Data commit

Task/Update-a-configuration-file/Perl/update-a-configuration-file.pl

@@ -0,0 +1,98 @@
+use warnings;
+use strict;
+
+my $needspeeling         = 0;
+my $seedsremoved         = 1;
+my $numberofstrawberries = 62000;
+my $numberofbananas      = 1024;
+my $favouritefruit       = 'bananas';
+
+my @out;
+
+sub config {
+    my (@config) = <DATA>;
+    push @config, "NUMBEROFSTRAWBERRIES $numberofstrawberries\n"
+        unless grep { /^;*[ \t]*NUMBEROFSTRAWBERRIES\b/; } @config;
+
+    foreach my $line (@config) {
+
+        if (substr($line, 0, 1) eq '#') {
+            push @out, $line;
+            next;
+        }
+
+        next if $line =~ /^[;\t ]+$/;
+
+        my ($option, $option_name);
+
+        if ($line =~ /^([A-Z]+[0-9]*)/) {
+            $option_name = lc $1;
+            $option      = eval "\\\$$option_name";
+            my $value = eval "\${$option_name}";
+
+            if ($value) {
+                $$option = $value;
+            }
+            else {
+                $line    = '; ' . $line;
+                $$option = undef;
+            }
+        }
+        elsif ($line =~ /^;+\s*([A-Z]+[0-9]*)/) {
+            $option_name = lc $1;
+            $option      = eval "\\\$$option_name";
+            my $value = eval "\${$option_name}";
+
+            if ($value) {
+                $line =~ s/^;+\s*//;
+                $$option = $value == 1 ? '' : $value;
+            }
+            else {
+                $$option = undef;
+            }
+        }
+
+        if (defined $$option) {
+            push @out, "\U$option_name\E $$option\n"
+                unless grep { /^\U$option_name\E\b/; } @out;
+        }
+        else {
+            $line =~ s/\s*[^[:ascii:]]+\s*$//;
+            $line =~ s/[[:cntrl:]\s]+$//;
+            push(@out, "$line\n");
+        }
+    }
+}
+
+config();
+
+my $file = join('', @out);
+$file =~ s/\n{3,}/\n\n/g;
+
+print $file;
+
+__DATA__
+# This is a configuration file in standard configuration file format
+#
+# Lines begininning with a hash or a semicolon are ignored by the application
+# program. Blank lines are also ignored by the application program.
+
+# The first word on each non comment line is the configuration option.
+# Remaining words or numbers on the line are configuration parameter
+# data fields.
+
+# Note that configuration option names are not case sensitive. However,
+# configuration parameter data is case sensitive and the lettercase must
+# be preserved.
+
+# This is a favourite fruit
+FAVOURITEFRUIT banana
+
+# This is a boolean that should be set
+NEEDSPEELING
+
+# This boolean is commented out
+; SEEDSREMOVED
+
+# How many bananas we have
+NUMBEROFBANANAS 48