diff --git a/build_linux64/libamsstring4.linux64.a b/build_linux64/libamsstring4.linux64.a
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diff --git a/build_linux64/objstore/amsstring4_bintextencoding.o b/build_linux64/objstore/amsstring4_bintextencoding.o
index e27774c..20132cd 100644
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diff --git a/build_linux64/objstore/amsstring4_class.o b/build_linux64/objstore/amsstring4_class.o
index 97cbf55..be08aea 100644
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diff --git a/build_linux64/objstore/amsstring4_convenience1.o b/build_linux64/objstore/amsstring4_convenience1.o
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diff --git a/build_linux64/objstore/amsstring4_portability.o b/build_linux64/objstore/amsstring4_portability.o
index be9c445..ce4db38 100644
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diff --git a/build_linux64/objstore/amsstring4_template.o b/build_linux64/objstore/amsstring4_template.o
index 66e27a5..03f1437 100644
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diff --git a/build_linux64/objstore/amsstring4_tests1.o b/build_linux64/objstore/amsstring4_tests1.o
index 6ff44cd..07cb23d 100644
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diff --git a/build_linux64/objstore/amsstring4_unicode.o b/build_linux64/objstore/amsstring4_unicode.o
index 52f47f6..8102b28 100644
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diff --git a/build_linux64/tests b/build_linux64/tests
index 70249fe..d53356e 100644
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diff --git a/include/amsstring4/amsstring4.hpp b/include/amsstring4/amsstring4.hpp
index 1460803..f495d32 100644
--- a/include/amsstring4/amsstring4.hpp
+++ b/include/amsstring4/amsstring4.hpp
@@ -185,14 +185,21 @@ amsarray<amsstring> splitpath(const amsstring &s);
 //selects between the outermost set of delimitleft and delimitright chars
 amsstring select_between(const amsstring &s, const ams_chartype delimitleft, const ams_chartype delimitright);
 
+//selects between the outermost set of delimitleft and delimitright strings
+//if delimitleft or delimitright strings are empty, selects the left or right end of the array
+amsstring select_between(const amsstring &s, const ams_chartype *delimitleft, const ams_chartype *delimitright); //
+
 amsstring concatenate(const amsarray<amsstring> &slist);
 
+//adds \n between each line in the concatenated string
+amsstring concat_lines(const amsarray<amsstring> &lns);//
+
 
 
 void freadline(FILE *fp, amsstring *s);
-void freadlines(FILE *fp, std::vector<amsstring> *lines);
+void freadlines(FILE *fp, amsarray<amsstring> *lines);
 void fwritelines(FILE *fp, amsstring *s);
-void fwritelines(FILE *fp, std::vector<amsstring> *lines);
+void fwritelines(FILE *fp, amsarray<amsstring> *lines);
 void freadtxtfile(FILE *fp, amsstring *s);
 
 int readtextfile(const amsstring fname, amsstring *s);
diff --git a/include/amsstring4/amsstring4_tests.hpp b/include/amsstring4/amsstring4_tests.hpp
index 25b5aa4..9795998 100644
--- a/include/amsstring4/amsstring4_tests.hpp
+++ b/include/amsstring4/amsstring4_tests.hpp
@@ -19,7 +19,7 @@ namespace ams
 
     void amsstring4_test_concatenation_operators();
     
-    
+    void amsstring4_test_convenience1a();
 
 };
 
diff --git a/src/amsstring4/amsstring4_class.cpp b/src/amsstring4/amsstring4_class.cpp
index 4a6c68f..f988166 100644
--- a/src/amsstring4/amsstring4_class.cpp
+++ b/src/amsstring4/amsstring4_class.cpp
@@ -793,8 +793,8 @@ namespace ams
       cc = 0;
       for(I=length-indstart-1;I>=0;I--)
       {
-        c1 = cstring[I];
-        c2 = findstr[J];
+        if(I>=0 && I<length) c1 = cstring[I];
+        if(J>=0 && J<findstrlen) c2 = findstr[J];
         b1 = casesens&&(c1==c2);
         b2 = (!casesens)&&(ams::tolower(c1)==ams::tolower(c2));
         beq = b1 || b2;
@@ -808,7 +808,7 @@ namespace ams
         {
           cc+=1;
           J--;
-          if(cc==findstrlen || J<0)
+          if(cc>=findstrlen || J<0)
           {
             ret = I;
             break;
@@ -1270,7 +1270,7 @@ namespace ams
       return;
     }
     
-    void freadlines(FILE *fp, std::vector<amsstring> *lines)
+    void freadlines(FILE *fp, amsarray<amsstring> *lines)
     {
       amsstring ln;
       //note - this does not resize the lines to zero, just adds to them
@@ -1294,7 +1294,7 @@ namespace ams
       return;
     }
     
-    void fwritelines(FILE *fp, std::vector<amsstring> *lines)
+    void fwritelines(FILE *fp, amsarray<amsstring> *lines)
     {
       int I;
       if(fp!=NULL && lines!=NULL)
diff --git a/src/amsstring4/amsstring4_convenience1.cpp b/src/amsstring4/amsstring4_convenience1.cpp
index e9f848a..efb473a 100644
--- a/src/amsstring4/amsstring4_convenience1.cpp
+++ b/src/amsstring4/amsstring4_convenience1.cpp
@@ -440,4 +440,162 @@ amsstring concatenate(const amsarray<amsstring> &slist)
     return ret;
 }
 
+void amsstring4_test_findright()
+{
+  amsstring s1,s2;
+  int I;
+  int I1,I2,I3,I4;
+
+  s1 = "sdkfjskdfksd";
+  for(I=-1;I<s1.length+2;I++)
+  {
+    s2 = s1;
+    s2.insert(I,".");
+    I1 = s2.find('.');
+    I2 = s2.find(".");
+    I3 = s2.findright('.');
+    I4 = s2.findright(".");
+
+    printf("s = '%s'\n",s2.cstring);
+    printf("Found . at (%d,%d,%d,%d)\n",I1,I2,I3,I4);
+  }
+
+  printf("\n\n");
+  for(I=-1;I<s1.length+2;I++)
+  {
+    s2 = s1;
+    s2.insert(I,".");
+    s2.insert(I+3,".");
+    I1 = s2.find('.');
+    I2 = s2.find(".");
+    I3 = s2.findright('.');
+    I4 = s2.findright(".");
+
+    printf("s = '%s'\n",s2.cstring);
+    printf("Found . at (%d,%d,%d,%d)\n",I1,I2,I3,I4);
+  }
+
+  printf("\n\n");
+  for(I=-1;I<s1.length+2;I++)
+  {
+    s2 = s1;
+    s2.insert(I,"FND");
+    I1 = s2.find("FND");
+    I2 = s2.findright("FND");
+
+    printf("s = '%s'\n",s2.cstring);
+    printf("Found . at (%d,%d)\n",I1,I2);
+  }
+
+  printf("\n\n");
+  for(I=-1;I<s1.length+2;I++)
+  {
+    s2 = s1;
+    s2.insert(I,"FND");
+    s2.insert(I+5,"FND");
+    I1 = s2.find("FND");
+    I2 = s2.findright("FND");
+    I3 = s2.find("FNF");
+    I4 = s2.findright("FNF");
+
+    printf("s = '%s'\n",s2.cstring);
+    printf("Found . at (%d,%d,%d,%d)\n",I1,I2,I3,I4);
+  }
+}
+
+void amsstring4_test_convenience1a()
+{
+  amsstring s1,s2;
+  amsarray<amsstring> sa;
+  int I;
+
+  s1 = "a string\nwith multiple\nlines\n\r";
+  sa = splitlines(s1);
+  for(I=0;I<sa.length;I++)
+  {
+    printf("%d:%d: %s\n",I,sa[I].length,sa[I].cstring);
+  }
+
+  printf("\n\n");
+  s1 = " some, comma, separated,variables,,";
+  sa = split(s1,',');
+  for(I=0;I<sa.length;I++)
+  {
+    printf("%d:%d: %s\n",I,sa[I].length,sa[I].cstring);
+  }
+
+  printf("\n\n");
+  s1 = " some:: oddly:: separated:variables::";
+  sa = split(s1,"::");
+  for(I=0;I<sa.length;I++)
+  {
+    printf("%d:%d: %s\n",I,sa[I].length,sa[I].cstring);
+  }
+
+  printf("\n\n");
+  s1 = "  a string  with lots\tof\t\twhitespace ";
+  sa = splitwhitespace(s1);
+  for(I=0;I<sa.length;I++)
+  {
+    printf("%d:%d: %s\n",I,sa[I].length,sa[I].cstring);
+  }
+
+  s2 = stripwhitespace(s1);
+  printf("s1 = '%s'\ns2='%s'\n",s1.cstring,s2.cstring);
+  s2 = stripallwhitespace(s1);
+  printf("s3 = '%s'\n",s2.cstring);
+  
+  s1 = "astring.with.separatorchars";
+  printf("'%s' split: '%s' '%s'\n",s1.cstring,splitfirst(s1,'.')[0].cstring, splitfirst(s1,'.')[1].cstring);
+  s1 = "astring_without_separatorchars";
+  printf("'%s' split: '%s' '%s'\n",s1.cstring,splitfirst(s1,'.')[0].cstring, splitfirst(s1,'.')[1].cstring);
+  
+  s1 = "astring::with::separator:strs";
+  printf("'%s' split: '%s' '%s'\n",s1.cstring,splitfirst(s1,"::")[0].cstring, splitfirst(s1,"::")[1].cstring);
+  s1 = "astring_without_separatorstrs";
+  printf("'%s' split: '%s' '%s'\n",s1.cstring,splitfirst(s1,"::")[0].cstring, splitfirst(s1,"::")[1].cstring);
+
+  s1 = "somefilewithoutextension";
+  sa = splitext(s1);
+  printf("splitext('%s') = ['%s','%s']\n",s1.cstring,sa[0].cstring,sa[1].cstring);
+
+  s1 = "somefilewithalittleext.";
+  sa = splitext(s1);
+  printf("splitext('%s') = ['%s','%s']\n",s1.cstring,sa[0].cstring,sa[1].cstring);
+
+  s1 = "somefilewith.anextension";
+  sa = splitext(s1);
+  printf("splitext('%s') = ['%s','%s']\n",s1.cstring,sa[0].cstring,sa[1].cstring);
+
+  s1 = "somefilewith.many.extensions";
+  sa = splitext(s1);
+  printf("splitext('%s') = ['%s','%s']\n",s1.cstring,sa[0].cstring,sa[1].cstring);
+
+  s1 = "somepathnoseparators";
+  sa = splitpath(s1);
+  printf("splitpath('%s') = ['%s','%s']\n",s1.cstring,sa[0].cstring,sa[1].cstring);
+
+  s1 = "\\someotherpath";
+  sa = splitpath(s1);
+  printf("splitpath('%s') = ['%s','%s']\n",s1.cstring,sa[0].cstring,sa[1].cstring);
+
+  s1 = "/someotherpath";
+  sa = splitpath(s1);
+  printf("splitpath('%s') = ['%s','%s']\n",s1.cstring,sa[0].cstring,sa[1].cstring);
+
+  s1 = "C:\\someotherpath";
+  sa = splitpath(s1);
+  printf("splitpath('%s') = ['%s','%s']\n",s1.cstring,sa[0].cstring,sa[1].cstring);
+
+  s1 = "C:\\some\\other\\path";
+  sa = splitpath(s1);
+  printf("splitpath('%s') = ['%s','%s']\n",s1.cstring,sa[0].cstring,sa[1].cstring);
+
+  s1 = "/some/other/path";
+  sa = splitpath(s1);
+  printf("splitpath('%s') = ['%s','%s']\n",s1.cstring,sa[0].cstring,sa[1].cstring);
+
+
+}   
+
 };//end namespace ams
\ No newline at end of file
diff --git a/src/amsstring4/amsstring4_tests1.cpp b/src/amsstring4/amsstring4_tests1.cpp
index 106bfa0..a673a81 100644
--- a/src/amsstring4/amsstring4_tests1.cpp
+++ b/src/amsstring4/amsstring4_tests1.cpp
@@ -313,17 +313,16 @@ namespace ams
         int I;
         amsstring q1;
         amsarray<amsstring> lns;
-        std::vector<amsstring> lns2;
         q1 = "This is a \n string on \n multiple \r\n lines\n\n with CR\\LFs\n";
         //q1 = "\n\n";
         //q1 = "";
         //q1 = "More malformed\r string nonsense\n\r\n\r\r\na";
     
         printf("q1='%s'\n",q1.cstring);
-        splitlines(&q1,&lns2);
-        for(I=0;I<lns2.size();I++)
+        splitlines(&q1,&lns);
+        for(I=0;I<lns.size();I++)
         {
-            printf("Line %d: '%s'\n",I,lns2[I].cstring);
+            printf("Line %d: '%s'\n",I,lns[I].cstring);
         }
         return;
     }
@@ -331,7 +330,7 @@ namespace ams
     void amsstring4_test_split()
     {
         amsstring q1;
-        std::vector<amsstring> strs;
+        amsarray<amsstring> strs;
         int I;
     
         q1 = "this is a string  to split  ";
@@ -396,7 +395,7 @@ namespace ams
     void amsstring4_test_strip()
     {
         amsstring q1;
-        std::vector<amsstring> strs;
+        amsarray<amsstring> strs;
         int I;
     
         q1 = "   ";
@@ -425,7 +424,7 @@ namespace ams
         FILE *fp2 = NULL;
         int I;
         amsstring q;
-        std::vector<amsstring> q2;
+        amsarray<amsstring> q2;
     
         fp = fopen("./ref/0p375_hexbolt.scad","r");
         fp2 = fopen("./ref/testrewrite.scad","w+");
diff --git a/src/main.cpp b/src/main.cpp
index f6c09ed..a1e5042 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -21,6 +21,8 @@ int main(int argc, char* argv[])
     // amsstring4_test_freadwrite();
 
     // amsstring4_test_concatenation_operators(); 
+
+    amsstring4_test_convenience1a();
     
     return ret;
 }
\ No newline at end of file