Add an example for checking from a given dictionary

.helix/config.toml

@@ -0,0 +1 @@
+editor.workspace-lsp-roots = ["examples"]

Cargo.toml

@@ -13,3 +13,6 @@ rust-version = "1.60"
 regex = "1"
 # TODO: investigate using smartstring to cut down on allocations since
 # there are plenty of small strings.
+
+[dev-dependencies]
+xdg = "2.5"

examples/check.rs

@@ -0,0 +1,64 @@
+use std::time::Instant;
+
+use spellbook::Dictionary;
+use xdg::BaseDirectories;
+
+fn main() {
+    let mut args = std::env::args().skip(1);
+    let arg1 = match args.next() {
+        Some(arg) => arg,
+        None => {
+            eprintln!("Usage: check [LANG] WORD");
+            std::process::exit(1);
+        }
+    };
+    let (lang, word) = match args.next() {
+        Some(arg2) => (arg1, arg2),
+        None => ("en_US".to_string(), arg1),
+    };
+
+    let base = BaseDirectories::new().expect("Could not determine XDG directories");
+    let (dic_path, aff_path) = match base.get_data_dirs().iter().find_map(|dir| {
+        let subdir = dir.join("hunspell");
+        if !subdir.is_dir() {
+            return None;
+        }
+
+        let dic = subdir.join(format!("{lang}.dic"));
+        let aff = subdir.join(format!("{lang}.aff"));
+        if dic.is_file() && aff.is_file() {
+            Some((dic, aff))
+        } else {
+            None
+        }
+    }) {
+        Some((dic, aff)) => (dic, aff),
+        None => {
+            eprintln!("Could not find the {lang} dictionary");
+            std::process::exit(1);
+        }
+    };
+    let dic_text = std::fs::read_to_string(dic_path).unwrap();
+    let aff_text = std::fs::read_to_string(aff_path).unwrap();
+
+    let now = Instant::now();
+    let dict = Dictionary::compile(&aff_text, &dic_text).unwrap();
+    println!(
+        "Compiled the {lang} dictionary in {}ms",
+        now.elapsed().as_millis()
+    );
+
+    let now = Instant::now();
+    if dict.check(&word) {
+        println!(
+            "\"{word}\" is in the dictionary (checked in {}µs)",
+            now.elapsed().as_micros()
+        );
+    } else {
+        eprintln!(
+            "\"{word}\" is NOT in the dictionary (checked in {}µs)",
+            now.elapsed().as_micros()
+        );
+        std::process::exit(1);
+    }
+}