implement split filter

src/filters.rs

@@ -244,6 +244,31 @@ pub fn last(input: &Value, _args: &[Value]) -> FilterResult {
     }
 }
 
+pub fn split(input: &Value, args: &[Value]) -> FilterResult {
+    // Make sure there is only 1 argument to split
+    if args.len() != 1 {
+        return Err(InvalidArgumentCount(format!("expected 1, {} given", args.len())));
+    }
+
+
+    match *input {
+        Str(ref string_to_split) => {
+            // the input String is in fact a String
+            match args.first() { // Check the first (and only) argument
+                Some(&Str(ref split_string)) => {
+                    // The split string argument is also in fact a String
+                    // Split and construct resulting Array
+                    Ok(Array(string_to_split.split(split_string)
+                        .map(|x| Str(String::from(x)))
+                        .collect()))
+                }
+                _ => Err(InvalidArgument(0, "expected String argument to split".to_owned())),
+            }
+        }
+        _ => Err(InvalidType("String expected".to_owned())),
+    }
+}
+
 #[cfg(test)]
 mod tests {
 
@@ -402,4 +427,12 @@ mod tests {
                    tos!("last"));
         assert_eq!(unit!(last, Array(vec![])), tos!(""));
     }
+
+    #[test]
+    fn unit_split() {
+        assert_eq!(unit!(split, tos!("a, b, c"), &[tos!(", ")]),
+                   Array(vec![tos!("a"), tos!("b"), tos!("c")]));
+        assert_eq!(unit!(split, tos!("a~b"), &[tos!("~")]),
+                   Array(vec![tos!("a"), tos!("b")]));
+    }
 }

src/template.rs

@@ -2,6 +2,7 @@ use Renderable;
 use context::Context;
 use filters::{size, upcase, downcase, capitalize, minus, plus, times, divided_by, ceil, floor,
               round, prepend, append, first, last, pluralize, replace};
+use filters::split;
 use error::Result;
 
 pub struct Template {
@@ -28,6 +29,7 @@ impl Renderable for Template {
         context.add_filter("append", Box::new(append));
         context.add_filter("replace", Box::new(replace));
         context.add_filter("pluralize", Box::new(pluralize));
+        context.add_filter("split", Box::new(split));
 
         let mut buf = String::new();
         for el in &self.elements {

tests/filters.rs

@@ -211,3 +211,31 @@ pub fn append() {
     let output = template.render(&mut data);
     assert_eq!(output.unwrap(), Some("roobarblifo".to_string()));
 }
+
+#[test]
+// Got this test from example at https://shopify.github.io/liquid/filters/split/
+// This is an additional test to verify the comma/space parsing is also working
+// from https://github.com/cobalt-org/liquid-rust/issues/41
+pub fn split_with_comma() {
+    let text = "{% assign beatles = \"John, Paul, George, Ringo\" | split: \", \" %}{% for member in beatles %}{{ member }}\n{% endfor %}";
+    let options : LiquidOptions = Default::default();
+    let template = parse(&text, options).unwrap();
+
+    let mut data = Context::new();
+
+    let output = template.render(&mut data);
+    assert_eq!(output.unwrap(), Some("John\nPaul\nGeorge\nRingo\n".to_string()));
+}
+
+#[test]
+// This test verifies that issue https://github.com/cobalt-org/liquid-rust/issues/40 is fixed (that split works)
+pub fn split_no_comma() {
+    let text = "{% assign letters = \"a~b~c\" | split:\"~\" %}{% for letter in letters %}LETTER: {{ letter }}\n{% endfor %}";
+    let options : LiquidOptions = Default::default();
+    let template = parse(&text, options).unwrap();
+
+    let mut data = Context::new();
+
+    let output = template.render(&mut data);
+    assert_eq!(output.unwrap(), Some("LETTER: a\nLETTER: b\nLETTER: c\n".to_string()));
+}