Add prime-factors exercise (#220)

config.json

@@ -557,6 +557,14 @@
         "prerequisites": [],
         "difficulty": 5
       },
+      {
+        "slug": "prime-factors",
+        "name": "Prime Factors",
+        "uuid": "48187959-1ed3-4327-94e9-aac4013f223c",
+        "practices": [],
+        "prerequisites": [],
+        "difficulty": 5
+      },
       {
         "slug": "run-length-encoding",
         "name": "Run-Length Encoding",

exercises/practice/prime-factors/.docs/instructions.md

@@ -0,0 +1,36 @@
+# Instructions
+
+Compute the prime factors of a given natural number.
+
+A prime number is only evenly divisible by itself and 1.
+
+Note that 1 is not a prime number.
+
+## Example
+
+What are the prime factors of 60?
+
+- Our first divisor is 2.
+  2 goes into 60, leaving 30.
+- 2 goes into 30, leaving 15.
+  - 2 doesn't go cleanly into 15.
+    So let's move on to our next divisor, 3.
+- 3 goes cleanly into 15, leaving 5.
+  - 3 does not go cleanly into 5.
+    The next possible factor is 4.
+  - 4 does not go cleanly into 5.
+    The next possible factor is 5.
+- 5 does go cleanly into 5.
+- We're left only with 1, so now, we're done.
+
+Our successful divisors in that computation represent the list of prime factors of 60: 2, 2, 3, and 5.
+
+You can check this yourself:
+
+```text
+2 * 2 * 3 * 5
+= 4 * 15
+= 60
+```
+
+Success!

exercises/practice/prime-factors/.meta/config.json

@@ -0,0 +1,19 @@
+{
+  "authors": [
+    "erikschierboom"
+  ],
+  "files": {
+    "solution": [
+      "prime-factors.8th"
+    ],
+    "test": [
+      "test.8th"
+    ],
+    "example": [
+      ".meta/example.8th"
+    ]
+  },
+  "blurb": "Compute the prime factors of a given natural number.",
+  "source": "The Prime Factors Kata by Uncle Bob",
+  "source_url": "https://web.archive.org/web/20221026171801/http://butunclebob.com/ArticleS.UncleBob.ThePrimeFactorsKata"
+}

exercises/practice/prime-factors/.meta/example.8th

@@ -0,0 +1,23 @@
+: increment-factor \ n n -- n n
+    repeat
+    2dup n:mod !if ;then
+    dup 2 n:= !if n:1+ then n:1+
+    again
+;
+
+: factors \ n -- a
+    a:new >r 2 
+
+    repeat
+      over 1 n:>
+      !if      
+        2drop break
+      else
+        increment-factor
+        swap over n:/ swap
+        dup r> a:push >r
+      then  
+    again
+
+    r>
+;

exercises/practice/prime-factors/.meta/tests.toml

@@ -0,0 +1,46 @@
+# This is an auto-generated file.
+#
+# Regenerating this file via `configlet sync` will:
+# - Recreate every `description` key/value pair
+# - Recreate every `reimplements` key/value pair, where they exist in problem-specifications
+# - Remove any `include = true` key/value pair (an omitted `include` key implies inclusion)
+# - Preserve any other key/value pair
+#
+# As user-added comments (using the # character) will be removed when this file
+# is regenerated, comments can be added via a `comment` key.
+
+[924fc966-a8f5-4288-82f2-6b9224819ccd]
+description = "no factors"
+
+[17e30670-b105-4305-af53-ddde182cb6ad]
+description = "prime number"
+
+[238d57c8-4c12-42ef-af34-ae4929f94789]
+description = "another prime number"
+
+[f59b8350-a180-495a-8fb1-1712fbee1158]
+description = "square of a prime"
+
+[756949d3-3158-4e3d-91f2-c4f9f043ee70]
+description = "product of first prime"
+
+[bc8c113f-9580-4516-8669-c5fc29512ceb]
+description = "cube of a prime"
+
+[7d6a3300-a4cb-4065-bd33-0ced1de6cb44]
+description = "product of second prime"
+
+[073ac0b2-c915-4362-929d-fc45f7b9a9e4]
+description = "product of third prime"
+
+[6e0e4912-7fb6-47f3-a9ad-dbcd79340c75]
+description = "product of first and second prime"
+
+[00485cd3-a3fe-4fbe-a64a-a4308fc1f870]
+description = "product of primes and non-primes"
+
+[02251d54-3ca1-4a9b-85e1-b38f4b0ccb91]
+description = "product of primes"
+
+[070cf8dc-e202-4285-aa37-8d775c9cd473]
+description = "factors include a large prime"

exercises/practice/prime-factors/libs/exercism/test

@@ -0,0 +1,174 @@
+needs console/loaded
+needs utils/latebind 
+
+\ -----------------------------------------------------------------
+
+ns: test
+
+-1 var, test-count
+var tests-passed
+var tests-failed
+var tests-skipped
+true var, run-test
+
+\ Some utility words
+
+
+: test-passed \ s x x --   \\ test name, expected value, actual value
+    2drop
+    1 tests-passed n:+!
+    con:green con:onBlack . space " ... OK" . con:white con:onBlack cr
+;
+
+: test-skipped \ s --
+    1 tests-skipped n:+!
+    con:cyan con:onBlack . space " ... SKIPPED" . con:white con:onBlack cr
+;
+
+: test-failed \ s x x --   \\ test name, expected value, actual value
+    1 tests-failed n:+!
+    rot
+    con:red con:onBlack . space " ... FAIL" . con:white con:onBlack cr
+    "    Actual:    «" . . "»" . cr
+    "    Expected:  «" . . "»" . cr cr
+;
+
+: isword?  \ x -- x f
+   dup  >kind  ns:w   n:= 
+;
+
+: run-test? \ -- T
+   run-test @ if true else "RUN_ALL_TESTS" getenv n:>bool then
+;
+
+\ Num passed + num skipped + num failed should == num tests
+: all-tests-run? \ -- T
+    tests-passed @ tests-skipped @ tests-failed @ n:+ n:+
+    test-count @ n:=
+;
+
+\ returns true if x is a date, false otherwise
+: date? \ x -- x T
+    dup >kind ns:d n:=
+;
+
+\ adapted from 8th forum -- https://8th-dev.com/forum/index.php/topic,2745.0.html
+: eq? \ x x -- T
+   \ are the items the same kind?
+   2dup >kind swap >kind n:=
+   !if 2drop false ;then
+
+   \ same kind: try different comparators
+   number? if n:= ;then
+   string? if s:= ;then
+   array?  if ' eq? a:= 2nip ;then
+   map?    if ' eq? m:= 2nip ;then
+   date?   if d:= ;then
+
+   \ otherwise fall back to 'lazy evaluation'
+   G:l: =
+;
+
+: eps_eq? \ n x x -- T
+   \ are the items the same kind?
+   2dup >kind swap >kind n:=
+   !if 2drop false ;then
+   number? !if 2drop false ;then  
+   rot n:~=
+;
+
+: check-depth \ ... n -- ...
+  dup>r
+  n:1+ depth n:=
+  !if
+    con:red con:onBlack 
+    "PANIC: expected stack depth to be " . r> . cr
+    "Stack is:" . cr
+    .s cr
+    255 die
+  then
+  rdrop
+;
+
+\ -----------------------------------------------------------------
+
+\ status report at end of run
+( all-tests-run?  
+  !if con:red con:onBlack "... FAIL - not all tests completed" . con:white con:onBlack cr then
+) onexit
+
+\ Print a summary of the tests run
+( con:white con:onBlack
+  test-count   @ . space "tests planned - " .
+  tests-passed @ . space "passed - " .
+  tests-skipped @ . space "skipped - " .
+  tests-failed @ . space "failed" . cr
+) onexit
+
+\ -----------------------------------------------------------------
+\ The public-facing words
+\ -----------------------------------------------------------------
+
+: equal? \ s x w -- | s w x --
+   run-test? !if 2drop test-skipped ;; then
+   isword? !if swap then
+   w:exec
+   3 check-depth
+   2dup             \ so test-failed can show actual and expected
+   eq? if test-passed else test-failed then
+;
+
+: approx_equal? \ s x w n -- | s w x n --
+   run-test? !if 3drop test-skipped ;; then
+   -rot isword? !if swap then
+   w:exec
+   4 check-depth
+   3dup            \ so test-failed can show actual and expected
+   eps_eq?
+   if rot drop test-passed else rot drop test-failed then
+;
+
+: true? \ s w --
+   run-test? !if drop test-skipped ;; then
+   w:exec
+   2 check-depth
+   true swap dup    \ so test-failed can show actual and expected
+   if test-passed else test-failed then 
+;
+
+: false? \ s w --
+   run-test? !if drop test-skipped ;; then
+   w:exec
+   2 check-depth
+   false swap dup    \ so test-failed can show actual and expected
+   !if test-passed else test-failed then 
+;
+
+: null? \ s w --
+   run-test? !if drop test-skipped ;; then
+   w:exec
+   2 check-depth
+   null swap dup     \ so test-failed can show actual and expected
+   G:null? nip if test-passed else test-failed then 
+;
+
+: SKIP-REST-OF-TESTS false run-test ! ;
+
+: tests \ n -- 
+    test-count ! 
+;
+
+\ Set the exit status:
+\   0 = all OK
+\   1 = not all tests were run (some error occurred)
+\   2 = some tests failed
+: end-of-tests \ --
+    all-tests-run?
+    if
+      tests-failed @ 0 n:= if 0 else 2 then
+    else
+      1
+    then
+    die
+;
+

exercises/practice/prime-factors/prime-factors.8th

@@ -0,0 +1,3 @@
+: factors \ n -- a
+
+;

exercises/practice/prime-factors/test.8th

@@ -0,0 +1,69 @@
+"prime-factors.8th" f:include
+needs exercism/test
+with: test
+12 tests
+
+"No factors"
+    ( 1 factors )
+    []
+    equal?
+
+SKIP-REST-OF-TESTS
+
+"Prime number"
+    ( 2 factors )
+    [2]
+    equal?
+
+"Another prime number"
+    ( 3 factors )
+    [3]
+    equal?
+
+"Square of a prime"
+    ( 9 factors )
+    [3, 3]
+    equal?
+
+"Product of first prime"
+    ( 4 factors )
+    [2, 2]
+    equal?
+
+"Cube of a prime"
+    ( 8 factors )
+    [2, 2, 2]
+    equal?
+
+"Product of second prime"
+    ( 27 factors )
+    [3, 3, 3]
+    equal?
+
+"Product of third prime"
+    ( 625 factors )
+    [5, 5, 5, 5]
+    equal?
+
+"Product of first and second prime"
+    ( 6 factors )
+    [2, 3]
+    equal?
+
+"Product of primes and non-primes"
+    ( 12 factors )
+    [2, 2, 3]
+    equal?
+
+"Product of primes"
+    ( 901255 factors )
+    [5, 17, 23, 461]
+    equal?
+
+"Factors include a large prime"
+    ( 93819012551 factors )
+    [11, 9539, 894119]
+    equal?
+
+end-of-tests
+;with