Add len and split methods to the default methods

hornbeam_interpreter/src/functions/defaults.rs

@@ -9,7 +9,12 @@ use super::TemplateAccessibleMethod;
 const DEFAULT_TEMPLATE_ACCESSIBLE_METHODS: &'static [(
     &'static str,
     fn(Value, Vec<Value>) -> Result<Value, String>,
-)] = &[("leftpad", leftpad), ("urlencode", urlencode)];
+)] = &[
+    ("leftpad", leftpad),
+    ("urlencode", urlencode),
+    ("len", len),
+    ("split", split),
+];
 
 /// Return a map of the default suggested template-accessible methods.
 pub fn default_template_accessible_methods() -> BTreeMap<String, TemplateAccessibleMethod> {
@@ -24,6 +29,9 @@ pub fn default_template_accessible_methods() -> BTreeMap<String, TemplateAccessi
         .collect()
 }
 
+/// Left-pads a string to a given length using a given padding character.
+///
+/// `<Str>.leftpad(<Int>, <Str>) -> Str`
 pub fn leftpad(obj: Value, args: Vec<Value>) -> Result<Value, String> {
     let Value::Str(string_to_pad) = obj else {
         return Err(format!("{obj:?} is not a string: can't leftpad!"));
@@ -60,6 +68,9 @@ pub fn leftpad(obj: Value, args: Vec<Value>) -> Result<Value, String> {
     Ok(Value::Str(Arc::new(result)))
 }
 
+/// URL-encodes sensitive characters in a string.
+///
+/// `<Str>.urlencode() -> Str`
 pub fn urlencode(obj: Value, args: Vec<Value>) -> Result<Value, String> {
     let Value::Str(string_to_encode) = obj else {
         return Err(format!("{obj:?} is not a string: can't urlencode!"));
@@ -72,3 +83,47 @@ pub fn urlencode(obj: Value, args: Vec<Value>) -> Result<Value, String> {
         percent_encoding::utf8_percent_encode(&string_to_encode, NON_ALPHANUMERIC).to_string(),
     )))
 }
+
+/// Returns the length of a given string or list.
+///
+/// - `<Str>.len() -> Int`
+/// - `<List>.len() -> Int`
+pub fn len(obj: Value, args: Vec<Value>) -> Result<Value, String> {
+    if args.len() != 0 {
+        return Err(format!("len takes 0 args, not {}", args.len()));
+    }
+
+    match obj {
+        Value::Str(string) => Ok(Value::Int(string.len() as i64)),
+        Value::List(list) => Ok(Value::Int(list.len() as i64)),
+        _ => {
+            return Err(format!(
+                "{obj:?} is not a string or list: can't get length!"
+            ));
+        }
+    }
+}
+
+/// Splits a string by given delimiters.
+///
+/// `<Str>.split(<Str>) -> List of Str`
+pub fn split(obj: Value, args: Vec<Value>) -> Result<Value, String> {
+    if args.len() != 1 {
+        return Err(format!("split takes 1 arg, not {}", args.len()));
+    }
+
+    let Value::Str(string_to_split) = obj else {
+        return Err(format!("{obj:?} is not a string: can't split!"));
+    };
+
+    let Value::Str(delimiter) = &args[0] else {
+        return Err(format!("first arg is not a string: can't split!"));
+    };
+
+    let result = string_to_split
+        .split(delimiter.as_str())
+        .map(|segment| Value::Str(Arc::new(segment.to_owned())))
+        .collect();
+
+    Ok(Value::List(result))
+}

hornbeam_interpreter/tests/snapshots.rs

@@ -75,6 +75,13 @@ br
 "padded to 15: ${$sts.carrot.leftpad(15, 'M')}"
 br
 "urlencoded: ${$sts.carrot.urlencode()}"
+br
+"length: ${$sts.carrot.len()}"
+br
+"split on A: "
+for $part in $sts.carrot.split("A")
+    "($part)"
+    br
         "#
     ))
 }

hornbeam_interpreter/tests/snapshots/snapshots__snapshot_003.snap

@@ -1,5 +1,5 @@
 ---
 source: hornbeam_interpreter/tests/snapshots.rs
-expression: "simple_render(r#\"\n\"unpadded: ${$sts.carrot}\"\nbr\n\"padded to 15: ${$sts.carrot.leftpad(15, 'M')}\"\nbr\n\"urlencoded: ${$sts.carrot.urlencode()}\"\n        \"#)"
+expression: "simple_render(r#\"\n\"unpadded: ${$sts.carrot}\"\nbr\n\"padded to 15: ${$sts.carrot.leftpad(15, 'M')}\"\nbr\n\"urlencoded: ${$sts.carrot.urlencode()}\"\nbr\n\"length: ${$sts.carrot.len()}\"\nbr\n\"split on A: \"\nfor $part in $sts.carrot.split(\"A\")\n    \"($part)\"\n    br\n        \"#)"
 ---
-unpadded: mmm CARROT!<br>padded to 15: MMMMmmm CARROT!<br>urlencoded: mmm%20CARROT%21
+unpadded: mmm CARROT!<br>padded to 15: MMMMmmm CARROT!<br>urlencoded: mmm%20CARROT%21<br>length: 11<br>split on A: (mmm C)<br>(RROT!)<br>