1 files changed, 37 insertions, 0 deletions
diff --git a/src/eval/str.rs b/src/eval/str.rs
new file mode 100644
index 00000000..3b4349a1
--- /dev/null
+++ b/src/eval/str.rs
@@ -0,0 +1,37 @@
+use super::{Array, Value};
+use crate::diag::StrResult;
+use crate::util::EcoString;
+
+/// Extra methods on strings.
+pub trait StrExt {
+    /// Repeat a string a number of times.
+    fn repeat(&self, n: i64) -> StrResult<EcoString>;
+
+    /// Split this string at whitespace or a specific pattern.
+    fn split(&self, at: Option<EcoString>) -> Array;
+}
+
+impl StrExt for EcoString {
+    fn repeat(&self, n: i64) -> StrResult<EcoString> {
+        let n = usize::try_from(n)
+            .ok()
+            .and_then(|n| self.len().checked_mul(n).map(|_| n))
+            .ok_or_else(|| format!("cannot repeat this string {} times", n))?;
+
+        Ok(self.repeat(n))
+    }
+
+    fn split(&self, at: Option<EcoString>) -> Array {
+        if let Some(pat) = at {
+            self.as_str()
+                .split(pat.as_str())
+                .map(|s| Value::Str(s.into()))
+                .collect()
+        } else {
+            self.as_str()
+                .split_whitespace()
+                .map(|s| Value::Str(s.into()))
+                .collect()
+        }
+    }
+}