Feature: sort --reverse (#21)

semver

@@ -35,9 +35,9 @@ sub usage() {
     say STDERR "  $program increment-minor <version>";
     say STDERR "  $program increment-patch <version>";
     say STDERR "  $program init";
-    say STDERR "  $program sort -";
+    say STDERR "  $program sort [-r | --reverse] -";
     say STDERR "  $program validate <string>";
-    say STDERR "  $program (-h | --help)";
+    say STDERR "  $program [-h | --help]";
     say STDERR "";
     say STDERR "Options:";
     say STDERR "  -h --help  Show this help screen.";
@@ -299,7 +299,9 @@ sub semver::init {
     say "0.0.0";
 }
 
-sub semver::sort {
+sub semver::sort(&@) {
+    my ($sort_fn) = @_;
+
     my @lines = <STDIN>;
 
     chomp(@lines);
@@ -309,21 +311,25 @@ sub semver::sort {
         exit 1;
     }
 
-    @lines = sort {
-        my $result = semver::compare($a, $b);
-
-        if ($result eq $eq) {
-            return $a cmp $b;
-        } else {
-            return $result;
-        }
-    } @lines;
+    @lines = sort $sort_fn @lines;
 
     foreach my $line (@lines) {
         say $line;
     }
 }
 
+sub semver::sort_pair {
+    my ($a, $b) = @_;
+
+    my $result = semver::compare($a, $b);
+
+    if ($result eq $eq) {
+        return $a cmp $b;
+    } else {
+        return $result;
+    }
+}
+
 sub semver::validate {
     my ($str) = @_;
 
@@ -368,7 +374,11 @@ sub main {
     } elsif ($subcommand eq "increment-patch") {
         semver::increment_patch($args[1]);
     } elsif ($subcommand eq "sort") {
-        semver::sort();
+        if (grep { $_ eq "-r" || $_ eq "--reverse" } @args) {
+            semver::sort { semver::sort_pair($b, $a) };
+        } else {
+            semver::sort { semver::sort_pair($a, $b) };
+        }
     } elsif ($subcommand eq "validate") {
         semver::validate($args[1]);
     } elsif ($subcommand eq "compare") {

semver.1

@@ -49,6 +49,7 @@ increment-patch
 init
 .Nm
 sort
+.Op Fl r | Fl -reverse
 .Fl
 .Nm
 validate
@@ -171,9 +172,9 @@ can get the MINOR component of a
 .Ar version
 string.
 .Pp
-If
+The operation will fail if
 .Ar version
-is invalid, nothing will be printed, and the utility will exit with an error code.
+is invalid.
 .Ss get-patch
 .Nm
 can get the PATCH component of a
@@ -219,9 +220,7 @@ is invalid.
 .El
 .Ss grep
 .Nm
-can parse text from STDIN to extract zero or more Semantic Version strings, in the style of
-.Sq grep
-\&. It will tolerate quite noisy input.
+can parse text from STDIN to extract zero or more Semantic Version strings. It will tolerate quite noisy input.
 .Pp
 A candidate version
 .Sq string
@@ -289,11 +288,15 @@ can print the minimum Semantic Version
 to STDOUT. You can use this as a base-case initializer, for example in a script which fails to find any Semantic Versions in its input.
 .Ss sort
 .Nm
-can order a list of line-delimited Semantic Version strings from STDIN by precedence, in the style of
-.Sq sort
-\&.
+can sort a list of line-delimited Semantic Version strings from STDIN in precedence order (low-to-high).
+.Pp
+The sort subcommand understands the following options:
+.Bl -tag -width indent
+.It Fl r, Fl -reverse
+Sort in reverse order (high-to-low).
+.El
 .Pp
-If the input is invalid (i.e. it contains anything besides Semantic Versions and line delimiter characters), nothing will be printed, and the utility will exit with an error code.
+The operation will fail if the input is invalid (i.e. it contains anything besides Semantic Versions and line delimiter characters).
 .Pp
 Note: Some aspects of Semantic Version ordering are undefined in the specification. The
 .Nm
@@ -319,7 +322,7 @@ The
 .Nm
 utility understands the following command-line options:
 .Bl -tag -width indent
-.It Fl h, Fl help
+.It Fl h, Fl -help
 Display the usage screen.
 .El
 .Sh EXAMPLES

test/sort.bats

@@ -90,4 +90,24 @@ EOF
 )
 
     [[ "$(semver sort <<< "$input")" = "$expected" ]]
+}
+
+@test "sort: should reverse ordering with the -r (--reverse) flag" {
+    input=$(cat <<EOF
+1.0.0
+2.0.0
+1.0.0-SNAPSHOT
+1.0.0+2008
+EOF
+)
+
+    expected=$(cat <<EOF
+2.0.0
+1.0.0+2008
+1.0.0
+1.0.0-SNAPSHOT
+EOF
+)
+
+    [[ "$(semver sort -r <<< "$input")" = "$expected" ]] && [[ "$(semver sort --reverse <<< "$input")" = "$expected" ]]
 }