diff --git a/build/ludus.jimage b/build/ludus.jimage
index eed067a..85c35fc 100644
Binary files a/build/ludus.jimage and b/build/ludus.jimage differ
diff --git a/build/out.mjs b/build/out.mjs
index d8162e0..c00f957 100644
--- a/build/out.mjs
+++ b/build/out.mjs
@@ -6489,7 +6489,7 @@ var __emscripten_stack_alloc = (a0) => (__emscripten_stack_alloc = wasmExports['
 var _emscripten_stack_get_current = () => (_emscripten_stack_get_current = wasmExports['emscripten_stack_get_current'])();
 var ___cxa_is_pointer_type = createExportWrapper('__cxa_is_pointer_type', 1);
 var dynCall_jiji = Module['dynCall_jiji'] = createExportWrapper('dynCall_jiji', 5);
-var ___emscripten_embedded_file_data = Module['___emscripten_embedded_file_data'] = 1816104;
+var ___emscripten_embedded_file_data = Module['___emscripten_embedded_file_data'] = 1819008;
 function invoke_i(index) {
   var sp = stackSave();
   try {
diff --git a/build/out.wasm b/build/out.wasm
index 7f9e40f..436d5d6 100755
Binary files a/build/out.wasm and b/build/out.wasm differ
diff --git a/prelude.ld b/prelude.ld
index a64a5fe..fd4e1e2 100644
--- a/prelude.ld
+++ b/prelude.ld
@@ -279,9 +279,10 @@ fn concat {
 }
 
 fn set {
-	"Takes an ordered collection--list or tuple--and turns it into a set."
+	"Takes an ordered collection--list or tuple--and turns it into a set. Returns sets unharmed."
 	(xs as :list) -> fold (append, xs, ${})
 	(xs as :tuple) -> do xs > list > set
+	(xs as :set) -> xs
 }
 
 fn set? {
@@ -434,6 +435,11 @@ fn sentence {
 	(strs as :list) -> join (strs, " ")
 }
 
+fn to_number {
+	"Takes a string that presumably contains a representation of a number, and tries to give you back the number represented. Returns a result tuple."
+	(num as :string) -> base :to_number (num)
+}
+
 &&& boxes: mutable state and state changes
 
 fn box? {
@@ -1434,6 +1440,7 @@ pkg Prelude {
 	sum_of_squares & math 
 	tan & math
 	tau & math
+	to_number &strings numbers
 	trim & strings
 	tuple? & tuples
 	turn/deg & math
diff --git a/src/base.janet b/src/base.janet
index 7c5ffe4..6ce3977 100644
--- a/src/base.janet
+++ b/src/base.janet
@@ -1,6 +1,8 @@
 # A base library for Ludus
 # Only loaded in the prelude
 
+(import /src/scanner :as s)
+
 (defn bool [x] (if (= :^nil x) nil x))
 
 (defn ludus/and [& args] (every? (map bool args)))
@@ -248,6 +250,20 @@
     ([e] (break [:err e])))
   [:ok out])
 
+(defn to_number [str]
+  (when (string/find "&" str)
+    (break [:err (string "Could not parse `" str "` as a number")]))
+  (def scanned (s/scan (string/trim str)))
+  (when (< 0 (length (scanned :errors)))
+    (break [:err (string "Could not parse `" str "` as a number")]))
+  (def tokens (scanned :tokens))
+  (when (< 3 (length tokens))
+    (break [:err (string "Could not parse `" str "` as a number")]))
+  (def fst (first tokens))
+  (when (not= :number (fst :type))
+    (break [:err (string "Could not parse `" str "` as a number")]))
+  [:ok (fst :literal)])
+
 (def ctx {
   "add" +
   "and" ludus/and
@@ -304,6 +320,7 @@
   "sub" -
   "tan" math/tan
   "to_list" to_list
+  "to_number" to_number
   "trim" string/trim
   "triml" string/triml
   "trimr" string/trimr
@@ -317,4 +334,4 @@
     (set (b (keyword k)) v))
   b))
 
-
+(to_number "     123  a  ")
diff --git a/src/scanner.janet b/src/scanner.janet
index b7f89d1..e593728 100644
--- a/src/scanner.janet
+++ b/src/scanner.janet
@@ -349,8 +349,7 @@
       (recur (-> scanner (scan-token) (next-token)))))
   (recur (new-scanner source input)))
 
-(comment
-# (do
-  (def source "add 1 2 () four")
-  (scan source)
-)
+# (comment
+(do
+  (def source "    -123  ")
+  (length ((scan source) :tokens)))