Lingua::EN::Inflect(3)User Contributed Perl DocumentatioLingua::EN::Inflect(3)NAMELingua::EN::Inflect - Convert singular to plural. Select "a" or "an".
VERSION
This document describes version 1.892 of Lingua::EN::InflectSYNOPSIS
use Lingua::EN::Inflect qw ( PL PL_N PL_V PL_ADJ NO NUM
PL_eq PL_N_eq PL_V_eq PL_ADJ_eq
A AN
PART_PRES
ORD NUMWORDS
WORDLIST
inflect classical
def_noun def_verb def_adj def_a def_an );
# UNCONDITIONALLY FORM THE PLURAL
print "The plural of ", $word, " is ", PL($word), "\n";
# CONDITIONALLY FORM THE PLURAL
print "I saw $cat_count ", PL("cat",$cat_count), "\n";
# FORM PLURALS FOR SPECIFIC PARTS OF SPEECH
print PL_N("I",$N1), PL_V("saw",$N1),
PL_ADJ("my",$N2), PL_N("saw",$N2), "\n";
# DEAL WITH "0/1/N" -> "no/1/N" TRANSLATION:
print "There ", PL_V("was",$errors), NO(" error",$errors), "\n";
# USE DEFAULT COUNTS:
print NUM($N1,""), PL("I"), PL_V(" saw"), NUM($N2), PL_N(" saw");
print "There ", NUM($errors,''), PL_V("was"), NO(" error"), "\n";
# COMPARE TWO WORDS "NUMBER-INSENSITIVELY":
print "same\n" if PL_eq($word1, $word2);
print "same noun\n" if PL_N_eq($word1, $word2);
print "same verb\n" if PL_V_eq($word1, $word2);
print "same adj.\n" if PL_ADJ_eq($word1, $word2);
# ADD CORRECT "a" OR "an" FOR A GIVEN WORD:
print "Did you want ", A($thing), " or ", AN($idea), "\n";
# CONVERT NUMERALS INTO ORDINALS (i.e. 1->1st, 2->2nd, 3->3rd, etc.)
print "It was", ORD($position), " from the left\n";
# CONVERT NUMERALS TO WORDS (i.e. 1->"one", 101->"one hundred and one", etc.)
# IN A SCALAR CONTEXT: GET BACK A SINGLE STRING...
$words = NUMWORDS(1234); # "one thousand, two hundred and thirty-four"
$words = NUMWORDS(ORD(1234)); # "one thousand, two hundred and thirty-fourth"
# IN A LIST CONTEXT: GET BACK A LIST OF STRINGSi, ONE FOR EACH "CHUNK"...
@words = NUMWORDS(1234); # ("one thousand","two hundred and thirty-four")
# OPTIONAL PARAMETERS CHANGE TRANSLATION:
$words = NUMWORDS(12345, group=>1);
# "one, two, three, four, five"
$words = NUMWORDS(12345, group=>2);
# "twelve, thirty-four, five"
$words = NUMWORDS(12345, group=>3);
# "one twenty-three, forty-five"
$words = NUMWORDS(1234, 'and'=>'');
# "one thousand, two hundred thirty-four"
$words = NUMWORDS(1234, 'and'=>', plus');
# "one thousand, two hundred, plus thirty-four"
$words = NUMWORDS(555_1202, group=>1, zero=>'oh');
# "five, five, five, one, two, oh, two"
$words = NUMWORDS(555_1202, group=>1, one=>'unity');
# "five, five, five, unity, two, oh, two"
$words = NUMWORDS(123.456, group=>1, decimal=>'mark');
# "one two three mark four five six"
# LITERAL STYLE ONLY NAMES NUMBERS LESS THAN A CERTAIN THRESHOLD...
$words = NUMWORDS( 9, threshold=>10); # "nine"
$words = NUMWORDS( 10, threshold=>10); # "ten"
$words = NUMWORDS( 11, threshold=>10); # "11"
$words = NUMWORDS(1000, threshold=>10); # "1,000"
# JOIN WORDS INTO A LIST:
$list = WORDLIST("apple", "banana", "carrot");
# "apple, banana, and carrot"
$list = WORDLIST("apple", "banana");
# "apple and banana"
$list = WORDLIST("apple", "banana", "carrot", {final_sep=>""});
# "apple, banana and carrot"
# REQUIRE "CLASSICAL" PLURALS (EG: "focus"->"foci", "cherub"->"cherubim")
classical; # USE ALL CLASSICAL PLURALS
classical 1; # USE ALL CLASSICAL PLURALS
classical 0; # USE ALL MODERN PLURALS (DEFAULT)
classical 'zero'; # "no error" INSTEAD OF "no errors"
classical zero=>1; # "no error" INSTEAD OF "no errors"
classical zero=>0; # "no errors" INSTEAD OF "no error"
classical 'herd'; # "2 buffalo" INSTEAD OF "2 buffalos"
classical herd=>1; # "2 buffalo" INSTEAD OF "2 buffalos"
classical herd=>0; # "2 buffalos" INSTEAD OF "2 buffalo"
classical 'persons'; # "2 chairpersons" INSTEAD OF "2 chairpeople"
classical persons=>1; # "2 chairpersons" INSTEAD OF "2 chairpeople"
classical persons=>0; # "2 chairpeople" INSTEAD OF "2 chairpersons"
classical 'ancient'; # "2 formulae" INSTEAD OF "2 formulas"
classical ancient=>1; # "2 formulae" INSTEAD OF "2 formulas"
classical ancient=>0; # "2 formulas" INSTEAD OF "2 formulae"
# INTERPOLATE "PL()", "PL_N()", "PL_V()", "PL_ADJ()", A()", "AN()"
# "NUM()" AND "ORD()" WITHIN STRINGS:
print inflect("The plural of $word is PL($word)\n");
print inflect("I saw $cat_count PL("cat",$cat_count)\n");
print inflect("PL(I,$N1) PL_V(saw,$N1) PL(a,$N2) PL_N(saw,$N2)");
print inflect("NUM($N1,)PL(I)PL_V(saw) NUM($N2,)PL(a)PL_N(saw)");
print inflect("I saw NUM($cat_count) PL("cat")\nNUM()");
print inflect("There PL_V(was,$errors) NO(error,$errors)\n");
print inflect("There NUM($errors,) PL_V(was)NO(error)\n";
print inflect("Did you want A($thing) or AN($idea)\n");
print inflect("It was ORD($position) from the left\n");
# ADD USER-DEFINED INFLECTIONS (OVERRIDING INBUILT RULES):
def_noun "VAX" => "VAXen"; # SINGULAR => PLURAL
def_verb "will" => "shall", # 1ST PERSON SINGULAR => PLURAL
"will" => "will", # 2ND PERSON SINGULAR => PLURAL
"will" => "will", # 3RD PERSON SINGULAR => PLURAL
def_adj "hir" => "their", # SINGULAR => PLURAL
def_a "h" # "AY HALWAYS SEZ 'HAITCH'!"
def_an "horrendous.*" # "AN HORRENDOUS AFFECTATION"
DESCRIPTION
The exportable subroutines of Lingua::EN::Inflect provide plural
inflections, "a"/"an" selection for English words, and manipulation of
numbers as words
Plural forms of all nouns, most verbs, and some adjectives are
provided. Where appropriate, "classical" variants (for example:
"brother" -> "brethren", "dogma" -> "dogmata", etc.) are also provided.
Pronunciation-based "a"/"an" selection is provided for all English
words, and most initialisms.
It is also possible to inflect numerals (1,2,3) to ordinals (1st, 2nd,
3rd) and to english words ("one", "two", "three).
In generating these inflections, Lingua::EN::Inflect follows the Oxford
English Dictionary and the guidelines in Fowler's Modern English Usage,
preferring the former where the two disagree.
The module is built around standard British spelling, but is designed
to cope with common American variants as well. Slang, jargon, and other
English dialects are not explicitly catered for.
Where two or more inflected forms exist for a single word (typically a
"classical" form and a "modern" form), Lingua::EN::Inflect prefers the
more common form (typically the "modern" one), unless "classical"
processing has been specified (see "MODERN VS CLASSICAL INFLECTIONS").
FORMING PLURALS
Inflecting Plurals
All of the "PL_..." plural inflection subroutines take the word to be
inflected as their first argument and return the corresponding
inflection. Note that all such subroutines expect the singular form of
the word. The results of passing a plural form are undefined (and
unlikely to be correct).
The "PL_..." subroutines also take an optional second argument, which
indicates the grammatical "number" of the word (or of another word with
which the word being inflected must agree). If the "number" argument is
supplied and is not 1 (or "one" or "a", or some other adjective that
implies the singular), the plural form of the word is returned. If the
"number" argument does indicate singularity, the (uninflected) word
itself is returned. If the number argument is omitted, the plural form
is returned unconditionally.
The various subroutines are:
"PL_N($;$)"
The exportable subroutine "PL_N()" takes a singular English
noun or pronoun and returns its plural. Pronouns in the
nominative ("I" -> "we") and accusative ("me" -> "us") cases
are handled, as are possessive pronouns ("mine" -> "ours").
"PL_V($;$)"
The exportable subroutine "PL_V()" takes the singular form of a
conjugated verb (that is, one which is already in the correct
"person" and "mood") and returns the corresponding plural
conjugation.
"PL_ADJ($;$)"
The exportable subroutine "PL_ADJ()" takes the singular form of
certain types of adjectives and returns the corresponding
plural form. Adjectives that are correctly handled include:
"numerical" adjectives ("a" -> "some"), demonstrative
adjectives ("this" -> "these", "that" -> "those"), and
possessives ("my" -> "our", "cat's" -> "cats'", "child's" ->
"childrens'", etc.)
"PL($;$)"
The exportable subroutine "PL()" takes a singular English noun,
pronoun, verb, or adjective and returns its plural form. Where
a word has more than one inflection depending on its part of
speech (for example, the noun "thought" inflects to "thoughts",
the verb "thought" to "thought"), the (singular) noun sense is
preferred to the (singular) verb sense.
Hence "PL("knife")" will return "knives" ("knife" having been
treated as a singular noun), whereas "PL("knifes")" will return
"knife" ("knifes" having been treated as a 3rd person singular
verb).
The inherent ambiguity of such cases suggests that, where the
part of speech is known, "PL_N", "PL_V", and "PL_ADJ" should be
used in preference to "PL".
Note that all these subroutines ignore any whitespace surrounding the
word being inflected, but preserve that whitespace when the result is
returned. For example, "PL(" cat ")" returns " cats ".
Numbered plurals
The "PL_..." subroutines return only the inflected word, not the count
that was used to inflect it. Thus, in order to produce "I saw 3 ducks",
it is necessary to use:
print "I saw $N ", PL_N($animal,$N), "\n";
Since the usual purpose of producing a plural is to make it agree with
a preceding count, Lingua::EN::Inflect provides an exportable
subroutine ("NO($;$)") which, given a word and a(n optional) count,
returns the count followed by the correctly inflected word. Hence the
previous example can be rewritten:
print "I saw ", NO($animal,$N), "\n";
In addition, if the count is zero (or some other term which implies
zero, such as "zero", "nil", etc.) the count is replaced by the word
"no". Hence, if $N had the value zero, the previous example would print
the somewhat more elegant:
I saw no animals
rather than:
I saw 0 animals
Note that the name of the subroutine is a pun: the subroutine returns
either a number (a No.) or a "no", in front of the inflected word.
Reducing the number of counts required
In some contexts, the need to supply an explicit count to the various
"PL_..." subroutines makes for tiresome repetition. For example:
print PL_ADJ("This",$errors), PL_N(" error",$errors),
PL_V(" was",$errors), " fatal.\n";
Lingua::EN::Inflect therefore provides an exportable subroutine
("NUM($;$)") which may be used to set a persistent "default number"
value. If such a value is set, it is subsequently used whenever an
optional second "number" argument is omitted. The default value thus
set can subsequently be removed by calling "NUM()" with no arguments.
Hence we could rewrite the previous example:
NUM($errors);
print PL_ADJ("This"), PL_N(" error"), PL_V(" was"), "fatal.\n";
NUM();
Normally, "NUM()" returns its first argument, so that it may also be
"inlined" in contexts like:
print NUM($errors), PL_N(" error"), PL_V(" was"), " detected.\n"
print PL_ADJ("This"), PL_N(" error"), PL_V(" was"), "fatal.\n"
if $severity > 1;
However, in certain contexts (see "INTERPOLATING INFLECTIONS IN
STRINGS") it is preferable that "NUM()" return an empty string. Hence
"NUM()" provides an optional second argument. If that argument is
supplied (that is, if it is defined) and evaluates to false, "NUM"
returns an empty string instead of its first argument. For example:
print NUM($errors,0), NO("error"), PL_V(" was"), " detected.\n";
print PL_ADJ("This"), PL_N(" error"), PL_V(" was"), "fatal.\n"
if $severity > 1;
Number-insensitive equality
Lingua::EN::Inflect also provides a solution to the problem of
comparing words of differing plurality through the exportable
subroutines "PL_eq($$)", "PL_N_eq($$)", "PL_V_eq($$)", and
"PL_ADJ_eq($$)". Each of these subroutines takes two strings, and
compares them using the corresponding plural-inflection subroutine
("PL()", "PL_N()", "PL_V()", and "PL_ADJ()" respectively).
The comparison returns true if:
· the strings are "eq"-equal, or
· one string is "eq"-equal to a plural form of the other, or
· the strings are two different plural forms of the one word.
Hence all of the following return true:
PL_eq("index","index") # RETURNS "eq"
PL_eq("index","indexes") # RETURNS "s:p"
PL_eq("index","indices") # RETURNS "s:p"
PL_eq("indexes","index") # RETURNS "p:s"
PL_eq("indices","index") # RETURNS "p:s"
PL_eq("indices","indexes") # RETURNS "p:p"
PL_eq("indexes","indices") # RETURNS "p:p"
PL_eq("indices","indices") # RETURNS "eq"
As indicated by the comments in the previous example, the actual value
returned by the various "PL_eq" subroutines encodes which of the three
equality rules succeeded: "eq" is returned if the strings were
identical, "s:p" if the strings were singular and plural respectively,
"p:s" for plural and singular, and "p:p" for two distinct plurals.
Inequality is indicated by returning an empty string.
It should be noted that two distinct singular words which happen to
take the same plural form are not considered equal, nor are cases where
one (singular) word's plural is the other (plural) word's singular.
Hence all of the following return false:
PL_eq("base","basis") # ALTHOUGH BOTH -> "bases"
PL_eq("syrinx","syringe") # ALTHOUGH BOTH -> "syringes"
PL_eq("she","he") # ALTHOUGH BOTH -> "they"
PL_eq("opus","operas") # ALTHOUGH "opus" -> "opera" -> "operas"
PL_eq("taxi","taxes") # ALTHOUGH "taxi" -> "taxis" -> "taxes"
Note too that, although the comparison is "number-insensitive" it is
not case-insensitive (that is, "PL("time","Times")" returns false. To
obtain both number and case insensitivity, prefix both arguments with
"lc" (that is, "PL(lc "time", lc "Times")" returns true).
OTHER VERB FORMS
Present participles
"Lingua::EN::Inflect" also provides the "PART_PRES" subroutine, which
can take a 3rd person singular verb and correctly inflect it to its
present participle:
PART_PRES("runs") # "running"
PART_PRES("loves") # "loving"
PART_PRES("eats") # "eating"
PART_PRES("bats") # "batting"
PART_PRES("spies") # "spying"
PROVIDING INDEFINITE ARTICLES
Selecting indefinite articles
Lingua::EN::Inflect provides two exportable subroutines ("A($;$)" and
"AN($;$)") which will correctly prepend the appropriate indefinite
article to a word, depending on its pronunciation. For example:
A("cat") # -> "a cat"
AN("cat") # -> "a cat"
A("euphemism") # -> "a euphemism"
A("Euler number") # -> "an Euler number"
A("hour") # -> "an hour"
A("houri") # -> "a houri"
The two subroutines are identical in function and may be used
interchangeably. The only reason that two versions are provided is to
enhance the readability of code such as:
print "That is ", AN($errortype), " error\n;
print "That is ", A($fataltype), " fatal error\n;
Note that in both cases the actual article provided depends only on the
pronunciation of the first argument, not on the name of the subroutine.
"A()" and "AN()" will ignore any indefinite article that already exists
at the start of the string. Thus:
@half_arked = (
"a elephant",
"a giraffe",
"an ewe",
"a orangutan",
);
print A($_), "\n" for @half_arked;
# prints:
# an elephant
# a giraffe
# a ewe
# an orangutan
"A()" and "AN()" both take an optional second argument. As with the
"PL_..." subroutines, this second argument is a "number" specifier. If
its value is 1 (or some other value implying singularity), "A()" and
"AN()" insert "a" or "an" as appropriate. If the number specifier
implies plurality, ("A()" and "AN()" insert the actual second argument
instead. For example:
A("cat",1) # -> "a cat"
A("cat",2) # -> "2 cat"
A("cat","one") # -> "one cat"
A("cat","no") # -> "no cat"
Note that, as implied by the previous examples, "A()" and "AN()" both
assume that their job is merely to provide the correct qualifier for a
word (that is: "a", "an", or the specified count). In other words,
they assume that the word they are given has already been correctly
inflected for plurality. Hence, if $N has the value 2, then:
print A("cat",$N);
prints "2 cat", instead of "2 cats". The correct approach is to use:
print A(PL("cat",$N),$N);
or, better still:
print NO("cat",$N);
Note too that, like the various "PL_..." subroutines, whenever "A()"
and "AN()" are called with only one argument they are subject to the
effects of any preceding call to "NUM()". Hence, another possible
solution is:
NUM($N);
print A(PL("cat"));
Indefinite articles and initialisms
"Initialisms" (sometimes inaccurately called "acronyms") are terms
which have been formed from the initial letters of words in a phrase
(for example, "NATO", "NBL", "S.O.S.", "SCUBA", etc.)
Such terms present a particular challenge when selecting between "a"
and "an", since they are sometimes pronounced as if they were a single
word ("nay-tow", "sku-ba") and sometimes as a series of letter names
("en-eff-ell", "ess-oh-ess").
"A()" and "AN()" cope with this dichotomy using a series of inbuilt
rules, which may be summarized as:
1. If the word starts with a single letter, followed by a period
or dash (for example, "R.I.P.", "C.O.D.", "e-mail", "X-ray",
"T-square"), then choose the appropriate article for the sound
of the first letter ("an R.I.P.", "a C.O.D.", "an e-mail", "an
X-ray", "a T-square").
2. If the first two letters of the word are capitals, consonants,
and do not appear at the start of any known English word, (for
example, "LCD", "XML", "YWCA"), then once again choose "a" or
"an" depending on the sound of the first letter ("an LCD", "an
XML", "a YWCA").
3. Otherwise, assume the string is a capitalized word or a
pronounceable initialism (for example, "LED", "OPEC", "FAQ",
"UNESCO"), and therefore takes "a" or "an" according to the
(apparent) pronunciation of the entire word ("a LED", "an
OPEC", "a FAQ", "a UNESCO").
Note that rules 1 and 3 together imply that the presence or absence of
punctuation may change the selection of indefinite article for a
particular initialism (for example, "a FAQ" but "an F.A.Q.").
Indefinite articles and "soft H's"
Words beginning in the letter 'H' present another type of difficulty
when selecting a suitable indefinite article. In a few such words (for
example, "hour", "honour", "heir") the 'H' is not voiced at all, and so
such words inflect with "an". The remaining cases ("voiced H's") may be
divided into two categories: "hard H's" (such as "hangman",
"holograph", "hat", etc.) and "soft H's" (such as "hysterical",
"horrendous", "holy", etc.)
Hard H's always take "a" as their indefinite article, and soft H's
normally do so as well. But some English speakers prefer "an" for soft
H's (although the practice is now generally considered an affectation,
rather than a legitimate grammatical alternative).
At present, the "A()" and "AN()" subroutines ignore soft H's and use
"a" for any voiced 'H'. The author would, however, welcome feedback on
this decision (envisaging a possible future "soft H" mode).
INFLECTING ORDINALS
Occasionally it is useful to present an integer value as an ordinal
rather than as a numeral. For example:
Enter password (1st attempt): ********
Enter password (2nd attempt): *********
Enter password (3rd attempt): *********
No 4th attempt. Access denied.
To this end, Lingua::EN::Inflect provides the "ORD()" subroutine.
<ORD()> takes a single argument and forms its ordinal equivalent. If
the argument isn't a numerical integer, it just adds "-th".
CONVERTING NUMBERS TO WORDS
The exportable subroutine "NUMWORDS" takes a number (cardinal or
ordinal) and returns an English representation of that number. In a
scalar context a string is returned. Hence:
use Lingua::EN::Inflect qw( NUMWORDS );
$words = NUMWORDS(1234567);
puts the string:
"one million, two hundred and thirty-four thousand, five hundred and sixty-seven"
into $words.
In a list context each comma-separated chunk is returned as a separate
element. Hence:
@words = NUMWORDS(1234567);
puts the list:
("one million",
"two hundred and thirty-four thousand",
"five hundred and sixty-seven")
into @words.
Non-digits (apart from an optional leading plus or minus sign, any
decimal points, and ordinal suffixes -- see below) are silently
ignored, so the following all produce identical results:
NUMWORDS(5551202);
NUMWORDS(5_551_202);
NUMWORDS("5,551,202");
NUMWORDS("555-1202");
That last case is a little awkward since it's almost certainly a phone
number, and "five million, five hundred and fifty-one thousand, two
hundred and two" probably isn't what's wanted.
To overcome this, "NUMWORDS()" takes an optional named argument,
'group', which changes how numbers are translated. The argument must be
a positive integer less than four, which indicated how the digits of
the number are to be grouped. If the argument is 1, then each digit is
translated separately. If the argument is 2, pairs of digits (starting
from the left) are grouped together. If the argument is 3, triples of
numbers (again, from the left) are grouped. Hence:
NUMWORDS("555-1202", group=>1)
returns "five, five, five, one, two, zero, two", whilst:
NUMWORDS("555-1202", group=>2)
returns "fifty-five, fifty-one, twenty, two", and:
NUMWORDS("555-1202", group=>3)
returns "five fifty-five, one twenty, two".
Phone numbers are often written in words as
"five..five..five..one..two..zero..two", which is also easy to achieve:
join '..', NUMWORDS("555-1202", group=>1)
"NUMWORDS" also handles decimal fractions. Hence:
NUMWORDS("1.2345")
returns "one point two three four five" in a scalar context and
"("one","point","two","three","four","five")") in an array context.
Exponent form ("1.234e56") is not yet handled.
Multiple decimal points are only translated in one of the "grouping"
modes. Hence:
NUMWORDS(101.202.303)
returns "one hundred and one point two zero two three zero three",
whereas:
NUMWORDS(101.202.303, group=>1)
returns "one zero one point two zero two point three zero three".
The digit '0' is unusual in that in may be translated to English as
"zero", "oh", or "nought". To cater for this diversity, "NUMWORDS" may
be passed a named argument, 'zero', which may be set to the desired
translation of '0'. For example:
print join "..", NUMWORDS("555-1202", group=>3, zero=>'oh')
prints "five..five..five..one..two..oh..two". By default, zero is
rendered as "zero".
Likewise, the digit '1' may be rendered as "one" or "a/an" (or very
occasionally other variants), depending on the context. So there is a
'one' argument as well:
print NUMWORDS($_, one=>'a solitary', zero=>'no more'),
PL(" bottle of beer on the wall\n", $_)
for (3,2,1,0);
# prints:
# three bottles of beer on the wall
# two bottles of beer on the wall
# a solitary bottle of beer on the wall
# no more bottles of beer on the wall
Care is needed if the word "a/an" is to be used as a 'one' value.
Unless the next word is known in advance, it's almost always necessary
to use the "A" function as well:
print A( NUMWORDS(1, one=>'a') . " $_\n")
for qw(cat aardvark ewe hour);
# prints:
# a cat
# an aardvark
# a ewe
# an hour
Another major regional variation in number translation is the use of
"and" in certain contexts. The named argument 'and' allows the
programmer to specify how "and" should be handled. Hence:
print scalar NUMWORDS("765", 'and'=>'')
prints "seven hundred sixty-five", instead of "seven hundred and sixty-
five". By default, the "and" is included.
The translation of the decimal point is also subject to variation (with
"point", "dot", and "decimal" being the favorites). The named argument
'decimal' allows the programmer to how the decimal point should be
rendered. Hence:
print scalar NUMWORDS("666.124.64.101", group=>3, decimal=>'dot')
prints "six sixty-six, dot, one twenty-four, dot, sixty-four, dot, one
zero one" By default, the decimal point is rendered as "point".
"NUMWORDS" also handles the ordinal forms of numbers. So:
print scalar NUMWORDS('1st');
print scalar NUMWORDS('3rd');
print scalar NUMWORDS('202nd');
print scalar NUMWORDS('1000000th');
print:
first
third
two hundred and twenty-second
one millionth
Two common idioms in this regard are:
print scalar NUMWORDS(ORD($number));
and:
print scalar ORD(NUMWORDS($number));
These are identical in effect, except when $number contains a decimal:
$number = 99.09;
print scalar NUMWORDS(ORD($number)); # ninety-ninth point zero nine
print scalar ORD(NUMWORDS($number)); # ninety-nine point zero ninth
Use whichever you feel is most appropriate.
CONVERTING LISTS OF WORDS TO PHRASES
When creating a list of words, commas are used between adjacent items,
except if the items contain commas, in which case semicolons are used.
But if there are less than two items, the commas/semicolons are omitted
entirely. The final item also has a conjunction (usually "and" or "or")
before it. And although it's technically incorrect (and sometimes
misleading), some people prefer to omit the comma before that final
conjunction, even when there are more than two items.
That's complicated enough to warrant its own subroutine: "WORDLIST()".
This subroutine expects a list of words, possibly with one or more hash
references containing options. It returns a string that joins the list
together in the normal English usage. For example:
print "You chose ", WORDLIST(@selected_items), "\n";
# You chose barley soup, roast beef, and Yorkshire pudding
print "You chose ", WORDLIST(@selected_items, {final_sep=>""}), "\n";
# You chose barley soup, roast beef and Yorkshire pudding
print "Please chose ", WORDLIST(@side_orders, {conj=>"or"}), "\n";
# Please chose salad, vegetables, or ice-cream
The available options are:
Option named Specifies Default value
conj Final conjunction "and"
sep Inter-item separator ","
last_sep Final separator value of 'sep' option
INTERPOLATING INFLECTIONS IN STRINGS
By far the commonest use of the inflection subroutines is to produce
message strings for various purposes. For example:
print NUM($errors), PL_N(" error"), PL_V(" was"), " detected.\n";
print PL_ADJ("This"), PL_N(" error"), PL_V(" was"), "fatal.\n"
if $severity > 1;
Unfortunately the need to separate each subroutine call detracts
significantly from the readability of the resulting code. To ameliorate
this problem, Lingua::EN::Inflect provides an exportable string-
interpolating subroutine (inflect($)), which recognizes calls to the
various inflection subroutines within a string and interpolates them
appropriately.
Using "inflect" the previous example could be rewritten:
print inflect "NUM($errors) PL_N(error)PL_V(was) detected.\n";
print inflect "PL_ADJ(This)PL_N(error)PL_V(was) fatal.\n"
if $severity > 1;
Note that "inflect" also correctly handles calls to the "NUM()"
subroutine (whether interpolated or antecedent). The "inflect()"
subroutine has a related extra feature, in that it automatically
cancels any "default number" value before it returns its interpolated
string. This means that calls to "NUM()" which are embedded in an
"inflect()"-interpolated string do not "escape" and interfere with
subsequent inflections.
MODERN VS CLASSICAL INFLECTIONS
Certain words, mainly of Latin or Ancient Greek origin, can form
plurals either using the standard English "-s" suffix, or with their
original Latin or Greek inflections. For example:
PL("stigma") # -> "stigmas" or "stigmata"
PL("torus") # -> "toruses" or "tori"
PL("index") # -> "indexes" or "indices"
PL("millennium") # -> "millenniums" or "millennia"
PL("ganglion") # -> "ganglions" or "ganglia"
PL("octopus") # -> "octopuses" or "octopodes"
Lingua::EN::Inflect caters to such words by providing an "alternate
state" of inflection known as "classical mode". By default, words are
inflected using their contemporary English plurals, but if classical
mode is invoked, the more traditional plural forms are returned
instead.
The exportable subroutine "classical()" controls this feature. If
"classical()" is called with no arguments, it unconditionally invokes
classical mode. If it is called with a single argument, it turns all
classical inflects on or off (depending on whether the argument is true
or false). If called with two or more arguments, those arguments
specify which aspects of classical behaviour are to be used.
Thus:
classical; # SWITCH ON CLASSICAL MODE
print PL("formula"); # -> "formulae"
classical 0; # SWITCH OFF CLASSICAL MODE
print PL("formula"); # -> "formulas"
classical $cmode; # CLASSICAL MODE IFF $cmode
print PL("formula"); # -> "formulae" (IF $cmode)
# -> "formulas" (OTHERWISE)
classical herd=>1; # SWITCH ON CLASSICAL MODE FOR "HERD" NOUNS
print PL("wilderbeest"); # -> "wilderbeest"
classical names=>1; # SWITCH ON CLASSICAL MODE FOR NAMES
print PL("sally"); # -> "sallies"
print PL("Sally"); # -> "Sallys"
Note however that "classical()" has no effect on the inflection of
words which are now fully assimilated. Hence:
PL("forum") # ALWAYS -> "forums"
PL("criterion") # ALWAYS -> "criteria"
LEI assumes that a capitalized word is a person's name. So it forms the
plural according to the rules for names (which is that you don't
inflect, you just add -s or -es). You can choose to turn that behaviour
off (it's on by the default, even when the module isn't in classical
mode) by calling "classical(names=>0)".
USER-DEFINED INFLECTIONS
Adding plurals at run-time
Lingua::EN::Inflect provides five exportable subroutines which allow
the programmer to override the module's behaviour for specific cases:
"def_noun($$)"
The "def_noun" subroutine takes a pair of string arguments: the
singular and plural forms of the noun being specified. The
singular form specifies a pattern to be interpolated (as
"m/^(?:$first_arg)$/i"). Any noun matching this pattern is
then replaced by the string in the second argument. The second
argument specifies a string which is interpolated after the
match succeeds, and is then used as the plural form. For
example:
def_noun 'cow' => 'kine';
def_noun '(.+i)o' => '$1i';
def_noun 'spam(mer)?' => '\\$\\%\\@#\\$\\@#!!';
Note that both arguments should usually be specified in single
quotes, so that they are not interpolated when they are
specified, but later (when words are compared to them). As
indicated by the last example, care also needs to be taken with
certain characters in the second argument, to ensure that they
are not unintentionally interpolated during comparison.
The second argument string may also specify a second variant of
the plural form, to be used when "classical" plurals have been
requested. The beginning of the second variant is marked by a
'|' character:
def_noun 'cow' => 'cows|kine';
def_noun '(.+i)o' => '$1os|$1i';
def_noun 'spam(mer)?' => '\\$\\%\\@#\\$\\@#!!|varmints';
If no classical variant is given, the specified plural form is
used in both normal and "classical" modes.
If the second argument is "undef" instead of a string, then the
current user definition for the first argument is removed, and
the standard plural inflection(s) restored.
Note that in all cases, later plural definitions for a
particular singular form replace earlier definitions of the
same form. For example:
# FIRST, HIDE THE MODERN FORM....
def_noun 'aviatrix' => 'aviatrices';
# LATER, HIDE THE CLASSICAL FORM...
def_noun 'aviatrix' => 'aviatrixes';
# FINALLY, RESTORE THE DEFAULT BEHAVIOUR...
def_noun 'aviatrix' => undef;
Special care is also required when defining general patterns
and associated specific exceptions: put the more specific cases
after the general pattern. For example:
def_noun '(.+)us' => '$1i'; # EVERY "-us" TO "-i"
def_noun 'bus' => 'buses'; # EXCEPT FOR "bus"
This "try-most-recently-defined-first" approach to matching
user-defined words is also used by "def_verb", "def_a" and
"def_an".
"def_verb($$$$$$)"
The "def_verb" subroutine takes three pairs of string arguments
(that is, six arguments in total), specifying the singular and
plural forms of the three "persons" of verb. As with
"def_noun", the singular forms are specifications of run-time-
interpolated patterns, whilst the plural forms are
specifications of (up to two) run-time-interpolated strings:
def_verb 'am' => 'are',
'are' => 'are|art",
'is' => 'are';
def_verb 'have' => 'have',
'have' => 'have",
'ha(s|th)' => 'have';
Note that as with "def_noun", modern/classical variants of
plurals may be separately specified, subsequent definitions
replace previous ones, and "undef"'ed plural forms revert to
the standard behaviour.
"def_adj($$)"
The "def_adj" subroutine takes a pair of string arguments,
which specify the singular and plural forms of the adjective
being defined. As with "def_noun" and "def_adj", the singular
forms are specifications of run-time-interpolated patterns,
whilst the plural forms are specifications of (up to two) run-
time-interpolated strings:
def_adj 'this' => 'these',
def_adj 'red' => 'red|gules',
As previously, modern/classical variants of plurals may be
separately specified, subsequent definitions replace previous
ones, and "undef"'ed plural forms revert to the standard
behaviour.
def_a($) and def_an($)
The "def_a" and "def_an" subroutines each take a single
argument, which specifies a pattern. If a word passed to "A()"
or "AN()" matches this pattern, it will be prefixed
(unconditionally) with the corresponding indefinite article.
For example:
def_a 'error';
def_a 'in.+';
def_an 'mistake';
def_an 'error';
As with the other "def_..." subroutines, such redefinitions are
sequential in effect so that, after the above example, "error"
will be inflected with "an".
The $HOME/.inflectrc file
When it is imported, Lingua::EN::Inflect executes (as Perl code) the
contents of any file named .inflectrc which it finds in the in the
directory where Lingua/EN/Inflect.pm is installed, or in the current
home directory ($ENV{HOME}), or in both. Note that the code is
executed within the Lingua::EN::Inflect namespace.
Hence the user or the local Perl guru can make appropriate calls to
"def_noun", "def_verb", etc. in one of these .inflectrc files, to
permanently and universally modify the behaviour of the module. For
example
> cat /usr/local/lib/perl5/Text/Inflect/.inflectrc
def_noun "UNIX" => "UN*X|UNICES";
def_verb "teco" => "teco", # LITERALLY: "to edit with TECO"
"teco" => "teco",
"tecos" => "teco";
def_a "Euler.*"; # "Yewler" TURNS IN HIS GRAVE
Note that calls to the "def_..." subroutines from within a program will
take precedence over the contents of the home directory .inflectrc
file, which in turn takes precedence over the system-wide .inflectrc
file.
DIAGNOSTICS
On loading, if the Perl code in a .inflectrc file is invalid
(syntactically or otherwise), an appropriate fatal error is issued. A
common problem is not ending the file with something that evaluates to
true (as the five "def_..." subroutines do).
Using the five "def_..." subroutines directly in a program may also
result in fatal diagnostics, if a (singular) pattern or an interpolated
(plural) string is somehow invalid.
Specific diagnostics related to user-defined inflections are:
"Bad user-defined singular pattern:\n\t %s"
The singular form of a user-defined noun or verb (as defined by
a call to "def_noun", "def_verb", "def_adj", "def_a" or
"def_an") is not a valid Perl regular expression. The actual
Perl error message is also given.
"Bad user-defined plural string: '%s'"
The plural form(s) of a user-defined noun or verb (as defined
by a call to "def_noun", "def_verb" or "def_adj") is not a
valid Perl interpolated string (usually because it interpolates
some undefined variable).
"Bad .inflectrc file (%s):\n %s"
Some other problem occurred in loading the named local or
global .inflectrc file. The Perl error message (including the
line number) is also given.
There are no diagnosable run-time error conditions for the actual
inflection subroutines, except "NUMWORDS" and hence no run-time
diagnostics. If the inflection subroutines are unable to form a plural
via a user-definition or an inbuilt rule, they just "guess" the
commonest English inflection: adding "-s" for nouns, removing "-s" for
verbs, and no inflection for adjectives.
"Lingua::EN::Inflect::NUMWORDS()" can "die" with the following
messages:
"Bad grouping option: %s"
The optional argument to "NUMWORDS()" wasn't 1, 2 or 3.
"Number out of range"
"NUMWORDS()" was passed a number larger than
999,999,999,999,999,999,999,999,999,999,999,999 (that is: nine
hundred and ninety-nine decillion, nine hundred and ninety-nine
nonillion, nine hundred and ninety-nine octillion, nine hundred
and ninety-nine septillion, nine hundred and ninety-nine
sextillion, nine hundred and ninety-nine quintillion, nine
hundred and ninety-nine quadrillion, nine hundred and ninety-
nine trillion, nine hundred and ninety-nine billion, nine
hundred and ninety-nine million, nine hundred and ninety-nine
thousand, nine hundred and ninety-nine :-)
The problem is that "NUMWORDS" doesn't know any words for
number components bigger than "decillion".
OTHER ISSUES
2nd Person precedence
If a verb has identical 1st and 2nd person singular forms, but
different 1st and 2nd person plural forms, then when its plural is
constructed, the 2nd person plural form is always preferred.
The author is not currently aware of any such verbs in English, but is
not quite arrogant enough to assume ipso facto that none exist.
Nominative precedence
The singular pronoun "it" presents a special problem because its plural
form can vary, depending on its "case". For example:
It ate my homework -> They ate my homework
It ate it -> They ate them
I fed my homework to it -> I fed my homework to them
As a consequence of this ambiguity, "PL()" or "PL_N" have been
implemented so that they always return the nominative plural (that is,
"they").
However, when asked for the plural of an unambiguously accusative "it"
(namely, "PL("to it")", "PL_N("from it")", "PL("with it")", etc.), both
subroutines will correctly return the accusative plural ("to them",
"from them", "with them", etc.)
The plurality of zero
The rules governing the choice between:
There were no errors.
and
There was no error.
are complex and often depend more on intent rather than content. Hence
it is infeasible to specify such rules algorithmically.
Therefore, Lingua::EN::Text contents itself with the following
compromise: If the governing number is zero, inflections always return
the plural form unless the appropriate "classical" inflection is in
effect, in which case the singular form is always returned.
Thus, the sequence:
NUM(0);
print inflect "There PL(was)NO(choice)";
produces "There were no choices", whereas:
classical 'zero'; # or: classical(zero=>1);
NUM(0);
print inflect "There PL(was)NO(choice)";
it will print "There was no choice".
Homographs with heterogeneous plurals
Another context in which intent (and not content) sometimes determines
plurality is where two distinct meanings of a word require different
plurals. For example:
Three basses were stolen from the band's equipment trailer.
Three bass were stolen from the band's aquarium.
I put the mice next to the cheese.
I put the mouses next to the computers.
Several thoughts about leaving crossed my mind.
Several thought about leaving across my lawn.
Lingua::EN::Inflect handles such words in two ways:
· If both meanings of the word are the same part of speech (for
example, "bass" is a noun in both sentences above), then one
meaning is chosen as the "usual" meaning, and only that
meaning's plural is ever returned by any of the inflection
subroutines.
· If each meaning of the word is a different part of speech (for
example, "thought" is both a noun and a verb), then the noun's
plural is returned by "PL()" and "PL_N()" and the verb's plural
is returned only by "PL_V()".
Such contexts are, fortunately, uncommon (particularly "same-part-of-
speech" examples). An informal study of nearly 600 "difficult plurals"
indicates that "PL()" can be relied upon to "get it right" about 98% of
the time (although, of course, ichthyophilic guitarists or cyber-
behaviouralists may experience higher rates of confusion).
If the choice of a particular "usual inflection" is considered
inappropriate, it can always be reversed with a preliminary call to the
corresponding "def_..." subroutine.
NOTE
I'm not taking any further correspondence on:
"octopi".
Despite the populist pandering of certain New World dictionaries,
the plural is "octopuses" or (for the pendantic classicist)
"octopodes". The suffix "-pus" is Greek, not Latin, so the plural
is "-podes", not "pi".
"virus".
Had no plural in Latin (possibly because it was a mass noun). The
only plural is the Anglicized "viruses".
AUTHORS
Damian Conway (damian@conway.org) Matthew Persico (ORD inflection)
BUGS AND IRRITATIONS
The endless inconsistencies of English.
(Please report words for which the correct plural or indefinite article
is not formed, so that the reliability of Lingua::EN::Inflect can be
improved.)
COPYRIGHT
Copyright (c) 1997-2009, Damian Conway. All Rights Reserved.
This module is free software. It may be used, redistributed
and/or modified under the same terms as Perl itself.
POD ERRORS
Hey! The above document had some coding errors, which are explained
below:
Around line 2744:
You forgot a '=back' before '=head1'
perl v5.14.2 2010-06-28 Lingua::EN::Inflect(3)
