diff --git a/Expression.cpp b/Expression.cpp
index ec1455c..b0d03eb 100644
--- a/Expression.cpp
+++ b/Expression.cpp
@@ -6,10 +6,13 @@ namespace jet {
 
    Expression::Expression(coreutils::ZString &in) : MString() {
       std::cout << "Expression construction:" << in << std::endl;
-
+      
       Operand op1(in);
       
       boolean = op1.boolean;
+      string = op1.string;
+
+      std::cout << "Leaving expression string: " << string << std::endl;
    }
 
    Expression::~Expression() {}
diff --git a/Expression.h b/Expression.h
index 875b9d9..6d02c93 100644
--- a/Expression.h
+++ b/Expression.h
@@ -15,6 +15,7 @@ namespace  jet {
       double getNumericResult();
       coreutils::ZString getStringResult();
       bool boolean;
+      coreutils::ZString string;
    };
 
 }
diff --git a/Operand.cpp b/Operand.cpp
index deaf72f..6b87f10 100644
--- a/Operand.cpp
+++ b/Operand.cpp
@@ -1,15 +1,56 @@
 #include "Operand.h"
+#include "Exception.h"
 
 namespace jet {
 
    Operand::Operand(coreutils::ZString &in) {
 
+      in.skipWhitespace();
+
+      if(in.ifNext("SUBSTRING")) {
+	 if(!in.ifNext("("))
+	   throw coreutils::Exception("Expecting ( for SUBSTRING parameters.");
+	 Operand parm1(in);
+	 if(!in.ifNext(","))
+	   throw coreutils::Exception("Expecting , in SUBSTRING expression.");
+	 Operand parm2(in);
+	 if(in.ifNext(")")) {	      
+	    string = parm1.string.substring(parm2.string.asInteger());
+	 }
+	 else if(!in.ifNext(","))
+	   throw coreutils::Exception("Expecting , in SUBSTRING expression.");
+	 Operand parm3(in);
+	 if(in.ifNext(")")) {
+	    string = parm1.string.substring(parm2.string.asInteger(), parm3.string.asInteger());
+	 }
+	 else
+	   throw coreutils::Exception("Expecting ) at end of substring expression.");
+      }
+  
+      else if(in.ifNext("LEFT")) {
+	 
+      } else if(in.ifNext("RIGHT")) {
+	 
+      } else if(in.ifNext("TRIM")) {
+	 
+      } else if(in.ifNext("TOUPPER")) {
+	 
+      } else if(in.ifNext("TOLOWER")) {
+	 
+      } else if(in.ifNext("REVERSE")) {
+	 
+      } else if(in.ifNext("CONCAT")) {
+	 
+      }
+      
       if(in.ifNext("true")) {
 	 boolean = true;
+	 string = "true";
 	 return;
       }
       if(in.ifNext("false")) {
 	 boolean = false;
+	 string = "false";
 	 return;
       }
       
diff --git a/Operand.h b/Operand.h
index 0d6b523..d4ffb38 100644
--- a/Operand.h
+++ b/Operand.h
@@ -16,13 +16,13 @@ namespace jet {
       bool isString();
       bool isVariable();
 
-
       ///
       /// boolean is set by internal processes to return the boolean
       /// equivilent value.
       ///
       
       bool boolean;
+      coreutils::ZString string;
       
     private:
 //      dataType enum ={};
diff --git a/Tag.cpp b/Tag.cpp
index 1c10823..be5e096 100644
--- a/Tag.cpp
+++ b/Tag.cpp
@@ -7,8 +7,10 @@
 #include "__for.h"
 #include "__if.h"
 #include "__read.h"
+#include "__write.h"
 #include "__set.h"
 #include "__call.h"
+#include "__system.h"
 #include "__jet.h"
 #include "__while.h"
 #include <iostream>
@@ -119,11 +121,17 @@ namespace jet {
 	    } else if(ifTagName(in, "read")) {
 	       __read _read(in, out, global);
 	       continue;
+	    } else if(ifTagName(in, "write")) {
+	       __write _write(in, out, global);
+	       continue;
 	    } else if(ifTagName(in, "set")) {
 	       __set _set(in, out, global);
 	       continue;
 	    } else if(ifTagName(in, "call")) {
-	       __call _set(in, out, global);
+	       __call _call(in, out, global);
+	       continue;
+	    } else if(ifTagName(in, "system")) {
+	       __system _system(in, out, global);
 	       continue;
 	    } else if(ifTagName(in, "while")) {
 	       __while _while(in, out, global);
diff --git a/__call.cpp b/__call.cpp
index d2157fc..33ec9aa 100644
--- a/__call.cpp
+++ b/__call.cpp
@@ -1,4 +1,4 @@
-#include "__system.h"
+#include "__call.h"
 #include "Exception.h"
 #include "MString.h"
 #include <stdlib.h>
@@ -8,7 +8,7 @@
 
 namespace jet {
    
-   __system::__system(coreutils::ZString &in, coreutils::MString &out, Global &global) : Tag(in, out, global) {
+   __call::__call(coreutils::ZString &in, coreutils::MString &out, Global &global) : Tag(in, out, global) {
       if(hasContainer)
 	throw coreutils::Exception("call cannot have a container.");	
       if(!variableDefined(coreutils::ZString("pgm")))
@@ -51,7 +51,6 @@ namespace jet {
       else 
 	out.read(fdo[0]);               
       waitpid(pid, &status, 0);
-      std::cout << "status: " << status << std::endl;
    }
    
 }
diff --git a/__call.h b/__call.h
index bea3b18..09beb14 100644
--- a/__call.h
+++ b/__call.h
@@ -1,14 +1,14 @@
-#ifndef ____system_h__
-#define ____system_h__
+#ifndef ____call_h__
+#define ____call_h__
 
 #include "Tag.h"
 
 namespace jet {
    
-   class __system : public Tag {
+   class __call : public Tag {
    
     public:
-      __system(coreutils::ZString &in, coreutils::MString &out, Global &global);
+      __call(coreutils::ZString &in, coreutils::MString &out, Global &global);
 
     private:
       int pid;
diff --git a/__set.cpp b/__set.cpp
index 6b5fead..102f02a 100644
--- a/__set.cpp
+++ b/__set.cpp
@@ -22,7 +22,7 @@ namespace jet {
 	 if(variableDefined("expr")) {
 	    if(variableDefined("eval"))
 	      throw coreutils::Exception("Cannot use eval with expr.");
-	    global.variables[variables["name"]] = Expression(variables["expr"]);	    
+	    global.variables[variables["name"]] = Expression(variables["expr"]).string;	    
 	 } else if(hasContainer) {
 	    if(evaluate) {
 	       global.variables[variables["name"]] = out;	       
diff --git a/__system.cpp b/__system.cpp
index 89b2650..d2157fc 100644
--- a/__system.cpp
+++ b/__system.cpp
@@ -1,4 +1,4 @@
-#include "__call.h"
+#include "__system.h"
 #include "Exception.h"
 #include "MString.h"
 #include <stdlib.h>
@@ -8,7 +8,7 @@
 
 namespace jet {
    
-   __call::__call(coreutils::ZString &in, coreutils::MString &out, Global &global) : Tag(in, out, global) {
+   __system::__system(coreutils::ZString &in, coreutils::MString &out, Global &global) : Tag(in, out, global) {
       if(hasContainer)
 	throw coreutils::Exception("call cannot have a container.");	
       if(!variableDefined(coreutils::ZString("pgm")))
diff --git a/__system.h b/__system.h
index 09beb14..bea3b18 100644
--- a/__system.h
+++ b/__system.h
@@ -1,14 +1,14 @@
-#ifndef ____call_h__
-#define ____call_h__
+#ifndef ____system_h__
+#define ____system_h__
 
 #include "Tag.h"
 
 namespace jet {
    
-   class __call : public Tag {
+   class __system : public Tag {
    
     public:
-      __call(coreutils::ZString &in, coreutils::MString &out, Global &global);
+      __system(coreutils::ZString &in, coreutils::MString &out, Global &global);
 
     private:
       int pid;
diff --git a/testjet.cpp b/testjet.cpp
index a14d3da..47e639c 100644
--- a/testjet.cpp
+++ b/testjet.cpp
@@ -10,14 +10,17 @@ int main(int argc, char **argv) {
 			   " <comment>This is a comment and should not show up in the output.</comment>\n"
 			   " <html>\n"
 			   " <set name=\"ix\" value=\"1\" />\n"
-			   " <set name=\"theexpr\" expr=\"true\" />\n"
+			   " <set name=\"theexpr\" expr=\"SUBSTRING(\"abcdefg\",1,3)\" />\n"
+			   " <set name=\"theexpr2\" expr=\"5+3\" />\n"
+			   " theexpr=($[theexpr])\n"
+			   " theexpr2($[theexpr2])\n"
 			   " <set name=\"varname$[ix]\" value=\"vardata\" scope=\"global\" />\n"
 			   " <set name=\"noeval\" eval=\"no\">this is the value store in #[name].</set>\n"
 			   " <set name=\"thename\" eval=\"yes\">this is the value store in #[name].</set>\n"
 			   " <set name=\"newname\" scope=\"global\">another container value</set>\n"
 			   " >>>$[noeval]<<<\n"
 			   " >>>$[thename]<<<\n"
-			   " local: >>>#[name]<<<\n"
+			   " local: >>>#[namex]<<<\n"
 			   " <mysql key=\"uu\">\n"
 			   "  <if value1=\"X\" value2=\"Y\" type=\"ne\">\n"
 			   "   789\n"
@@ -32,9 +35,9 @@ int main(int argc, char **argv) {
 			   "  -->#[ix]<--\n"
 			   " </for>\n"
 			   " <call pgm=\"/usr/bin/ls\" arg1=\"-al\" name=\"ls\" />\n"
-			   " $[ls]\n"
+			   " $[lsi]\n"
 			   " <read file=\"compile\" name=\"file\" />\n"
-			   " $[file]\n"
+			   " $[filex]\n"
 			   " </html>\n"
 			   "</jet>\n");