RogerBW solutions for challenge no. 227

19 files changed, 1980 insertions, 0 deletions

diff --git a/challenge-227/roger-bell-west/javascript/ch-1.js b/challenge-227/roger-bell-west/javascript/ch-1.js
new file mode 100755
index 0000000000..f1d67fa55f
--- /dev/null
+++ b/challenge-227/roger-bell-west/javascript/ch-1.js
@@ -0,0 +1,20 @@
+#! /usr/bin/node
+
+"use strict"
+
+function friday13th(y) {
+    let f = 0;
+    for (let m = 1; m <= 12; m++) {
+        if (new Date(y, m-1, 13, 12, 0, 0).getDay() == 5) {
+            f++;
+        }
+    }
+    return f;
+}
+
+if (friday13th(2023) == 2) {
+  process.stdout.write("Pass");
+} else {
+  process.stdout.write("FAIL");
+}
+process.stdout.write("\n");
diff --git a/challenge-227/roger-bell-west/javascript/ch-2.js b/challenge-227/roger-bell-west/javascript/ch-2.js
new file mode 100755
index 0000000000..ac7ff3fbfc
--- /dev/null
+++ b/challenge-227/roger-bell-west/javascript/ch-2.js
@@ -0,0 +1,209 @@
+#! /usr/bin/node
+
+"use strict"
+
+function roman2int(roman) {
+    if (roman == "") {
+        return 0;
+    }
+    for (let s of [
+        [ 'M', 1000 ],
+        [ 'CM', 900 ],
+        [ 'D', 500 ],
+        [ 'CD', 400 ],
+        [ 'C', 100 ],
+        [ 'XC', 90 ],
+        [ 'L', 50 ],
+        [ 'XL', 40 ],
+        [ 'X', 10 ],
+        [ 'IX', 9 ],
+        [ 'V', 5 ],
+        [ 'IV', 4 ],
+        [ 'I', 1 ],
+    ]) {
+        if (roman.startsWith(s[0])) {
+            return s[1] + roman2int(roman.slice(s[0].length));
+        }
+    }
+    return 0;
+}
+
+function int2roman(n0) {
+    let number = n0;
+    let mn = "";
+    for (let s of [
+        [ 'M', 1000 ],
+        [ 'CM', 900 ],
+        [ 'D', 500 ],
+        [ 'CD', 400 ],
+        [ 'C', 100 ],
+        [ 'XC', 90 ],
+        [ 'L', 50 ],
+        [ 'XL', 40 ],
+        [ 'X', 10 ],
+        [ 'IX', 9 ],
+        [ 'V', 5 ],
+        [ 'IV', 4 ],
+        [ 'I', 1 ],
+    ]) {
+        while (s[1] <= number) {
+            mn += s[0]
+            number -= s[1];
+        }
+    }
+    return mn;
+}
+
+function romanmaths(ax) {
+    const elems = ax.split(" ");
+    const a = roman2int(elems[0]);
+    const b = roman2int(elems[2]);
+    let c = -1;
+    if (elems[1] == "+") {
+        c = a + b;
+    } else if (elems[1] == "-") {
+        c = a - b;
+    } else if (elems[1] == "*") {
+        c = a * b;
+    } else if (elems[1] == "/") {
+        if (a % b == 0) {
+            c = a / b;
+        }
+    } else if (elems[1] == "**") {
+        c = a ** b;
+    }
+    if (c > 3999 || c < 0) {
+        return 'non potest';
+    } else if (c == 0) {
+        return 'nulla';
+    } else {
+        return int2roman(c);
+    }
+}
+
+if (roman2int('I') == 1) {
+  process.stdout.write("Pass");
+} else {
+  process.stdout.write("FAIL");
+}
+process.stdout.write(" ");
+if (roman2int('II') == 2) {
+  process.stdout.write("Pass");
+} else {
+  process.stdout.write("FAIL");
+}
+process.stdout.write(" ");
+if (roman2int('IV') == 4) {
+  process.stdout.write("Pass");
+} else {
+  process.stdout.write("FAIL");
+}
+process.stdout.write(" ");
+if (roman2int('IX') == 9) {
+  process.stdout.write("Pass");
+} else {
+  process.stdout.write("FAIL");
+}
+process.stdout.write(" ");
+if (roman2int('XXX') == 30) {
+  process.stdout.write("Pass");
+} else {
+  process.stdout.write("FAIL");
+}
+process.stdout.write(" ");
+if (roman2int('MDCLXVI') == 1666) {
+  process.stdout.write("Pass");
+} else {
+  process.stdout.write("FAIL");
+}
+process.stdout.write(" ");
+if (int2roman(1) == 'I') {
+  process.stdout.write("Pass");
+} else {
+  process.stdout.write("FAIL");
+}
+process.stdout.write(" ");
+if (int2roman(2) == 'II') {
+  process.stdout.write("Pass");
+} else {
+  process.stdout.write("FAIL");
+}
+process.stdout.write(" ");
+if (int2roman(4) == 'IV') {
+  process.stdout.write("Pass");
+} else {
+  process.stdout.write("FAIL");
+}
+process.stdout.write(" ");
+if (int2roman(9) == 'IX') {
+  process.stdout.write("Pass");
+} else {
+  process.stdout.write("FAIL");
+}
+process.stdout.write(" ");
+if (int2roman(30) == 'XXX') {
+  process.stdout.write("Pass");
+} else {
+  process.stdout.write("FAIL");
+}
+process.stdout.write(" ");
+if (int2roman(1666) == 'MDCLXVI') {
+  process.stdout.write("Pass");
+} else {
+  process.stdout.write("FAIL");
+}
+process.stdout.write(" ");
+if (romanmaths('IV + V') == 'IX') {
+  process.stdout.write("Pass");
+} else {
+  process.stdout.write("FAIL");
+}
+process.stdout.write(" ");
+if (romanmaths('M - I') == 'CMXCIX') {
+  process.stdout.write("Pass");
+} else {
+  process.stdout.write("FAIL");
+}
+process.stdout.write(" ");
+if (romanmaths('X / II') == 'V') {
+  process.stdout.write("Pass");
+} else {
+  process.stdout.write("FAIL");
+}
+process.stdout.write(" ");
+if (romanmaths('XI * VI') == 'LXVI') {
+  process.stdout.write("Pass");
+} else {
+  process.stdout.write("FAIL");
+}
+process.stdout.write(" ");
+if (romanmaths('VII ** III') == 'CCCXLIII') {
+  process.stdout.write("Pass");
+} else {
+  process.stdout.write("FAIL");
+}
+process.stdout.write(" ");
+if (romanmaths('V - V') == 'nulla') {
+  process.stdout.write("Pass");
+} else {
+  process.stdout.write("FAIL");
+}
+process.stdout.write(" ");
+if (romanmaths('V / II') == 'non potest') {
+  process.stdout.write("Pass");
+} else {
+  process.stdout.write("FAIL");
+}
+process.stdout.write(" ");
+if (romanmaths('MMM + M') == 'non potest') {
+  process.stdout.write("Pass");
+} else {
+  process.stdout.write("FAIL");
+}
+process.stdout.write(" ");
+if (romanmaths('V - X') == 'non potest') {
+  process.stdout.write("Pass");
+} else {
+  process.stdout.write("FAIL");
+}
+process.stdout.write("\n");
diff --git a/challenge-227/roger-bell-west/kotlin/ch-1.kt b/challenge-227/roger-bell-west/kotlin/ch-1.kt
new file mode 100644
index 0000000000..33a112b884
--- /dev/null
+++ b/challenge-227/roger-bell-west/kotlin/ch-1.kt
@@ -0,0 +1,22 @@
+import java.time.LocalDate
+
+fun friday13th(y: Int): Int {
+    var f = 0
+    for (m in 1..12) {
+        if (LocalDate.of(y, m, 13).dayOfWeek.getValue() == 5) {
+            f += 1
+        }
+    }
+    return f
+}
+
+fun main() {
+
+    if (friday13th(2023) == 2) {
+        print("Pass")
+    } else {
+        print("Fail")
+    }
+    println("")
+
+}
diff --git a/challenge-227/roger-bell-west/kotlin/ch-2.kt b/challenge-227/roger-bell-west/kotlin/ch-2.kt
new file mode 100644
index 0000000000..d3be43c216
--- /dev/null
+++ b/challenge-227/roger-bell-west/kotlin/ch-2.kt
@@ -0,0 +1,223 @@
+fun roman2int(roman: String): Int {
+    if (roman == "") {
+        return 0
+    }
+    for (s in listOf(
+        Pair( "M", 1000 ),
+        Pair( "CM", 900 ),
+        Pair( "D", 500 ),
+        Pair( "CD", 400 ),
+        Pair( "C", 100 ),
+        Pair( "XC", 90 ),
+        Pair( "L", 50 ),
+        Pair( "XL", 40 ),
+        Pair( "X", 10 ),
+        Pair( "IX", 9 ),
+        Pair( "V", 5 ),
+        Pair( "IV", 4 ),
+        Pair( "I", 1 ),
+    )) {
+        if (roman.startsWith(s.first)) {
+            return s.second + roman2int(roman.slice(s.first.length .. roman.length-1))
+        }
+    }
+    return 0
+}
+
+fun int2roman(n0: Int): String {
+    var number = n0
+    var mn = ""
+    for (s in listOf(
+        Pair( "M", 1000 ),
+        Pair( "CM", 900 ),
+        Pair( "D", 500 ),
+        Pair( "CD", 400 ),
+        Pair( "C", 100 ),
+        Pair( "XC", 90 ),
+        Pair( "L", 50 ),
+        Pair( "XL", 40 ),
+        Pair( "X", 10 ),
+        Pair( "IX", 9 ),
+        Pair( "V", 5 ),
+        Pair( "IV", 4 ),
+        Pair( "I", 1 ),
+    )) {
+        while (s.second <= number) {
+            mn += s.first
+            number -= s.second
+        }
+    }
+    return mn
+}
+
+fun intPow(x0: Int,pow0: Int): Int {
+    var x=x0
+    var pow=pow0
+    var ret=1
+    while (pow > 0) {
+        if ( (pow and 1) == 1 ) {
+            ret *= x
+        }
+        x *= x
+        pow = pow shr 1
+    }
+    return ret
+}
+
+fun romanmaths(ax: String): String {
+    val elems = ax.split(" ")
+    val a = roman2int(elems[0])
+    val b = roman2int(elems[2])
+    var c = -1
+    if (elems[1] == "+") {
+        c = a + b
+    } else if (elems[1] == "-") {
+        c = a - b
+    } else if (elems[1] == "*") {
+        c = a * b
+    } else if (elems[1] == "/") {
+        if (a % b == 0) {
+            c = a / b
+        }
+    } else if (elems[1] == "**") {
+        c = intPow(a, b)
+    }
+    if (c > 3999 || c < 0) {
+        return "non potest"
+    } else if (c == 0) {
+        return "nulla"
+    } else {
+        return int2roman(c)
+    }
+}
+
+fun main() {
+
+    if (roman2int("I") == 1) {
+        print("Pass")
+    } else {
+        print("Fail")
+    }
+    print(" ")
+    if (roman2int("II") == 2) {
+        print("Pass")
+    } else {
+        print("Fail")
+    }
+    print(" ")
+    if (roman2int("IV") == 4) {
+        print("Pass")
+    } else {
+        print("Fail")
+    }
+    print(" ")
+    if (roman2int("IX") == 9) {
+        print("Pass")
+    } else {
+        print("Fail")
+    }
+    print(" ")
+    if (roman2int("XXX") == 30) {
+        print("Pass")
+    } else {
+        print("Fail")
+    }
+    print(" ")
+    if (roman2int("MDCLXVI") == 1666) {
+        print("Pass")
+    } else {
+        print("Fail")
+    }
+    print(" ")
+    if (int2roman(1) == "I") {
+        print("Pass")
+    } else {
+        print("Fail")
+    }
+    print(" ")
+    if (int2roman(2) == "II") {
+        print("Pass")
+    } else {
+        print("Fail")
+    }
+    print(" ")
+    if (int2roman(4) == "IV") {
+        print("Pass")
+    } else {
+        print("Fail")
+    }
+    print(" ")
+    if (int2roman(9) == "IX") {
+        print("Pass")
+    } else {
+        print("Fail")
+    }
+    print(" ")
+    if (int2roman(30) == "XXX") {
+        print("Pass")
+    } else {
+        print("Fail")
+    }
+    print(" ")
+    if (int2roman(1666) == "MDCLXVI") {
+        print("Pass")
+    } else {
+        print("Fail")
+    }
+    print(" ")
+    if (romanmaths("IV + V") == "IX") {
+        print("Pass")
+    } else {
+        print("Fail")
+    }
+    print(" ")
+    if (romanmaths("M - I") == "CMXCIX") {
+        print("Pass")
+    } else {
+        print("Fail")
+    }
+    print(" ")
+    if (romanmaths("X / II") == "V") {
+        print("Pass")
+    } else {
+        print("Fail")
+    }
+    print(" ")
+    if (romanmaths("XI * VI") == "LXVI") {
+        print("Pass")
+    } else {
+        print("Fail")
+    }
+    print(" ")
+    if (romanmaths("VII ** III") == "CCCXLIII") {
+        print("Pass")
+    } else {
+        print("Fail")
+    }
+    print(" ")
+    if (romanmaths("V - V") == "nulla") {
+        print("Pass")
+    } else {
+        print("Fail")
+    }
+    print(" ")
+    if (romanmaths("V / II") == "non potest") {
+        print("Pass")
+    } else {
+        print("Fail")
+    }
+    print(" ")
+    if (romanmaths("MMM + M") == "non potest") {
+        print("Pass")
+    } else {
+        print("Fail")
+    }
+    print(" ")
+    if (romanmaths("V - X") == "non potest") {
+        print("Pass")
+    } else {
+        print("Fail")
+ }
+    println("")
+
+}
diff --git a/challenge-227/roger-bell-west/lua/ch-1.lua b/challenge-227/roger-bell-west/lua/ch-1.lua
new file mode 100755
index 0000000000..09c6bdcd3d
--- /dev/null
+++ b/challenge-227/roger-bell-west/lua/ch-1.lua
@@ -0,0 +1,37 @@
+#! /usr/bin/lua
+
+function idiv(a0, b)
+   local a = math.abs(a0)
+   local q = a // b
+   if a0 < 0 then
+      q = -q
+   end
+   return q
+end
+
+function ymd2jd(y, m, d)
+   local mn = idiv(m - 14, 12)
+   return idiv((y + 4800 + mn) * 1461, 4) + idiv((m - 2 - 12 * mn) * 367, 12) - idiv(idiv(y + 4900 + mn, 100) * 3, 4) + d - 32075
+end
+
+function jd2dow(jd)
+   return (jd + 1) % 7
+end
+
+function friday13th(y)
+   local f = 0
+   for m = 1, 12 do
+      if jd2dow(ymd2jd(y, m, 13)) == 5 then
+         f = f + 1
+      end
+   end
+   return f
+end
+
+if friday13th(2023) == 2 then
+  io.write("Pass")
+else
+  io.write("FAIL")
+end
+print("")
+
diff --git a/challenge-227/roger-bell-west/lua/ch-2.lua b/challenge-227/roger-bell-west/lua/ch-2.lua
new file mode 100755
index 0000000000..75d6ed9884
--- /dev/null
+++ b/challenge-227/roger-bell-west/lua/ch-2.lua
@@ -0,0 +1,240 @@
+#! /usr/bin/lua
+
+function roman2int(roman)
+   if roman == "" then
+      return 0
+   end
+   for _, s in ipairs({
+      { 'M', 1000 },
+      { 'CM', 900 },
+      { 'D', 500 },
+      { 'CD', 400 },
+      { 'C', 100 },
+      { 'XC', 90 },
+      { 'L', 50 },
+      { 'XL', 40 },
+      { 'X', 10 },
+      { 'IX', 9 },
+      { 'V', 5 },
+      { 'IV', 4 },
+      { 'I', 1 }
+   }) do
+      if string.find(roman, s[1], 1, true) == 1 then
+         return s[2] + roman2int(string.sub(roman, #s[1] + 1))
+      end
+   end
+   return 0
+end
+
+function int2roman(n0)
+   local number = n0
+   local mn = ""
+   for _, s in ipairs({
+      { 'M', 1000 },
+      { 'CM', 900 },
+      { 'D', 500 },
+      { 'CD', 400 },
+      { 'C', 100 },
+      { 'XC', 90 },
+      { 'L', 50 },
+      { 'XL', 40 },
+      { 'X', 10 },
+      { 'IX', 9 },
+      { 'V', 5 },
+      { 'IV', 4 },
+      { 'I', 1 }
+   }) do
+      while s[2] <= number do
+         mn = mn .. s[1]
+         number = number - s[2]
+      end
+   end
+   return mn
+end
+
+-- bart at https://stackoverflow.com/questions/1426954/split-string-in-lua
+function split(inputstr, sep)
+   sep=sep or '%s'
+   local t={}
+   for field,s in string.gmatch(inputstr, "([^"..sep.."]*)("..sep.."?)") do
+      table.insert(t,field)
+      if s=="" then
+         return t
+      end
+   end
+end
+
+function romanmaths(ax)
+   local elems = split(ax, " ")
+   local a = roman2int(elems[1])
+   local b = roman2int(elems[3])
+   local c = -1
+   if elems[2] == "+" then
+      c = a + b
+   elseif elems[2] == "-" then
+      c = a - b
+   elseif elems[2] == "*" then
+      c = a * b
+   elseif elems[2] == "/" then
+      if a % b == 0 then
+         c = a // b
+      end
+   elseif elems[2] == "**" then
+      c = a ^ b
+   end
+   if c > 3999 or c < 0 then
+      return "non potest"
+   elseif c == 0 then
+      return "nulla"
+   else
+      return int2roman(c)
+   end
+end
+
+if roman2int("I") == 1 then
+  io.write("Pass")
+else
+  io.write("FAIL")
+end
+io.write(" ")
+
+if roman2int("II") == 2 then
+  io.write("Pass")
+else
+  io.write("FAIL")
+end
+io.write(" ")
+
+if roman2int("IV") == 4 then
+  io.write("Pass")
+else
+  io.write("FAIL")
+end
+io.write(" ")
+
+if roman2int("IX") == 9 then
+  io.write("Pass")
+else
+  io.write("FAIL")
+end
+io.write(" ")
+
+if roman2int("XXX") == 30 then
+  io.write("Pass")
+else
+  io.write("FAIL")
+end
+io.write(" ")
+
+if roman2int("MDCLXVI") == 1666 then
+  io.write("Pass")
+else
+  io.write("FAIL")
+end
+io.write(" ")
+
+if int2roman(1) == "I" then
+  io.write("Pass")
+else
+  io.write("FAIL")
+end
+io.write(" ")
+
+if int2roman(2) == "II" then
+  io.write("Pass")
+else
+  io.write("FAIL")
+end
+io.write(" ")
+
+if int2roman(4) == "IV" then
+  io.write("Pass")
+else
+  io.write("FAIL")
+end
+io.write(" ")
+
+if int2roman(9) == "IX" then
+  io.write("Pass")
+else
+  io.write("FAIL")
+end
+io.write(" ")
+
+if int2roman(30) == "XXX" then
+  io.write("Pass")
+else
+  io.write("FAIL")
+end
+io.write(" ")
+
+if int2roman(1666) == "MDCLXVI" then
+  io.write("Pass")
+else
+  io.write("FAIL")
+end
+io.write(" ")
+
+if romanmaths("IV + V") == "IX" then
+  io.write("Pass")
+else
+  io.write("FAIL")
+end
+io.write(" ")
+
+if romanmaths("M - I") == "CMXCIX" then
+  io.write("Pass")
+else
+  io.write("FAIL")
+end
+io.write(" ")
+
+if romanmaths("X / II") == "V" then
+  io.write("Pass")
+else
+  io.write("FAIL")
+end
+io.write(" ")
+
+if romanmaths("XI * VI") == "LXVI" then
+  io.write("Pass")
+else
+  io.write("FAIL")
+end
+io.write(" ")
+
+if romanmaths("VII ** III") == "CCCXLIII" then
+  io.write("Pass")
+else
+  io.write("FAIL")
+end
+io.write(" ")
+
+if romanmaths("V - V") == "nulla" then
+  io.write("Pass")
+else
+  io.write("FAIL")
+end
+io.write(" ")
+
+if romanmaths("V / II") == "non potest" then
+  io.write("Pass")
+else
+  io.write("FAIL")
+end
+io.write(" ")
+
+if romanmaths("MMM + M") == "non potest" then
+  io.write("Pass")
+else
+  io.write("FAIL")
+end
+io.write(" ")
+
+if romanmaths("V - X") == "non potest" then
+  io.write("Pass")
+else
+  io.write("FAIL")
+end
+print("")
+
diff --git a/challenge-227/roger-bell-west/perl/ch-1.pl b/challenge-227/roger-bell-west/perl/ch-1.pl
new file mode 100755
index 0000000000..1e51393880
--- /dev/null
+++ b/challenge-227/roger-bell-west/perl/ch-1.pl
@@ -0,0 +1,21 @@
+#! /usr/bin/perl
+
+use strict;
+use warnings;
+use experimental 'signatures';
+
+use Test::More tests => 1;
+
+is(friday13th(2023), 2, 'example 1');
+
+use Time::Local qw(timegm_modern);
+
+sub friday13th($y) {
+    my $f = 0;
+    foreach my $m (1 .. 12) {
+        if ((gmtime(timegm_modern(0, 0, 12, 13, $m - 1, $y)))[6] == 5 ) {
+            $f++;
+        }
+    }
+    return $f;
+}
diff --git a/challenge-227/roger-bell-west/perl/ch-2.pl b/challenge-227/roger-bell-west/perl/ch-2.pl
new file mode 100755
index 0000000000..9988ccb895
--- /dev/null
+++ b/challenge-227/roger-bell-west/perl/ch-2.pl
@@ -0,0 +1,108 @@
+#! /usr/bin/perl
+
+use strict;
+use warnings;
+use experimental 'signatures';
+
+use Test::More tests => 21;
+
+is(roman2int('I'), 1, 'example 1');
+is(roman2int('II'), 2, 'example 2');
+is(roman2int('IV'), 4, 'example 3');
+is(roman2int('IX'), 9, 'example 4');
+is(roman2int('XXX'), 30, 'example 5');
+is(roman2int('MDCLXVI'), 1666, 'example 6');
+is(int2roman(1), 'I', 'example 7');
+is(int2roman(2), 'II', 'example 8');
+is(int2roman(4), 'IV', 'example 9');
+is(int2roman(9), 'IX', 'example 10');
+is(int2roman(30), 'XXX', 'example 11');
+is(int2roman(1666), 'MDCLXVI', 'example 12');
+is(romanmaths('IV + V'), 'IX', 'example 13');
+is(romanmaths('M - I'), 'CMXCIX', 'example 14');
+is(romanmaths('X / II'), 'V', 'example 15');
+is(romanmaths('XI * VI'), 'LXVI', 'example 16');
+is(romanmaths('VII ** III'), 'CCCXLIII', 'example 17');
+is(romanmaths('V - V'), 'nulla', 'example 18');
+is(romanmaths('V / II'), 'non potest', 'example 19');
+is(romanmaths('MMM + M'), 'non potest', 'example 20');
+is(romanmaths('V - X'), 'non potest', 'example 21');
+
+sub roman2int($roman) {
+  if ($roman eq '') {
+    return 0;
+  }
+  foreach my $s (
+    [ 'M', 1000 ],
+    [ 'CM', 900 ],
+    [ 'D', 500 ],
+    [ 'CD', 400 ],
+    [ 'C', 100 ],
+    [ 'XC', 90 ],
+    [ 'L', 50 ],
+    [ 'XL', 40 ],
+    [ 'X', 10 ],
+    [ 'IX', 9 ],
+    [ 'V', 5 ],
+    [ 'IV', 4 ],
+    [ 'I', 1 ],
+      ) {
+    if (index($roman, $s->[0]) == 0) {
+      return $s->[1] + roman2int(substr($roman, length($s->[0])));
+    }
+  }
+  return 0;
+}
+
+sub int2roman($n0) {
+    my $number = $n0;
+    my $mn = "";
+    foreach my $s (
+        [ 'M', 1000 ],
+        [ 'CM', 900 ],
+        [ 'D', 500 ],
+        [ 'CD', 400 ],
+        [ 'C', 100 ],
+        [ 'XC', 90 ],
+        [ 'L', 50 ],
+        [ 'XL', 40 ],
+        [ 'X', 10 ],
+        [ 'IX', 9 ],
+        [ 'V', 5 ],
+        [ 'IV', 4 ],
+        [ 'I', 1 ],
+    ) {
+        while ($s->[1] <= $number) {
+            $mn .= $s->[0];
+            $number -= $s->[1];
+        }
+    }
+    return $mn;
+}
+
+sub romanmaths($ax) {
+    my @elems = split ' ',$ax;
+    my $a = roman2int($elems[0]);
+    my $b = roman2int($elems[2]);
+    my $c = -1;
+    if ($elems[1] eq '+') {
+        $c = $a + $b;
+    } elsif ($elems[1] eq '-') {
+        $c = $a - $b;
+    } elsif ($elems[1] eq '*') {
+        $c = $a * $b;
+    } elsif ($elems[1] eq '/') {
+        if ($a % $b == 0) {
+            $c = $a / $b;
+        }
+    } elsif ($elems[1] eq '**') {
+        $c = $a ** $b;
+    }
+    if ($c > 3999 || $c < 0) {
+        return 'non potest';
+    } elsif ($c == 0) {
+        return 'nulla';
+    } else {
+        return int2roman($c);
+    }
+}
diff --git a/challenge-227/roger-bell-west/postscript/ch-1.ps b/challenge-227/roger-bell-west/postscript/ch-1.ps
new file mode 100644
index 0000000000..747c8c6085
--- /dev/null
+++ b/challenge-227/roger-bell-west/postscript/ch-1.ps
@@ -0,0 +1,72 @@
+%!PS
+
+% begin included library code
+% see https://codeberg.org/Firedrake/postscript-libraries/
+/test.end {
+    ( ) print
+    test.count 0 gt {
+        (Passed ) print
+        test.pass (...) cvs print
+        (/) print
+        test.count (...) cvs print
+        ( \() print
+        test.pass 100 mul test.count idiv (...) cvs print
+        (%\)) print
+        (\r\n) print
+    } if
+} bind def
+
+/test.start {
+    print (:) print
+    /test.pass 0 def
+    /test.count 0 def
+} bind def
+
+/ymd2jd {
+    4 dict begin
+    aload pop
+    /d exch def
+    /m exch def
+    /y exch def
+    /mn m 14 sub 12 idiv def
+    y 4800 add mn add 1461 mul 4 idiv
+    mn 12 mul neg 2 sub m add 367 mul 12 idiv add
+    y 4900 add mn add 100 idiv 3 mul 4 idiv sub
+    d add
+    32075 sub
+    end
+} bind def
+
+/test {
+    /test.count test.count 1 add def
+    {
+        /test.pass test.pass 1 add def
+    } {
+        ( ) print
+        test.count (....) cvs print
+        (-fail) print
+    } ifelse
+} bind def
+
+/jd2dow {
+    1 add 7 mod 
+} bind def
+
+
+% end included library code
+
+/friday13th {
+    1 dict begin
+    /y exch def
+    0
+    1 1 12 {
+        [ exch y exch 13 ] ymd2jd jd2dow 5 eq {
+            1 add
+        } if
+    } for
+    end
+} bind def
+
+(friday13th) test.start
+2023 friday13th 2 eq test
+test.end
diff --git a/challenge-227/roger-bell-west/postscript/ch-2.ps b/challenge-227/roger-bell-west/postscript/ch-2.ps
new file mode 100644
index 0000000000..c9a46fb250
--- /dev/null
+++ b/challenge-227/roger-bell-west/postscript/ch-2.ps
@@ -0,0 +1,293 @@
+%!PS
+
+% begin included library code
+% see https://codeberg.org/Firedrake/postscript-libraries/
+/strsplit % (ajbjc) (j) -> [ (a) (b) (c) ]
+{
+    1 dict begin
+    /sep exch def
+    [ exch
+      {
+          dup length 0 eq {
+              pop
+              exit
+          } {
+              sep search {
+                  exch pop
+                  dup length 0 eq {
+                      pop
+                  } {
+                      exch
+                  } ifelse
+              } {
+                  ()
+              } ifelse
+          } ifelse
+      } loop
+    ]
+    end
+} bind def
+
+/strjoin % [(a) (b) (c)] (j) -> (ajbjc)
+{
+    3 dict begin
+    /j exch def
+    dup 0 get /out exch def
+    /first true def
+    {
+        first {
+            pop
+            /first false def
+        } {
+            out j strconcat
+            exch strconcat
+            /out exch def
+        } ifelse
+    } forall
+    out
+    end
+} bind def
+
+/deepeq {
+    2 dict begin
+    /a exch def
+    /b exch def
+    a type b type eq {
+        a type /dicttype eq {
+            a length b length eq {
+                <<
+                    a {
+                        pop
+                        true
+                    } forall
+                    b {
+                        pop
+                        true
+                    } forall
+                >>
+                true exch
+                {
+                    pop
+                    dup a exch known {
+                        dup b exch known {
+                            dup a exch get exch b exch get deepeq not {
+                                pop false
+                            } if
+                        } {
+                            false
+                        } ifelse
+                    } {
+                        false
+                    } ifelse
+                } forall
+            } {
+                false
+            } ifelse
+        } {
+            a type dup /arraytype eq exch /stringtype eq or {
+                a length b length eq {
+                    true
+                    0 1 a length 1 sub {
+                        dup a exch get exch b exch get deepeq not {
+                            pop false
+                            exit
+                        } if
+                    } for
+                } {
+                    false
+                } ifelse
+            } {
+                a b eq
+            } ifelse
+        } ifelse
+    } {
+        false
+    } ifelse
+    end
+} bind def
+
+/strconcat % (a) (b) -> (ab)  
+{ exch dup length
+  2 index length add string
+  dup dup 4 2 roll copy length
+  4 -1 roll putinterval
+} bind def
+
+/