add food chain exercise

exercises/practice/food-chain/food_chain.odin

@@ -0,0 +1,93 @@
+package food_chain
+
+import "core:strings"
+
+Animal :: struct {
+	name:      string,
+	name_long: Maybe(string),
+	phrase:    string,
+	next:      Maybe(^Animal),
+}
+
+fly := Animal {
+	name   = "fly",
+	phrase = "I don't know why she swallowed the fly. Perhaps she'll die.",
+}
+spider := Animal {
+	name      = "spider",
+	name_long = "spider that wriggled and jiggled and tickled inside her",
+	phrase    = "It wriggled and jiggled and tickled inside her.",
+	next      = &fly,
+}
+bird := Animal {
+	name   = "bird",
+	phrase = "How absurd to swallow a bird!",
+	next   = &spider,
+}
+cat := Animal {
+	name   = "cat",
+	phrase = "Imagine that, to swallow a cat!",
+	next   = &bird,
+}
+dog := Animal {
+	name   = "dog",
+	phrase = "What a hog, to swallow a dog!",
+	next   = &cat,
+}
+goat := Animal {
+	name   = "goat",
+	phrase = "Just opened her throat and swallowed a goat!",
+	next   = &dog,
+}
+cow := Animal {
+	name   = "cow",
+	phrase = "I don't know how she swallowed a cow!",
+	next   = &goat,
+}
+horse := Animal {
+	name   = "horse",
+	phrase = "She's dead, of course!",
+}
+
+verses := [8]Animal{fly, spider, bird, cat, dog, goat, cow, horse}
+
+generate_verse :: proc(builder: ^strings.Builder, i: int) {
+	animal: Maybe(^Animal) = &verses[i]
+	node, ok := animal.?
+	if !ok {
+		return
+	}
+	strings.write_string(builder, "I know an old lady who swallowed a ")
+	strings.write_string(builder, node.name)
+	strings.write_string(builder, ".\n")
+	if node.next != nil {
+		strings.write_string(builder, node.phrase)
+		strings.write_rune(builder, '\n')
+	}
+	for {
+		node := animal.? or_break
+		if node.next == nil {
+			strings.write_string(builder, node.phrase)
+			strings.write_rune(builder, '\n')
+		} else {
+			next := node.next.?
+			strings.write_string(builder, "She swallowed the ")
+			strings.write_string(builder, node.name)
+			strings.write_string(builder, " to catch the ")
+			name := next.name_long.? or_else next.name
+			strings.write_string(builder, name)
+			strings.write_string(builder, ".\n")
+		}
+		animal = node.next
+	}
+}
+
+recite :: proc(start, end: int) -> string {
+	builder := strings.builder_make()
+	defer strings.builder_destroy(&builder)
+	for i in start - 1 ..< end {
+		generate_verse(&builder, i)
+		strings.write_rune(&builder, '\n')
+	}
+	return strings.trim_right_space(strings.to_string(builder))
+}

exercises/practice/food-chain/food_chain_test.odin

@@ -0,0 +1,179 @@
+package food_chain
+import "core:testing"
+
+@(test)
+test_fly :: proc(t: ^testing.T) {
+	expected := `I know an old lady who swallowed a fly.
+I don't know why she swallowed the fly. Perhaps she'll die.`
+
+
+	actual := recite(1, 1)
+	testing.expect_value(t, actual, expected)
+}
+@(test)
+test_spider :: proc(t: ^testing.T) {
+	expected := `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.`
+
+
+	actual := recite(2, 2)
+	testing.expect_value(t, actual, expected)
+}
+@(test)
+test_bird :: proc(t: ^testing.T) {
+	expected := `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.`
+
+
+	actual := recite(3, 3)
+	testing.expect_value(t, actual, expected)
+}
+@(test)
+test_cat :: proc(t: ^testing.T) {
+	expected := `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.`
+
+
+	actual := recite(4, 4)
+	testing.expect_value(t, actual, expected)
+}
+@(test)
+test_dog :: proc(t: ^testing.T) {
+	expected := `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.`
+
+
+	actual := recite(5, 5)
+	testing.expect_value(t, actual, expected)
+}
+@(test)
+test_goat :: proc(t: ^testing.T) {
+	expected := `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.`
+
+
+	actual := recite(6, 6)
+	testing.expect_value(t, actual, expected)
+}
+@(test)
+test_cow :: proc(t: ^testing.T) {
+	expected := `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.`
+
+
+	actual := recite(7, 7)
+	testing.expect_value(t, actual, expected)
+}
+@(test)
+test_horse :: proc(t: ^testing.T) {
+	expected := `I know an old lady who swallowed a horse.
+She's dead, of course!`
+
+
+	actual := recite(8, 8)
+	testing.expect_value(t, actual, expected)
+}
+@(test)
+test_multiple_verse :: proc(t: ^testing.T) {
+	expected := `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.`
+
+
+	actual := recite(1, 3)
+	testing.expect_value(t, actual, expected)
+}
+@(test)
+test_full_song :: proc(t: ^testing.T) {
+	expected := `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!`
+
+
+	actual := recite(1, 8)
+	testing.expect_value(t, actual, expected)
+}