diff --git a/assets/test_prelude.ld b/assets/test_prelude.ld
index 0d7ceae..e788a59 100644
--- a/assets/test_prelude.ld
+++ b/assets/test_prelude.ld
@@ -859,52 +859,14 @@ fn butlast {
 }
 
 fn indices_of {
-	"Takes a list or string and returns a list of all the indices where the scrutinee appears. Returns an empty list if the scrutinee does not appear in the search target."
-	(target as :list, scrutinee) -> {
-		fn searcher ((i, indices), curr) -> if eq? (scrutinee, curr)
-				then (inc (i), append (indices, i))
-				else (inc (i), indices)
-		let (_, idxes) = fold (searcher, target, (0, []))
-		idxes
-	}
-	& (target as :string, scrutinee as :string) -> {
-	& 	let scrut_len = count (scrutinee)
-	& 	fn searcher ((i, indices), curr) -> {
-	& 		let srch_substr = slice_n (remaining, scrut_len)
-	& 		if eq? (scrutinee, srch_substr)
-	& 			then (inc (i), append (indices, i))
-	& 			else (inc (i), indices)
-	& 	}
-	& 	let (_, idxes) = fold (searcher, target, (0, []))
-	& 	idxes
-	& }
+	"Takes a list or string and returns a list of all the indices where the target appears. Returns an empty list if the target does not appear in the scrutinee."
+		(scrutinee as :list, target) -> base :indices_of (scrutinee, target)
 }
 
 fn index_of {
 	"Takes a list or string returns the first index at which the scrutinee appears. Returns `nil` if the scrutinee does not appear in the search target."
-	(target as :list, scrutinee) -> first (indices_of (target, scrutinee))
-	(target as :string, scrutinee as :string) -> first (indices_of (target, scrutinee))
+	(scrutinee as :list, target) -> base :index_of (scrutinee, target)
 }
-& 	(target as :list, scrutinee) -> loop (0) with {
-& 		(i) if gte? (i, count (target)) -> nil
-& 		(i) -> if eq? (scrutinee, at (target, i))
-& 			then i
-& 			else recur (inc (i))
-& 	}
-& 	(target as :string, scrutinee as :string) -> {
-& 		let scrut_len = count (scrutinee)
-& 		loop (0, target) with {
-& 			(i, "") -> nil  
-& 			(i, remaining) -> {
-& 				let srch_substr = slice_n (remaining, scrut_len)
-& 				if eq? (scrutinee, srch_substr)
-& 					then i
-& 					else recur (inc (i), rest (remaining))
-& 			}
-& 		}
-& 	}
-& }
-
 
 &&& keywords: funny names
 fn keyword? {
diff --git a/pkg/rudus.d.ts b/pkg/rudus.d.ts
index bb38565..86c1521 100644
--- a/pkg/rudus.d.ts
+++ b/pkg/rudus.d.ts
@@ -14,8 +14,8 @@ export interface InitOutput {
   readonly __wbindgen_malloc: (a: number, b: number) => number;
   readonly __wbindgen_realloc: (a: number, b: number, c: number, d: number) => number;
   readonly __wbindgen_export_6: WebAssembly.Table;
-  readonly closure359_externref_shim: (a: number, b: number, c: any) => void;
-  readonly closure382_externref_shim: (a: number, b: number, c: any, d: any) => void;
+  readonly closure361_externref_shim: (a: number, b: number, c: any) => void;
+  readonly closure384_externref_shim: (a: number, b: number, c: any, d: any) => void;
   readonly __wbindgen_start: () => void;
 }
 
diff --git a/pkg/rudus.js b/pkg/rudus.js
index d045a63..2e86394 100644
--- a/pkg/rudus.js
+++ b/pkg/rudus.js
@@ -240,13 +240,13 @@ function _assertNum(n) {
 function __wbg_adapter_20(arg0, arg1, arg2) {
     _assertNum(arg0);
     _assertNum(arg1);
-    wasm.closure359_externref_shim(arg0, arg1, arg2);
+    wasm.closure361_externref_shim(arg0, arg1, arg2);
 }
 
 function __wbg_adapter_46(arg0, arg1, arg2, arg3) {
     _assertNum(arg0);
     _assertNum(arg1);
-    wasm.closure382_externref_shim(arg0, arg1, arg2, arg3);
+    wasm.closure384_externref_shim(arg0, arg1, arg2, arg3);
 }
 
 async function __wbg_load(module, imports) {
@@ -403,8 +403,8 @@ function __wbg_get_imports() {
         _assertBoolean(ret);
         return ret;
     };
-    imports.wbg.__wbindgen_closure_wrapper8162 = function() { return logError(function (arg0, arg1, arg2) {
-        const ret = makeMutClosure(arg0, arg1, 360, __wbg_adapter_20);
+    imports.wbg.__wbindgen_closure_wrapper8168 = function() { return logError(function (arg0, arg1, arg2) {
+        const ret = makeMutClosure(arg0, arg1, 362, __wbg_adapter_20);
         return ret;
     }, arguments) };
     imports.wbg.__wbindgen_debug_string = function(arg0, arg1) {
diff --git a/pkg/rudus_bg.wasm b/pkg/rudus_bg.wasm
index f1317c2..0e5af42 100644
Binary files a/pkg/rudus_bg.wasm and b/pkg/rudus_bg.wasm differ
diff --git a/pkg/rudus_bg.wasm.d.ts b/pkg/rudus_bg.wasm.d.ts
index af356e0..e654bfa 100644
--- a/pkg/rudus_bg.wasm.d.ts
+++ b/pkg/rudus_bg.wasm.d.ts
@@ -9,6 +9,6 @@ export const __wbindgen_free: (a: number, b: number, c: number) => void;
 export const __wbindgen_malloc: (a: number, b: number) => number;
 export const __wbindgen_realloc: (a: number, b: number, c: number, d: number) => number;
 export const __wbindgen_export_6: WebAssembly.Table;
-export const closure359_externref_shim: (a: number, b: number, c: any) => void;
-export const closure382_externref_shim: (a: number, b: number, c: any, d: any) => void;
+export const closure361_externref_shim: (a: number, b: number, c: any) => void;
+export const closure384_externref_shim: (a: number, b: number, c: any, d: any) => void;
 export const __wbindgen_start: () => void;
diff --git a/src/base.rs b/src/base.rs
index c541058..55d2f91 100644
--- a/src/base.rs
+++ b/src/base.rs
@@ -123,6 +123,27 @@ pub fn words(str: &Value) -> Value {
     Value::list(words)
 }
 
+pub fn index_of(scrutinee: &Value, target: &Value) -> Value {
+    let scrutinee = scrutinee.as_list();
+    for (i, value) in scrutinee.iter().enumerate() {
+        if value == target {
+            return Value::from_usize(i);
+        }
+    }
+    Value::Nil
+}
+
+pub fn indices_of(scrutinee: &Value, target: &Value) -> Value {
+    let scrutinee = scrutinee.as_list();
+    let mut indices = Vector::new();
+    for (i, value) in scrutinee.iter().enumerate() {
+        if value == target {
+            indices.push_back(Value::from_usize(i))
+        }
+    }
+    Value::list(indices)
+}
+
 // TODO: figure out how to get to opportunistic mutation here
 pub fn concat(x: &Value, y: &Value) -> Value {
     match (x, y) {
@@ -662,6 +683,14 @@ pub fn make_base() -> Value {
         ("gt?", Value::BaseFn(Box::new(BaseFn::Binary("gt?", gt)))),
         ("gte?", Value::BaseFn(Box::new(BaseFn::Binary("gte?", gte)))),
         ("inc", Value::BaseFn(Box::new(BaseFn::Unary("inc", inc)))),
+        (
+            "index_of",
+            Value::BaseFn(Box::new(BaseFn::Binary("index_of", index_of))),
+        ),
+        (
+            "indices_of",
+            Value::BaseFn(Box::new(BaseFn::Binary("indices_of", indices_of))),
+        ),
         ("last", Value::BaseFn(Box::new(BaseFn::Unary("last", last)))),
         ("list", Value::BaseFn(Box::new(BaseFn::Unary("list", list)))),
         ("lt?", Value::BaseFn(Box::new(BaseFn::Binary("lt?", lt)))),