diff --git a/src/strings.sol b/src/strings.sol
index 31e76096..b449645a 100644
--- a/src/strings.sol
+++ b/src/strings.sol
@@ -66,7 +66,7 @@ library strings {
      * @param self The string to make a slice from.
      * @return A newly allocated slice containing the entire string.
      */
-    function toSlice(string self) internal pure returns (slice) {
+    function toSlice(string memory self) internal pure returns (slice memory) {
         uint ptr;
         assembly {
             ptr := add(self, 0x20)
@@ -112,7 +112,7 @@ library strings {
      * @return A new slice containing the value of the input argument up to the
      *         first null.
      */
-    function toSliceB32(bytes32 self) internal pure returns (slice ret) {
+    function toSliceB32(bytes32 self) internal pure returns (slice memory ret) {
         // Allocate space for `self` in memory, copy it there, and point ret at it
         assembly {
             let ptr := mload(0x40)
@@ -128,7 +128,7 @@ library strings {
      * @param self The slice to copy.
      * @return A new slice containing the same data as `self`.
      */
-    function copy(slice self) internal pure returns (slice) {
+    function copy(slice memory self) internal pure returns (slice memory) {
         return slice(self._len, self._ptr);
     }
 
@@ -137,7 +137,7 @@ library strings {
      * @param self The slice to copy.
      * @return A newly allocated string containing the slice's text.
      */
-    function toString(slice self) internal pure returns (string) {
+    function toString(slice memory self) internal pure returns (string memory) {
         string memory ret = new string(self._len);
         uint retptr;
         assembly { retptr := add(ret, 32) }
@@ -154,7 +154,7 @@ library strings {
      * @param self The slice to operate on.
      * @return The length of the slice in runes.
      */
-    function len(slice self) internal pure returns (uint l) {
+    function len(slice memory self) internal pure returns (uint l) {
         // Starting at ptr-31 means the LSB will be the byte we care about
         uint ptr = self._ptr - 31;
         uint end = ptr + self._len;
@@ -182,7 +182,7 @@ library strings {
      * @param self The slice to operate on.
      * @return True if the slice is empty, False otherwise.
      */
-    function empty(slice self) internal pure returns (bool) {
+    function empty(slice memory self) internal pure returns (bool) {
         return self._len == 0;
     }
 
@@ -195,7 +195,7 @@ library strings {
      * @param other The second slice to compare.
      * @return The result of the comparison.
      */
-    function compare(slice self, slice other) internal pure returns (int) {
+    function compare(slice memory self, slice memory other) internal pure returns (int) {
         uint shortest = self._len;
         if (other._len < self._len)
             shortest = other._len;
@@ -231,7 +231,7 @@ library strings {
      * @param self The second slice to compare.
      * @return True if the slices are equal, false otherwise.
      */
-    function equals(slice self, slice other) internal pure returns (bool) {
+    function equals(slice memory self, slice memory other) internal pure returns (bool) {
         return compare(self, other) == 0;
     }
 
@@ -242,7 +242,7 @@ library strings {
      * @param rune The slice that will contain the first rune.
      * @return `rune`.
      */
-    function nextRune(slice self, slice rune) internal pure returns (slice) {
+    function nextRune(slice memory self, slice memory rune) internal pure returns (slice memory) {
         rune._ptr = self._ptr;
 
         if (self._len == 0) {
@@ -284,7 +284,7 @@ library strings {
      * @param self The slice to operate on.
      * @return A slice containing only the first rune from `self`.
      */
-    function nextRune(slice self) internal pure returns (slice ret) {
+    function nextRune(slice memory self) internal pure returns (slice memory ret) {
         nextRune(self, ret);
     }
 
@@ -293,7 +293,7 @@ library strings {
      * @param self The slice to operate on.
      * @return The number of the first codepoint in the slice.
      */
-    function ord(slice self) internal pure returns (uint ret) {
+    function ord(slice memory self) internal pure returns (uint ret) {
         if (self._len == 0) {
             return 0;
         }
@@ -342,7 +342,7 @@ library strings {
      * @param self The slice to hash.
      * @return The hash of the slice.
      */
-    function keccak(slice self) internal pure returns (bytes32 ret) {
+    function keccak(slice memory self) internal pure returns (bytes32 ret) {
         assembly {
             ret := keccak256(mload(add(self, 32)), mload(self))
         }
@@ -354,7 +354,7 @@ library strings {
      * @param needle The slice to search for.
      * @return True if the slice starts with the provided text, false otherwise.
      */
-    function startsWith(slice self, slice needle) internal pure returns (bool) {
+    function startsWith(slice memory self, slice memory needle) internal pure returns (bool) {
         if (self._len < needle._len) {
             return false;
         }
@@ -380,7 +380,7 @@ library strings {
      * @param needle The slice to search for.
      * @return `self`
      */
-    function beyond(slice self, slice needle) internal pure returns (slice) {
+    function beyond(slice memory self, slice memory needle) internal pure returns (slice memory) {
         if (self._len < needle._len) {
             return self;
         }
@@ -409,7 +409,7 @@ library strings {
      * @param needle The slice to search for.
      * @return True if the slice starts with the provided text, false otherwise.
      */
-    function endsWith(slice self, slice needle) internal pure returns (bool) {
+    function endsWith(slice memory self, slice memory needle) internal pure returns (bool) {
         if (self._len < needle._len) {
             return false;
         }
@@ -437,7 +437,7 @@ library strings {
      * @param needle The slice to search for.
      * @return `self`
      */
-    function until(slice self, slice needle) internal pure returns (slice) {
+    function until(slice memory self, slice memory needle) internal pure returns (slice memory) {
         if (self._len < needle._len) {
             return self;
         }
@@ -459,8 +459,6 @@ library strings {
         return self;
     }
 
-    event log_bytemask(bytes32 mask);
-
     // Returns the memory address of the first byte of the first occurrence of
     // `needle` in `self`, or the first byte after `self` if not found.
     function findPtr(uint selflen, uint selfptr, uint needlelen, uint needleptr) private pure returns (uint) {
@@ -550,7 +548,7 @@ library strings {
      * @param needle The text to search for.
      * @return `self`.
      */
-    function find(slice self, slice needle) internal pure returns (slice) {
+    function find(slice memory self, slice memory needle) internal pure returns (slice memory) {
         uint ptr = findPtr(self._len, self._ptr, needle._len, needle._ptr);
         self._len -= ptr - self._ptr;
         self._ptr = ptr;
@@ -565,7 +563,7 @@ library strings {
      * @param needle The text to search for.
      * @return `self`.
      */
-    function rfind(slice self, slice needle) internal pure returns (slice) {
+    function rfind(slice memory self, slice memory needle) internal pure returns (slice memory) {
         uint ptr = rfindPtr(self._len, self._ptr, needle._len, needle._ptr);
         self._len = ptr - self._ptr;
         return self;
@@ -581,7 +579,7 @@ library strings {
      * @param token An output parameter to which the first token is written.
      * @return `token`.
      */
-    function split(slice self, slice needle, slice token) internal pure returns (slice) {
+    function split(slice memory self, slice memory needle, slice memory token) internal pure returns (slice memory) {
         uint ptr = findPtr(self._len, self._ptr, needle._len, needle._ptr);
         token._ptr = self._ptr;
         token._len = ptr - self._ptr;
@@ -604,7 +602,7 @@ library strings {
      * @param needle The text to search for in `self`.
      * @return The part of `self` up to the first occurrence of `delim`.
      */
-    function split(slice self, slice needle) internal pure returns (slice token) {
+    function split(slice memory self, slice memory needle) internal pure returns (slice memory token) {
         split(self, needle, token);
     }
 
@@ -618,7 +616,7 @@ library strings {
      * @param token An output parameter to which the first token is written.
      * @return `token`.
      */
-    function rsplit(slice self, slice needle, slice token) internal pure returns (slice) {
+    function rsplit(slice memory self, slice memory needle, slice memory token) internal pure returns (slice memory) {
         uint ptr = rfindPtr(self._len, self._ptr, needle._len, needle._ptr);
         token._ptr = ptr;
         token._len = self._len - (ptr - self._ptr);
@@ -640,7 +638,7 @@ library strings {
      * @param needle The text to search for in `self`.
      * @return The part of `self` after the last occurrence of `delim`.
      */
-    function rsplit(slice self, slice needle) internal pure returns (slice token) {
+    function rsplit(slice memory self, slice memory needle) internal pure returns (slice memory token) {
         rsplit(self, needle, token);
     }
 
@@ -650,7 +648,7 @@ library strings {
      * @param needle The text to search for in `self`.
      * @return The number of occurrences of `needle` found in `self`.
      */
-    function count(slice self, slice needle) internal pure returns (uint cnt) {
+    function count(slice memory self, slice memory needle) internal pure returns (uint cnt) {
         uint ptr = findPtr(self._len, self._ptr, needle._len, needle._ptr) + needle._len;
         while (ptr <= self._ptr + self._len) {
             cnt++;
@@ -664,7 +662,7 @@ library strings {
      * @param needle The text to search for in `self`.
      * @return True if `needle` is found in `self`, false otherwise.
      */
-    function contains(slice self, slice needle) internal pure returns (bool) {
+    function contains(slice memory self, slice memory needle) internal pure returns (bool) {
         return rfindPtr(self._len, self._ptr, needle._len, needle._ptr) != self._ptr;
     }
 
@@ -675,7 +673,7 @@ library strings {
      * @param other The second slice to concatenate.
      * @return The concatenation of the two strings.
      */
-    function concat(slice self, slice other) internal pure returns (string) {
+    function concat(slice memory self, slice memory other) internal pure returns (string memory) {
         string memory ret = new string(self._len + other._len);
         uint retptr;
         assembly { retptr := add(ret, 32) }
@@ -692,7 +690,7 @@ library strings {
      * @return A newly allocated string containing all the slices in `parts`,
      *         joined with `self`.
      */
-    function join(slice self, slice[] parts) internal pure returns (string) {
+    function join(slice memory self, slice[] memory parts) internal pure returns (string memory) {
         if (parts.length == 0)
             return "";