From 50dc516836ac5e91f4f60a60b9a307b375247e7c Mon Sep 17 00:00:00 2001
From: Christian Bauer <Christian.Bauer@uni-mainz.de>
Date: Thu, 5 Apr 2001 21:02:26 +0000
Subject: [PATCH] subs() performs "syntactic substitution" as in Maple; you can
 substitute any object by any other object (even numerics) but only when the
 object subs() is called on exactly matches an object on the left-hand side of
 the substitution list; expairseq still doesn't substitute its numeric
 coefficients so substituting numerics will not replace them in all occurences
 (this shouldn't matter, though)

---
 ginac/basic.cpp     | 39 ++++++++++++++++++---------------------
 ginac/container.pl  |  6 +++---
 ginac/expairseq.cpp |  2 +-
 ginac/function.pl   | 14 --------------
 ginac/indexed.cpp   | 13 -------------
 ginac/indexed.h     |  1 -
 ginac/power.cpp     |  2 +-
 ginac/symbol.cpp    | 13 -------------
 ginac/symbol.h      |  1 -
 ginac/tensor.cpp    | 12 ------------
 ginac/tensor.h      |  2 --
 11 files changed, 23 insertions(+), 82 deletions(-)

diff --git a/ginac/basic.cpp b/ginac/basic.cpp
index 1b388259..c4e17cd5 100644
--- a/ginac/basic.cpp
+++ b/ginac/basic.cpp
@@ -31,10 +31,6 @@
 #include "symbol.h"
 #include "lst.h"
 #include "ncmul.h"
-#include "idx.h"
-#include "indexed.h"
-#include "tensor.h"
-#include "function.h"
 #include "archive.h"
 #include "utils.h"
 #include "debugmsg.h"
@@ -341,10 +337,17 @@ bool basic::contract_with(exvector::iterator self, exvector::iterator other, exv
 	return false;
 }
 
-/** Substitute a set of symbols by arbitrary expressions. The ex returned
+/** Substitute a set of objects by arbitrary expressions. The ex returned
  *  will already be evaluated. */
 ex basic::subs(const lst & ls, const lst & lr) const
 {
+	GINAC_ASSERT(ls.nops() == lr.nops());
+
+	for (unsigned i=0; i<ls.nops(); i++) {
+		if (is_equal(*ls.op(i).bp))
+			return lr.op(i);
+	}
+
 	return *this;
 }
 
@@ -466,11 +469,11 @@ ex basic::expand(unsigned options) const
 
 // public
 
-/** Substitute objects (symbols, indices, tensors, functions, indexed) in
- *  expression and return the result as a new expression.  There are two
- *  valid types of replacement arguments: 1) a relational like object==ex
- *  and 2) a list of relationals lst(object1==ex1,object2==ex2,...), which
- *  is converted to subs(lst(object1,object2,...),lst(ex1,ex2,...)). */
+/** Substitute objects in an expression (syntactic substitution) and return
+ *  the result as a new expression.  There are two valid types of
+ *  replacement arguments: 1) a relational like object==ex and 2) a list of
+ *  relationals lst(object1==ex1,object2==ex2,...), which is converted to
+ *  subs(lst(object1,object2,...),lst(ex1,ex2,...)). */
 ex basic::subs(const ex & e) const
 {
 	if (e.info(info_flags::relation_equal)) {
@@ -482,20 +485,14 @@ ex basic::subs(const ex & e) const
 	lst ls;
 	lst lr;
 	for (unsigned i=0; i<e.nops(); i++) {
-		if (!e.op(i).info(info_flags::relation_equal)) {
+		ex r = e.op(i);
+		if (!r.info(info_flags::relation_equal)) {
 			throw(std::invalid_argument("basic::subs(ex): argument must be a list or equations"));
 		}
-		ex s = e.op(i).op(0);
-		ex r = e.op(i).op(1);
-		if (!is_ex_of_type(s, symbol) && !is_ex_of_type(s, idx) &&
-		    !is_ex_of_type(s, tensor) && !is_ex_of_type(s, function) &&
-			!is_ex_of_type(s, indexed)) {
-			throw(std::invalid_argument("basic::subs(ex): lhs must be a symbol, idx, tensor, function or indexed"));
-		}
-		ls.append(s);
-		lr.append(r);
+		ls.append(r.op(0));
+		lr.append(r.op(1));
 	}
-	return subs(ls,lr);
+	return subs(ls, lr);
 }
 
 /** Compare objects to establish canonical ordering.
diff --git a/ginac/container.pl b/ginac/container.pl
index 571330f9..1a591ab3 100755
--- a/ginac/container.pl
+++ b/ginac/container.pl
@@ -502,9 +502,9 @@ ex ${CONTAINER}::derivative(const symbol & s) const
 ex ${CONTAINER}::subs(const lst & ls, const lst & lr) const
 {
 	${STLT} * vp=subschildren(ls,lr);
-	if (vp==0) {
-		return *this;
-	}
+	if (vp==0)
+		return inherited::subs(ls, lr);
+
 	return this${CONTAINER}(vp);
 }
 
diff --git a/ginac/expairseq.cpp b/ginac/expairseq.cpp
index 43754ea2..09a38af5 100644
--- a/ginac/expairseq.cpp
+++ b/ginac/expairseq.cpp
@@ -337,7 +337,7 @@ ex expairseq::subs(const lst &ls, const lst &lr) const
 {
 	epvector *vp = subschildren(ls,lr);
 	if (vp==0)
-		return *this;
+		return inherited::subs(ls, lr);
 	
 	return thisexpairseq(vp,overall_coeff);
 }
diff --git a/ginac/function.pl b/ginac/function.pl
index f6e7b332..b36df872 100755
--- a/ginac/function.pl
+++ b/ginac/function.pl
@@ -345,7 +345,6 @@ public:
 	ex evalf(int level=0) const;
 	unsigned calchash(void) const;
 	ex series(const relational & r, int order, unsigned options = 0) const;
-	ex subs(const lst & ls, const lst & lr) const;
 	ex thisexprseq(const exvector & v) const;
 	ex thisexprseq(exvector * vp) const;
 protected:
@@ -822,19 +821,6 @@ ${series_switch_statement}
 	throw(std::logic_error("function::series(): invalid nparams"));
 }
 
-ex function::subs(const lst & ls, const lst & lr) const
-{
-	GINAC_ASSERT(ls.nops() == lr.nops());
-
-	for (unsigned i=0; i<ls.nops(); i++) {
-		if (is_ex_of_type(ls.op(i), function) &&
-		    compare_same_type(ex_to_function(ls.op(i)))==0)
-			return lr.op(i);
-	}
-
-	return inherited::subs(ls, lr);
-}
-
 // protected
 
 
diff --git a/ginac/indexed.cpp b/ginac/indexed.cpp
index c530c1f4..5277bf89 100644
--- a/ginac/indexed.cpp
+++ b/ginac/indexed.cpp
@@ -369,19 +369,6 @@ ex indexed::coeff(const ex & s, int n) const
 		return n==0 ? ex(*this) : _ex0();
 }
 
-ex indexed::subs(const lst & ls, const lst & lr) const
-{
-	GINAC_ASSERT(ls.nops() == lr.nops());
-
-	for (unsigned i=0; i<ls.nops(); i++) {
-		if (is_ex_of_type(ls.op(i), indexed) &&
-		    compare_same_type(ex_to_indexed(ls.op(i)))==0)
-			return lr.op(i);
-	}
-
-	return inherited::subs(ls, lr);
-}
-
 ex indexed::thisexprseq(const exvector & v) const
 {
 	return indexed(symmetry, v);
diff --git a/ginac/indexed.h b/ginac/indexed.h
index 5b349782..e98375d3 100644
--- a/ginac/indexed.h
+++ b/ginac/indexed.h
@@ -159,7 +159,6 @@ public:
 	int degree(const ex & s) const;
 	int ldegree(const ex & s) const;
 	ex coeff(const ex & s, int n = 1) const;
-	ex subs(const lst & ls, const lst & lr) const;
 	exvector get_free_indices(void) const;
 
 protected:
diff --git a/ginac/power.cpp b/ginac/power.cpp
index f5d877e6..c2885565 100644
--- a/ginac/power.cpp
+++ b/ginac/power.cpp
@@ -476,7 +476,7 @@ ex power::subs(const lst & ls, const lst & lr) const
 
 	if (are_ex_trivially_equal(basis,subsed_basis)&&
 		are_ex_trivially_equal(exponent,subsed_exponent)) {
-		return *this;
+		return inherited::subs(ls, lr);
 	}
 	
 	return power(subsed_basis, subsed_exponent);
diff --git a/ginac/symbol.cpp b/ginac/symbol.cpp
index 8547ffef..09e4192b 100644
--- a/ginac/symbol.cpp
+++ b/ginac/symbol.cpp
@@ -221,19 +221,6 @@ ex symbol::eval(int level) const
 	}
 }
 
-ex symbol::subs(const lst & ls, const lst & lr) const
-{
-	GINAC_ASSERT(ls.nops() == lr.nops());
-
-	for (unsigned i=0; i<ls.nops(); i++) {
-		if (is_ex_exactly_of_type(ls.op(i),symbol)) {
-			if (compare_same_type(ex_to_symbol(ls.op(i)))==0)
-				return lr.op(i);
-		}
-	}
-	return *this;
-}
-
 // protected
 
 /** Implementation of ex::diff() for single differentiation of a symbol.
diff --git a/ginac/symbol.h b/ginac/symbol.h
index 16dcab0c..c147c89f 100644
--- a/ginac/symbol.h
+++ b/ginac/symbol.h
@@ -86,7 +86,6 @@ public:
 	ex series(const relational & s, int order, unsigned options = 0) const;
 	ex normal(lst &sym_lst, lst &repl_lst, int level = 0) const;
 	ex to_rational(lst &repl_lst) const;
-	ex subs(const lst & ls, const lst & lr) const;
 protected:
 	ex derivative(const symbol & s) const;
 	int compare_same_type(const basic & other) const;
diff --git a/ginac/tensor.cpp b/ginac/tensor.cpp
index b53d6f7d..c7a68bf2 100644
--- a/ginac/tensor.cpp
+++ b/ginac/tensor.cpp
@@ -166,18 +166,6 @@ DEFAULT_PRINT(tensmetric, "g")
 DEFAULT_PRINT(minkmetric, "eta")
 DEFAULT_PRINT(tensepsilon, "eps")
 
-ex tensor::subs(const lst & ls, const lst & lr) const
-{
-	GINAC_ASSERT(ls.nops() == lr.nops());
-
-	for (unsigned i=0; i<ls.nops(); i++) {
-		if (is_ex_of_type(ls.op(i), tensor) &&
-		    compare_same_type(ex_to_tensor(ls.op(i)))==0)
-			return lr.op(i);
-	}
-	return *this;
-}
-
 /** Automatic symbolic evaluation of an indexed delta tensor. */
 ex tensdelta::eval_indexed(const basic & i) const
 {
diff --git a/ginac/tensor.h b/ginac/tensor.h
index ac991d5f..65c86c45 100644
--- a/ginac/tensor.h
+++ b/ginac/tensor.h
@@ -40,8 +40,6 @@ protected:
 	tensor(unsigned ti);
 
 	// functions overriding virtual functions from bases classes
-public:
-	ex subs(const lst & ls, const lst & lr) const;
 protected:
 	unsigned return_type(void) const { return return_types::noncommutative_composite; }
 };
-- 
2.44.0