added wordcount filter (#649)

minijinja-contrib/src/filters/mod.rs

@@ -214,3 +214,27 @@ pub fn truncate(state: &State, value: Value, kwargs: Kwargs) -> Result<String, E
     result.push_str(end);
     Ok(result)
 }
+
+/// Counts the words in a string.
+///
+/// ```jinja
+/// {{ "Hello world!"|wordcount }}
+/// ```
+pub fn wordcount(value: Value) -> Result<Value, Error> {
+    let s = value.as_str().unwrap_or_default();
+    let mut count: u32 = 0;
+    let mut in_word = false;
+
+    // Iterate through characters, counting transitions from non-word to word chars
+    for c in s.chars() {
+        let is_word_char = c.is_alphanumeric() || c == '_';
+        if is_word_char && !in_word {
+            count += 1;
+            in_word = true;
+        } else if !is_word_char {
+            in_word = false;
+        }
+    }
+
+    Ok(Value::from(count))
+}

minijinja-contrib/tests/filters.rs

@@ -1,5 +1,5 @@
 use minijinja::{context, Environment};
-use minijinja_contrib::filters::pluralize;
+use minijinja_contrib::filters::{pluralize, wordcount};
 use similar_asserts::assert_eq;
 
 #[test]
@@ -202,3 +202,68 @@ fn test_truncate() {
         "invalid operation: expected length >= 3, got 1 (in <string>:1)"
     );
 }
+
+#[test]
+fn test_wordcount() {
+    let mut env = Environment::new();
+    env.add_filter("wordcount", wordcount);
+
+    assert_eq!(
+        env.render_str(
+            "{{ text|wordcount }}",
+            context! {
+                text => "Hello world! How are you?"
+            }
+        )
+        .unwrap(),
+        "5"
+    );
+
+    // Test empty string
+    assert_eq!(
+        env.render_str(
+            "{{ text|wordcount }}",
+            context! {
+                text => ""
+            }
+        )
+        .unwrap(),
+        "0"
+    );
+
+    // Test multiple whitespace
+    assert_eq!(
+        env.render_str(
+            "{{ text|wordcount }}",
+            context! {
+                text => "Hello    world!   Test"
+            }
+        )
+        .unwrap(),
+        "3"
+    );
+
+    // Test other word separators
+    assert_eq!(
+        env.render_str(
+            "{{ text|wordcount }}",
+            context! {
+                text => "hello-again@world! It's_me!"
+            }
+        )
+        .unwrap(),
+        "5"
+    );
+
+    // Test multiple other word separators
+    assert_eq!(
+        env.render_str(
+            "{{ text|wordcount }}",
+            context! {
+                text => "hello--again@-!world"
+            }
+        )
+        .unwrap(),
+        "3"
+    );
+}