diff --git a/src/libexpr/eval.cc b/src/libexpr/eval.cc
index bd7bac0f1..f8282c400 100644
--- a/src/libexpr/eval.cc
+++ b/src/libexpr/eval.cc
@@ -572,20 +572,7 @@ std::optional<EvalState::Doc> EvalState::getDoc(Value & v)
         }
 
         if (exprLambda->docComment) {
-            auto begin = positions[exprLambda->docComment.begin];
-            auto end = positions[exprLambda->docComment.end];
-            auto docCommentStr = begin.getSnippetUpTo(end);
-
-            // Strip "/**" and "*/"
-            constexpr size_t prefixLen = 3;
-            constexpr size_t suffixLen = 2;
-            docStr = docCommentStr.substr(prefixLen, docCommentStr.size() - prefixLen - suffixLen);
-            if (docStr.empty())
-                return {};
-            // Turn the now missing "/**" into indentation
-            docStr = "   " + docStr;
-            // Strip indentation (for the whole, potentially multi-line string)
-            docStr = stripIndentation(docStr);
+            docStr = exprLambda->docComment.getInnerText(positions);
         }
 
         if (name.empty()) {
diff --git a/src/libexpr/nixexpr.cc b/src/libexpr/nixexpr.cc
index 6e705c314..5479dd79e 100644
--- a/src/libexpr/nixexpr.cc
+++ b/src/libexpr/nixexpr.cc
@@ -641,4 +641,22 @@ size_t SymbolTable::totalSize() const
     return n;
 }
 
+std::string DocComment::getInnerText(const PosTable & positions) const {
+    auto beginPos = positions[begin];
+    auto endPos = positions[end];
+    auto docCommentStr = beginPos.getSnippetUpTo(endPos);
+
+    // Strip "/**" and "*/"
+    constexpr size_t prefixLen = 3;
+    constexpr size_t suffixLen = 2;
+    std::string docStr = docCommentStr.substr(prefixLen, docCommentStr.size() - prefixLen - suffixLen);
+    if (docStr.empty())
+        return {};
+    // Turn the now missing "/**" into indentation
+    docStr = "   " + docStr;
+    // Strip indentation (for the whole, potentially multi-line string)
+    docStr = stripIndentation(docStr);
+    return docStr;
+}
+
 }
diff --git a/src/libexpr/nixexpr.hh b/src/libexpr/nixexpr.hh
index 913f46ff9..803b5ed8f 100644
--- a/src/libexpr/nixexpr.hh
+++ b/src/libexpr/nixexpr.hh
@@ -60,6 +60,8 @@ struct DocComment {
      */
     operator bool() const { return static_cast<bool>(begin); }
 
+    std::string getInnerText(const PosTable & positions) const;
+
 };
 
 /**