NAME
Elatin3 - Run-time routines for Latin3.pm
SYNOPSIS
use
Elatin3;
Elatin3::
split
(...);
Elatin3::
tr
(...);
Elatin3::
chop
(...);
Elatin3::
index
(...);
Elatin3::
rindex
(...);
Elatin3::
lc
(...);
Elatin3::lc_;
Elatin3::
lcfirst
(...);
Elatin3::lcfirst_;
Elatin3::
uc
(...);
Elatin3::uc_;
Elatin3::
ucfirst
(...);
Elatin3::ucfirst_;
Elatin3::fc(...);
Elatin3::fc_;
Elatin3::ignorecase(...);
Elatin3::capture(...);
Elatin3::
chr
(...);
Elatin3::chr_;
Elatin3::
glob
(...);
Elatin3::glob_;
# "no Elatin3;" not supported
ABSTRACT
This module has run-time routines for use Latin3 software automatically, you do not have to use.
BUGS AND LIMITATIONS
I have tested and verified this software using the best of my ability. However, a software containing much regular expression is bound to contain some bugs. Thus, if you happen to find a bug that's in Latin3 software and not your own program, you can try to reduce it to a minimal test case and then report it to the following author's address. If you have an idea that could make this a more useful tool, please let everyone share it.
HISTORY
This Elatin3 module first appeared in ActivePerl Build 522 Built under MSWin32 Compiled at Nov 2 1999 09:52:28
AUTHOR
INABA Hitoshi <ina@cpan.org>
This project was originated by INABA Hitoshi. For any questions, use <ina@cpan.org> so we can share this file.
LICENSE AND COPYRIGHT
This module is free software; you can redistribute it and/or modify it under the same terms as Perl itself. See perlartistic.
This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
EXAMPLES
Split string
@split
= Elatin3::
split
(/pattern/,
$string
,
$limit
);
@split
= Elatin3::
split
(/pattern/,
$string
);
@split
= Elatin3::
split
(/pattern/);
@split
= Elatin3::
split
(
''
,
$string
,
$limit
);
@split
= Elatin3::
split
(
''
,
$string
);
@split
= Elatin3::
split
(
''
);
@split
= Elatin3::
split
();
@split
= Elatin3::
split
;
This subroutine scans a string
given
by
$string
for
separators, and splits the
string into a list of substring, returning the resulting list value in list
context or the count of substring in
scalar
context. Scalar context also causes
split
to
write
its result to
@_
, but this usage is deprecated. The separators
are determined by repeated pattern matching, using the regular expression
given
in /pattern/, so the separators may be of any size and need not be the same
string on every match. (The separators are not ordinarily returned; exceptions
are discussed later in this section.) If the /pattern/ doesn't match the string
at all, Elatin3::
split
returns the original string as a single substring, If it
matches once, you get two substrings, and so on. You may supply regular
expression modifiers to the /pattern/, like /pattern/i, /pattern/x, etc. The
//m modifier is assumed
when
you
split
on the pattern /^/.
If
$limit
is specified and positive, the subroutine splits into
no
more than that
many fields (though it may
split
into fewer
if
it runs out of separators). If
$limit
is negative, it is treated as
if
an arbitrarily large
$limit
has
been
specified If
$limit
is omitted or zero, trailing null fields are stripped from
the result (which potential users of
pop
would
do
wel to remember). If
$string
is omitted, the subroutine splits the
$_
string. If /pattern/ is also omitted or
is the literal space,
" "
, the subroutine
split
on whitespace, /\s+/,
after
skipping any leading whitespace.
A /pattern/ of /^/ is secretly treated
if
it it were /^/m, since it isn't much
use
otherwise.
String of any
length
can be
split
:
@chars
= Elatin3::
split
(//,
$word
);
@fields
= Elatin3::
split
(/:/,
$line
);
@words
= Elatin3::
split
(
" "
,
$paragraph
);
@lines
= Elatin3::
split
(/^/,
$buffer
);
A pattern capable of matching either the null string or something longer than
the null string (
for
instance, a pattern consisting of any single character
modified by a * or ?) will
split
the value of
$string
into separate characters
wherever it matches the null string between characters; nonnull matches will
skip over the matched separator characters in the usual fashion. (In other words,
a pattern won't match in one spot more than once, even
if
it matched
with
a zero
width.) For example:
print
join
(
":"
=> Elatin3::
split
(/ */,
"hi there"
));
produces the output
"h:i:t:h:e:r:e"
. The space disappers because it matches
as part of the separator. As a trivial case, the null pattern // simply splits
into separate characters, and spaces
do
not disappear. (For normal pattern
matches, a // pattern would repeat the
last
successfully matched pattern, but
Elatin3::
split
's pattern is exempt from that wrinkle.)
The
$limit
parameter splits only part of a string:
my
(
$login
,
$passwd
,
$remainder
) = Elatin3::
split
(/:/,
$_
, 3);
We encourage you to
split
to lists of names like this to make your code
self-documenting. (For purposes of error checking, note that
$remainder
would
be undefined
if
there were fewer than three fields.) When assigning to a list,
if
$limit
is omitted, Perl supplies a
$limit
one larger than the number of
variables in the list, to avoid unneccessary work. For the
split
above,
$limit
would have been 4 by
default
, and
$remainder
would have received only the third
field, not all the rest of the fields. In
time
-critical applications, it behooves
you not to
split
into more fields than you really need. (The trouble
with
powerful languages it that they let you be powerfully stupid at
times
.)
We said earlier that the separators are not returned, but
if
the /pattern/
contains parentheses, then the substring matched by
each
pair of parentheses is
included in the resulting list, interspersed
with
the fields that are ordinarily
returned. Here's a simple example:
Elatin3::
split
(/([-,])/,
"1-10,20"
);
which produces the list value:
(1,
"-"
, 10,
","
, 20)
With more parentheses, a field is returned
for
each
pair, even
if
some pairs
don't match, in which case undefined
values
are returned in those positions. So
if
you
say
:
Elatin3::
split
(/(-)|(,)/,
"1-10,20"
);
you get the value:
(1,
"-"
,
undef
, 10,
undef
,
","
, 20)
The /pattern/ argument may be replaced
with
an expression to specify patterns
that vary at runtime. As
with
ordinary patterns, to
do
run-
time
compilation only
once,
use
/
$variable
/o.
As a special case,
if
the expression is a single space (
" "
), the subroutine
splits on whitespace just as Elatin3::
split
with
no
arguments does. Thus,
Elatin3::
split
(
" "
) can be used to emulate awk's
default
behavior. In contrast,
Elatin3::
split
(/ /) will give you as many null initial fields as there are
leading spaces. (Other than this special case,
if
you supply a string instead
of a regular expression, it'll be interpreted as a regular expression anyway.)
string and to collapse intervaning stretches of whitespace into a single
space:
$string
=
join
(
" "
, Elatin3::
split
(
" "
,
$string
));
The following example splits an RFC822 message header into a hash containing
$head
{
'Date'
},
$head
{
'Subject'
}, and so on. It uses the trick of assigning a
list of pairs to a hash, because separators altinate
with
separated fields, It
users parentheses to
return
part of
each
separator as part of the returned list
value. Since the
split
pattern is guaranteed to
return
things in pairs by virtue
of containing one set of parentheses, the hash assignment is guaranteed to
receive a list consisting of key/value pairs, where
each
key is the name of a
header field. (Unfortunately, this technique loses information
for
multiple lines
with
the same key field, such as Received-By lines. Ah well)
$header
=~ s/\n\s+/ /g;
# Merge continuation lines.
%head
= (
"FRONTSTUFF"
, Elatin3::
split
(/^(\S*?):\s*/m,
$header
));
The following example processes the entries in a Unix passwd(5) file. You could
leave out the
chomp
, in which case
$shell
would have a newline on the end of it.
open
(PASSWD,
"/etc/passwd"
);
while
(<PASSWD>) {
chomp
;
# remove trailing newline.
(
$login
,
$passwd
,
$uid
,
$gid
,
$gcos
,
$home
,
$shell
) =
Elatin3::
split
(/:/);
...
}
Here's how process
each
word of
each
line of
each
file of input to create a
word-frequency hash.
while
(<>) {
for
my
$word
(Elatin3::
split
()) {
$count
{
$word
}++;
}
}
The inverse of Elatin3::
split
is
join
, except that
join
can only
join
with
the
same separator between all fields. To break apart a string
with
fixed-position
fields,
use
unpack
.
Processing long
$string
(over 32766 octets) requires Perl 5.010001 or later.
Transliteration
$tr
= Elatin3::
tr
(
$variable
,
$bind_operator
,
$searchlist
,
$replacementlist
,
$modifier
);
$tr
= Elatin3::
tr
(
$variable
,
$bind_operator
,
$searchlist
,
$replacementlist
);
This is the transliteration (sometimes erroneously called translation) operator,
which is like the y/// operator in the Unix sed program, only better, in
everybody's humble opinion.
This subroutine scans a Latin-3 string character by character and replaces all
occurrences of the characters found in
$searchlist
with
the corresponding character
in
$replacementlist
. It returns the number of characters replaced or deleted.
If
no
Latin-3 string is specified via =~ operator, the
$_
variable is translated.
$modifier
are:
---------------------------------------------------------------------------
Modifier Meaning
---------------------------------------------------------------------------
c Complement
$searchlist
.
d Delete found but unreplaced characters.
s Squash duplicate replaced characters.
r Return transliteration and leave the original string untouched.
---------------------------------------------------------------------------
print
Elatin3::
tr
(
'bookkeeper'
,
'=~'
,
'boep'
,
'peob'
,
'r'
);
# prints 'peekkoobor'
Chop string
$chop
= Elatin3::
chop
(
@list
);
$chop
= Elatin3::
chop
();
$chop
= Elatin3::
chop
;
This subroutine chops off the
last
character of a string variable and returns the
character chopped. The Elatin3::
chop
subroutine is used primary to remove the newline
from the end of an input recoed, and it is more efficient than using a
substitution. If that
's all you'
re doing, then it would be safer to
use
chomp
,
since Elatin3::
chop
always shortens the string
no
matter what's there, and
chomp
is more selective. If
no
argument is
given
, the subroutine chops the
$_
variable.
You cannot Elatin3::
chop
a literal, only a variable. If you Elatin3::
chop
a list of
variables,
each
string in the list is chopped:
@lines
= `cat myfile`;
Elatin3::
chop
(
@lines
);
You can Elatin3::
chop
anything that is an lvalue, including an assignment:
Elatin3::
chop
(
$cwd
= `pwd`);
Elatin3::
chop
(
$answer
= <STDIN>);
This is different from:
$answer
= Elatin3::
chop
(
$tmp
= <STDIN>);
# WRONG
which puts a newline into
$answer
because Elatin3::
chop
returns the character
chopped, not the remaining string (which is in
$tmp
). One way to get the result
intended here is
with
substr
:
$answer
=
substr
<STDIN>, 0, -1;
But this is more commonly written as:
Elatin3::
chop
(
$answer
= <STDIN>);
In the most general case, Elatin3::
chop
can be expressed using
substr
:
$last_code
= Elatin3::
chop
(
$var
);
$last_code
=
substr
(
$var
, -1, 1,
""
);
# same thing
Elatin3::
chop
more than one character,
use
substr
as an lvalue, assigning a null
string. The following removes the
last
five characters of
$caravan
:
substr
(
$caravan
, -5) =
''
;
The negative subscript causes
substr
to count from the end of the string instead
form of
substr
, creating something of a quintuple Elatin3::
chop
;
$tail
=
substr
(
$caravan
, -5, 5,
''
);
This is all dangerous business dealing
with
characters instead of graphemes. Perl
doesn't really have a grapheme mode, so you have to deal
with
them yourself.
Index string
$byte_pos
= Elatin3::
index
(
$string
,
$substr
,
$byte_offset
);
$byte_pos
= Elatin3::
index
(
$string
,
$substr
);
This subroutine searches
for
one string within another. It returns the byte position
of the first occurrence of
$substring
in
$string
. The
$byte_offset
,
if
specified,
says how many bytes from the start to skip
before
beginning to look. Positions are
based at 0. If the substring is not found, the subroutine returns one less than the
base, ordinarily -1. To work your way through a string, you might
say
:
$byte_pos
= -1;
while
((
$byte_pos
= Elatin3::
index
(
$string
,
$lookfor
,
$byte_pos
)) > -1) {
print
"Found at $byte_pos\n"
;
$byte_pos
++;
}
Reverse index string
$byte_pos
= Elatin3::
rindex
(
$string
,
$substr
,
$byte_offset
);
$byte_pos
= Elatin3::
rindex
(
$string
,
$substr
);
This subroutine works just like Elatin3::
index
except that it returns the byte
position of the
last
occurrence of
$substring
in
$string
(a
reverse
Elatin3::
index
).
The subroutine returns -1
if
$substring
is not found.
$byte_offset
,
if
specified,
is the rightmost byte position that may be returned. To work your way through a
string backward,
say
:
$byte_pos
=
length
(
$string
);
while
((
$byte_pos
= Latin3::
rindex
(
$string
,
$lookfor
,
$byte_pos
)) >= 0) {
print
"Found at $byte_pos\n"
;
$byte_pos
--;
}
Lower case string
$lc
= Elatin3::
lc
(
$string
);
$lc
= Elatin3::lc_;
This subroutine returns a lowercased version of Latin-3
$string
(or
$_
,
if
$string
is omitted). This is the internal subroutine implementing the \L escape
in double-quoted strings.
software.
Lower case first character of string
$lcfirst
= Elatin3::
lcfirst
(
$string
);
$lcfirst
= Elatin3::lcfirst_;
This subroutine returns a version of Latin-3
$string
with
the first character
lowercased (or
$_
,
if
$string
is omitted). This is the internal subroutine
implementing the \l escape in double-quoted strings.
Upper case string
$uc
= Elatin3::
uc
(
$string
);
$uc
= Elatin3::uc_;
This subroutine returns an uppercased version of Latin-3
$string
(or
$_
,
if
$string
is omitted). This is the internal subroutine implementing the \U escape
software.
Upper case first character of string
$ucfirst
= Elatin3::
ucfirst
(
$string
);
$ucfirst
= Elatin3::ucfirst_;
This subroutine returns a version of Latin-3
$string
with
the first character
titlecased and other characters left alone (or
$_
,
if
$string
is omitted).
Titlecase is
"Camel"
for
an initial capital that
has
(or expects to have)
lowercase characters following it, not uppercase ones. Exsamples are the first
letter of a sentence, of a person's name, of a newspaper headline, or of most
words in a title. Characters
with
no
titlecase mapping
return
the uppercase
mapping instead. This is the internal subroutine implementing the \u escape in
double-quoted strings.
To capitalize a string by mapping its first character to titlecase and the rest
to lowercase,
use
:
$titlecase
= Elatin3::
ucfirst
(
substr
(
$word
,0,1)) . Elatin3::
lc
(
substr
(
$word
,1));
or
$string
=~ s/(\w)((?>\w*))/\u$1\L$2/g;
Do not
use
:
$do_not_use
= Elatin3::
ucfirst
(Elatin3::
lc
(
$word
));
or
"\u\L$word"
, because that can produce a different and incorrect answer
with
certain characters. The titlecase of something that
's been lowercased doesn'
t
always produce the same thing titlecasing the original produces.
Because titlecasing only makes sense at the start of a string that's followed
by lowercase characters, we can't think of any reason you might want to titlecase
every character in a string.
See also P.287 A Case of Mistaken Identity
in Chapter 6: Unicode
of ISBN 978-0-596-00492-7 Programming Perl 4th Edition.
Fold case string
P.860 fc
in Chapter 27: Functions
of ISBN 978-0-596-00492-7 Programming Perl 4th Edition.
$fc
= Elatin3::fc(
$string
);
$fc
= Elatin3::fc_;
New to Latin3 software, this subroutine returns the full Unicode-like casefold of
Latin-3
$string
(or
$_
,
if
omitted). This is the internal subroutine implementing
the \F escape in double-quoted strings.
Just as title-case is based on uppercase but different, foldcase is based on
lowercase but different. In ASCII there is a one-to-one mapping between only
two cases, but in other encoding there is a one-to-many mapping and between three
cases. Because that's too many combinations to check manually
each
time
, a fourth
casemap called foldcase was invented as a common intermediary
for
the other three.
It is not a case itself, but it is a casemap.
To compare whether two strings are the same without regard to case,
do
this:
Elatin3::fc(
$a
) eq Elatin3::fc(
$b
)
The reliable way to compare string case-insensitively was
with
the /i pattern
modifier, because Latin3 software
has
always used casefolding semantics
for
case-insensitive pattern matches. Knowing this, you can emulate equality
comparisons like this:
sub
fc_eq ($$) {
my
(
$a
,
$b
) =
@_
;
return
$a
=~ /\A\Q
$b
\E\z/i;
}
Make ignore case string
@ignorecase
= Elatin3::ignorecase(
@string
);
Make capture number
$capturenumber
= Elatin3::capture(
$string
);
Make character
$chr
= Elatin3::
chr
(
$code
);
$chr
= Elatin3::chr_;
This subroutine returns a programmer-visible character, character represented by
that
$code
in the character set. For example, Elatin3::
chr
(65) is
"A"
in either
Filename expansion (globbing)
@glob
= Elatin3::
glob
(
$string
);
@glob
= Elatin3::glob_;
This subroutine returns the value of
$string
with
filename expansions the way a
DOS-like shell would expand them, returning the
next
successive name on
each
call. If
$string
is omitted,
$_
is globbed instead. This is the internal
subroutine implementing the <*> and
glob
operator.
This subroutine function
when
the pathname ends
with
chr
(0x5C) on MSWin32.
For ease of
use
, the algorithm matches the DOS-like shell's style of expansion,
not the UNIX-like shell's. An asterisk (
"*"
) matches any sequence of any
character (including none). A question mark (
"?"
) matches any one character or
none. A tilde (
"~"
) expands to a home directory, as in
"~/.*rc"
for
all the
current user
's "rc" files, or "~jane/Mail/*" for all of Jane'
s mail files.
Note that all path components are case-insensitive, and that backslashes and
forward slashes are both accepted, and preserved. You may have to double the
backslashes
if
you are putting them in literally, due to double-quotish parsing
of the pattern by perl.
patterns such as <*.c *.h>. If you want to
glob
filenames that might contain
it. For example, to
glob
filenames that have an
"e"
followed by a space followed
@spacies
= <
"*e f*"
>;
@spacies
= Elatin3::
glob
(
'"*e f*"'
);
@spacies
= Elatin3::
glob
(
q("*e f*")
);
If you had to get a variable through, you could
do
this:
@spacies
= Elatin3::
glob
(
"'*${var}e f*'"
);
@spacies
= Elatin3::
glob
(
qq("*${var}e f*")
);
Another way on MSWin32
# relative path
@relpath_file
=
split
(/\n/,`dir /b wildcard\\here*.txt 2>NUL`);
# absolute path
@abspath_file
=
split
(/\n/,`dir /s /b wildcard\\here*.txt 2>NUL`);
# on COMMAND.COM
@relpath_file
=
split
(/\n/,`dir /b wildcard\\here*.txt`);
@abspath_file
=
split
(/\n/,`dir /s /b wildcard\\here*.txt`);