From e8a5670eff8e1d38bb7e32aad17fb8d2f74cebe8 Mon Sep 17 00:00:00 2001
From: rajithv <rajith.vidanaarachchi@gmail.com>
Date: Thu, 9 Jun 2016 09:43:19 +0530
Subject: [PATCH 01/12] FunctionSymbol class and its methods

---
 ext/symengine/ruby_function.c   | 28 ++++++++++++++++++++++++++++
 ext/symengine/ruby_function.h   |  2 ++
 ext/symengine/symengine.c       |  6 ++++--
 ext/symengine/symengine.h       |  1 +
 ext/symengine/symengine_utils.c |  2 ++
 5 files changed, 37 insertions(+), 2 deletions(-)

diff --git a/ext/symengine/ruby_function.c b/ext/symengine/ruby_function.c
index e8be33a..e92c4b3 100644
--- a/ext/symengine/ruby_function.c
+++ b/ext/symengine/ruby_function.c
@@ -37,3 +37,31 @@ IMPLEMENT_ONE_ARG_FUNC(gamma);
 
 #undef IMPLEMENT_ONE_ARG_FUNC
 
+VALUE cfunction_functionsymbol_init(VALUE self, VALUE args)
+{
+    int argc = NUM2INT(rb_funcall(args, rb_intern("length"), 0, NULL));
+    printf("%d\n", argc);
+    VALUE first = rb_ary_shift(args);
+    if( TYPE(first) != T_STRING ){
+        rb_raise(rb_eTypeError, "String expected as first argument");
+    }
+    char *name = StringValueCStr( first );
+
+    basic_struct *cargs[argc];
+    int i;
+    for(i = 0; i < argc; i++){
+        cargs[i] = basic_new_heap();
+        sympify(rb_ary_shift(args), cargs[i]);
+    }
+    
+    basic_struct *this;
+    Data_Get_Struct(self, basic_struct, this);
+
+    function_symbol_set(this, name, cargs);
+    
+    for(i = 0; i < argc; i++){
+        basic_free_heap(cargs[i]);
+    }
+    return self;
+}
+
diff --git a/ext/symengine/ruby_function.h b/ext/symengine/ruby_function.h
index e55b63b..b271353 100644
--- a/ext/symengine/ruby_function.h
+++ b/ext/symengine/ruby_function.h
@@ -37,4 +37,6 @@ VALUE cfunction_dirichlet_eta(VALUE self, VALUE operand1);
 VALUE cfunction_zeta(VALUE self, VALUE operand1);
 VALUE cfunction_gamma(VALUE self, VALUE operand1);
 
+VALUE cfunction_functionsymbol_init(VALUE self, VALUE args);
+
 #endif //RUBY_FUNCTION_H_
diff --git a/ext/symengine/symengine.c b/ext/symengine/symengine.c
index 8ca3d36..1be6f58 100644
--- a/ext/symengine/symengine.c
+++ b/ext/symengine/symengine.c
@@ -113,10 +113,12 @@ void Init_symengine() {
     c_dirichlet_eta = rb_define_class_under(m_symengine, "Dirichlet_eta", c_function);
     c_zeta = rb_define_class_under(m_symengine, "Zeta", c_function);
     c_gamma = rb_define_class_under(m_symengine, "Gamma", c_function);
-
-    //Abs Class
     c_abs = rb_define_class_under(m_symengine, "Abs", c_function);
 
+    //FunctionSymbol Class
+    c_function_symbol = rb_define_class_under(m_symengine, "FunctionSymbol", c_function);
+    rb_define_method(c_function_symbol, "initialize", cfunction_functionsymbol_init, -2);
+
     //TrigFunction SubClasses
     c_sin = rb_define_class_under(m_symengine, "Sin", c_trig_function);
     c_cos = rb_define_class_under(m_symengine, "Cos", c_trig_function);
diff --git a/ext/symengine/symengine.h b/ext/symengine/symengine.h
index 21259a6..0ac1e03 100644
--- a/ext/symengine/symengine.h
+++ b/ext/symengine/symengine.h
@@ -19,6 +19,7 @@ VALUE c_add;
 VALUE c_mul;
 VALUE c_pow;
 VALUE c_function;
+VALUE c_function_symbol;
 VALUE c_trig_function;
 VALUE c_hyperbolic_function;
 VALUE c_lambertw;
diff --git a/ext/symengine/symengine_utils.c b/ext/symengine/symengine_utils.c
index a3ccbf1..418ecca 100644
--- a/ext/symengine/symengine_utils.c
+++ b/ext/symengine/symengine_utils.c
@@ -101,6 +101,8 @@ VALUE Klass_of_Basic(const basic_struct *basic_ptr) {
             return c_mul;
         case SYMENGINE_POW:
             return c_pow;
+        case SYMENGINE_FUNCTIONSYMBOL:
+            return c_function_symbol;
         case SYMENGINE_ABS:
             return c_abs;
         case SYMENGINE_SIN:

From b5a91fd12c2a0b5aac1ec440a249082aa1241d88 Mon Sep 17 00:00:00 2001
From: rajithv <rajith.vidanaarachchi@gmail.com>
Date: Thu, 9 Jun 2016 15:37:03 +0530
Subject: [PATCH 02/12] FunctionSymbol init working

---
 ext/symengine/ruby_function.c | 26 ++++++++++++++++++--------
 1 file changed, 18 insertions(+), 8 deletions(-)

diff --git a/ext/symengine/ruby_function.c b/ext/symengine/ruby_function.c
index e92c4b3..1f0537f 100644
--- a/ext/symengine/ruby_function.c
+++ b/ext/symengine/ruby_function.c
@@ -1,5 +1,7 @@
 #include "ruby_function.h"
 
+typedef struct CVecBasic CVecBasic;
+
 #define IMPLEMENT_ONE_ARG_FUNC(func) \
 VALUE cfunction_ ## func(VALUE self, VALUE operand1) { \
     return function_onearg(basic_ ## func, operand1); \
@@ -40,28 +42,36 @@ IMPLEMENT_ONE_ARG_FUNC(gamma);
 VALUE cfunction_functionsymbol_init(VALUE self, VALUE args)
 {
     int argc = NUM2INT(rb_funcall(args, rb_intern("length"), 0, NULL));
-    printf("%d\n", argc);
+    printf("argc : %d\n", argc);
     VALUE first = rb_ary_shift(args);
     if( TYPE(first) != T_STRING ){
         rb_raise(rb_eTypeError, "String expected as first argument");
     }
     char *name = StringValueCStr( first );
+    char *c;
+    
+    CVecBasic *cargs = vecbasic_new();
+
+    //basic_struct *cargs[argc];
 
-    basic_struct *cargs[argc];
+    basic x;
+    basic y;
+    basic_new_stack(x);
     int i;
-    for(i = 0; i < argc; i++){
-        cargs[i] = basic_new_heap();
-        sympify(rb_ary_shift(args), cargs[i]);
+    for(i = 0; i < argc-1; i++){
+        printf("%d : ", i);
+        sympify(rb_ary_shift(args), x);
+        vecbasic_push_back(cargs, x);
     }
+
+    basic_free_stack(x);
     
     basic_struct *this;
     Data_Get_Struct(self, basic_struct, this);
 
     function_symbol_set(this, name, cargs);
     
-    for(i = 0; i < argc; i++){
-        basic_free_heap(cargs[i]);
-    }
+    vecbasic_free(cargs);
     return self;
 }
 

From 2dd2966428dda01857a370922af69761220c91e8 Mon Sep 17 00:00:00 2001
From: rajithv <rajith.vidanaarachchi@gmail.com>
Date: Thu, 9 Jun 2016 19:52:14 +0530
Subject: [PATCH 03/12] Removed commented code and print statements. Added an
 error for no arguments

---
 ext/symengine/ruby_function.c | 19 ++++++++-----------
 1 file changed, 8 insertions(+), 11 deletions(-)

diff --git a/ext/symengine/ruby_function.c b/ext/symengine/ruby_function.c
index 1f0537f..1f16bd7 100644
--- a/ext/symengine/ruby_function.c
+++ b/ext/symengine/ruby_function.c
@@ -41,37 +41,34 @@ IMPLEMENT_ONE_ARG_FUNC(gamma);
 
 VALUE cfunction_functionsymbol_init(VALUE self, VALUE args)
 {
-    int argc = NUM2INT(rb_funcall(args, rb_intern("length"), 0, NULL));
-    printf("argc : %d\n", argc);
+    int argc = NUM2INT(rb_ary_length(args));
+    if(argc == 0){
+        rb_raise(rb_eTypeError, "Arguments Expected");
+    }
+
     VALUE first = rb_ary_shift(args);
     if( TYPE(first) != T_STRING ){
         rb_raise(rb_eTypeError, "String expected as first argument");
     }
-    char *name = StringValueCStr( first );
-    char *c;
+    char *name = StringValueCStr(first);
     
     CVecBasic *cargs = vecbasic_new();
 
-    //basic_struct *cargs[argc];
-
     basic x;
-    basic y;
     basic_new_stack(x);
     int i;
     for(i = 0; i < argc-1; i++){
-        printf("%d : ", i);
         sympify(rb_ary_shift(args), x);
         vecbasic_push_back(cargs, x);
     }
-
-    basic_free_stack(x);
     
     basic_struct *this;
     Data_Get_Struct(self, basic_struct, this);
-
     function_symbol_set(this, name, cargs);
     
     vecbasic_free(cargs);
+    basic_free_stack(x);
+
     return self;
 }
 

From 0e92c92bde6f8218d3c4a22be22110501bc5ae82 Mon Sep 17 00:00:00 2001
From: Rajith Vidanaarachchi <rajith.vidanaarachchi@gmail.com>
Date: Fri, 10 Jun 2016 20:56:15 +0530
Subject: [PATCH 04/12] Changed rb_ary_length to RARRAY_LEN

---
 ext/symengine/ruby_function.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/ext/symengine/ruby_function.c b/ext/symengine/ruby_function.c
index 1f16bd7..e33de98 100644
--- a/ext/symengine/ruby_function.c
+++ b/ext/symengine/ruby_function.c
@@ -41,7 +41,7 @@ IMPLEMENT_ONE_ARG_FUNC(gamma);
 
 VALUE cfunction_functionsymbol_init(VALUE self, VALUE args)
 {
-    int argc = NUM2INT(rb_ary_length(args));
+    int argc = RARRAY_LEN(args);
     if(argc == 0){
         rb_raise(rb_eTypeError, "Arguments Expected");
     }

From e38cf80833b1eb109a684fe4f3c0821490df2c76 Mon Sep 17 00:00:00 2001
From: Rajith Vidanaarachchi <rajith.vidanaarachchi@gmail.com>
Date: Fri, 10 Jun 2016 21:01:42 +0530
Subject: [PATCH 05/12] Added Subs class

---
 ext/symengine/symengine.c       | 3 +++
 ext/symengine/symengine.h       | 1 +
 ext/symengine/symengine_utils.c | 2 ++
 3 files changed, 6 insertions(+)

diff --git a/ext/symengine/symengine.c b/ext/symengine/symengine.c
index 1be6f58..4b3bb02 100644
--- a/ext/symengine/symengine.c
+++ b/ext/symengine/symengine.c
@@ -93,6 +93,9 @@ void Init_symengine() {
     rb_define_const(m_symengine, "E", cconstant_e());
     rb_define_const(m_symengine, "EULER_GAMMA", cconstant_euler_gamma());
     rb_define_const(m_symengine, "I", cconstant_i());
+    
+    //Subs class
+    c_subs = rb_define_class_under(m_symengine, "Subs", c_basic);
 
     //Add class
     c_add = rb_define_class_under(m_symengine, "Add", c_basic);
diff --git a/ext/symengine/symengine.h b/ext/symengine/symengine.h
index 0ac1e03..dd9d387 100644
--- a/ext/symengine/symengine.h
+++ b/ext/symengine/symengine.h
@@ -15,6 +15,7 @@ VALUE c_rational;
 VALUE c_complex;
 VALUE c_complex_double;
 VALUE c_constant;
+VALUE c_subs;
 VALUE c_add;
 VALUE c_mul;
 VALUE c_pow;
diff --git a/ext/symengine/symengine_utils.c b/ext/symengine/symengine_utils.c
index 418ecca..eac0df0 100644
--- a/ext/symengine/symengine_utils.c
+++ b/ext/symengine/symengine_utils.c
@@ -95,6 +95,8 @@ VALUE Klass_of_Basic(const basic_struct *basic_ptr) {
             return c_complex_double;
         case SYMENGINE_CONSTANT:
             return c_constant;
+        case SYMENGINE_SUBS:
+            return c_subs;
         case SYMENGINE_ADD:
             return c_add;
         case SYMENGINE_MUL:

From 310b7bf03b4e2d856150a088072f1e75ce29d537 Mon Sep 17 00:00:00 2001
From: Rajith Vidanaarachchi <rajith.vidanaarachchi@gmail.com>
Date: Fri, 10 Jun 2016 21:51:14 +0530
Subject: [PATCH 06/12] Added specs for FunctionSymbol

---
 spec/function_symbol_spec.rb | 33 +++++++++++++++++++++++++++++++++
 1 file changed, 33 insertions(+)
 create mode 100644 spec/function_symbol_spec.rb

diff --git a/spec/function_symbol_spec.rb b/spec/function_symbol_spec.rb
new file mode 100644
index 0000000..233ef53
--- /dev/null
+++ b/spec/function_symbol_spec.rb
@@ -0,0 +1,33 @@
+describe SymEngine::FunctionSymbol do
+
+  let(:x) { sym('x') }
+  let(:y) { sym('y') }
+  let(:z) { sym('z') }
+
+  describe '.new' do
+    context 'with symbols' do
+      subject { SymEngine::FunctionSymbol.new('f', x, y, z) }
+      it { is_expected.to be_a SymEngine::FunctionSymbol }
+    end
+
+    context 'with compound arguments' do
+      subject { SymEngine::FunctionSymbol.new('f', 2*x, y, SymEngine::sin(z)) }
+      it { is_expected.to be_a SymEngine::FunctionSymbol }
+    end
+  end
+  
+  context '#diff' do
+    let(:fun) { (SymEngine::FunctionSymbol.new('f', 2*x, y, SymEngine::sin(z))) }
+    context 'by variable' do
+        subject { fun.diff(x)/2 }
+        it { is_expected.to be_a SymEngine::Subs }
+      end
+
+      context 'by constant' do
+        subject { fun.diff(2) }
+        it { is_expected.to be_nil }
+      end
+  end
+end
+
+

From 4c538accd45bca47526582ff211cfe329a9f1f96 Mon Sep 17 00:00:00 2001
From: Rajith Vidanaarachchi <rajith.vidanaarachchi@gmail.com>
Date: Fri, 10 Jun 2016 21:54:07 +0530
Subject: [PATCH 07/12] SymEngine version changed

---
 symengine_version.txt | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/symengine_version.txt b/symengine_version.txt
index 7c04801..c5bccf3 100644
--- a/symengine_version.txt
+++ b/symengine_version.txt
@@ -1,2 +1,3 @@
-b91c64a3b82f15133f4a7df64749523bb0bed185
+1d80d81096b66c08ad3fe4e43ee586cd91b5ccf8
+
 

From ceeb75737b8c92e22522f28865ba897a5cfee1a6 Mon Sep 17 00:00:00 2001
From: Rajith Vidanaarachchi <rajith.vidanaarachchi@gmail.com>
Date: Sun, 12 Jun 2016 01:07:07 +0530
Subject: [PATCH 08/12] Formatting Corrections

---
 ext/symengine/ruby_function.c | 6 +++---
 symengine_version.txt         | 2 --
 2 files changed, 3 insertions(+), 5 deletions(-)

diff --git a/ext/symengine/ruby_function.c b/ext/symengine/ruby_function.c
index e33de98..017a8b7 100644
--- a/ext/symengine/ruby_function.c
+++ b/ext/symengine/ruby_function.c
@@ -42,12 +42,12 @@ IMPLEMENT_ONE_ARG_FUNC(gamma);
 VALUE cfunction_functionsymbol_init(VALUE self, VALUE args)
 {
     int argc = RARRAY_LEN(args);
-    if(argc == 0){
+    if (argc == 0) {
         rb_raise(rb_eTypeError, "Arguments Expected");
     }
 
     VALUE first = rb_ary_shift(args);
-    if( TYPE(first) != T_STRING ){
+    if (TYPE(first) != T_STRING) {
         rb_raise(rb_eTypeError, "String expected as first argument");
     }
     char *name = StringValueCStr(first);
@@ -57,7 +57,7 @@ VALUE cfunction_functionsymbol_init(VALUE self, VALUE args)
     basic x;
     basic_new_stack(x);
     int i;
-    for(i = 0; i < argc-1; i++){
+    for (i = 0; i < argc-1; i++) {
         sympify(rb_ary_shift(args), x);
         vecbasic_push_back(cargs, x);
     }
diff --git a/symengine_version.txt b/symengine_version.txt
index c5bccf3..8c84fb4 100644
--- a/symengine_version.txt
+++ b/symengine_version.txt
@@ -1,3 +1 @@
 1d80d81096b66c08ad3fe4e43ee586cd91b5ccf8
-
-

From 91b414b075fe1be2d92d22195f805cf5ad5091ce Mon Sep 17 00:00:00 2001
From: Rajith Vidanaarachchi <rajith.vidanaarachchi@gmail.com>
Date: Sun, 12 Jun 2016 23:59:02 +0530
Subject: [PATCH 09/12] Fixing the function_symbol_spec.rb

---
 spec/function_symbol_spec.rb | 11 +++--------
 1 file changed, 3 insertions(+), 8 deletions(-)

diff --git a/spec/function_symbol_spec.rb b/spec/function_symbol_spec.rb
index 233ef53..47cc0d5 100644
--- a/spec/function_symbol_spec.rb
+++ b/spec/function_symbol_spec.rb
@@ -19,14 +19,9 @@
   context '#diff' do
     let(:fun) { (SymEngine::FunctionSymbol.new('f', 2*x, y, SymEngine::sin(z))) }
     context 'by variable' do
-        subject { fun.diff(x)/2 }
-        it { is_expected.to be_a SymEngine::Subs }
-      end
-
-      context 'by constant' do
-        subject { fun.diff(2) }
-        it { is_expected.to be_nil }
-      end
+      subject { fun.diff(x)/2 }
+      it { is_expected.to be_a SymEngine::Subs }
+    end
   end
 end
 

From 8932ada3a748c7e02f0035a66c15e16b2586fdd3 Mon Sep 17 00:00:00 2001
From: Rajith Vidanaarachchi <rajith.vidanaarachchi@gmail.com>
Date: Mon, 13 Jun 2016 16:19:36 +0530
Subject: [PATCH 10/12] UndefFunction

---
 ext/symengine/symengine_utils.c |  3 +--
 lib/symengine.rb                |  6 +++++-
 lib/symengine/undef_function.rb | 13 +++++++++++++
 3 files changed, 19 insertions(+), 3 deletions(-)
 create mode 100644 lib/symengine/undef_function.rb

diff --git a/ext/symengine/symengine_utils.c b/ext/symengine/symengine_utils.c
index fa24842..e4385f1 100644
--- a/ext/symengine/symengine_utils.c
+++ b/ext/symengine/symengine_utils.c
@@ -8,7 +8,6 @@ void sympify(VALUE operand2, basic_struct *cbasic_operand2) {
     VALUE a, b;
     double f;
     char *c;
-    rb_cBigDecimal = CLASS_OF(rb_eval_string("BigDecimal.new('0.0001')"));
 
     switch(TYPE(operand2)) {
         case T_FIXNUM:
@@ -63,7 +62,7 @@ void sympify(VALUE operand2, basic_struct *cbasic_operand2) {
         case T_DATA:
             c = rb_obj_classname(operand2);
             #ifdef HAVE_SYMENGINE_MPFR
-            if(CLASS_OF(operand2) == rb_cBigDecimal){
+            if (strcmp(c, "BigDecimal") == 0) {
                 c = RSTRING_PTR( rb_funcall(operand2, rb_intern("to_s"), 1, rb_str_new2("F")) );
                 real_mpfr_set_str(cbasic_operand2, c, 200);
                 break;
diff --git a/lib/symengine.rb b/lib/symengine.rb
index 21d4c7d..36c8806 100644
--- a/lib/symengine.rb
+++ b/lib/symengine.rb
@@ -1,6 +1,5 @@
 module SymEngine
   class << self
-
     # Defines a shortcut for SymEngine::Symbol.new() allowing multiple symbols
     # to be created all at once.
     #
@@ -29,6 +28,10 @@ def symbols ary_or_string, *params
       end
     end
   end
+  
+  def SymEngine.Function(n)
+    return SymEngine::UndefFunction.new(n)
+  end
 end
 
 require 'symengine/symengine'
@@ -37,3 +40,4 @@ def symbols ary_or_string, *params
 require 'symengine/integer'
 require 'symengine/complex'
 require 'symengine/complex_double'
+require 'symengine/undef_function'
diff --git a/lib/symengine/undef_function.rb b/lib/symengine/undef_function.rb
new file mode 100644
index 0000000..8982b8b
--- /dev/null
+++ b/lib/symengine/undef_function.rb
@@ -0,0 +1,13 @@
+module SymEngine
+  class UndefFunction
+    
+    def initialize(n)
+        @name = n
+    end
+    
+    def call(*args)
+        SymEngine::FunctionSymbol.new(@name, *args)
+    end
+    
+  end
+end

From 8a298f030733d080c989c73a7cfb659935182e2e Mon Sep 17 00:00:00 2001
From: Rajith Vidanaarachchi <rajith.vidanaarachchi@gmail.com>
Date: Mon, 13 Jun 2016 22:40:45 +0530
Subject: [PATCH 11/12] Moving Function() inside SymEngine module's self class

---
 lib/symengine.rb | 9 ++++-----
 1 file changed, 4 insertions(+), 5 deletions(-)

diff --git a/lib/symengine.rb b/lib/symengine.rb
index 36c8806..e4d3477 100644
--- a/lib/symengine.rb
+++ b/lib/symengine.rb
@@ -26,11 +26,10 @@ def symbols ary_or_string, *params
       ary_or_string.map do |symbol_or_string| 
         SymEngine::Symbol.new(symbol_or_string)
       end
-    end
-  end
-  
-  def SymEngine.Function(n)
-    return SymEngine::UndefFunction.new(n)
+    end    
+    def Function(n)
+      return SymEngine::UndefFunction.new(n)
+    end    
   end
 end
 

From 6c0fe5dba124cb328abd4db8b87dc973e52f2403 Mon Sep 17 00:00:00 2001
From: Rajith Vidanaarachchi <rajith.vidanaarachchi@gmail.com>
Date: Mon, 13 Jun 2016 22:58:00 +0530
Subject: [PATCH 12/12] Spec for UndefFunction and it's call method

---
 spec/function_symbol_spec.rb | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/spec/function_symbol_spec.rb b/spec/function_symbol_spec.rb
index 47cc0d5..f73d2eb 100644
--- a/spec/function_symbol_spec.rb
+++ b/spec/function_symbol_spec.rb
@@ -23,6 +23,18 @@
       it { is_expected.to be_a SymEngine::Subs }
     end
   end
+  
+  context 'Initializing with UndefFunctions' do
+    let(:fun) { SymEngine::Function('f') }
+    context 'UndefFunction' do
+      subject { fun }
+      it { is_expected.to be_a SymEngine::UndefFunction }
+    end   
+    context 'using call method for UndefFunction' do
+      subject { fun.(x, y, z) }
+      it { is_expected.to be_a SymEngine::FunctionSymbol }
+    end
+  end
 end