Add pig-latin exercise (#118)

config.json

@@ -330,6 +330,14 @@
         "prerequisites": [],
         "difficulty": 5
       },
+      {
+        "slug": "pig-latin",
+        "name": "Pig Latin",
+        "uuid": "b820d82b-0539-443a-b929-1ff12d16212c",
+        "practices": [],
+        "prerequisites": [],
+        "difficulty": 5
+      },
       {
         "slug": "sieve",
         "name": "Sieve",

exercises/practice/pig-latin/.docs/instructions.md

@@ -0,0 +1,46 @@
+# Instructions
+
+Your task is to translate text from English to Pig Latin.
+The translation is defined using four rules, which look at the pattern of vowels and consonants at the beginning of a word.
+These rules look at each word's use of vowels and consonants:
+
+- vowels: the letters `a`, `e`, `i`, `o`, and `u`
+- consonants: the other 21 letters of the English alphabet
+
+## Rule 1
+
+If a word begins with a vowel, or starts with `"xr"` or `"yt"`, add an `"ay"` sound to the end of the word.
+
+For example:
+
+- `"apple"` -> `"appleay"` (starts with vowel)
+- `"xray"` -> `"xrayay"` (starts with `"xr"`)
+- `"yttria"` -> `"yttriaay"` (starts with `"yt"`)
+
+## Rule 2
+
+If a word begins with one or more consonants, first move those consonants to the end of the word and then add an `"ay"` sound to the end of the word.
+
+For example:
+
+- `"pig"` -> `"igp"` -> `"igpay"` (starts with single consonant)
+- `"chair"` -> `"airch"` -> `"airchay"` (starts with multiple consonants)
+- `"thrush"` -> `"ushthr"` -> `"ushthray"` (starts with multiple consonants)
+
+## Rule 3
+
+If a word starts with zero or more consonants followed by `"qu"`, first move those consonants (if any) and the `"qu"` part to the end of the word, and then add an `"ay"` sound to the end of the word.
+
+For example:
+
+- `"quick"` -> `"ickqu"` -> `"ickquay"` (starts with `"qu"`, no preceding consonants)
+- `"square"` -> `"aresqu"` -> `"aresquay"` (starts with one consonant followed by `"qu`")
+
+## Rule 4
+
+If a word starts with one or more consonants followed by `"y"`, first move the consonants preceding the `"y"`to the end of the word, and then add an `"ay"` sound to the end of the word.
+
+Some examples:
+
+- `"my"` -> `"ym"` -> `"ymay"` (starts with single consonant followed by `"y"`)
+- `"rhythm"` -> `"ythmrh"` -> `"ythmrhay"` (starts with multiple consonants followed by `"y"`)

exercises/practice/pig-latin/.docs/introduction.md

@@ -0,0 +1,8 @@
+# Introduction
+
+Your parents have challenged you and your sibling to a game of two-on-two basketball.
+Confident they'll win, they let you score the first couple of points, but then start taking over the game.
+Needing a little boost, you start speaking in [Pig Latin][pig-latin], which is a made-up children's language that's difficult for non-children to understand.
+This will give you the edge to prevail over your parents!
+
+[pig-latin]: https://en.wikipedia.org/wiki/Pig_latin

exercises/practice/pig-latin/.meta/config.json

@@ -0,0 +1,19 @@
+{
+  "authors": [
+    "keiravillekode"
+  ],
+  "files": {
+    "solution": [
+      "pig_latin.s"
+    ],
+    "test": [
+      "pig_latin_test.c"
+    ],
+    "example": [
+      ".meta/example.s"
+    ]
+  },
+  "blurb": "Implement a program that translates from English to Pig Latin.",
+  "source": "The Pig Latin exercise at Test First Teaching by Ultrasaurus",
+  "source_url": "https://github.com/ultrasaurus/test-first-teaching/blob/master/learn_ruby/pig_latin/"
+}

exercises/practice/pig-latin/.meta/example.s

@@ -0,0 +1,110 @@
+.data
+vowels:
+        /* non-zero for 'a' 'e' 'i' 'o' 'u' 'y' */
+        .byte 1,0,0,0,1,0,0,0,1,0,0,0,0,0,1,0,0,0,0,0,1,0,0,0,1,0
+
+.text
+.globl translate
+
+/*
+# | Register | Usage        | Type    | Description                             |
+# | -------- | ------------ | ------- | --------------------------------------- |
+# | `x0`     | input/output | address | output pointer                          |
+# | `x1`     | input        | address | beginning of word(s)                    |
+# | `x3`     | temporary    | byte    | previous letter in word                 |
+# | `x4`     | temporary    | byte    | current letter in word                  |
+# | `x5`     | temporary    | byte    | second letter in word                   |
+# | `x6`     | temporary    | byte    | non-zero when current letter is a vowel |
+# | `x7`     | temporary    | byte    | 'a'                                     |
+# | `x8`     | temporary    | byte    | 'y'                                     |
+# | `x9`     | temporary    | address | vowels table, minus 'a'                 |
+# | `x10`    | temporary    | address | position in current word                |
+# | `x11`    | temporary    | address | end of current word                     |
+*/
+
+/* extern void translate(char *buffer, const char *phrase); */
+translate:
+        mov     w7, #'a'
+        mov     w8, #'y'
+        adrp    x9, vowels
+        add     x9, x9, :lo12:vowels
+        sub     x9, x9, x7              /* vowels table, minus 'a' */
+
+start_word:
+        mov     x10, x1                 /* beginning of word */
+        ldrb    w4, [x1]                /* first letter in word */
+        cbz     w4, return
+
+        ldrb    w5, [x1, #1]            /* second letter in word */
+        ldrb    w6, [x9, x4]            /* non-zero if first letter is a vowel or 'y' */
+        cbnz    w6, check_yt
+
+check_xr:
+        cmp     w4, #'x'
+        bne     consonant
+
+        cmp     w5, 'r'
+        bne     consonant
+
+        b       vowel                   /* Treat initial 'x' 'r' as vowel */
+
+check_yt:
+        cmp     w4, #'y'
+        bne     vowel
+
+        cmp     w5, #'t'
+        beq     vowel                   /* Treat initial 'y' 't' as vowel */
+
+consonant:
+        mov     w3, w4                  /* previous letter */
+        ldrb    w4, [x10, #1]!          /* current letter in word, pre-increment x10 */
+        cmp     w4, w7
+        blt     vowel                   /* jump forward as we have reached the end of the word */
+
+        ldrb    w6, [x9, x4]            /* non-zero if current letter is a vowel or 'y' */
+        cbz     w6, consonant
+
+        cmp     w4, #'u'
+        bne     vowel
+
+        cmp     w3, #'q'
+        bne     vowel
+
+        add     x10, x10, #1            /* group 'u' after 'q' with leading consonants */
+
+vowel:
+                                        /* Letters x1 (inclusive) through x10 (exclusive)
+                                           will be output after the word's remaining letters. */
+        mov     x11, x10
+        b       check_for_remaining_letters
+
+copy_remaining_letters:
+        add     x11, x11, #1
+        strb    w4, [x0], #1
+
+check_for_remaining_letters:
+        ldrb    w4, [x11]
+        cmp     w4, w7
+        bge     copy_remaining_letters
+
+        b       check_for_leading_consonants
+
+copy_leading_consonants:
+        ldrb    w5, [x1], #1
+        strb    w5, [x0], #1
+
+check_for_leading_consonants:
+        cmp     x1, x10
+        bne     copy_leading_consonants
+
+        strb    w7, [x0], #1            /* 'a', post-increment output pointer */
+        strb    w8, [x0], #1            /* 'y', post-increment output pointer */
+        cbz     w4, return              /* Check for null terminator */
+
+        strb    w4, [x0], #1            /* Output space between words, post-increment output pointer */
+        add     x1, x11, #1             /* Start of next word */
+        b       start_word
+
+return:
+        strb    wzr, [x0]
+        ret

exercises/practice/pig-latin/.meta/tests.toml

@@ -0,0 +1,76 @@
+# 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.
+
+[11567f84-e8c6-4918-aedb-435f0b73db57]
+description = "ay is added to words that start with vowels -> word beginning with a"
+
+[f623f581-bc59-4f45-9032-90c3ca9d2d90]
+description = "ay is added to words that start with vowels -> word beginning with e"
+
+[7dcb08b3-23a6-4e8a-b9aa-d4e859450d58]
+description = "ay is added to words that start with vowels -> word beginning with i"
+
+[0e5c3bff-266d-41c8-909f-364e4d16e09c]
+description = "ay is added to words that start with vowels -> word beginning with o"
+
+[614ba363-ca3c-4e96-ab09-c7320799723c]
+description = "ay is added to words that start with vowels -> word beginning with u"
+
+[bf2538c6-69eb-4fa7-a494-5a3fec911326]
+description = "ay is added to words that start with vowels -> word beginning with a vowel and followed by a qu"
+
+[e5be8a01-2d8a-45eb-abb4-3fcc9582a303]
+description = "first letter and ay are moved to the end of words that start with consonants -> word beginning with p"
+
+[d36d1e13-a7ed-464d-a282-8820cb2261ce]
+description = "first letter and ay are moved to the end of words that start with consonants -> word beginning with k"
+
+[d838b56f-0a89-4c90-b326-f16ff4e1dddc]
+description = "first letter and ay are moved to the end of words that start with consonants -> word beginning with x"
+
+[bce94a7a-a94e-4e2b-80f4-b2bb02e40f71]
+description = "first letter and ay are moved to the end of words that start with consonants -> word beginning with q without a following u"
+
+[c01e049a-e3e2-451c-bf8e-e2abb7e438b8]
+description = "some letter clusters are treated like a single consonant -> word beginning with ch"
+
+[9ba1669e-c43f-4b93-837a-cfc731fd1425]
+description = "some letter clusters are treated like a single consonant -> word beginning with qu"
+
+[92e82277-d5e4-43d7-8dd3-3a3b316c41f7]
+description = "some letter clusters are treated like a single consonant -> word beginning with qu and a preceding consonant"
+
+[79ae4248-3499-4d5b-af46-5cb05fa073ac]
+description = "some letter clusters are treated like a single consonant -> word beginning with th"
+
+[e0b3ae65-f508-4de3-8999-19c2f8e243e1]
+description = "some letter clusters are treated like a single consonant -> word beginning with thr"
+
+[20bc19f9-5a35-4341-9d69-1627d6ee6b43]
+description = "some letter clusters are treated like a single consonant -> word beginning with sch"
+
+[54b796cb-613d-4509-8c82-8fbf8fc0af9e]
+description = "some letter clusters are treated like a single vowel -> word beginning with yt"
+
+[8c37c5e1-872e-4630-ba6e-d20a959b67f6]
+description = "some letter clusters are treated like a single vowel -> word beginning with xr"
+
+[a4a36d33-96f3-422c-a233-d4021460ff00]
+description = "position of y in a word determines if it is a consonant or a vowel -> y is treated like a consonant at the beginning of a word"
+
+[adc90017-1a12-4100-b595-e346105042c7]
+description = "position of y in a word determines if it is a consonant or a vowel -> y is treated like a vowel at the end of a consonant cluster"
+
+[29b4ca3d-efe5-4a95-9a54-8467f2e5e59a]
+description = "position of y in a word determines if it is a consonant or a vowel -> y as second letter in two letter word"
+
+[44616581-5ce3-4a81-82d0-40c7ab13d2cf]
+description = "phrases are translated -> a whole phrase"

exercises/practice/pig-latin/Makefile

@@ -0,0 +1,36 @@
+AS = aarch64-linux-gnu-as
+CC = aarch64-linux-gnu-gcc
+
+CFLAGS = -g -Wall -Wextra -pedantic -Werror
+LDFLAGS =
+
+ALL_LDFLAGS = -pie -Wl,--fatal-warnings
+
+ALL_CFLAGS = -std=c99 -fPIE $(CFLAGS)
+ALL_LDFLAGS += $(LDFLAGS)
+
+C_OBJS = $(patsubst %.c,%.o,$(wildcard *.c))
+AS_OBJS = $(patsubst %.s,%.o,$(wildcard *.s))
+ALL_OBJS = $(filter-out example.o,$(C_OBJS) $(AS_OBJS) vendor/unity.o)
+
+CC_CMD = $(CC) $(ALL_CFLAGS) -c -o $@ $<
+
+all: tests
+	qemu-aarch64 -L /usr/aarch64-linux-gnu ./$<
+
+tests: $(ALL_OBJS)
+	@$(CC) $(ALL_CFLAGS) $(ALL_LDFLAGS) -o $@ $(ALL_OBJS)
+
+%.o: %.s
+	@$(AS) -o $@ $<
+
+%.o: %.c
+	@$(CC_CMD)
+
+vendor/unity.o: vendor/unity.c vendor/unity.h vendor/unity_internals.h
+	@$(CC_CMD)
+
+clean:
+	@rm -f *.o vendor/*.o tests
+
+.PHONY: all clean

exercises/practice/pig-latin/pig_latin.s

@@ -0,0 +1,5 @@
+.text
+.globl translate
+
+translate:
+    ret