第7章： 正则表达式

　　

#! /usr/bin/perl
use strict;
use warnings;

print " ----------------------------------simple_pattern_metacharacter_quantifier-------------------------- ";
$_ = "asteriskasterisk hash access unpack_func";
for (/as.*e/){
    print "matched. ";
}
for (/(asterisk)+/){
    print "matched*2. ";
}
for(/unpack.*|lvalue|alignment/){
    print "matched*3. ";
}
my @escaped = "asteriskasterisk hash access unpack_func";
print @escaped;
print "@escaped";
foreach(@escaped){
    print $_;
}
print " ";
print $escaped[0];
print " ";
unless( $escaped[1] ){
    print "$escaped[1] is undef.";
}
print " ----------------------------------simple_pattern_metacharacter_quantifier-------------------------- ";

print " ----------------------------------_alternative_-------------------------- ";
print $_." ";
for(/access (unpack|indices)_func/){
    print "matched*4. ";
}
print " ----------------------------------_alternative_-------------------------- ";

print " ----------------------------------_character_class-------------------------- ";
$_ = 'z';
for(/[a-cw-z]/){
    print "matched*5. ";
    print "00";
    print " ";
    print "177";
}
$_ = "The HAL-9000 requires 8 authorization.";
if(/HAL-[0-9]+/){
    print "HAL computers mentioned."
}
print " ----------------------------------_character_class-------------------------- ";

print " ----------------------------------_character_class_shortcut-------------------------- ";
if(/HAL-d+/){
    print "HAL computers mentioned. matched*5. ";
}
if(/requires w authorization/){
    print "matched*6. ";
}
print " ----------------------------------_character_class_shortcut-------------------------- ";

print " ----------------------------------exercise_ch7_-------------------------- ";
$_ = "aligning Alignrick or veralign.";
if(/align/){
    print "matched*7. ";
}
open ARROW_NOTATION, "< file_4_ex_ch7.txt";
my $counter = 8;
while(<ARROW_NOTATION>){
    chomp;
    my $arraow_syntax = $_;
    #for(/[a|A]lign/){
    for(/./){
        print "matched*$counter. ";
        $counter++;
        print $arraow_syntax." ";
    }
}
close ARROW_NOTATION;
print " ----------------------------------exercise_ch7_-------------------------- ";

print " ----------------------------------exercise_ch7_4-------------------------- ";
while(<>){
    if(/[A-Z][a-z]+/){
        print $_." " ;
    }
    if(/[a-z][A-Z]/){
        print $_." " ;
    }
}
print " ----------------------------------exercise_ch7_4-------------------------- ";