MDK::Common::Func

Section: User Contributed Perl Documentation (3)
Updated: 2014-01-24
Page Index
 

NAME

MDK::Common::Func - miscellaneous functions  

SYNOPSIS

    use MDK::Common::Func qw(:all);

 

EXPORTS

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.
 

SEE ALSO

MDK::Common


 

Index

NAME
SYNOPSIS
EXPORTS
SEE ALSO
LinuxReviews : manual page archive : man3pm