diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -341,6 +341,7 @@
 	util/error.cpp
 	util/moneystr.cpp
 	util/settings.cpp
+	util/spanparsing.cpp
 	util/strencodings.cpp
 	util/string.cpp
 	util/system.cpp
diff --git a/src/Makefile.am b/src/Makefile.am
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -248,6 +248,7 @@
   util/error.h \
   util/macros.h \
   util/moneystr.h \
+  util/spanparsing.h \
   util/system.h \
   util/settings.h \
   util/string.h \
@@ -560,6 +561,7 @@
   util/system.cpp \
   util/moneystr.cpp \
   util/settings.cpp \
+  util/spanparsing.cpp \
   util/strencodings.cpp \
   util/string.cpp \
   util/threadnames.cpp \
diff --git a/src/script/descriptor.cpp b/src/script/descriptor.cpp
--- a/src/script/descriptor.cpp
+++ b/src/script/descriptor.cpp
@@ -11,6 +11,7 @@
 #include <script/standard.h>
 #include <span.h>
 #include <util/bip32.h>
+#include <util/spanparsing.h>
 #include <util/strencodings.h>
 #include <util/system.h>
 
@@ -733,68 +734,6 @@
     P2SH,
 };
 
-/**
- * Parse a constant. If successful, sp is updated to skip the constant and
- * return true.
- */
-bool Const(const std::string &str, Span<const char> &sp) {
-    if ((size_t)sp.size() >= str.size() &&
-        std::equal(str.begin(), str.end(), sp.begin())) {
-        sp = sp.subspan(str.size());
-        return true;
-    }
-    return false;
-}
-
-/**
- * Parse a function call. If successful, sp is updated to be the function's
- * argument(s).
- */
-bool Func(const std::string &str, Span<const char> &sp) {
-    if ((size_t)sp.size() >= str.size() + 2 && sp[str.size()] == '(' &&
-        sp[sp.size() - 1] == ')' &&
-        std::equal(str.begin(), str.end(), sp.begin())) {
-        sp = sp.subspan(str.size() + 1, sp.size() - str.size() - 2);
-        return true;
-    }
-    return false;
-}
-
-/** Return the expression that sp begins with, and update sp to skip it. */
-Span<const char> Expr(Span<const char> &sp) {
-    int level = 0;
-    auto it = sp.begin();
-    while (it != sp.end()) {
-        if (*it == '(') {
-            ++level;
-        } else if (level && *it == ')') {
-            --level;
-        } else if (level == 0 && (*it == ')' || *it == ',')) {
-            break;
-        }
-        ++it;
-    }
-    Span<const char> ret = sp.first(it - sp.begin());
-    sp = sp.subspan(it - sp.begin());
-    return ret;
-}
-
-/** Split a string on every instance of sep, returning a vector. */
-std::vector<Span<const char>> Split(const Span<const char> &sp, char sep) {
-    std::vector<Span<const char>> ret;
-    auto it = sp.begin();
-    auto start = it;
-    while (it != sp.end()) {
-        if (*it == sep) {
-            ret.emplace_back(start, it);
-            start = it + 1;
-        }
-        ++it;
-    }
-    ret.emplace_back(start, it);
-    return ret;
-}
-
 /**
  * Parse a key path, being passed a split list of elements (the first element is
  * ignored).
@@ -827,6 +766,8 @@
 std::unique_ptr<PubkeyProvider> ParsePubkeyInner(const Span<const char> &sp,
                                                  FlatSigningProvider &out,
                                                  std::string &error) {
+    using namespace spanparsing;
+
     auto split = Split(sp, '/');
     std::string str(split[0].begin(), split[0].end());
     if (str.size() == 0) {
@@ -881,6 +822,8 @@
 std::unique_ptr<PubkeyProvider> ParsePubkey(const Span<const char> &sp,
                                             FlatSigningProvider &out,
                                             std::string &error) {
+    using namespace spanparsing;
+
     auto origin_split = Split(sp, ']');
     if (origin_split.size() > 2) {
         error = "Multiple ']' characters found for a single pubkey";
@@ -929,6 +872,8 @@
                                             ParseScriptContext ctx,
                                             FlatSigningProvider &out,
                                             std::string &error) {
+    using namespace spanparsing;
+
     auto expr = Expr(sp);
     if (Func("pk", expr)) {
         auto pubkey = ParsePubkey(expr, out, error);
@@ -1125,6 +1070,8 @@
  */
 bool CheckChecksum(Span<const char> &sp, bool require_checksum,
                    std::string &error, std::string *out_checksum = nullptr) {
+    using namespace spanparsing;
+
     auto check_split = Split(sp, '#');
     if (check_split.size() > 2) {
         error = "Multiple '#' symbols";
diff --git a/src/util/spanparsing.h b/src/util/spanparsing.h
new file mode 100644
--- /dev/null
+++ b/src/util/spanparsing.h
@@ -0,0 +1,31 @@
+// Copyright (c) 2018 The Bitcoin Core developers
+// Distributed under the MIT software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+#ifndef BITCOIN_UTIL_SPANPARSING_H
+#define BITCOIN_UTIL_SPANPARSING_H
+
+#include <span.h>
+
+#include <string>
+#include <vector>
+
+namespace spanparsing {
+
+/** Parse a constant. If successful, sp is updated to skip the constant and
+ * return true. */
+bool Const(const std::string &str, Span<const char> &sp);
+
+/** Parse a function call. If successful, sp is updated to be the function's
+ * argument(s). */
+bool Func(const std::string &str, Span<const char> &sp);
+
+/** Return the expression that sp begins with, and update sp to skip it. */
+Span<const char> Expr(Span<const char> &sp);
+
+/** Split a string on every instance of sep, returning a vector. */
+std::vector<Span<const char>> Split(const Span<const char> &sp, char sep);
+
+} // namespace spanparsing
+
+#endif // BITCOIN_UTIL_SPANPARSING_H
diff --git a/src/util/spanparsing.cpp b/src/util/spanparsing.cpp
new file mode 100644
--- /dev/null
+++ b/src/util/spanparsing.cpp
@@ -0,0 +1,66 @@
+// Copyright (c) 2018 The Bitcoin Core developers
+// Distributed under the MIT software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+#include <util/spanparsing.h>
+
+#include <span.h>
+
+#include <string>
+#include <vector>
+
+namespace spanparsing {
+
+bool Const(const std::string &str, Span<const char> &sp) {
+    if (size_t(sp.size()) >= str.size() &&
+        std::equal(str.begin(), str.end(), sp.begin())) {
+        sp = sp.subspan(str.size());
+        return true;
+    }
+    return false;
+}
+
+bool Func(const std::string &str, Span<const char> &sp) {
+    if (size_t(sp.size()) >= str.size() + 2 && sp[str.size()] == '(' &&
+        sp[sp.size() - 1] == ')' &&
+        std::equal(str.begin(), str.end(), sp.begin())) {
+        sp = sp.subspan(str.size() + 1, sp.size() - str.size() - 2);
+        return true;
+    }
+    return false;
+}
+
+Span<const char> Expr(Span<const char> &sp) {
+    int level = 0;
+    auto it = sp.begin();
+    while (it != sp.end()) {
+        if (*it == '(') {
+            ++level;
+        } else if (level && *it == ')') {
+            --level;
+        } else if (level == 0 && (*it == ')' || *it == ',')) {
+            break;
+        }
+        ++it;
+    }
+    Span<const char> ret = sp.first(it - sp.begin());
+    sp = sp.subspan(it - sp.begin());
+    return ret;
+}
+
+std::vector<Span<const char>> Split(const Span<const char> &sp, char sep) {
+    std::vector<Span<const char>> ret;
+    auto it = sp.begin();
+    auto start = it;
+    while (it != sp.end()) {
+        if (*it == sep) {
+            ret.emplace_back(start, it);
+            start = it + 1;
+        }
+        ++it;
+    }
+    ret.emplace_back(start, it);
+    return ret;
+}
+
+} // namespace spanparsing