diff --git a/spork/base64.janet b/spork/base64.janet
index 81cb4b5..de74188 100644
--- a/spork/base64.janet
+++ b/spork/base64.janet
@@ -96,10 +96,10 @@
   ```
   [s]
   (if-not (empty? s)
-    (let [without-padding (peg/replace-all "=" "" s)
+    (let [without-padding (string/replace-all "=" "" s)
           padded? (not (zero? (% (length without-padding) 4)))
           quadruples (partition 4 without-padding)
           bytes (map quadruples->bytes quadruples)
           base64 (apply string bytes)]
-      (if padded? (slice base64 0 -2) base64))
+      (if padded? (slice base64 0 (dec (length base64))) base64))
     ""))
diff --git a/spork/cjanet.janet b/spork/cjanet.janet
index 82ae00a..7247552 100644
--- a/spork/cjanet.janet
+++ b/spork/cjanet.janet
@@ -509,7 +509,7 @@
 (defn emit-declare
   "Emit a declaration of a variable or constant."
   [binding & form]
-  (def storage-classes (slice form 0 -2))
+  (def storage-classes (slice form 0 (dec (length form))))
   (def v (last form))
   (when (next storage-classes)
     (emit-storage-classes storage-classes))
diff --git a/spork/httpf.janet b/spork/httpf.janet
index f68db55..c2c87f0 100644
--- a/spork/httpf.janet
+++ b/spork/httpf.janet
@@ -116,7 +116,7 @@
   (put mime-read-default path read-mime)
   (put mime-render-default path render-mime)
   (if (string/has-suffix? "/" path)
-    (add-route server (string/slice path 0 -2) docstring schema handler read-mime render-mime)
+    (add-route server (string/slice path 0 (dec (length path))) docstring schema handler read-mime render-mime)
     server))
 
 (defn add-bindings-as-routes
diff --git a/spork/misc.janet b/spork/misc.janet
index 64155cd..adc4c04 100644
--- a/spork/misc.janet
+++ b/spork/misc.janet
@@ -28,7 +28,7 @@
                                 "\n" (string/replace indent "" x))]
       # Remove trailing newline to mimic long string newline omission.
       (if (= (chr "\n") (last y))
-        (slice y 0 -2)
+        (slice y 0 (dec (length y)))
         y))
     x))
 
@@ -200,14 +200,14 @@
   "Trim the specified prefix of a string if it has one"
   [prefix str]
   (if (string/has-prefix? prefix str)
-    (slice str (length prefix) -1)
+    (slice str (length prefix))
     str))
 
 (defn trim-suffix
   "Trim the specified suffix of a string if it has one"
   [suffix str]
   (if (string/has-suffix? suffix str)
-    (slice str 0 (* -1 (+ 1 (length suffix))))
+    (slice str 0 (- (length str) (length suffix)))
     str))
 
 (defmacro log
@@ -278,7 +278,7 @@
                'if cnd
                (tuple 'set res
                       (tuple (first ope) res
-                             ;(tuple/slice ope 1 -1)))))
+                             ;(tuple/slice ope 1)))))
            (partition 2 clauses))
        ,res)))
 
diff --git a/spork/path.janet b/spork/path.janet
index f834cd7..48f2a14 100644
--- a/spork/path.janet
+++ b/spork/path.janet
@@ -18,7 +18,7 @@
   (if-let [m (peg/match ext-peg path (length path))]
     (let [i (m 0)]
       (if (= (path i) 46)
-        (string/slice path (m 0) -1)))))
+        (string/slice path (m 0))))))
 
 (defn- redef
   "Redef a value, keeping all metadata."
@@ -63,7 +63,7 @@
                   path
                   (length path))]
        (let [[p] m]
-         (string/slice path p -1))
+         (string/slice path p))
        path)))
 
 (defmacro- decl-parts
@@ -130,7 +130,7 @@
      (def target-parts (,(symbol pre "/parts") (,(symbol pre "/abspath") target)))
      (def same-parts (length (take-until identity (map not= source-parts target-parts))))
      (def up-walk (array/new-filled (- (length source-parts) same-parts) ".."))
-     (def down-walk (tuple/slice target-parts same-parts -1))
+     (def down-walk (tuple/slice target-parts same-parts))
      (,(symbol pre "/join") ;up-walk ;down-walk)))
 
 #