implement and test string.split #95 (#96)

Co-authored-by: David James <xpe@ixm.local>

crates/compiler/src/builtin/functions/string.rs

@@ -115,6 +115,53 @@ pub(crate) fn str_slice(mut args: ArgumentResult, visitor: &mut Visitor) -> Sass
     }
 }
 
+/// https://sass-lang.com/documentation/modules/string/#split
+///
+/// Returns a bracketed, comma-separated list of substrings of $string
+/// that are separated by $separator. The $separators aren’t included
+/// in these substrings.
+///
+/// If $limit is a number 1 or higher, this splits on at most that many
+/// $separators (and so returns at most $limit + 1 strings). The last
+/// substring contains the rest of the string, including any remaining
+/// $separators.
+pub(crate) fn str_split(mut args: ArgumentResult, visitor: &mut Visitor) -> SassResult<Value> {
+    args.max_args(3)?;
+
+    let s1 = args
+        .get_err(0, "string")?
+        .assert_string_with_name("string", args.span())?
+        .0;
+
+    let separator = args
+        .get_err(1, "separator")?
+        .assert_string_with_name("separator", args.span())?
+        .0;
+
+    let limit = args.default_arg(2, "limit", Value::Null);
+
+    let vec = if matches!(limit, Value::Null) {
+        s1.split(&separator)
+            .map(|s| Value::String(s.to_string(), QuoteKind::Quoted))
+            .collect()
+    } else {
+        let limit = limit.assert_number_with_name("limit", args.span())?;
+        let limit_int = limit.assert_int_with_name("limit", args.span())?;
+        if limit_int < 1 {
+            return Err((
+                format!("$limit: Must be greater than 1, was {}.", limit_int),
+                args.span(),
+            )
+                .into());
+        }
+        // note: `1 + limit_int` is required to match dart-sass
+        s1.splitn(1 + limit_int as usize, &separator)
+            .map(|s| Value::String(s.to_string(), QuoteKind::Quoted))
+            .collect()
+    };
+    Ok(Value::List(vec, ListSeparator::Comma, Brackets::Bracketed))
+}
+
 pub(crate) fn str_index(mut args: ArgumentResult, visitor: &mut Visitor) -> SassResult<Value> {
     args.max_args(2)?;
     let s1 = args

crates/compiler/src/builtin/modules/string.rs

@@ -1,7 +1,8 @@
 use crate::builtin::{
     modules::Module,
     string::{
-        quote, str_index, str_insert, str_length, str_slice, to_lower_case, to_upper_case, unquote,
+        quote, str_index, str_insert, str_length, str_slice, str_split, to_lower_case,
+        to_upper_case, unquote,
     },
 };
 
@@ -14,6 +15,7 @@ pub(crate) fn declare(f: &mut Module) {
     f.insert_builtin("insert", str_insert);
     f.insert_builtin("length", str_length);
     f.insert_builtin("slice", str_slice);
+    f.insert_builtin("split", str_split);
     f.insert_builtin("to-lower-case", to_lower_case);
     f.insert_builtin("to-upper-case", to_upper_case);
     #[cfg(feature = "random")]

crates/lib/tests/strings.rs

@@ -308,3 +308,30 @@ test!(
     ",
     "a {\n  color: \"aaa\";\n}\n"
 );
+test!(
+    str_split_abc_space,
+    "@use 'sass:string';
+    foo {
+        bar: string.split('a b c', ' ');
+    }
+    ",
+    "foo {\n  bar: [\"a\", \"b\", \"c\"];\n}\n"
+);
+test!(
+    str_split_abc_space_1,
+    "@use 'sass:string';
+    foo {
+        bar: string.split('a b c', ' ', 1);
+    }
+    ",
+    "foo {\n  bar: [\"a\", \"b c\"];\n}\n"
+);
+test!(
+    str_split_rgb_comma,
+    "@use 'sass:string';
+    foo {
+        bar: string.split('red,green,blue', ',');
+    }
+    ",
+    "foo {\n  bar: [\"red\", \"green\", \"blue\"];\n}\n"
+);