diff --git a/build_linux64/libamsstring4.linux64.a b/build_linux64/libamsstring4.linux64.a
index c6cf565..5c9e1d8 100644
Binary files a/build_linux64/libamsstring4.linux64.a and b/build_linux64/libamsstring4.linux64.a differ
diff --git a/build_linux64/objstore/amsstring4_class.o b/build_linux64/objstore/amsstring4_class.o
index 277400e..5b485c7 100644
Binary files a/build_linux64/objstore/amsstring4_class.o and b/build_linux64/objstore/amsstring4_class.o differ
diff --git a/build_linux64/objstore/amsstring4_convenience1.o b/build_linux64/objstore/amsstring4_convenience1.o
index 09f4649..838ff70 100644
Binary files a/build_linux64/objstore/amsstring4_convenience1.o and b/build_linux64/objstore/amsstring4_convenience1.o differ
diff --git a/include/amsstring4/amsstring4.hpp b/include/amsstring4/amsstring4.hpp
index 07322a7..1460803 100644
--- a/include/amsstring4/amsstring4.hpp
+++ b/include/amsstring4/amsstring4.hpp
@@ -103,28 +103,35 @@ public:
     void append(const ams_chartype *other);
     void append(const ams_chartype other);
 
-    amsstring operator+(const amsstring &other);
-    const amsstring operator+(const amsstring &other) const;
-    amsstring operator+(const ams_chartype *other);
-    const amsstring operator+(const ams_chartype *other) const;
-    amsstring operator+(const ams_chartype other);
-    const amsstring operator+(const ams_chartype other) const;
+    amsstring operator+(const amsstring &other) const;
+    amsstring operator+(const ams_chartype *other) const;
+    amsstring operator+(const ams_chartype other) const;
 
     //Find
     int find(const amsstring findstr, const int indstart=0, const bool casesens=1) const;
     int find(const ams_chartype *findstr, const int indstart=0, const bool casesens=1) const;
     int find(const ams_chartype c, const int indstart=0, const bool casesens=1) const;
 
+    //todo
+    // finds first instance starting from length-indstart-1 from the right
+    int findright(const amsstring findstr, const int indstart=0, const bool casesens=1) const;
+    int findright(const ams_chartype *findstr, const int indstart=0, const bool casesens=1) const;
+    int findright(const ams_chartype c, const int indstart=0, const bool casesens=1) const;
+
     //formatted input
     int sprintf(int bufflen, const ams_chartype *formatstring, ...);
 
     void tolower();
     void toupper();
+    amsstring lower() const;
+    amsstring upper() const;
 
-    bool isvalidnumber();
-    double strtonum();
+    bool isvalidnumber() const;
+    double strtonum() const;
 
     //updated convenience functions as class members
+    //todo
+
 };
 
 //needs work
diff --git a/src/amsstring4/amsstring4_class.cpp b/src/amsstring4/amsstring4_class.cpp
index 2af8e14..c38044b 100644
--- a/src/amsstring4/amsstring4_class.cpp
+++ b/src/amsstring4/amsstring4_class.cpp
@@ -779,6 +779,17 @@ namespace ams
       }
       return;
     }
+
+    amsstring amsstring::lower() const
+    {
+        amsstring ret = *this;
+        int I;
+        for(I=0;I<length;I++)
+        {
+          ret.cstring[I] = (ams_chartype) ams::tolower(ret.cstring[I]);
+        }
+        return ret;
+    }
     
     void amsstring::toupper()
     {
@@ -789,6 +800,17 @@ namespace ams
       }
       return;
     }
+
+    amsstring amsstring::upper() const
+    {
+        amsstring ret = *this;
+        int I;
+        for(I=0;I<length;I++)
+        {
+          ret.cstring[I] = (ams_chartype) ams::toupper(ret.cstring[I]);
+        }
+        return ret;
+    }
     
     int amsstring::sprintf(int bufflen, const ams_chartype *formatstring, ...)
     {
@@ -815,7 +837,7 @@ namespace ams
     }
     
     //also returns true for nan
-    bool amsstring::isvalidnumber()
+    bool amsstring::isvalidnumber() const
     {
       bool ret = 0;
       double d;
@@ -840,60 +862,11 @@ namespace ams
       return ret;
     }
     
-    double amsstring::strtonum()
+    double amsstring::strtonum() const 
     {
       return amsstrtonum(this->cstring);
     }
     
-    
-    void splitlines(amsstring *s, std::vector<amsstring> *lns)
-    {
-      int I,I1,I2;
-      amsstring q;
-      int mode;
-      ams_chartype c;
-    
-      lns->resize(0);
-    
-      I1 = 0;
-      I = 0;
-      mode = 0;
-      while(I<s->size())
-      {
-        c = s->at(I);
-        if(mode==0 && c==ams_char_cr)
-        {
-          mode=1;
-          I2 = I;
-        }
-        else if(mode==0 && c==ams_char_lf)
-        {
-          mode = 0;
-          I2 = I;
-          s->substring(I1,I2,&q);
-          lns->push_back(q);
-          I1 = I+1;
-        }
-        else if(mode==1 && c==ams_char_lf)
-        {
-          mode = 0;
-          s->substring(I1,I2,&q);
-          lns->push_back(q);
-          I1 = I+1;
-        }
-        else if(mode==1)
-        {
-          mode = 0;
-        }
-    
-        I = I + 1;
-      }
-      s->substring(I1,s->length,&q);
-      lns->push_back(q);
-    
-      return;
-    }
-    
     void splitlines(const amsstring *s, ams::amsarray<amsstring> *lns)
     {
       int I,I1,I2;
@@ -942,106 +915,7 @@ namespace ams
       return;
     }
     
-    /*
-    void splitlines(amsstring *s, std::vector<amsstring> *lns)
-    {
-      //windows uses \r\n, linux uses \n as a line delimiter
-      int I;
-      amsstring q;
-      lns->resize(0);
-      int ind1 = 0;
-      int ind2 = 0;
-      int mode = 0;
-      int cs;
-      I = 0;
-      ams_chartype c;
-    
-    
-      while(I<s->length)
-      {
-        c = s->cstring[I];
-        cs = 0; //has the character been 'consumed' by the state machine?
-        if(c=='\n'&&mode==0&&cs==0)
-        {
-    
-          cs = 1;
-          ind2 = I-1;
-          ind2 = ams::max<int>(0,ind2);
-          s->substring(ind1,ind2+1,&q);
-          lns->push_back(q);
-          ind1 = I+1;
-          ind2 = I+1;
-          ind1 = ams::min<int>(s->length,ind1);
-          ind2 = ams::min<int>(s->length,ind2);
-        }
-        if(c=='\r'&&mode==0&&cs==0)
-        {
-          cs = 1;
-          mode = 1;
-        }
-        if(c=='\n'&&mode==1&&cs==0)
-        {
-          cs = 1;
-          ind2 = I-2;
-          ind2 = ams::max<int>(0,ind2);
-          s->substring(ind1,ind2+1,&q);
-          lns->push_back(q);
-          ind1 = I+1;
-          ind2 = I+1;
-          ind1 = ams::min<int>(s->length,ind1);
-          ind2 = ams::min<int>(s->length,ind2);
-          mode = 0;
-        }
-        I = I + 1;
-      }
-      if(ind1<s->length)
-      {
-        s->substring(ind1,s->length+1,&q);
-        lns->push_back(q);
-      }
-    
-      return;
-    }
-    */
-    
-    // void split(const amsstring *s, const ams_chartype delimitchar, std::vector<amsstring> *lns)
-    // {
-    //   amsstring q;
-    //   lns->resize(0);
-    
-    
-    //   int I = 0;
-    //   int ind1;
-    //   int ind2;
-    //   //int cs;
-    //   ind1 = 0;
-    //   ams_chartype c;
-    //   while(I<s->length)
-    //   {
-    //     c = s->cstring[I];
-    //     //cs = 0;
-    //     if(c==delimitchar)
-    //     {
-    //       ind2 = I;
-    //       ind2 = max<int>(0,ind2);
-    //       s->substring(ind1,ind2,&q);
-    //       lns->push_back(q);
-    //       ind1 = I+1;
-    //       ind2 = I+1;
-    //       ind1 = min<int>(s->length,ind1);
-    //       ind2 = min<int>(s->length,ind2);
-    //     }
-    
-    //     I = I + 1;
-    //   }
-    //   if(ind1<s->length&&s->cstring[ind1]!=delimitchar)
-    //   {
-    //     s->substring(ind1,s->length,&q);
-    //     lns->push_back(q);
-    //   }
-    
-    //   return;
-    // }
+
     
     void split(const amsstring *s, const ams_chartype delimitchar, ams::amsarray<amsstring> *lns)
     {
@@ -1082,84 +956,6 @@ namespace ams
       return;
     }
     
-    // void split(const amsstring *s, const ams_chartype *delimitstr, std::vector<amsstring> *lns)
-    // {
-    //   amsstring q;
-    //   int I;
-    //   int ind1,ind2;
-    //   int cs;
-    //   int cnt;
-    //   ams_chartype c;
-    //   int N = amsstring_strlen(delimitstr);
-      
-    //   if(lns!=NULL && delimitstr!=NULL)
-    //   {
-    //     if(N>0)
-    //     {
-    //       lns->resize(0);
-    
-    //       ind1 = 0;
-    //       I = 0;
-    //       cs = 0;
-    //       cnt = 0;
-    //       while(I<s->size())
-    //       {
-    //         c = s->at(I);
-    //         if(cs==0 && c==delimitstr[cnt])
-    //         {
-    //           cs=1;
-    //           ind2 = I;
-    //           cnt = cnt+1;
-    //         }
-    //         else if(cs==1 && c==delimitstr[cnt])
-    //         {
-    //           cs=1;
-    //           cnt = cnt+1;
-    //         }
-    //         else if(cs==1 && c!=delimitstr[cnt])
-    //         {
-    //           cs = 0;
-    //           ind2 = ind1;
-    //           cnt = 0;
-    //           I = I - 1; //step back so you can evaluate this char again
-    //         }
-    
-    //         if(cnt>=N)
-    //         {
-    //           //cut string from (ind1,ind2)
-    //           cs = 0;
-    
-    //           ind1 = min<int>(ind1,s->size());
-    //           ind1 = max<int>(ind1,0);
-    //           ind2 = min<int>(ind2,s->size());
-    //           ind2 = max<int>(ind2,0);
-    //           ind2 = max<int>(ind2,ind1);
-    
-    //           s->substring(ind1,ind2,&q);
-    //           lns->push_back(q);
-              
-    //           ind1 = I + 1;
-    //           ind2 = I + 1;
-    //           cnt = 0;
-    //         }
-    //         I = I + 1;
-    //       }
-    
-    //       if(ind1<s->size())
-    //       {
-    //         s->substring(ind1,s->size(),&q);
-    //         lns->push_back(q);
-    //       }
-    //     } //N>0
-    //     else
-    //     {
-    //       lns->push_back(*s);
-    //     }
-    //   } //lns!=NULL
-    
-    //   return;
-    // }
-    
     void split(const amsstring *s, const ams_chartype *delimitstr, ams::amsarray<amsstring> *lns)
     {
       amsstring q;
@@ -1238,63 +1034,12 @@ namespace ams
       return;
     }
     
-    // void split(const amsstring *s, amsstring *delimitstr, std::vector<amsstring> *lns)
-    // {
-    //   split(s,delimitstr->cstring,lns);
-    //   return;
-    // }
-    
     void split(const amsstring *s, amsstring *delimitstr, ams::amsarray<amsstring> *lns)
     {
       split(s,delimitstr->cstring,lns);
       return;
     }
     
-    
-    // void splitwhitespace(const amsstring *s, std::vector<amsstring> *lns)
-    // {
-    //   int I;
-    //   int mode;
-    //   ams_chartype c;
-    //   int ind1 = 0;
-    //   int ind2 = 0;
-    //   I = 0;
-    //   mode = 0;
-    //   amsstring q;
-    //   bool qf = 0;
-    
-    //   if(s!=NULL && lns!=NULL)
-    //   {
-    //     lns->resize(0);
-    //     while(qf==0)
-    //     {
-    //       c = s->cstring[I];
-    //       if(!(isspace(c)||c==' '||c=='\t')&&mode==0)
-    //       {
-    //         mode = 1;
-    //         ind1 = I;
-    //         ind1 = ams::max<int>(0,ind1);
-    //       }
-    //       if((isspace(c)||c==' '||c=='\t'||c=='\0')&&mode==1)
-    //       {
-    //         mode = 0;
-    //         ind2 = I;
-    //         ind2 = ams::min<int>(ind2,s->length);
-    //         s->substring(ind1,ind2,&q);
-    //         //printf("debug: %d, %s\n",I,q.cstring);
-    //         lns->push_back(q);
-    //       }
-    //       if(I>=s->length)
-    //       {
-    //         qf = 1;
-    //       }
-    
-    //       I = I + 1;
-    //     }
-    //   } //test null pointers
-    //   return;
-    // }
-    
     void splitwhitespace(const amsstring *s, ams::amsarray<amsstring> *lns)
     {
       int I;
@@ -1520,7 +1265,7 @@ namespace ams
       return ret;
     }
     
-    amsstring amsstring::operator+(const amsstring &other)
+    amsstring amsstring::operator+(const amsstring &other) const
     {
       amsstring ret;
       amsstring q1 = *this;
@@ -1531,18 +1276,7 @@ namespace ams
       return ret;
     }
     
-    const amsstring amsstring::operator+(const amsstring &other) const
-    {
-      amsstring ret;
-      amsstring q1 = *this;
-      amsstring q2 = other;
-      ret = "";
-      ret.append(q1);
-      ret.append(q2);
-      return ret;
-    }
-    
-    amsstring amsstring::operator+(const ams_chartype *other)
+    amsstring amsstring::operator+(const ams_chartype *other) const
     {
       amsstring ret;
       amsstring q1 = *this;
@@ -1552,27 +1286,7 @@ namespace ams
       return ret;
     }
     
-    const amsstring amsstring::operator+(const ams_chartype *other) const
-    {
-      amsstring ret;
-      amsstring q1 = *this;
-      ret = "";
-      ret.append(q1);
-      ret.append(other);
-      return ret;
-    }
-    
-    amsstring amsstring::operator+(const ams_chartype other)
-    {
-      amsstring ret;
-      amsstring q1 = *this;
-      ret = "";
-      ret.append(q1);
-      ret.append(other);
-      return ret;
-    }
-    
-    const amsstring amsstring::operator+(const ams_chartype other) const
+    amsstring amsstring::operator+(const ams_chartype other) const
     {
       amsstring ret;
       amsstring q1 = *this;
@@ -1581,6 +1295,7 @@ namespace ams
       ret.append(other);
       return ret;
     }
+
     
 
 };
\ No newline at end of file
diff --git a/src/amsstring4/amsstring4_convenience1.cpp b/src/amsstring4/amsstring4_convenience1.cpp
index b770561..632a82a 100644
--- a/src/amsstring4/amsstring4_convenience1.cpp
+++ b/src/amsstring4/amsstring4_convenience1.cpp
@@ -3,16 +3,236 @@
 namespace ams
 {
 
+//Updated convenience functions: updated for a more python style
 amsarray<amsstring> splitlines(const amsstring &s)
 {
     amsarray<amsstring> ret;
-    splitlines(&s,&ret);
+
+    int I,I1,I2;
+    amsstring q;
+    int mode;
+    ams_chartype c;
+  
+    ret.resize(0);
+  
+    I1 = 0;
+    I = 0;
+    mode = 0;
+    while(I<s.size())
+    {
+      c = s.at(I);
+      if(mode==0 && c==ams_char_cr)
+      {
+        mode=1;
+        I2 = I;
+      }
+      else if(mode==0 && c==ams_char_lf)
+      {
+        mode = 0;
+        I2 = I;
+        s.substring(I1,I2,&q);
+        ret.push_back(q);
+        I1 = I+1;
+      }
+      else if(mode==1 && c==ams_char_lf)
+      {
+        mode = 0;
+        s.substring(I1,I2,&q);
+        ret.push_back(q);
+        I1 = I+1;
+      }
+      else if(mode==1)
+      {
+        mode = 0;
+      }
+  
+      I = I + 1;
+    }
+    s.substring(I1,s.length,&q);
+    ret.push_back(q);
+
     return ret;
 }
+
 amsarray<amsstring> split(const amsstring &s, const ams_chartype delimitchar)
 {
     amsarray<amsstring> ret;
+    amsstring q;
+    ret.resize(0);
+  
+  
+    int I = 0;
+    int ind1;
+    int ind2;
+    //int cs;
+    ind1 = 0;
+    ams_chartype c;
+    while(I<s.length)
+    {
+      c = s.cstring[I];
+      //cs = 0;
+      if(c==delimitchar)
+      {
+        ind2 = I;
+        ind2 = max<int>(0,ind2);
+        s.substring(ind1,ind2,&q);
+        ret.push_back(q);
+        ind1 = I+1;
+        ind2 = I+1;
+        ind1 = min<int>(s.length,ind1);
+        ind2 = min<int>(s.length,ind2);
+      }
+  
+      I = I + 1;
+    }
+    if(ind1<s.length&&s.cstring[ind1]!=delimitchar)
+    {
+      s.substring(ind1,s.length,&q);
+      ret.push_back(q);
+    }
+
+    return ret;
+}
+
+static int amsstring_strlen(const ams_chartype *c)
+{
+  int I;
+  if(c!=NULL)
+  {
+    I = 0;
+    while(c[I]!='\0')
+    {
+      I++;
+    }
+    return I;
+    //return strlen((const char*) c);
+  }
+  else
+    return 0;
+}
+
+amsarray<amsstring> split(const amsstring &s, const ams_chartype *delimitstr)
+{
+    amsarray<amsstring> ret;
+
+    amsstring q;
+    int I;
+    int ind1,ind2;
+    int cs;
+    int cnt;
+    ams_chartype c;
+    int N = amsstring_strlen(delimitstr);
     
+    if(delimitstr!=NULL)
+    {
+      if(N>0)
+      {
+        ret.resize(0);
+  
+        ind1 = 0;
+        I = 0;
+        cs = 0;
+        cnt = 0;
+        while(I<s.size())
+        {
+          c = s.at(I);
+          if(cs==0 && c==delimitstr[cnt])
+          {
+            cs=1;
+            ind2 = I;
+            cnt = cnt+1;
+          }
+          else if(cs==1 && c==delimitstr[cnt])
+          {
+            cs=1;
+            cnt = cnt+1;
+          }
+          else if(cs==1 && c!=delimitstr[cnt])
+          {
+            cs = 0;
+            ind2 = ind1;
+            cnt = 0;
+            I = I - 1; //step back so you can evaluate this char again
+          }
+  
+          if(cnt>=N)
+          {
+            //cut string from (ind1,ind2)
+            cs = 0;
+  
+            ind1 = min<int>(ind1,s.size());
+            ind1 = max<int>(ind1,0);
+            ind2 = min<int>(ind2,s.size());
+            ind2 = max<int>(ind2,0);
+            ind2 = max<int>(ind2,ind1);
+  
+            s.substring(ind1,ind2,&q);
+            ret.push_back(q);
+            
+            ind1 = I + 1;
+            ind2 = I + 1;
+            cnt = 0;
+          }
+          I = I + 1;
+        }
+  
+        if(ind1<s.size())
+        {
+          s.substring(ind1,s.size(),&q);
+          ret.push_back(q);
+        }
+      } //N>0
+      else
+      {
+        ret.push_back(s);
+      }
+    } //ret!=NULL
+
+    return ret;
+}
+
+//splits into two guaranteed pieces
+//if a delimitchar or delimitstr is not encountered, the first piece will contain the entire string and the second will be ""
+amsarray<amsstring> splitfirst(const amsstring &s, const ams_chartype delimitchar)
+{
+    amsarray<amsstring> ret;
+    int ind;
+
+    ret.resize(2);
+    ind = s.find(delimitchar);
+    if(ind>=0)
+    {
+        ret[0] = s.substring(0,ind);
+        ret[1] = s.substring(ind+1,s.length);
+    }
+    else
+    {
+        ret[0] = s;
+        ret[1] = "";
+    }
+
+    return ret;
+}
+
+amsarray<amsstring> splitfirst(const amsstring &s, const ams_chartype *delimitstr)
+{
+    amsarray<amsstring> ret;
+    int ind;
+
+    ret.resize(2);
+
+    ind = s.find(delimitstr);
+    if(ind>=0)
+    {
+        ret[0] = s.substring(0,ind);
+        ret[1] = s.substring(ind+amsstring_strlen(delimitstr),s.length);
+    }
+    else
+    {
+        ret[0] = s;
+        ret[1] = "";
+    }
+
     return ret;
 }
 
@@ -21,6 +241,43 @@ amsarray<amsstring> splitwhitespace(const amsstring &s)
 {
     amsarray<amsstring> ret;
 
+    int I;
+    int mode;
+    ams_chartype c;
+    int ind1 = 0;
+    int ind2 = 0;
+    I = 0;
+    mode = 0;
+    amsstring q;
+    bool qf = 0;
+  
+    ret.resize(0);
+    while(qf==0)
+    {
+        c = s.cstring[I];
+        if(!(isspace(c)||c==' '||c=='\t')&&mode==0)
+        {
+            mode = 1;
+            ind1 = I;
+            ind1 = ams::max<int>(0,ind1);
+        }
+        if((isspace(c)||c==' '||c=='\t'||c=='\0')&&mode==1)
+        {
+            mode = 0;
+            ind2 = I;
+            ind2 = ams::min<int>(ind2,s.length);
+            s.substring(ind1,ind2,&q);
+            //printf("debug: %d, %s\n",I,q.cstring);
+            ret.push_back(q);
+        }
+        if(I>=s.length)
+        {
+            qf = 1;
+        }
+
+        I = I + 1;
+    }
+
     return ret;
 }
 
@@ -38,6 +295,8 @@ amsstring stripallwhitespace(const amsstring &s)
     return ret;
 }
 
+//splits into two guaranteed pieces
+//if an extension separator . is not encountered, the first piece will contain the entire string, the second ""
 amsarray<amsstring> splitext(const amsstring &s)
 {
     amsarray<amsstring> ret;
@@ -45,6 +304,8 @@ amsarray<amsstring> splitext(const amsstring &s)
     return ret;
 }
 
+//splits into two guaranteed pieces
+//if a path separator is not encountered, the second piece will contain the entire string, and the first ""
 amsarray<amsstring> splitpath(const amsstring &s)
 {
     amsarray<amsstring> ret;
@@ -60,4 +321,11 @@ amsstring select_between(const amsstring &s, const ams_chartype delimitleft, con
     return ret;
 }
 
+amsstring concatenate(const amsarray<amsstring> &slist)
+{
+    amsstring ret;
+
+    return ret;
+}
+
 };//end namespace ams
\ No newline at end of file