Implement exercise 'food-chain'

config.json

@@ -428,6 +428,14 @@
         "prerequisites": [],
         "difficulty": 5
       },
+      {
+        "slug": "food-chain",
+        "name": "Food Chain",
+        "uuid": "fb4bd2e9-9ca0-41e3-90c7-1adad92d0dd1",
+        "practices": [],
+        "prerequisites": [],
+        "difficulty": 5
+      },
       {
         "slug": "matching-brackets",
         "name": "Matching Brackets",

config.yaml

@@ -386,6 +386,13 @@ exercises:
     prerequisites: []
     difficulty: 5
 
+  - slug: food-chain
+    name: Food Chain
+    uuid: fb4bd2e9-9ca0-41e3-90c7-1adad92d0dd1
+    practices: []
+    prerequisites: []
+    difficulty: 5
+
   - slug: matching-brackets
     name: Matching Brackets
     uuid: a6c79db6-925c-45c3-8a59-aa9d96a4740b

exercises/practice/food-chain/.docs/instructions.md

@@ -0,0 +1,64 @@
+# Instructions
+
+Generate the lyrics of the song 'I Know an Old Lady Who Swallowed a Fly'.
+
+While you could copy/paste the lyrics, or read them from a file, this problem is much more interesting if you approach it algorithmically.
+
+This is a [cumulative song][cumulative-song] of unknown origin.
+
+This is one of many common variants.
+
+```text
+I know an old lady who swallowed a fly.
+I don't know why she swallowed the fly. Perhaps she'll die.
+
+I know an old lady who swallowed a spider.
+It wriggled and jiggled and tickled inside her.
+She swallowed the spider to catch the fly.
+I don't know why she swallowed the fly. Perhaps she'll die.
+
+I know an old lady who swallowed a bird.
+How absurd to swallow a bird!
+She swallowed the bird to catch the spider that wriggled and jiggled and tickled inside her.
+She swallowed the spider to catch the fly.
+I don't know why she swallowed the fly. Perhaps she'll die.
+
+I know an old lady who swallowed a cat.
+Imagine that, to swallow a cat!
+She swallowed the cat to catch the bird.
+She swallowed the bird to catch the spider that wriggled and jiggled and tickled inside her.
+She swallowed the spider to catch the fly.
+I don't know why she swallowed the fly. Perhaps she'll die.
+
+I know an old lady who swallowed a dog.
+What a hog, to swallow a dog!
+She swallowed the dog to catch the cat.
+She swallowed the cat to catch the bird.
+She swallowed the bird to catch the spider that wriggled and jiggled and tickled inside her.
+She swallowed the spider to catch the fly.
+I don't know why she swallowed the fly. Perhaps she'll die.
+
+I know an old lady who swallowed a goat.
+Just opened her throat and swallowed a goat!
+She swallowed the goat to catch the dog.
+She swallowed the dog to catch the cat.
+She swallowed the cat to catch the bird.
+She swallowed the bird to catch the spider that wriggled and jiggled and tickled inside her.
+She swallowed the spider to catch the fly.
+I don't know why she swallowed the fly. Perhaps she'll die.
+
+I know an old lady who swallowed a cow.
+I don't know how she swallowed a cow!
+She swallowed the cow to catch the goat.
+She swallowed the goat to catch the dog.
+She swallowed the dog to catch the cat.
+She swallowed the cat to catch the bird.
+She swallowed the bird to catch the spider that wriggled and jiggled and tickled inside her.
+She swallowed the spider to catch the fly.
+I don't know why she swallowed the fly. Perhaps she'll die.
+
+I know an old lady who swallowed a horse.
+She's dead, of course!
+```
+
+[cumulative-song]: https://en.wikipedia.org/wiki/Cumulative_song

exercises/practice/food-chain/.meta/.yamlscript/exercise.mk

@@ -0,0 +1 @@
+YS_VERSION := 0.1.75

exercises/practice/food-chain/.meta/Makefile

@@ -0,0 +1,28 @@
+SHELL := bash
+
+BASE := $(shell pwd)
+
+export YS_VERSION := 0.1.79
+
+YS_LOCAL_PREFIX := ../../../../.local/v$(YS_VERSION)
+
+YS_LOCAL_BIN := $(YS_LOCAL_PREFIX)/bin
+
+YS_BIN := $(YS_LOCAL_BIN)/ys-$(YS_VERSION)
+
+TEST_FILE ?= $(wildcard *-test.ys)
+
+
+export PATH := $(YS_LOCAL_BIN):$(PATH)
+
+export YSPATH := $(BASE)
+
+
+default:
+
+test: $(YS_BIN)
+	prove -v $(TEST_FILE)
+
+$(YS_BIN):
+	curl -s https://yamlscript.org/install | \
+	  BIN=1 VERSION=$(YS_VERSION) PREFIX=$(YS_LOCAL_PREFIX) bash >/dev/null

exercises/practice/food-chain/.meta/config.json

@@ -0,0 +1,23 @@
+{
+  "authors": [
+    "ingydotnet"
+  ],
+  "files": {
+    "solution": [
+      "food-chain.ys"
+    ],
+    "test": [
+      "food-chain-test.ys",
+      "GNUmakefile",
+      "Makefile",
+      ".yamlscript/exercise.mk",
+      ".yamlscript/exercism-ys-installer"
+    ],
+    "example": [
+      ".meta/food-chain.ys"
+    ]
+  },
+  "blurb": "Generate the lyrics of the song 'I Know an Old Lady Who Swallowed a Fly'.",
+  "source": "Wikipedia",
+  "source_url": "https://en.wikipedia.org/wiki/There_Was_an_Old_Lady_Who_Swallowed_a_Fly"
+}

exercises/practice/food-chain/.meta/food-chain-test.ys

@@ -0,0 +1,173 @@
+#!/usr/bin/env ys-0
+
+require ys::taptest: :all
+
+use: food-chain
+
+# JSON doesn't allow for multi-line strings, so all verses are presented
+# here as arrays of strings. It's up to the test generator to join the
+# lines together with line breaks.
+# Some languages test for the verse() method, which takes a start verse
+# and optional end verse, but other languages have only tested for the full poem.
+# For those languages in the latter category, you may wish to only
+# implement the full song test and leave the rest alone, ignoring the start
+# and end verse fields.
+
+test::
+- name: Fly
+  code: recite(1 1)
+  want:
+  - I know an old lady who swallowed a fly.
+  - I don't know why she swallowed the fly. Perhaps she'll die.
+  uuid: 751dce68-9412-496e-b6e8-855998c56166
+
+- name: Spider
+  code: recite(2 2)
+  want:
+  - I know an old lady who swallowed a spider.
+  - It wriggled and jiggled and tickled inside her.
+  - She swallowed the spider to catch the fly.
+  - I don't know why she swallowed the fly. Perhaps she'll die.
+  uuid: 6c56f861-0c5e-4907-9a9d-b2efae389379
+
+- name: Bird
+  code: recite(3 3)
+  want:
+  - I know an old lady who swallowed a bird.
+  - How absurd to swallow a bird!
+  - She swallowed the bird to catch the spider that wriggled and jiggled and tickled inside her.
+  - She swallowed the spider to catch the fly.
+  - I don't know why she swallowed the fly. Perhaps she'll die.
+  uuid: 3edf5f33-bef1-4e39-ae67-ca5eb79203fa
+
+- name: Cat
+  code: recite(4 4)
+  want:
+  - I know an old lady who swallowed a cat.
+  - Imagine that, to swallow a cat!
+  - She swallowed the cat to catch the bird.
+  - She swallowed the bird to catch the spider that wriggled and jiggled and tickled inside her.
+  - She swallowed the spider to catch the fly.
+  - I don't know why she swallowed the fly. Perhaps she'll die.
+  uuid: e866a758-e1ff-400e-9f35-f27f28cc288f
+
+- name: Dog
+  code: recite(5 5)
+  want:
+  - I know an old lady who swallowed a dog.
+  - What a hog, to swallow a dog!
+  - She swallowed the dog to catch the cat.
+  - She swallowed the cat to catch the bird.
+  - She swallowed the bird to catch the spider that wriggled and jiggled and tickled inside her.
+  - She swallowed the spider to catch the fly.
+  - I don't know why she swallowed the fly. Perhaps she'll die.
+  uuid: 3f02c30e-496b-4b2a-8491-bc7e2953cafb
+
+- name: Goat
+  code: recite(6 6)
+  want:
+  - I know an old lady who swallowed a goat.
+  - Just opened her throat and swallowed a goat!
+  - She swallowed the goat to catch the dog.
+  - She swallowed the dog to catch the cat.
+  - She swallowed the cat to catch the bird.
+  - She swallowed the bird to catch the spider that wriggled and jiggled and tickled inside her.
+  - She swallowed the spider to catch the fly.
+  - I don't know why she swallowed the fly. Perhaps she'll die.
+  uuid: 4b3fd221-01ea-46e0-825b-5734634fbc59
+
+- name: Cow
+  code: recite(7 7)
+  want:
+  - I know an old lady who swallowed a cow.
+  - I don't know how she swallowed a cow!
+  - She swallowed the cow to catch the goat.
+  - She swallowed the goat to catch the dog.
+  - She swallowed the dog to catch the cat.
+  - She swallowed the cat to catch the bird.
+  - She swallowed the bird to catch the spider that wriggled and jiggled and tickled inside her.
+  - She swallowed the spider to catch the fly.
+  - I don't know why she swallowed the fly. Perhaps she'll die.
+  uuid: 1b707da9-7001-4fac-941f-22ad9c7a65d4
+
+- name: Horse
+  code: recite(8 8)
+  want:
+  - I know an old lady who swallowed a horse.
+  - She's dead, of course!
+  uuid: 3cb10d46-ae4e-4d2c-9296-83c9ffc04cdc
+
+- name: Multiple verses
+  code: recite(1 3)
+  want:
+  - I know an old lady who swallowed a fly.
+  - I don't know why she swallowed the fly. Perhaps she'll die.
+  - ''
+  - I know an old lady who swallowed a spider.
+  - It wriggled and jiggled and tickled inside her.
+  - She swallowed the spider to catch the fly.
+  - I don't know why she swallowed the fly. Perhaps she'll die.
+  - ''
+  - I know an old lady who swallowed a bird.
+  - How absurd to swallow a bird!
+  - She swallowed the bird to catch the spider that wriggled and jiggled and tickled inside her.
+  - She swallowed the spider to catch the fly.
+  - I don't know why she swallowed the fly. Perhaps she'll die.
+  uuid: 22b863d5-17e4-4d1e-93e4-617329a5c050
+
+- name: Full song
+  code: recite(1 8)
+  want:
+  - I know an old lady who swallowed a fly.
+  - I don't know why she swallowed the fly. Perhaps she'll die.
+  - ''
+  - I know an old lady who swallowed a spider.
+  - It wriggled and jiggled and tickled inside her.
+  - She swallowed the spider to catch the fly.
+  - I don't know why she swallowed the fly. Perhaps she'll die.
+  - ''
+  - I know an old lady who swallowed a bird.
+  - How absurd to swallow a bird!
+  - She swallowed the bird to catch the spider that wriggled and jiggled and tickled inside her.
+  - She swallowed the spider to catch the fly.
+  - I don't know why she swallowed the fly. Perhaps she'll die.
+  - ''
+  - I know an old lady who swallowed a cat.
+  - Imagine that, to swallow a cat!
+  - She swallowed the cat to catch the bird.
+  - She swallowed the bird to catch the spider that wriggled and jiggled and tickled inside her.
+  - She swallowed the spider to catch the fly.
+  - I don't know why she swallowed the fly. Perhaps she'll die.
+  - ''
+  - I know an old lady who swallowed a dog.
+  - What a hog, to swallow a dog!
+  - She swallowed the dog to catch the cat.
+  - She swallowed the cat to catch the bird.
+  - She swallowed the bird to catch the spider that wriggled and jiggled and tickled inside her.
+  - She swallowed the spider to catch the fly.
+  - I don't know why she swallowed the fly. Perhaps she'll die.
+  - ''
+  - I know an old lady who swallowed a goat.
+  - Just opened her throat and swallowed a goat!
+  - She swallowed the goat to catch the dog.
+  - She swallowed the dog to catch the cat.
+  - She swallowed the cat to catch the bird.
+  - She swallowed the bird to catch the spider that wriggled and jiggled and tickled inside her.
+  - She swallowed the spider to catch the fly.
+  - I don't know why she swallowed the fly. Perhaps she'll die.
+  - ''
+  - I know an old lady who swallowed a cow.
+  - I don't know how she swallowed a cow!
+  - She swallowed the cow to catch the goat.
+  - She swallowed the goat to catch the dog.
+  - She swallowed the dog to catch the cat.
+  - She swallowed the cat to catch the bird.
+  - She swallowed the bird to catch the spider that wriggled and jiggled and tickled inside her.
+  - She swallowed the spider to catch the fly.
+  - I don't know why she swallowed the fly. Perhaps she'll die.
+  - ''
+  - I know an old lady who swallowed a horse.
+  - She's dead, of course!
+  uuid: e626b32b-745c-4101-bcbd-3b13456893db
+
+done: 10

exercises/practice/food-chain/.meta/food-chain.ys

@@ -0,0 +1,40 @@
+!yamlscript/v0
+
+barn =::
+- fly: I don't know why she swallowed the fly. Perhaps she'll die.
+- spider: It wriggled and jiggled and tickled inside her.
+- bird: How absurd to swallow a bird!
+- cat: Imagine that, to swallow a cat!
+- dog: What a hog, to swallow a dog!
+- goat: Just opened her throat and swallowed a goat!
+- cow: I don't know how she swallowed a cow!
+- horse: She's dead, of course!
+
+defn recite(start-verse end-verse):
+  drop-last:
+    reduce: add-verse [] (start-verse.-- .. end-verse.--)
+
+defn add-verse(lines verse):
+  animal =: barn.$verse.first().0
+  lines =: conj(lines "I know an old lady who swallowed a $animal.")
+  lines =: conj(lines barn.$verse.first().1)
+  lines =:
+    if 0 < verse < barn.#.--:
+      conj _ barn.0:first.1:
+        reduce _ lines (verse .. 0):
+          fn(lines verse):
+            lines =:
+              if verse.?:
+                then:
+                  animal1 animal2 =:
+                    L(barn.$verse.first().0 barn.nth(verse.--):first.0)
+                  line =: "She swallowed the $animal1 to catch the $animal2."
+                  line =:
+                    if animal2 == 'spider':
+                      replace(line /\./ replace(barn.1:first.1 /It/ ' that'))
+                      line
+                  conj lines: line
+                else: lines
+            =>: lines
+      =>: lines
+  conj lines: ''