diff --git a/include/cif++/compound.hpp b/include/cif++/compound.hpp
index 16de77f..bd39710 100644
--- a/include/cif++/compound.hpp
+++ b/include/cif++/compound.hpp
@@ -179,7 +179,7 @@ class compound
 	friend class compound_factory_impl;
 	friend class local_compound_factory_impl;
 
-	compound(cif::datablock &db);
+	compound(datablock &db);
 
 	std::string m_id;
 	std::string m_name;
@@ -270,11 +270,15 @@ class compound_factory
 		return is_std_base(res_name) or is_std_peptide(res_name);
 	}
 
+	/// Return whether @a res_name is water
 	bool is_water(std::string_view res_name) const
 	{
 		return res_name == "HOH" or res_name == "H2O" or res_name == "WAT";
 	}
 
+	/// Return whether @a res_name already exists, without creating it.
+	bool exists(std::string_view res_name) const;
+
 	/// \brief Create the compound object for \a id
 	///
 	/// This will create the compound instance for \a id if it doesn't exist already.
@@ -331,14 +335,14 @@ class compound_factory
 class compound_source
 {
   public:
-	compound_source(const cif::file &file)
+	compound_source(const file &file)
 	{
-		cif::compound_factory::instance().push_dictionary(file);
+		compound_factory::instance().push_dictionary(file);
 	}
 
 	~compound_source()
 	{
-		cif::compound_factory::instance().pop_dictionary();
+		compound_factory::instance().pop_dictionary();
 	}
 };
 
diff --git a/include/cif++/datablock.hpp b/include/cif++/datablock.hpp
index bdaae69..c29d1d1 100644
--- a/include/cif++/datablock.hpp
+++ b/include/cif++/datablock.hpp
@@ -43,7 +43,7 @@ namespace cif
 
 /**
  * @brief A datablock is a list of category objects with some additional features
- * 
+ *
  */
 
 class datablock : public std::list<category>
@@ -53,7 +53,7 @@ class datablock : public std::list<category>
 
 	/**
 	 * @brief Construct a new datablock object with name @a name
-	 * 
+	 *
 	 * @param name The name for the new datablock
 	 */
 	datablock(std::string_view name)
@@ -80,7 +80,7 @@ class datablock : public std::list<category>
 	{
 		std::swap(a.m_name, b.m_name);
 		std::swap(a.m_validator, b.m_validator);
-		std::swap(static_cast<std::list<category>&>(a), static_cast<std::list<category>&>(b));
+		std::swap(static_cast<std::list<category> &>(a), static_cast<std::list<category> &>(b));
 	}
 
 	// --------------------------------------------------------------------
@@ -92,7 +92,7 @@ class datablock : public std::list<category>
 
 	/**
 	 * @brief Set the name of this datablock to @a name
-	 * 
+	 *
 	 * @param name The new name
 	 */
 	void set_name(std::string_view name)
@@ -102,27 +102,27 @@ class datablock : public std::list<category>
 
 	/**
 	 * @brief Attempt to load the dictionary specified in audit_conform category
-	 * 
+	 *
 	 */
 	void load_dictionary();
 
 	/**
 	 * @brief Set the validator object to @a v
-	 * 
+	 *
 	 * @param v The new validator object, may be null
 	 */
 	void set_validator(const validator *v);
 
 	/**
 	 * @brief Get the validator object
-	 * 
+	 *
 	 * @return const validator* The validator or nullptr if there is none
 	 */
 	const validator *get_validator() const;
 
 	/**
 	 * @brief Validates the content of this datablock and all its content
-	 * 
+	 *
 	 * @return true If the content is valid
 	 * @return false If the content is not valid
 	 */
@@ -131,7 +131,7 @@ class datablock : public std::list<category>
 	/**
 	 * @brief Validates all contained data for valid links between parents and children
 	 * as defined in the validator
-	 * 
+	 *
 	 * @return true If all links are valid
 	 * @return false If all links are not valid
 	 */
@@ -140,7 +140,7 @@ class datablock : public std::list<category>
 	/**
 	 * @brief Strip removes all categories and items that are invalid according
 	 * to the assigned validator. Will also add a valid audit_conform block.
-	 * 
+	 *
 	 * @return true if the remaining datablock is valid
 	 */
 	bool strip();
@@ -150,7 +150,7 @@ class datablock : public std::list<category>
 	/**
 	 * @brief Return the category named @a name, will create a new and empty
 	 * category named @a name if it does not exist.
-	 * 
+	 *
 	 * @param name The name of the category to return
 	 * @return category& Reference to the named category
 	 */
@@ -159,7 +159,7 @@ class datablock : public std::list<category>
 	/**
 	 * @brief Return the const category named @a name, will return a reference
 	 * to a static empty category if it was not found.
-	 * 
+	 *
 	 * @param name The name of the category to return
 	 * @return category& Reference to the named category
 	 */
@@ -168,7 +168,7 @@ class datablock : public std::list<category>
 	/**
 	 * @brief Return a pointer to the category named @a name or nullptr if
 	 * it does not exist.
-	 * 
+	 *
 	 * @param name The name of the category
 	 * @return category* Pointer to the category found or nullptr
 	 */
@@ -177,13 +177,12 @@ class datablock : public std::list<category>
 	/**
 	 * @brief Return a pointer to the category named @a name or nullptr if
 	 * it does not exist.
-	 * 
+	 *
 	 * @param name The name of the category
 	 * @return category* Pointer to the category found or nullptr
 	 */
 	const category *get(std::string_view name) const;
 
-
 	/**
 	 * @brief Return true if this datablock contains a non-empty category
 	 */
@@ -197,7 +196,7 @@ class datablock : public std::list<category>
 	 * new one if it is not found. The result is a tuple of an iterator
 	 * pointing to the category and a boolean indicating whether the category
 	 * was created or not.
-	 * 
+	 *
 	 * @param name The name for the category
 	 * @return std::tuple<iterator, bool> A tuple containing an iterator pointing
 	 * at the category and a boolean indicating whether the category was newly
diff --git a/src/compound.cpp b/src/compound.cpp
index 7fa0324..2ca7b92 100644
--- a/src/compound.cpp
+++ b/src/compound.cpp
@@ -24,14 +24,38 @@
  * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
-#include "cif++.hpp"
+#include "cif++/compound.hpp" // for compound_atom, compound_bond, compoun...
 
-#include <filesystem>
-#include <fstream>
-#include <map>
-#include <mutex>
-#include <numeric>
-#include <shared_mutex>
+#include "cif++/atom_type.hpp" // for atom_type_traits
+#include "cif++/category.hpp"  // for category
+#include "cif++/datablock.hpp" // for datablock
+#include "cif++/file.hpp"      // for file
+#include "cif++/item.hpp"      // for item
+#include "cif++/iterator.hpp"  // for iterator_proxy
+#include "cif++/parser.hpp"    // for parser
+#include "cif++/point.hpp"     // for distance, point
+#include "cif++/row.hpp"       // for tie, row_initializer, tie_wrap
+#include "cif++/text.hpp"      // for iequals, replace_all, iset
+#include "cif++/utilities.hpp" // for load_resource, VERBOSE, colour_type
+
+#include <algorithm>    // for find_if
+#include <cstddef>      // for size_t
+#include <exception>    // for exception, throw_with_nested
+#include <filesystem>   // for path, exists
+#include <fstream>      // for char_traits, basic_ostream, operator<<
+#include <iomanip>      // for operator<<, quoted
+#include <iostream>     // for clog, cout, cerr
+#include <limits>       // for numeric_limits
+#include <list>         // for _List_iterator
+#include <map>          // for allocator, map, _Rb_tree_iterator
+#include <memory>       // for shared_ptr, unique_ptr, __shared_ptr_...
+#include <optional>     // for optional
+#include <shared_mutex> // for shared_lock, shared_timed_mutex
+#include <stdexcept>    // for runtime_error, invalid_argument, out_...
+#include <string>       // for basic_string, string, operator==, ope...
+#include <string_view>  // for string_view, basic_string_view
+#include <utility>      // for pair, exchange, move
+#include <vector>       // for vector
 
 namespace fs = std::filesystem;
 
@@ -140,7 +164,7 @@ compound::compound(cif::datablock &db)
 
 	cif::tie(m_id, m_name, m_type, m_formula, m_formula_weight, m_formal_charge, one_letter_code, m_parent_id) =
 		chemComp.front().get("id", "name", "type", "formula", "formula_weight", "pdbx_formal_charge", "one_letter_code", "mon_nstd_parent_comp_id");
-	
+
 	if (one_letter_code.length() == 1)
 		m_one_letter_code = one_letter_code.front();
 
@@ -159,7 +183,7 @@ compound::compound(cif::datablock &db)
 		if (stereo_config.empty())
 			atom.stereo_config = stereo_config_type::N;
 		else
-		atom.stereo_config = parse_stereo_config_from_string(stereo_config);
+			atom.stereo_config = parse_stereo_config_from_string(stereo_config);
 		m_atoms.push_back(std::move(atom));
 	}
 
@@ -172,7 +196,7 @@ compound::compound(cif::datablock &db)
 		if (valueOrder.empty())
 			bond.type = bond_type::sing;
 		else
-		bond.type = parse_bond_type_from_string(valueOrder);
+			bond.type = parse_bond_type_from_string(valueOrder);
 		m_bonds.push_back(std::move(bond));
 	}
 }
@@ -231,12 +255,12 @@ float compound::bond_length(const std::string &atomId_1, const std::string &atom
 
 bool compound::is_peptide() const
 {
-	return iequals(m_type, "l-peptide linking")	or iequals(m_type, "peptide linking");
+	return iequals(m_type, "l-peptide linking") or iequals(m_type, "peptide linking");
 }
 
 bool compound::is_base() const
 {
-	return iequals(m_type, "dna linking")	or iequals(m_type, "rna linking");
+	return iequals(m_type, "dna linking") or iequals(m_type, "rna linking");
 }
 
 // --------------------------------------------------------------------
@@ -294,12 +318,31 @@ class compound_factory_impl : public std::enable_shared_from_this<compound_facto
 			delete c;
 	}
 
+	virtual bool exists_self(const std::string &id) const
+	{
+		if (m_missing.contains(id))
+			return false;
+
+		if (std::find_if(m_compounds.begin(), m_compounds.end(), [id](compound *c)
+				{ return c->id() == id; }) != m_compounds.end())
+			return true;
+
+		return m_next and m_next->exists_self(id);
+	}
+
+	bool exists(std::string_view id)
+	{
+		std::shared_lock lock(mMutex);
+
+		return exists_self(std::string{ id });
+	}
+
 	compound *get(std::string id)
 	{
 		std::shared_lock lock(mMutex);
 
 		compound *result = nullptr;
-		
+
 		for (auto impl = shared_from_this(); impl; impl = impl->m_next)
 		{
 			result = impl->create(id);
@@ -363,7 +406,9 @@ compound *compound_factory_impl::create(const std::string &id)
 	if (m_missing.contains(id))
 		return nullptr;
 
-	if (auto i = find_if(m_compounds.begin(), m_compounds.end(), [id](compound *c) { return c->id() == id; }); i != m_compounds.end())
+	if (auto i = find_if(m_compounds.begin(), m_compounds.end(), [id](compound *c)
+			{ return c->id() == id; });
+		i != m_compounds.end())
 		return *i;
 
 	compound *result = nullptr;
@@ -454,7 +499,6 @@ class local_compound_factory_impl : public compound_factory_impl
 	compound *create(const std::string &id) override;
 
   private:
-
 	compound *construct_compound(const datablock &db, const std::string &id, const std::string &name, const std::string &three_letter_code, const std::string &group);
 
 	cif::file m_local_file;
@@ -465,7 +509,9 @@ compound *local_compound_factory_impl::create(const std::string &id)
 	if (m_missing.contains(id))
 		return nullptr;
 
-	if (auto i = find_if(m_compounds.begin(), m_compounds.end(), [id](compound *c) { return c->id() == id; }); i != m_compounds.end())
+	if (auto i = find_if(m_compounds.begin(), m_compounds.end(), [id](compound *c)
+			{ return c->id() == id; });
+		i != m_compounds.end())
 		return *i;
 
 	compound *result = nullptr;
@@ -510,12 +556,10 @@ compound *local_compound_factory_impl::construct_compound(const datablock &rdb,
 
 	float formula_weight = 0;
 	int formal_charge = 0;
-	std::map<std::string,std::size_t> formula_data;
+	std::map<std::string, std::size_t> formula_data;
 
 	for (std::size_t ord = 1; const auto &[atom_id, type_symbol, type, charge, x, y, z, xi, yi, zi] :
-		rdb["chem_comp_atom"].rows<std::string, std::string, std::string, int,
-			std::optional<float>, std::optional<float>, std::optional<float>,
-			std::optional<float>, std::optional<float>, std::optional<float>>(
+		rdb["chem_comp_atom"].rows<std::string, std::string, std::string, int, std::optional<float>, std::optional<float>, std::optional<float>, std::optional<float>, std::optional<float>, std::optional<float>>(
 			"atom_id", "type_symbol", "type", "charge",
 			"model_Cartn_x", "model_Cartn_y", "model_Cartn_z",
 			"pdbx_model_Cartn_x_ideal", "pdbx_model_Cartn_y_ideal", "pdbx_model_Cartn_z_ideal"))
@@ -525,16 +569,14 @@ compound *local_compound_factory_impl::construct_compound(const datablock &rdb,
 
 		formula_data[type_symbol] += 1;
 
-		db["chem_comp_atom"].emplace({
-			{ "comp_id", id },
+		db["chem_comp_atom"].emplace({ { "comp_id", id },
 			{ "atom_id", atom_id },
 			{ "type_symbol", type_symbol },
 			{ "charge", charge },
-			{ "model_Cartn_x",  x.has_value() ? x : xi, 3 },
-			{ "model_Cartn_y",  y.has_value() ? y : yi, 3 },
-			{ "model_Cartn_z",  z.has_value() ? z : zi, 3 },
-			{ "pdbx_ordinal", ord++ }
-		});
+			{ "model_Cartn_x", x.has_value() ? x : xi, 3 },
+			{ "model_Cartn_y", y.has_value() ? y : yi, 3 },
+			{ "model_Cartn_z", z.has_value() ? z : zi, 3 },
+			{ "pdbx_ordinal", ord++ } });
 
 		formal_charge += charge;
 	}
@@ -551,21 +593,19 @@ compound *local_compound_factory_impl::construct_compound(const datablock &rdb,
 		else if (cif::iequals(type, "triple") or cif::iequals(type, "trip"))
 			value_order = "TRIP";
 
-		db["chem_comp_bond"].emplace({
-			{ "comp_id", id },
+		db["chem_comp_bond"].emplace({ { "comp_id", id },
 			{ "atom_id_1", atom_id_1 },
 			{ "atom_id_2", atom_id_2 },
 			{ "value_order", value_order },
 			{ "pdbx_aromatic_flag", aromatic },
 			// TODO: fetch stereo_config info from chem_comp_chir
-			{ "pdbx_ordinal", ord++ }
-		});
+			{ "pdbx_ordinal", ord++ } });
 	}
 
 	db.emplace_back(rdb["pdbx_chem_comp_descriptor"]);
 
 	std::string formula;
-	for (bool first = true; const auto &[symbol, count]: formula_data)
+	for (bool first = true; const auto &[symbol, count] : formula_data)
 	{
 		if (std::exchange(first, false))
 			formula += ' ';
@@ -584,15 +624,13 @@ compound *local_compound_factory_impl::construct_compound(const datablock &rdb,
 	else
 		type = "NON-POLYMER";
 
-	db["chem_comp"].emplace({
-		{ "id", id },
+	db["chem_comp"].emplace({ { "id", id },
 		{ "name", name },
 		{ "type", type },
 		{ "formula", formula },
 		{ "pdbx_formal_charge", formal_charge },
 		{ "formula_weight", formula_weight },
-		{ "three_letter_code", three_letter_code }
-	});
+		{ "three_letter_code", three_letter_code } });
 
 	std::shared_lock lock(mMutex);
 
@@ -698,6 +736,11 @@ void compound_factory::pop_dictionary()
 		m_impl = m_impl->next();
 }
 
+bool compound_factory::exists(std::string_view id) const
+{
+	return m_impl and m_impl->exists(id);
+}
+
 const compound *compound_factory::create(std::string_view id)
 {
 	auto result = m_impl ? m_impl->get(std::string{ id }) : nullptr;
@@ -722,7 +765,7 @@ bool compound_factory::is_peptide(std::string_view res_name) const
 	bool result = is_std_peptide(res_name);
 	if (not result and m_impl)
 	{
-		auto compound = const_cast<compound_factory&>(*this).create(res_name);
+		auto compound = const_cast<compound_factory &>(*this).create(res_name);
 		result = compound != nullptr and compound->is_peptide();
 	}
 	return result;
@@ -734,7 +777,7 @@ bool compound_factory::is_base(std::string_view res_name) const
 	bool result = is_std_base(res_name);
 	if (not result and m_impl)
 	{
-		auto compound = const_cast<compound_factory&>(*this).create(res_name);
+		auto compound = const_cast<compound_factory &>(*this).create(res_name);
 		result = compound != nullptr and compound->is_base();
 	}
 	return result;
diff --git a/src/pdb/pdb2cif.cpp b/src/pdb/pdb2cif.cpp
index 18b05e4..3a83e7c 100644
--- a/src/pdb/pdb2cif.cpp
+++ b/src/pdb/pdb2cif.cpp
@@ -3142,7 +3142,6 @@ void PDBFileParser::ParseRemark350()
 	std::map<std::string, std::string> values;
 	std::vector<std::string> asymIdList;
 	std::smatch m;
-	cif::row_handle genR;
 
 	std::vector<double> mat, vec;
 
diff --git a/src/point.cpp b/src/point.cpp
index 323de8a..7d76013 100644
--- a/src/point.cpp
+++ b/src/point.cpp
@@ -25,17 +25,17 @@
  */
 
 #include "cif++/point.hpp"
-#include "cif++/matrix.hpp"
 
-#include <cassert>
-#include <random>
+#include "cif++/matrix.hpp" // for matrix_subtraction, matrix_cofactors
+
+#include <random> // for uniform_real_distribution, normal_distri...
 
 namespace cif
 {
 
 // --------------------------------------------------------------------
 
-template<typename T>
+template <typename T>
 quaternion_type<T> normalize(quaternion_type<T> q)
 {
 	std::valarray<double> t(4);
@@ -126,10 +126,9 @@ quaternion construct_for_dihedral_angle(point p1, point p2, point p3, point p4,
 	p4 -= p3;
 	p3 -= p3;
 
-	quaternion q;
 	auto axis = -p2;
-
 	float dh = dihedral_angle(p1, p2, p3, p4);
+
 	return construct_from_angle_axis(angle - dh, axis);
 }
 
@@ -293,9 +292,9 @@ quaternion align_points(const std::vector<point> &pa, const std::vector<point> &
 	}
 
 	quaternion q(
-		static_cast<float>(cf(maxR, 0)), 
-		static_cast<float>(cf(maxR, 1)), 
-		static_cast<float>(cf(maxR, 2)), 
+		static_cast<float>(cf(maxR, 0)),
+		static_cast<float>(cf(maxR, 1)),
+		static_cast<float>(cf(maxR, 2)),
 		static_cast<float>(cf(maxR, 3)));
 	q = normalize(q);