MDK::Common(3) User Contributed Perl Documentation MDK::Common(3)NAMEMDK::Common - miscellaneous functions
SYNOPSIS
use MDK::Common;
# exports all functions, equivalent to
use MDK::Common::DataStructure qw(:all);
use MDK::Common::File qw(:all);
use MDK::Common::Func qw(:all);
use MDK::Common::Math qw(:all);
use MDK::Common::String qw(:all);
use MDK::Common::System qw(:all);
use MDK::Common::Various qw(:all);
DESCRIPTION
"MDK::Common" is a collection of packages containing various simple
functions: MDK::Common::DataStructure, MDK::Common::File,
MDK::Common::Func, MDK::Common::Math, MDK::Common::String,
MDK::Common::System, MDK::Common::Various.
EXPORTS from MDK::Common::DataStructure.pmsort_numbers(LIST)
numerical sort (small numbers at beginning)
ikeys(HASH)
aka sorted integer keys, as simple as "sort { $a <=> $b } keys"
add2hash(HASH REF, HASH REF)
adds to the first hash the second hash if the key/value is not
already there
add2hash_
adds to the first hash the second hash if the key is not already
there
put_in_hash
adds to the first hash the second hash, crushing existing
key/values
member(SCALAR, LIST)
is the value in the list?
invbool(SCALAR REF)
toggles the boolean value
listlength(LIST)
returns the length of the list. Useful in list (opposed to array)
context:
sub f { "a", "b" }
my $l = listlength f();
whereas "scalar f()" would return "b"
deref(REF)
de-reference
deref_array(REF)
de-reference arrays:
deref_array [ "a", "b" ] #=> ("a", "b")
deref_array "a" #=> "a"
is_empty_array_ref(SCALAR)
is the scalar undefined or is the array empty
is_empty_hash_ref(SCALAR)
is the scalar undefined or is the hash empty
uniq(LIST)
returns the list with no duplicates (keeping the first elements)
uniq_ { CODE } LIST
returns the list with no duplicates according to the scalar results
of CODE on each element of LIST (keeping the first elements)
uniq_ { $_->[1] } [ 1, "fo" ], [ 2, "fob" ], [ 3, "fo" ], [ 4, "bar" ]
gives [ 1, "fo" ], [ 2, "fob" ], [ 4, "bar" ]
difference2(ARRAY REF, ARRAY REF)
returns the first list without the element of the second list
intersection(ARRAY REF, ARRAY REF, ...)
returns the elements which are in all lists
next_val_in_array(SCALAR, ARRAY REF)
finds the value that follow the scalar in the list (circular):
"next_val_in_array(3, [1, 2, 3])" gives 1 (do not use a list with
duplicates)
group_by2(LIST)
interprets the list as an ordered hash, returns a list of
[key,value]: "group_by2(1 =" 2, 3 => 4, 5 => 6)> gives "[1,2],
[3,4], [5,6]"
list2kv(LIST)
interprets the list as an ordered hash, returns the keys and the
values: "list2kv(1 =" 2, 3 => 4, 5 => 6)> gives "[1,3,5], [2,4,6]"
EXPORTS from MDK::Common::File.pmdirname(FILENAME)basename(FILENAME)
returns the dirname/basename of the file name
cat_(FILES)
returns the files contents: in scalar context it returns a single
string, in array context it returns the lines.
If no file is found, undef is returned
cat_or_die(FILENAME)
same as "cat_" but dies when something goes wrong
cat_utf8(FILES)
same as C(<cat_>) but reads utf8 encoded strings
cat_utf8_or_die(FILES)
same as C(<cat_or_die>) but reads utf8 encoded strings
cat__(FILEHANDLE REF)
returns the file content: in scalar context it returns a single
string, in array context it returns the lines
output(FILENAME, LIST)
creates a file and outputs the list (if the file exists, it is
clobbered)
output_utf8(FILENAME, LIST)
same as C(<output>) but writes utf8 encoded strings
secured_output(FILENAME, LIST)
likes output() but prevents insecured usage (it dies if somebody
try to exploit the race window between unlink() and creat())
append_to_file(FILENAME, LIST)
add the LIST at the end of the file
output_p(FILENAME, LIST)
just like "output" but creates directories if needed
output_with_perm(FILENAME, PERMISSION, LIST)
same as "output_p" but sets FILENAME permission to PERMISSION
(using chmod)
mkdir_p(DIRNAME)
creates the directory (make parent directories as needed)
rm_rf(FILES)
remove the files (including sub-directories)
cp_f(FILES, DEST)
just like "cp -f"
cp_af(FILES, DEST)
just like "cp -af"
cp_afx(FILES, DEST)
just like "cp -afx"
linkf(SOURCE, DESTINATION)
symlinkf(SOURCE, DESTINATION)
renamef(SOURCE, DESTINATION)
same as link/symlink/rename but removes the destination file first
touch(FILENAME)
ensure the file exists, set the modification time to current time
all(DIRNAME)
returns all the file in directory (except "." and "..")
all_files_rec(DIRNAME)
returns all the files in directory and the sub-directories (except
"." and "..")
glob_(STRING)
simple version of "glob": doesn't handle wildcards in directory
(eg: */foo.c), nor special constructs (eg: [0-9] or {a,b})
substInFile { CODE } FILENAME
executes the code for each line of the file. You can know the end
of the file is reached using "eof"
expand_symlinks(FILENAME)
expand the symlinks in the absolute filename:
"expand_symlinks("/etc/X11/X")" gives "/usr/X11R6/bin/XFree86"
openFileMaybeCompressed(FILENAME)
opens the file and returns the file handle. If the file is not
found, tries to gunzip the file + .gz
catMaybeCompressed(FILENAME)
cat_ alike. If the file is not found, tries to gunzip the file +
.gz
EXPORTS from MDK::Common::Func.pm
may_apply(CODE REF, SCALAR)
"may_apply($f, $v)" is "$f ? $f->($v) : $v"
may_apply(CODE REF, SCALAR, SCALAR)
"may_apply($f, $v, $otherwise)" is "$f ? $f->($v) : $otherwise"
if_(BOOL, LIST)
special constructs to workaround a missing perl feature: "if_($b,
"a", "b")" is "$b ? ("a", "b") : ()"
example of use: "f("a", if_(arch() =~ /i.86/, "b"), "c")" which is
not the same as "f("a", arch()=~ /i.86/ && "b", "c")"
if__(SCALAR, LIST)
if_ alike. Test if the value is defined
fold_left { CODE } LIST
if you don't know fold_left (aka foldl), don't use it ;p
fold_left { $::a + $::b } 1, 3, 6
gives 10 (aka 1+3+6)
mapn { CODE } ARRAY REF, ARRAY REF, ...
map lists in parallel:
mapn { $_[0] + $_[1] } [1, 2], [2, 4] # gives 3, 6
mapn { $_[0] + $_[1] + $_[2] } [1, 2], [2, 4], [3, 6] gives 6, 12
mapn_ { CODE } ARRAY REF, ARRAY REF, ...
mapn alike. The difference is what to do when the lists have not
the same length: mapn takes the minimum common elements, mapn_
takes the maximum list length and extend the lists with undef
values
find { CODE } LIST
returns the first element where CODE returns true (or returns
undef)
find { /foo/ } "fo", "fob", "foobar", "foobir"
gives "foobar"
any { CODE } LIST
returns 1 if CODE returns true for an element in LIST (otherwise
returns 0)
any { /foo/ } "fo", "fob", "foobar", "foobir"
gives 1
every { CODE } LIST
returns 1 if CODE returns true for every element in LIST (otherwise
returns 0)
every { /foo/ } "fo", "fob", "foobar", "foobir"
gives 0
map_index { CODE } LIST
just like "map", but set $::i to the current index in the list:
map_index { "$::i $_" } "a", "b"
gives "0 a", "1 b"
each_index { CODE } LIST
just like "map_index", but doesn't return anything
each_index { print "$::i $_\n" } "a", "b"
prints "0 a", "1 b"
grep_index { CODE } LIST
just like "grep", but set $::i to the current index in the list:
grep_index { $::i == $_ } 0, 2, 2, 3
gives (0, 2, 3)
find_index { CODE } LIST
returns the index of the first element where CODE returns true (or
throws an exception)
find_index { /foo/ } "fo", "fob", "foobar", "foobir"
gives 2
map_each { CODE } HASH
returns the list of results of CODE applied with $::a (key) and
$::b (value)
map_each { "$::a is $::b" } 1=>2, 3=>4
gives "1 is 2", "3 is 4"
grep_each { CODE } HASH
returns the hash key/value for which CODE applied with $::a (key)
and $::b (value) is true:
grep_each { $::b == 2 } 1=>2, 3=>4, 4=>2
gives 1=>2, 4=>2
partition { CODE } LIST
alike "grep", but returns both the list of matching elements and
non matching elements
my ($greater, $lower) = partition { $_ > 3 } 4, 2, 8, 0, 1
gives $greater = [ 4, 8 ] and $lower = [ 2, 0, 1 ]
before_leaving { CODE }
the code will be executed when the current block is finished
# create $tmp_file
my $b = before_leaving { unlink $tmp_file };
# some code that may throw an exception, the "before_leaving" ensures the
# $tmp_file will be removed
cdie(SCALAR)
aka conditional die. If a "cdie" is catched, the execution
continues after the cdie, not where it was catched (as happens with
die & eval)
If a "cdie" is not catched, it mutates in real exception that can
be catched with "eval"
cdie is useful when you want to warn about something weird, but
when you can go on. In that case, you cdie "something weird
happened", and the caller decide wether to go on or not. Especially
nice for libraries.
catch_cdie { CODE1 } sub { CODE2 }
If a "cdie" occurs while executing CODE1, CODE2 is executed. If
CODE2 returns true, the "cdie" is catched.
EXPORTS from MDK::Common::Math.pm
$PI the well-known constant
even(INT)odd(INT)
is the number even or odd?
sqr(FLOAT)sqr(3) gives 9
sign(FLOAT)
returns a value in { -1, 0, 1 }
round(FLOAT)
"round(1.2)" gives 1, "round(1.6)" gives 2
round_up(FLOAT, INT)
returns the number rounded up to the modulo: "round_up(11,10)"
gives 20
round_down(FLOAT, INT)
returns the number rounded down to the modulo: "round_down(11,10)"
gives 10
divide(INT, INT)
integer division (which is lacking in perl). In array context, also
returns the remainder: "($a, $b) = divide(10,3)" gives "$a is 3"
and "$b is 1"
min(LIST)max(LIST)
returns the minimum/maximum number in the list
or_(LIST)
is there a true value in the list?
and_(LIST)
are all values true in the list?
sum(LIST)product(LIST)
returns the sum/product of all the element in the list
factorial(INT)factorial(4) gives 24 (4*3*2)
OTHER in MDK::Common::Math.pm
the following functions are provided, but not exported:
factorize(INT)
"factorize(40)" gives "([2,3], [5,1])" as 40 = 2^3 + 5^1
decimal2fraction(FLOAT)
"decimal2fraction(1.3333333333)" gives "(4, 3)" ($PRECISION is used
to decide which precision to use)
poly2(a,b,c)
Solves the a*x2+b*x+c=0 polynomial: "poly2(1,0,-1)" gives "(1, -1)"
permutations(n,p)
A(n,p)
combinaisons(n,p)
C(n,p)
EXPORTS from MDK::Common::String.pm
bestMatchSentence(STRING, LIST)
finds in the list the best corresponding string
formatList(INT, LIST)
if the list size is bigger than INT, replace the remaining elements
with "...".
formatList(3, qw(a b c d e)) # => "a, b, c, ..."
formatError(STRING)
the string is something like "error at foo.pl line 2" that you get
when catching an exception. formatError will remove the "at ..." so
that you can nicely display the returned string to the user
formatTimeRaw(TIME)
the TIME is an epoch as returned by "time", the formatted time
looks like "23:59:00"
formatLines(STRING)
remove "\n"s when the next line doesn't start with a space.
Otherwise keep "\n"s to keep the indentation.
formatAlaTeX(STRING)
handle carriage return just like LaTeX: merge lines that are not
separated by an empty line
begins_with(STRING, STRING)
return true if first argument begins with the second argument. Use
this instead of regexps if you don't want regexps.
begins_with("hello world", "hello") # => 1
warp_text(STRING, INT)
return a list of lines which do not exceed INT characters (or a
string in scalar context)
warp_text(STRING)
warp_text at a default width (80)
EXPORTS from MDK::Common::System.pm
%compat_arch
architecture compatibility mapping (eg: k6 => i586, k7 => k6 ...)
%printable_chars
7 bit ascii characters
$sizeof_int
sizeof(int)
$bitof_int
$sizeof_int * 8
arch()
return the architecture (eg: i686, ppc, ia64, k7...)
typeFromMagic(FILENAME, LIST)
find the first corresponding magic in FILENAME. eg of LIST:
[ 'empty', 0, "\0\0\0\0" ],
[ 'grub', 0, "\xEBG", 0x17d, "stage1 \0" ],
[ 'lilo', 0x2, "LILO" ],
where each entry is [ magic_name, offset, string, offset, string,
... ].
list_passwd()
return the list of users as given by "getpwent" (see perlfunc)
list_home()
return the list of home (eg: /home/foo, /home/pixel, ...)
list_skels()
return the directories where we can find dot files: homes, /root
and /etc/skel
list_users()
return the list of unprivilegied users (aka those whose uid is
greater than 500 and who are not "nobody").
syscall_(NAME, PARA)
calls the syscall NAME
psizeof(STRING)
useful to know the length of a "pack" format string.
psizeof("I I I C C S") = 4 + 4 + 4 + 1 + 1 + 2 = 16
availableMemory()
size of swap + memory
availableRamMB()
size of RAM as reported by the BIOS (it is a round number that can
be displayed or given as "mem=128M" to the kernel)
!! "mem=..." is dangerous in 2.4 kernels
gettimeofday()
returns the epoch in microseconds
unix2dos(STRING)
takes care of CR/LF translation
whereis_binary(STRING)
return the first absolute file in $PATH (similar to which(1) and
whereis(1))
getVarsFromSh(FILENAME)
returns a hash associating shell variables to their value. useful
for config files such as /etc/sysconfig files
setVarsInSh(FILENAME, HASH REF)
write file in shell format association a shell variable + value for
each key/value
setVarsInSh(FILENAME, HASH REF, LIST)
restrict the fields that will be printed to LIST
setVarsInShMode(FILENAME, INT, HASH REF, LIST)
like setVarsInSh with INT being the chmod value for the config file
addVarsInSh(FILENAME, HASH REF)
like setVarsInSh but keeping the entries in the file
addVarsInSh(FILENAME, HASH REF, LIST)
like setVarsInSh but keeping the entries in the file
addVarsInShMode(FILENAME, INT, HASH REF, LIST)
like addVarsInShMode but keeping the entries in the file
setExportedVarsInCsh(FILENAME, HASH REF, LIST)
same as "setExportedVarsInSh" for csh format
template2file(FILENAME_IN, FILENAME_OUT, HASH)
read in a template file, replace keys @@@key@@@ with value, save it
in out file
template2userfile(PREFIX, FILENAME_IN, FILENAME_OUT, BOOL, HASH)
read in a template file, replace keys @@@key@@@ with value, save it
in every homes. If BOOL is true, overwrite existing files.
FILENAME_OUT must be a relative filename
read_gnomekderc(FILENAME, STRING)
reads GNOME-like and KDE-like config files (aka windows-like). You
must give a category. eg:
read_gnomekderc("/etc/skels/.kderc", 'KDE')
update_gnomekderc(FILENAME, STRING, HASH)
modifies GNOME-like and KDE-like config files (aka windows-like).
If the category doesn't exist, it creates it. eg:
update_gnomekderc("/etc/skels/.kderc", 'KDE',
kfmIconStyle => "Large")
fuzzy_pidofs(REGEXP)
return the list of process ids matching the regexp
OTHER in MDK::Common::System.pm
better_arch(ARCH1, ARCH2)
is ARCH1 compatible with ARCH2?
better_arch('i386', 'ia64') and better_arch('ia64', 'i386') are
false
better_arch('k7', 'k6') is true and better_arch('k6', 'k7') is
false
compat_arch(STRING)
test the architecture compatibility. eg:
compat_arch('i386') is false on a ia64
compat_arch('k6') is true on a k6 and k7 but false on a i386 and
i686
EXPORTS from MDK::Common::Various.pmfirst(LIST)
returns the first value. "first(XXX)" is an alternative for
"((XXX)[0])"
second(LIST)
returns the second value. "second(XXX)" is an alternative for
"((XXX)[1])"
top(LIST)
returns the last value. "top(@l)" is an alternative for $l[$#l]
to_bool(SCALAR)
returns a value in { 0, 1 }
to_int(STRING)
extracts the number from the string. You could use directly "int
"11 foo"", but you'll get Argument "11 foo" isn't numeric in int.
It also handles returns 11 for "foo 11 bar"
to_float(STRING)
extract a decimal number from the string
bool2text(SCALAR)
returns a value in { "true", "false" }
bool2yesno(SCALAR)
returns a value in { "yes", "no" }
text2bool(STRING)
inverse of "bool2text" and "bool2yesno"
chomp_(STRING)
non-mutable version of chomp: do not modify the argument, returns
the chomp'ed value. Also works on lists: "chomp_($a, $b)" is
equivalent to "chomp($a) ; chomp($b) ; ($a,$b)"
backtrace()
returns a string describing the backtrace. eg:
sub g { print "oops\n", backtrace() }
sub f { &g }
f();
gives
oops
main::g() called from /tmp/t.pl:2
main::f() called from /tmp/t.pl:4
internal_error(STRING)
another way to "die" with a nice error message and a backtrace
noreturn()
use this to ensure nobody uses the return value of the function.
eg:
sub g { print "g called\n"; noreturn }
sub f { print "g returns ", g() }
f();
gives
test.pl:3: main::f() expects a value from main::g(), but main::g() doesn't return any value
COPYRIGHT
Copyright (c) 2001-2005 Mandriva <pixel@mandriva.com>. All rights
reserved. This program is free software; you can redistribute it
and/or modify it under the same terms as Perl itself.
perl v5.18.1 2011-09-14 MDK::Common(3)
