Mathematical operators and functions
        +            adde         "add"
        -            deme         "subtract"
        -            nega         "negate"
        *            multiplica   "multiply"
        /            divide       "divide"
        %            recide       "lop off"
        **           eleva        "raise"
        &            consocia     "unite"
        |            interseca    "intersect"
        ^            discerne     "differentiate (between)"
        ++           preincresce  "increase beforehand"
        ++           postincresce "increase afterwards"
        --           predecresce  "decrease beforehand"
        --           postdecresce "decrease afterwards"
        abs          priva        "strip from"
        atan2        angula       "create an angle"
        sin          oppone       "oppose"
        cos          accuba       "lie beside"
        int          decolla      "behead"
        log          succide      "log a tree"
        sqrt         fode         "root into"
        rand         conice       "guess, cast lots"
        srand        prosemina    "to scatter seed"

  Logical and comparison operators
        !            non             "general negation"
        &&           atque           "empathic and"
        ||           vel             "emphatic or"
        and          -que            "and"
        or           -ve             "or"
        <            praestantiam    "precedence of"
        lt           praestantias    "precedences of"
        <=>          comparitiam     "comparison of"
        cmp          comparitias     "comparisons of"
        ==           aequalitam      "equality of"
        eq           aequalitas      "equalities of"

  Strings
        chomp        morde        "bite"
        chop         praecide     "cut short"
        chr          inde         "give a name to"
        hex          senidemi     "sixteen at a time"
        oct          octoni       "eight at a time"
        ord          numera       "number"
        lc           deminue      "diminish"
        lcfirst      minue        "diminish"
        uc           amplifica    "increase"
        ucfirst      amplia       "increase"
        quotemeta    excipe       "make an exception"
        crypt        huma         "inter"
        length       meta         "measure"
        pos          reperi       "locate"
        pack         convasa      "pack baggage"
        unpack       deconvasa    "unpack"
        split        scinde       "split"
        study        stude        "study"
        index        scruta       "search"
        join         coniunge     "join"
        substr       excerpe      "extract"

  Scalars, arrays, and hashes
        defined      confirma     "verify"
        undef        iani         "empty, make void"
        scalar       secerna      "to distinguish, isolate"
        reset        lusta        "cleanse"
        pop          decumula     "unstack"
        push         cumula       "stack"
        shift        decapita     "behead"
        unshift      capita       "crown"
        splice       iunge        "splice"
        grep         vanne        "winnow"
        map          applica      "apply to"
        sort         digere       "sort"
        reverse      retexe       "reverse"
        delete       dele         "delete"
        each         quisque      "each"
        exists       adfirma      "confirm"
        keys         nomina       "name"
        values       argue        "to disclose the contents"

  I/O
        open         evolute      "open a book"
        close        claude       "close a book"
        eof          extremus     "end of"
        read         lege         "read"
        getc         sublege      "pick up something"
        readline     perlege      "read through"
        print        scribe       "write"
        printf       describe     "describe"
        sprintf      rescribe     "rewrite"
        write        subscribe    "write under"
        pipe         inriga       "irrigate"
        tell         enunta       "tell"
        seek         conquire     "to seek out"
        ARGV         parametro    "(from) a parameter"
        DATA         nuntio       "(from) the information"
        STDIN        vestibulo    "(from) the entrance"
        STDOUT       egresso      "(to) the exit"
        STDERR       oraculo      "(to) the place where doom is pronounced"

  Control structures
        {...}        sic...cis                "as follows...to here"
        do           fac                      "do"
        sub {...}    factorem sic...cis       "one who does ...
        eval         aestima                  "evaluate"
        exit         exi                      "exit"
        for          per...in...fac           "for...in...do"
        foreach      per quisque...in...fac   "for each...in...do"
        goto         adi                      "go to"
        <label>:     inscribe <label>         "make a mark"
        return       redde                    "return"
        if           si...fac                 "if"
        unless       nisi...fac               "if not"
        until        donec...fac              "until"
        while        dum...fac                "while"
        wantarray    deside                   "want"
        last         ultimus                  "final"
        next         posterus                 "following"
        redo         reconatus                "trying again"
        continue     confectus                "complete"
        die          mori                     "die"
        warn         mone                     "warn"
        croak        coaxa                    "croak (like a frog)"
        carp         carpe                    "carp at"
        __DATA__     nuntius                  "information"
        __END__      finis                    "a boundary"

  Packages, classes, and modules
        ->           apud         "of the house of"
        ::           intra        "within"
        bless        benedice     "bless"
        caller       memora       "recount a history"
        package      domus        "house of"
        ref          agnosce      "identify"
        tie          liga         "tie"
        tied         exhibe       "display something"
        untie        solve        "to untie"
        require      require      "require"
        use          ute          "use"

  System and filesystem interaction
        chdir        demigrare    "migrate"
        chmod        permitte     "permit"
        chown        vende        "sell"
        fcntl        modera       "control"
        flock        confluee     "flock together"
        glob         inveni       "search"
        ioctl        impera       "command"
        link         copula       "link"
        unlink       decopula     "unlink"
        mkdir        aedifica     "build"
        rename       renomina     "rename"
        rmdir        excide       "raze"
        stat         exprime      "describe"
        truncate     trunca       "shorten"
        alarm        terre        "frighten"
        dump         mitte        "drop"
        exec         commuta      "transform"
        fork         furca        "fork"
        kill         interfice    "kill"
        sleep        dormi        "sleep"
        system       obsecra      "entreat a higher power"
        umask        dissimula    "mask"
        wait         manta        "wait for"

  Documentation
        =pod           ecce explico             "Behold! I explain"
        =for           ecce prosum              "Behold! I am for"
        =begin         ecce incipio             "Behold! I begin"
        =end           ecce finio               "Behold! I end"
        =head1         ecce intitulo primum     "Behold! I primarily entitle"
        =head2         ecce intitulo secundum   "Behold! I secondarily entitle"
        =head3         ecce intitulo tertium    "Behold! I tertiarily entitle"
        =head4         ecce intitulo quartum    "Behold! I quaternarily entitle"
        =head5         ecce intitulo quintum    "Behold! I quinarily entitle"
        =head6         ecce intitulo sextum     "Behold! I senarily entitle"
        =over          ecce ad dextram          "Behold! (I move) to the right"
        =back          ecce ad sinistram        "Behold! (I move) to the left"
        =item *        ecce facio punctum       "Behold! I make a point"
        =item 1.       ecce numero punctum      "Behold! I enumerate a point"
        =item <TERM>   ecce definio <TERM>      "Behold! I define <TERM>"
        =cut           ecce seco                "Behold! I cut"

  Miscellaneous
        ,            tum          "and then"
        .            sere         "conjoin"
        ..           conscribe    "enlist"
        \            ad           "towards"
        =            da           "give"
        #...         adnota       "annotate"
        (...         cum          "with"
        to_roman     come         "beautify"

DIIUDICATORES
The Lingua::Romana::Perligata module may issue the following diagnostic messages:

Aliquod barbarum inveni: '%s'
    Some foreign (non-Perligata) symbol was encountered. Commonly this is a semi-colon where a period should have been used, but any other non-alphanumeric will trigger the same error.

'-mentis' illicitum: '%s'
    Perl does not (yet) support lvalue subroutines that return arrays. Hence Perligata does not allow the -mentis suffix to be used on user-defined verbs.

Index '%s' ordinalis non est
    An index or key was specified as a numeral (e.g. unum), rather than an ordinal (e.g. primum).

'%s' immaturum est
    The symbol indicated (typically tum) appeared too early in the command (e.g. before any accusative).

Iussum nefastum: '%s'
    The indicated imperative verb was encountered where a resultative was expected (e.g. the imperative was incorrectly used as an argument to another subroutine or a conjunction).

Accusativum non junctum: '%s'
    The indicated accusative noun or clause appears in a command, but does not belong to any verb in the command.

Dativum non junctum: '%s'
    The indicated dative noun or clause appears in a command, but does not belong to any verb in the command.

Genitivum non junctum: '%s'
    The indicated genitive noun or clause appears in a command, but does not belong to any verb in the command.

Sententia imperfecta prope '%s'
    The command or clause is missing an imperative verb.

Exspectavi 'sic' sed inveni '%s'
    The beginning of a code block was expected at the point where the indicated word was found.

Exspectavi 'cis' sed inveni '%s'
    The end of a code block was expected at the point where the indicated word was found.

Exspectavi accusativum post 'per' sed inveni '%s'
    The per control structure takes an accusative noun after it. The indicated symbol was found instead.

'in' pro 'per' afuit
    The in in a per statement was missing.

'%s' dativus non est in 'per'
    After the in of a per statement a dative noun or clause is required. It was not found.

Iussa absentia per '%s'
    The block of the indicated control statement was missing.

Non intellexi: '%s'
    A general error message indicating the symbol was not understood in the context it appeared.

In addition to these diagnostics, additional debugging support is provided in the form of three arguments that may be passed to the call to "use Lingua::Romana::Perligata".

The first of these -- 'converte' ("translate") -- causes the module to translate the Perligata code into Perl and write it to STDOUT instead of executing it. This is useful when your Perligata compiles and runs, but does not execute as you expected.

The second argument that may be passed when loading the module is 'discribe' ("classify"), which causes the module to print a lexical analysis of the original Latin program. This is very handy for identifying incorrect inflections, etc.

The final argument -- 'investiga', ("trace") -- provides a blow-by-blow trace of the translation process, tracking eack of the internal stacks (the verb stack, the accusative stack, the dative stack, the block stack), and showing where each reduction is performed. This wealth of information tends to be useful only to those familiar with the internals of the module.

GRATIAE
Special thanks to Marc Moskowitz, John Crossley, Tom Christiansen, and Bennett Todd, for their invaluable feedback and suggestions. And my enduring gratitude to David Secomb and Deane Blackman for their heroic patience in helping me struggle with the perplexities of the lingua Romana.

SCRIPTOR
Damian Conway (damian@conway.org)

CIMICES
There are undoubtedly some very serious bugs lurking somewhere in code this funky :-) Bug reports and other feedback are most welcome.

Corrections to my very poor Latin are doubly welcome.

IUS TRANSCRIBENDI
Copyright (c) 2000-2020, Damian Conway. All Rights Reserved. This module is free software. It may be used, redistributed and/or modified under the terms of the Perl Artistic License
  (see http://www.perl.com/perl/misc/Artistic.html)