WIP dictionary

src/dict.zig

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+const std = @import("std");
+
+const Wordle = @import("wordle.zig");
+
+/// A statically-initialized dictionary of all Wordle words.
+var Dictionary: ?[]const Wordle.Word = null;
+
+/// Gets or statically initializes the dictionary.
+pub fn getDictionary() []const Wordle.Word {
+    if (Dictionary) |dict| {
+        return dict;
+    } else {
+        const dict = loadDict();
+        Dictionary = dict;
+        return dict;
+    }
+}
+
+/// Internal function to load the Wordle dictionary.
+fn loadDict() []const Wordle.Word {
+    // directly embed dictionary contents
+    const src = @embedFile("dict.txt");
+
+    // count lines (words)
+    var num: u64 = 0;
+    for (src, 0..) |char, idx| {
+        _ = idx;
+        if (char == '\n') {
+            num += 1;
+        }
+    }
+
+    // allocate all words
+    const dictionary = std.heap.smp_allocator.alloc(Wordle.Word, num) catch unreachable;
+
+    // return complete dictionary
+    return dictionary;
+}
+
+/// Tests if a word is in the dictionary.
+// TODO: binary search? need to assert that words are sorted
+pub fn isInDictionary(word: Wordle.Word) bool {
+    // exhaustively search through dictionary
+    for (getDictionary()) |entry| {
+        // compare each letter at a time
+        var match = true;
+        for (entry, word) |entryLetter, wordLetter| {
+            if (entryLetter != wordLetter) {
+                match = false;
+                break;
+            }
+        }
+
+        // if every letter matches, return a complete match
+        if (match) {
+            return true;
+        }
+    }
+
+    // if no word was found, return false
+    return false;
+}
+
+/// Asserts that a word literal is in the dictionary.
+fn expectDictionary(word: Wordle.WordLiteral) !void {
+    try std.testing.expect(isInDictionary(Wordle.strToWord(word)));
+}
+
+/// Asserts that a word literal is *not* in the dictionary.
+fn expectNotDictionary(word: Wordle.WordLiteral) !void {
+    try std.testing.expect(!isInDictionary(Wordle.strToWord(word)));
+}
+
+test "in dictionary" {
+    try expectDictionary("alone");
+}
+
+test "not in dictionary" {
+    try expectNotDictionary("hbzci");
+}