diff --git a/lib/glacier/string/string.cpp b/lib/glacier/string/string.cpp
index 3210080..744f2be 100644
--- a/lib/glacier/string/string.cpp
+++ b/lib/glacier/string/string.cpp
@@ -38,4 +38,9 @@ bool String::operator==(const String& other) {
   return true;
 }
 
+char String::operator[](uint64_t offset) const {
+  // FIXME: bounds check.
+  return cstr_[offset];
+}
+
 }  // namespace glcr
diff --git a/lib/glacier/string/string.h b/lib/glacier/string/string.h
index 081f208..f411522 100644
--- a/lib/glacier/string/string.h
+++ b/lib/glacier/string/string.h
@@ -15,6 +15,8 @@ class String {
 
   bool operator==(const String& str);
 
+  char operator[](uint64_t offset) const;
+
  private:
   char* cstr_;
   uint64_t length_;