From 47837c4973890ce46756f0865f2347f76bd2b015 Mon Sep 17 00:00:00 2001
From: Christian Bauer <Christian.Bauer@uni-mainz.de>
Date: Wed, 26 Mar 2003 19:59:47 +0000
Subject: [PATCH] - added stream manipulators index_dimensions and
 no_index_dimensions - using print() and print_context (and derived classes)
 in user code is now   deprecated in favor of the manipulators - print_options
 moved from flags.h to print.h - a symbol that appears multiple times in
 archives but is not listed in the   sym_lst passed to unarchive_ex() now
 receives the same serial number in   all occurrences, so GiNaC will treat it
 as one and the same symbol; this   made it necessary to remove the "const"
 from the second argument of   basic::unarchive() and the unarchiving
 constructor

---
 ginac/archive.cpp     | 14 +++++++----
 ginac/archive.h       |  4 ++--
 ginac/basic.cpp       |  8 +++----
 ginac/clifford.cpp    |  2 +-
 ginac/color.cpp       |  2 +-
 ginac/constant.cpp    |  4 ++--
 ginac/container.pl    |  4 ++--
 ginac/ex.cpp          |  7 ------
 ginac/ex.h            |  1 -
 ginac/expairseq.cpp   |  2 +-
 ginac/fderivative.cpp |  2 +-
 ginac/flags.h         |  8 -------
 ginac/function.pl     |  4 ++--
 ginac/idx.cpp         |  6 ++---
 ginac/indexed.cpp     |  2 +-
 ginac/matrix.cpp      |  2 +-
 ginac/numeric.cpp     |  2 +-
 ginac/operators.cpp   | 56 ++++++++++++++++++++++++++++++++++++-------
 ginac/operators.h     |  5 +++-
 ginac/power.cpp       |  2 +-
 ginac/print.h         | 17 +++++++++++++
 ginac/pseries.cpp     |  2 +-
 ginac/registrar.h     |  6 ++---
 ginac/relational.cpp  |  2 +-
 ginac/symbol.cpp      |  9 ++++---
 ginac/symmetry.cpp    |  2 +-
 ginac/tensor.cpp      |  4 ++--
 ginac/utils.h         |  4 ++--
 ginac/wildcard.cpp    |  2 +-
 29 files changed, 117 insertions(+), 68 deletions(-)

diff --git a/ginac/archive.cpp b/ginac/archive.cpp
index 28d8afc3..69a73441 100644
--- a/ginac/archive.cpp
+++ b/ginac/archive.cpp
@@ -26,6 +26,7 @@
 #include "archive.h"
 #include "registrar.h"
 #include "ex.h"
+#include "lst.h"
 #include "config.h"
 #include "tostring.h"
 
@@ -89,7 +90,8 @@ ex archive::unarchive_ex(const lst &sym_lst, const char *name) const
 
 found:
 	// Recursively unarchive all nodes, starting at the root node
-	return nodes[i->root].unarchive(sym_lst);
+	lst sym_lst_copy = sym_lst;
+	return nodes[i->root].unarchive(sym_lst_copy);
 }
 
 ex archive::unarchive_ex(const lst &sym_lst, unsigned index) const
@@ -98,7 +100,8 @@ ex archive::unarchive_ex(const lst &sym_lst, unsigned index) const
 		throw (std::range_error("index of archived expression out of range"));
 
 	// Recursively unarchive all nodes, starting at the root node
-	return nodes[exprs[index].root].unarchive(sym_lst);
+	lst sym_lst_copy = sym_lst;
+	return nodes[exprs[index].root].unarchive(sym_lst_copy);
 }
 
 ex archive::unarchive_ex(const lst &sym_lst, std::string &name, unsigned index) const
@@ -110,7 +113,8 @@ ex archive::unarchive_ex(const lst &sym_lst, std::string &name, unsigned index)
 	name = unatomize(exprs[index].name);
 
 	// Recursively unarchive all nodes, starting at the root node
-	return nodes[exprs[index].root].unarchive(sym_lst);
+	lst sym_lst_copy = sym_lst;
+	return nodes[exprs[index].root].unarchive(sym_lst_copy);
 }
 
 unsigned archive::num_expressions(void) const
@@ -432,7 +436,7 @@ bool archive_node::find_string(const std::string &name, std::string &ret, unsign
 	return false;
 }
 
-bool archive_node::find_ex(const std::string &name, ex &ret, const lst &sym_lst, unsigned index) const
+bool archive_node::find_ex(const std::string &name, ex &ret, lst &sym_lst, unsigned index) const
 {
 	archive_atom name_atom = a.atomize(name);
 	std::vector<property>::const_iterator i = props.begin(), iend = props.end();
@@ -493,7 +497,7 @@ void archive_node::get_properties(propinfovector &v) const
 
 
 /** Convert archive node to GiNaC expression. */
-ex archive_node::unarchive(const lst &sym_lst) const
+ex archive_node::unarchive(lst &sym_lst) const
 {
 	// Already unarchived? Then return cached unarchived expression.
 	if (has_expression)
diff --git a/ginac/archive.h b/ginac/archive.h
index b7e9ba98..8b7ae4f3 100644
--- a/ginac/archive.h
+++ b/ginac/archive.h
@@ -110,7 +110,7 @@ public:
 
 	/** Retrieve property of type "ex" from node.
 	 *  @return "true" if property was found, "false" otherwise */
-	bool find_ex(const std::string &name, ex &ret, const lst &sym_lst, unsigned index = 0) const;
+	bool find_ex(const std::string &name, ex &ret, lst &sym_lst, unsigned index = 0) const;
 
 	/** Retrieve property of type "ex" from node, returning the node of
 	 *  the sub-expression. */
@@ -119,7 +119,7 @@ public:
 	/** Return vector of properties stored in node. */
 	void get_properties(propinfovector &v) const;
 
-	ex unarchive(const lst &sym_lst) const;
+	ex unarchive(lst &sym_lst) const;
 	bool has_same_ex_as(const archive_node &other) const;
 
 	void forget(void);
diff --git a/ginac/basic.cpp b/ginac/basic.cpp
index a79ac065..85294cac 100644
--- a/ginac/basic.cpp
+++ b/ginac/basic.cpp
@@ -79,7 +79,7 @@ const basic & basic::operator=(const basic & other)
 //////////
 
 /** Construct object from archive_node. */
-basic::basic(const archive_node &n, const lst &sym_lst) : flags(0), refcount(0)
+basic::basic(const archive_node &n, lst &sym_lst) : flags(0), refcount(0)
 {
 	// Reconstruct tinfo_key from class name
 	std::string class_name;
@@ -128,7 +128,8 @@ void basic::print(const print_context & c, unsigned level) const
  *  debugger because it might not know what cout is.  This method can be
  *  invoked with no argument and it will simply print to stdout.
  *
- *  @see basic::print */
+ *  @see basic::print
+ *  @see basic::dbgprinttree */
 void basic::dbgprint(void) const
 {
 	this->print(std::cerr);
@@ -137,8 +138,7 @@ void basic::dbgprint(void) const
 
 /** Little wrapper around printtree to be called within a debugger.
  *
- *  @see basic::dbgprint
- *  @see basic::printtree */
+ *  @see basic::dbgprint */
 void basic::dbgprinttree(void) const
 {
 	this->print(print_tree(std::cerr));
diff --git a/ginac/clifford.cpp b/ginac/clifford.cpp
index 1ab5eef5..a8b87343 100644
--- a/ginac/clifford.cpp
+++ b/ginac/clifford.cpp
@@ -104,7 +104,7 @@ clifford::clifford(unsigned char rl, exvector * vp) : inherited(sy_none(), vp),
 // archiving
 //////////
 
-clifford::clifford(const archive_node &n, const lst &sym_lst) : inherited(n, sym_lst)
+clifford::clifford(const archive_node &n, lst &sym_lst) : inherited(n, sym_lst)
 {
 	unsigned rl;
 	n.find_unsigned("label", rl);
diff --git a/ginac/color.cpp b/ginac/color.cpp
index 9600065d..7405c4aa 100644
--- a/ginac/color.cpp
+++ b/ginac/color.cpp
@@ -99,7 +99,7 @@ color::color(unsigned char rl, exvector * vp) : inherited(sy_none(), vp), repres
 // archiving
 //////////
 
-color::color(const archive_node &n, const lst &sym_lst) : inherited(n, sym_lst)
+color::color(const archive_node &n, lst &sym_lst) : inherited(n, sym_lst)
 {
 	unsigned rl;
 	n.find_unsigned("label", rl);
diff --git a/ginac/constant.cpp b/ginac/constant.cpp
index 1557bc00..6fc37366 100644
--- a/ginac/constant.cpp
+++ b/ginac/constant.cpp
@@ -96,9 +96,9 @@ constant::constant(const std::string & initname, const numeric & initnumber, con
 // archiving
 //////////
 
-constant::constant(const archive_node &n, const lst &sym_lst) : inherited(n, sym_lst) {}
+constant::constant(const archive_node &n, lst &sym_lst) : inherited(n, sym_lst) {}
 
-ex constant::unarchive(const archive_node &n, const lst &sym_lst)
+ex constant::unarchive(const archive_node &n, lst &sym_lst)
 {
 	// Find constant by name (!! this is bad: 'twould be better if there
 	// was a list of all global constants that we could search)
diff --git a/ginac/container.pl b/ginac/container.pl
index 945622fe..7dcd0be6 100755
--- a/ginac/container.pl
+++ b/ginac/container.pl
@@ -398,7 +398,7 @@ ${constructors_implementation}
 //////////
 
 /** Construct object from archive_node. */
-${CONTAINER}::${CONTAINER}(const archive_node &n, const lst &sym_lst) : inherited(n, sym_lst)
+${CONTAINER}::${CONTAINER}(const archive_node &n, lst &sym_lst) : inherited(n, sym_lst)
 {
 	for (unsigned int i=0; true; i++) {
 		ex e;
@@ -410,7 +410,7 @@ ${CONTAINER}::${CONTAINER}(const archive_node &n, const lst &sym_lst) : inherite
 }
 
 /** Unarchive the object. */
-ex ${CONTAINER}::unarchive(const archive_node &n, const lst &sym_lst)
+ex ${CONTAINER}::unarchive(const archive_node &n, lst &sym_lst)
 {
 	return (new ${CONTAINER}(n, sym_lst))->setflag(status_flags::dynallocated);
 }
diff --git a/ginac/ex.cpp b/ginac/ex.cpp
index 2c31212c..3c6d5048 100644
--- a/ginac/ex.cpp
+++ b/ginac/ex.cpp
@@ -59,13 +59,6 @@ void ex::print(const print_context & c, unsigned level) const
 	bp->print(c, level);
 }
 
-/** Print expression to stream in a tree-like format suitable for debugging. */
-void ex::printtree(std::ostream & os) const
-{
-	GINAC_ASSERT(bp!=0);
-	bp->print(print_tree(os));
-}
-
 /** Little wrapper arount print to be called within a debugger. */
 void ex::dbgprint(void) const
 {
diff --git a/ginac/ex.h b/ginac/ex.h
index 5e8ac0de..3c8094b1 100644
--- a/ginac/ex.h
+++ b/ginac/ex.h
@@ -111,7 +111,6 @@ public:
 	}
 
 	void print(const print_context & c, unsigned level = 0) const;
-	void printtree(std::ostream & os) const;
 	void dbgprint(void) const;
 	void dbgprinttree(void) const;
 	bool info(unsigned inf) const { return bp->info(inf); }
diff --git a/ginac/expairseq.cpp b/ginac/expairseq.cpp
index 3e2b549c..c41c694b 100644
--- a/ginac/expairseq.cpp
+++ b/ginac/expairseq.cpp
@@ -146,7 +146,7 @@ expairseq::expairseq(epvector *vp, const ex &oc)
 // archiving
 //////////
 
-expairseq::expairseq(const archive_node &n, const lst &sym_lst) : inherited(n, sym_lst)
+expairseq::expairseq(const archive_node &n, lst &sym_lst) : inherited(n, sym_lst)
 #if EXPAIRSEQ_USE_HASHTAB
 	, hashtabsize(0)
 #endif
diff --git a/ginac/fderivative.cpp b/ginac/fderivative.cpp
index 8216179d..3b209387 100644
--- a/ginac/fderivative.cpp
+++ b/ginac/fderivative.cpp
@@ -73,7 +73,7 @@ fderivative::fderivative(unsigned ser, const paramset & params, exvector * vp) :
 // archiving
 //////////
 
-fderivative::fderivative(const archive_node &n, const lst &sym_lst) : inherited(n, sym_lst)
+fderivative::fderivative(const archive_node &n, lst &sym_lst) : inherited(n, sym_lst)
 {
 	unsigned i = 0;
 	while (true) {
diff --git a/ginac/flags.h b/ginac/flags.h
index 0427bc51..04c430c4 100644
--- a/ginac/flags.h
+++ b/ginac/flags.h
@@ -248,14 +248,6 @@ public:
 	};
 };
 
-/** Flags to control the behavior of print(). */
-class print_options {
-public:
-	enum {
-		print_index_dimensions = 0x0001 ///< print the dimensions of indices
-	};
-};
-
 } // namespace GiNaC
 
 #endif // ndef __GINAC_FLAGS_H__
diff --git a/ginac/function.pl b/ginac/function.pl
index fba34e20..ad372f55 100755
--- a/ginac/function.pl
+++ b/ginac/function.pl
@@ -630,7 +630,7 @@ function::function(unsigned ser, exvector * vp)
 //////////
 
 /** Construct object from archive_node. */
-function::function(const archive_node &n, const lst &sym_lst) : inherited(n, sym_lst)
+function::function(const archive_node &n, lst &sym_lst) : inherited(n, sym_lst)
 {
 	// Find serial number by function name
 	std::string s;
@@ -650,7 +650,7 @@ function::function(const archive_node &n, const lst &sym_lst) : inherited(n, sym
 }
 
 /** Unarchive the object. */
-ex function::unarchive(const archive_node &n, const lst &sym_lst)
+ex function::unarchive(const archive_node &n, lst &sym_lst)
 {
 	return (new function(n, sym_lst))->setflag(status_flags::dynallocated);
 }
diff --git a/ginac/idx.cpp b/ginac/idx.cpp
index 277bc316..55475568 100644
--- a/ginac/idx.cpp
+++ b/ginac/idx.cpp
@@ -103,18 +103,18 @@ spinidx::spinidx(const ex & v, const ex & d, bool cov, bool dot) : inherited(v,
 // archiving
 //////////
 
-idx::idx(const archive_node &n, const lst &sym_lst) : inherited(n, sym_lst)
+idx::idx(const archive_node &n, lst &sym_lst) : inherited(n, sym_lst)
 {
 	n.find_ex("value", value, sym_lst);
 	n.find_ex("dim", dim, sym_lst);
 }
 
-varidx::varidx(const archive_node &n, const lst &sym_lst) : inherited(n, sym_lst)
+varidx::varidx(const archive_node &n, lst &sym_lst) : inherited(n, sym_lst)
 {
 	n.find_bool("covariant", covariant);
 }
 
-spinidx::spinidx(const archive_node &n, const lst &sym_lst) : inherited(n, sym_lst)
+spinidx::spinidx(const archive_node &n, lst &sym_lst) : inherited(n, sym_lst)
 {
 	n.find_bool("dotted", dotted);
 }
diff --git a/ginac/indexed.cpp b/ginac/indexed.cpp
index 5799642a..695768f6 100644
--- a/ginac/indexed.cpp
+++ b/ginac/indexed.cpp
@@ -144,7 +144,7 @@ indexed::indexed(const symmetry & symm, exvector * vp) : inherited(vp), symtree(
 // archiving
 //////////
 
-indexed::indexed(const archive_node &n, const lst &sym_lst) : inherited(n, sym_lst)
+indexed::indexed(const archive_node &n, lst &sym_lst) : inherited(n, sym_lst)
 {
 	if (!n.find_ex("symmetry", symtree, sym_lst)) {
 		// GiNaC versions <= 0.9.0 had an unsigned "symmetry" property
diff --git a/ginac/matrix.cpp b/ginac/matrix.cpp
index fe24e09e..df1b4c91 100644
--- a/ginac/matrix.cpp
+++ b/ginac/matrix.cpp
@@ -108,7 +108,7 @@ matrix::matrix(unsigned r, unsigned c, const lst & l)
 // archiving
 //////////
 
-matrix::matrix(const archive_node &n, const lst &sym_lst) : inherited(n, sym_lst)
+matrix::matrix(const archive_node &n, lst &sym_lst) : inherited(n, sym_lst)
 {
 	if (!(n.find_unsigned("row", row)) || !(n.find_unsigned("col", col)))
 		throw (std::runtime_error("unknown matrix dimensions in archive"));
diff --git a/ginac/numeric.cpp b/ginac/numeric.cpp
index 9eaa715b..37a1ba3f 100644
--- a/ginac/numeric.cpp
+++ b/ginac/numeric.cpp
@@ -245,7 +245,7 @@ numeric::numeric(const cln::cl_N &z) : basic(TINFO_numeric)
 // archiving
 //////////
 
-numeric::numeric(const archive_node &n, const lst &sym_lst) : inherited(n, sym_lst)
+numeric::numeric(const archive_node &n, lst &sym_lst) : inherited(n, sym_lst)
 {
 	cln::cl_N ctorval = 0;
 
diff --git a/ginac/operators.cpp b/ginac/operators.cpp
index ae198706..d588b98d 100644
--- a/ginac/operators.cpp
+++ b/ginac/operators.cpp
@@ -283,26 +283,29 @@ static int my_ios_index()
 	return i;
 }
 
+// Stream format gets copied or destroyed
 static void my_ios_callback(std::ios_base::event ev, std::ios_base & s, int i)
 {
 	print_context *p = static_cast<print_context *>(s.pword(i));
 	if (ev == std::ios_base::erase_event) {
 		delete p;
 		s.pword(i) = 0;
-	} else if (ev == std::ios_base::copyfmt_event && p != 0) {
+	} else if (ev == std::ios_base::copyfmt_event && p != 0)
 		s.pword(i) = p->duplicate();
-	}
 }
 
 enum {
 	callback_registered = 1
 };
 
-static print_context *get_print_context(std::ios_base & s)
+// Get print_context associated with stream, may return 0 if no context has
+// been associated yet
+static inline print_context *get_print_context(std::ios_base & s)
 {
 	return static_cast<print_context *>(s.pword(my_ios_index()));
 }
 
+// Set print_context associated with stream, retain options
 static void set_print_context(std::ios_base & s, const print_context & c)
 {
 	int i = my_ios_index();
@@ -311,16 +314,38 @@ static void set_print_context(std::ios_base & s, const print_context & c)
 		s.register_callback(my_ios_callback, i);
 		s.iword(i) = flags | callback_registered;
 	}
-	delete static_cast<print_context *>(s.pword(i));
-	s.pword(i) = c.duplicate();
+	print_context *p = static_cast<print_context *>(s.pword(i));
+	unsigned options = p ? p->options : c.options;
+	delete p;
+	p = c.duplicate();
+	p->options = options;
+	s.pword(i) = p;
+}
+
+// Get options for print_context associated with stream
+static inline unsigned get_print_options(std::ios_base & s)
+{
+	print_context *p = get_print_context(s);
+	return p ? p->options : 0;
+}
+
+// Set options for print_context associated with stream
+static void set_print_options(std::ostream & s, unsigned options)
+{
+	print_context *p = get_print_context(s);
+	if (p == 0)
+		set_print_context(s, print_context(s, options));
+	else
+		p->options = options;
 }
 
 std::ostream & operator<<(std::ostream & os, const ex & e)
 {
-	if (get_print_context(os) == 0)
+	print_context *p = get_print_context(os);
+	if (p == 0)
 		e.print(print_context(os));
 	else
-		e.print(*get_print_context(os));
+		e.print(*p);
 	return os;
 }
 
@@ -332,6 +357,7 @@ std::istream & operator>>(std::istream & is, ex & e)
 std::ostream & dflt(std::ostream & os)
 {
 	set_print_context(os, print_context(os));
+	set_print_options(os, 0);
 	return os;
 }
 
@@ -359,6 +385,12 @@ std::ostream & tree(std::ostream & os)
 	return os;
 }
 
+std::ostream & csrc(std::ostream & os)
+{
+	set_print_context(os, print_csrc_double(os));
+	return os;
+}
+
 std::ostream & csrc_float(std::ostream & os)
 {
 	set_print_context(os, print_csrc_float(os));
@@ -377,9 +409,15 @@ std::ostream & csrc_cl_N(std::ostream & os)
 	return os;
 }
 
-std::ostream & csrc(std::ostream & os)
+std::ostream & index_dimensions(std::ostream & os)
 {
-	set_print_context(os, print_csrc_double(os));
+	set_print_options(os, get_print_options(os) | print_options::print_index_dimensions);
+	return os;
+}
+
+std::ostream & no_index_dimensions(std::ostream & os)
+{
+	set_print_options(os, get_print_options(os) & ~print_options::print_index_dimensions);
 	return os;
 }
 
diff --git a/ginac/operators.h b/ginac/operators.h
index fe72e6e3..33e1c3e6 100644
--- a/ginac/operators.h
+++ b/ginac/operators.h
@@ -91,10 +91,13 @@ std::ostream & latex(std::ostream & os);
 std::ostream & python(std::ostream & os);
 std::ostream & python_repr(std::ostream & os);
 std::ostream & tree(std::ostream & os);
+std::ostream & csrc(std::ostream & os); // same as csrc_double
 std::ostream & csrc_float(std::ostream & os);
 std::ostream & csrc_double(std::ostream & os);
 std::ostream & csrc_cl_N(std::ostream & os);
-std::ostream & csrc(std::ostream & os); // same as csrc_double
+
+std::ostream & index_dimensions(std::ostream & os);
+std::ostream & no_index_dimensions(std::ostream & os);
 
 } // namespace GiNaC
 
diff --git a/ginac/power.cpp b/ginac/power.cpp
index 6ca771a8..07a52ebe 100644
--- a/ginac/power.cpp
+++ b/ginac/power.cpp
@@ -73,7 +73,7 @@ DEFAULT_DESTROY(power)
 // archiving
 //////////
 
-power::power(const archive_node &n, const lst &sym_lst) : inherited(n, sym_lst)
+power::power(const archive_node &n, lst &sym_lst) : inherited(n, sym_lst)
 {
 	n.find_ex("basis", basis, sym_lst);
 	n.find_ex("exponent", exponent, sym_lst);
diff --git a/ginac/print.h b/ginac/print.h
index b98318c0..8d4fc2f8 100644
--- a/ginac/print.h
+++ b/ginac/print.h
@@ -28,6 +28,23 @@
 
 namespace GiNaC {
 
+
+/*
+ *  The following classes remain publicly visible for compatibility
+ *  reasons only. New code should use the iostream manipulators defined
+ *  in operators.h instead.
+ */
+
+
+/** Flags to control the behavior of a print_context. */
+class print_options {
+public:
+	enum {
+		print_index_dimensions = 0x0001 ///< print the dimensions of indices
+	};
+};
+
+
 /** Context for default (ginsh-parsable) output. */
 class print_context
 {
diff --git a/ginac/pseries.cpp b/ginac/pseries.cpp
index 0f1f08d9..0d2dde29 100644
--- a/ginac/pseries.cpp
+++ b/ginac/pseries.cpp
@@ -85,7 +85,7 @@ pseries::pseries(const ex &rel_, const epvector &ops_) : basic(TINFO_pseries), s
  *  Archiving
  */
 
-pseries::pseries(const archive_node &n, const lst &sym_lst) : inherited(n, sym_lst)
+pseries::pseries(const archive_node &n, lst &sym_lst) : inherited(n, sym_lst)
 {
 	for (unsigned int i=0; true; ++i) {
 		ex rest;
diff --git a/ginac/registrar.h b/ginac/registrar.h
index e620250e..77a6e873 100644
--- a/ginac/registrar.h
+++ b/ginac/registrar.h
@@ -34,7 +34,7 @@ class lst;
 
 
 /** Unarchiving function (static member function of every GiNaC class). */
-typedef ex (*unarch_func)(const archive_node &n, const lst &sym_lst);
+typedef ex (*unarch_func)(const archive_node &n, lst &sym_lst);
 
 
 /** Head of list of all registered_class_info structures. */
@@ -65,9 +65,9 @@ public: \
 	typedef supername inherited; \
 	static registered_class_info reg_info; \
 	virtual const char *class_name(void) const; \
-	classname(const archive_node &n, const lst &sym_lst); \
+	classname(const archive_node &n, lst &sym_lst); \
 	virtual void archive(archive_node &n) const; \
-	static ex unarchive(const archive_node &n, const lst &sym_lst);
+	static ex unarchive(const archive_node &n, lst &sym_lst);
 
 /** Macro for inclusion in the declaration of each registered class.
  *  It declares some functions that are common to all classes derived
diff --git a/ginac/relational.cpp b/ginac/relational.cpp
index 70dc5bd0..24fd7a05 100644
--- a/ginac/relational.cpp
+++ b/ginac/relational.cpp
@@ -62,7 +62,7 @@ relational::relational(const ex & lhs, const ex & rhs, operators oper) : basic(T
 // archiving
 //////////
 
-relational::relational(const archive_node &n, const lst &sym_lst) : inherited(n, sym_lst)
+relational::relational(const archive_node &n, lst &sym_lst) : inherited(n, sym_lst)
 {
 	unsigned int opi;
 	if (!(n.find_unsigned("op", opi)))
diff --git a/ginac/symbol.cpp b/ginac/symbol.cpp
index af98215a..43e3684c 100644
--- a/ginac/symbol.cpp
+++ b/ginac/symbol.cpp
@@ -93,7 +93,7 @@ symbol::symbol(const std::string & initname, const std::string & texname) : inhe
 //////////
 
 /** Construct object from archive_node. */
-symbol::symbol(const archive_node &n, const lst &sym_lst) : inherited(n, sym_lst)
+symbol::symbol(const archive_node &n, lst &sym_lst) : inherited(n, sym_lst)
 {
 	serial = next_serial++;
 	if (!(n.find_string("name", name)))
@@ -105,15 +105,18 @@ symbol::symbol(const archive_node &n, const lst &sym_lst) : inherited(n, sym_lst
 }
 
 /** Unarchive the object. */
-ex symbol::unarchive(const archive_node &n, const lst &sym_lst)
+ex symbol::unarchive(const archive_node &n, lst &sym_lst)
 {
 	ex s = (new symbol(n, sym_lst))->setflag(status_flags::dynallocated);
-	
+
 	// If symbol is in sym_lst, return the existing symbol
 	for (size_t i=0; i<sym_lst.nops(); i++) {
 		if (is_a<symbol>(sym_lst.op(i)) && (ex_to<symbol>(sym_lst.op(i)).name == ex_to<symbol>(s).name))
 			return sym_lst.op(i);
 	}
+
+	// Otherwise add new symbol to list and return it
+	sym_lst.append(s);
 	return s;
 }
 
diff --git a/ginac/symmetry.cpp b/ginac/symmetry.cpp
index 473bd5b9..2058a279 100644
--- a/ginac/symmetry.cpp
+++ b/ginac/symmetry.cpp
@@ -90,7 +90,7 @@ symmetry::symmetry(symmetry_type t, const symmetry &c1, const symmetry &c2) : ty
 //////////
 
 /** Construct object from archive_node. */
-symmetry::symmetry(const archive_node &n, const lst &sym_lst) : inherited(n, sym_lst)
+symmetry::symmetry(const archive_node &n, lst &sym_lst) : inherited(n, sym_lst)
 {
 	unsigned t;
 	if (!(n.find_unsigned("type", t)))
diff --git a/ginac/tensor.cpp b/ginac/tensor.cpp
index eef89a1e..5e95a414 100644
--- a/ginac/tensor.cpp
+++ b/ginac/tensor.cpp
@@ -107,7 +107,7 @@ DEFAULT_ARCHIVING(spinmetric)
 DEFAULT_UNARCHIVE(minkmetric)
 DEFAULT_UNARCHIVE(tensepsilon)
 
-minkmetric::minkmetric(const archive_node &n, const lst &sym_lst) : inherited(n, sym_lst)
+minkmetric::minkmetric(const archive_node &n, lst &sym_lst) : inherited(n, sym_lst)
 {
 	n.find_bool("pos_sig", pos_sig);
 }
@@ -118,7 +118,7 @@ void minkmetric::archive(archive_node &n) const
 	n.add_bool("pos_sig", pos_sig);
 }
 
-tensepsilon::tensepsilon(const archive_node &n, const lst &sym_lst) : inherited(n, sym_lst)
+tensepsilon::tensepsilon(const archive_node &n, lst &sym_lst) : inherited(n, sym_lst)
 {
 	n.find_bool("minkowski", minkowski);
 	n.find_bool("pos_sig", pos_sig);
diff --git a/ginac/utils.h b/ginac/utils.h
index b2ae4b1b..f21dfed4 100644
--- a/ginac/utils.h
+++ b/ginac/utils.h
@@ -465,13 +465,13 @@ DEFAULT_COPY(classname) \
 DEFAULT_DESTROY(classname)
 
 #define DEFAULT_UNARCHIVE(classname) \
-ex classname::unarchive(const archive_node &n, const lst &sym_lst) \
+ex classname::unarchive(const archive_node &n, lst &sym_lst) \
 { \
 	return (new classname(n, sym_lst))->setflag(status_flags::dynallocated); \
 }
 
 #define DEFAULT_ARCHIVING(classname) \
-classname::classname(const archive_node &n, const lst &sym_lst) : inherited(n, sym_lst) {} \
+classname::classname(const archive_node &n, lst &sym_lst) : inherited(n, sym_lst) {} \
 DEFAULT_UNARCHIVE(classname) \
 void classname::archive(archive_node &n) const \
 { \
diff --git a/ginac/wildcard.cpp b/ginac/wildcard.cpp
index c389c98f..22ab5f07 100644
--- a/ginac/wildcard.cpp
+++ b/ginac/wildcard.cpp
@@ -61,7 +61,7 @@ wildcard::wildcard(unsigned l) : label(l)
 // archiving
 //////////
 
-wildcard::wildcard(const archive_node &n, const lst &sym_lst) : inherited(n, sym_lst)
+wildcard::wildcard(const archive_node &n, lst &sym_lst) : inherited(n, sym_lst)
 {
 	n.find_unsigned("label", label);
 }
-- 
2.47.0