diff --git a/.gitignore b/.gitignore
index 685e9c6..5d4f84a 100644
--- a/.gitignore
+++ b/.gitignore
@@ -2,4 +2,5 @@
 y.tab.h
 parser.c
 scanner.c
-vslc
\ No newline at end of file
+vslc
+vgcore*
\ No newline at end of file
diff --git a/src/ir.c b/src/ir.c
index 4f457e6..39fffa9 100644
--- a/src/ir.c
+++ b/src/ir.c
@@ -6,6 +6,11 @@ extern tlhash_t *global_names;
 extern char **string_list;
 extern size_t n_string_list,stringc;
 
+struct scope_stack {
+  struct scope_stack *next;
+  tlhash_t *scope;
+};
+
 /* External interface */
 
 void create_symbol_table(void);
@@ -22,7 +27,10 @@ void
 create_symbol_table ( void )
 {
   global_names = malloc(sizeof(tlhash_t));
-  tlhash_init(global_names, 20);
+  if (tlhash_init(global_names, 1) != TLHASH_SUCCESS) {
+    printf("Couldn't initialize symbol table\n");
+    exit(1);
+  }
   find_globals();
   size_t n_globals = tlhash_size ( global_names );
   symbol_t *global_list[n_globals];
@@ -142,12 +150,31 @@ destroy_symbol_table ( void )
       destroy_symtab();
 }
 
-// Helper function
+// Insert a global symbol into the symbol table
+// These symbols are unique, so we use their name as the key
 void tlhash_insert_symbol(tlhash_t *tab, symbol_t *symbol)
 {
   tlhash_insert(tab, symbol->name, strlen(symbol->name), symbol);
 }
 
+// Insert a local symbol into the symbol table
+// These symbols can have the same names as other symbols,
+// so we generate an unique name for each
+void tlhash_insert_local_symbol(tlhash_t *tab, symbol_t *symbol, char *function_name, int seq)
+{
+  size_t size = strlen(function_name) + strlen(symbol->name) + 6;
+  char *key = calloc(size, sizeof(char*));
+  int result = snprintf(key, size, "%s:%s:%d", function_name, symbol->name, seq);
+
+  if (result < 0 || result >= size) {
+    printf("Couldn't create key for local symbol %s\n", symbol->name);
+    exit(1);
+  }
+
+  tlhash_insert(tab, key, size, symbol);
+  free(key);
+}
+
 void
 find_globals ( void )
 {
@@ -156,52 +183,270 @@ find_globals ( void )
 
   for (int i = 0; i < global_list->n_children; i++) {
     node_t *child = global_list->children[i];
-    symbol_t *symbol = malloc(sizeof(symbol_t));
-    symbol->node = child;
 
     if (child->type == DECLARATION) {
-      symbol->name = child->children[0]->children[0]->data;
-      symbol->type = SYM_GLOBAL_VAR;
+      for (int j = 0; j < child->children[0]->n_children; j++) {
+	symbol_t *symbol = malloc(sizeof(symbol_t));
+	symbol->locals = NULL;
+	symbol->node = child->children[0]->children[j];
+	symbol->name = symbol->node->data;
+	symbol->type = SYM_GLOBAL_VAR;
+	tlhash_insert_symbol(global_names, symbol);
+      }
     } else if (child->type == FUNCTION) {
+      symbol_t *symbol = malloc(sizeof(symbol_t));
+      symbol->node = child;
       symbol->name = child->children[0]->data;
       symbol->type = SYM_FUNCTION;
-      symbol->nparms = child->children[1]->n_children;
-      symbol->seq = function_count;
-      function_count++;
-
+      symbol->seq = function_count++;
       symbol->locals = malloc(sizeof(tlhash_t));
-      tlhash_init(symbol->locals, symbol->nparms/2);
-
-      for (int j = 0; j < symbol->nparms; j++) {
-	node_t *parameter = child->children[1]->children[j];
-        symbol_t *parameter_symbol = malloc(sizeof(symbol_t));
-	parameter_symbol->name = parameter->data;
-	parameter_symbol->type = SYM_PARAMETER;
-	parameter_symbol->node = parameter;
-	parameter_symbol->seq = j;
+      if (tlhash_init(symbol->locals, 1) != TLHASH_SUCCESS) {
+	printf("Couldn't initialize local symbol table for function %s\n", symbol->name);
+	exit(1);
+      }
 
-	tlhash_insert_symbol(symbol->locals, parameter_symbol);
+      if (child->children[1] != NULL) {
+	symbol->nparms = child->children[1]->n_children;
+      } else {
+	symbol->nparms = 0;
       }
+
+      tlhash_insert_symbol(global_names, symbol);
     } else {
-      // The node should be a variable or a function.
-      // Something is wrong
+      puts("The node should be a variable or a function. Something is wrong\n");
+      exit(1);
+    }
+  }
+}
+
+void
+bind_variable(symbol_t *function, node_t *identifier, struct scope_stack *stack)
+{
+  char *name = identifier->data;
+  symbol_t *symbol;
+
+  while (stack != NULL) {
+    int result = tlhash_lookup(stack->scope, name, strlen(name), &symbol);
+
+    if (result == TLHASH_SUCCESS) {
+      identifier->entry = symbol;
+      return;
+    } else if (result == TLHASH_ENOMEM) {
+      puts("Error in bind_variable: No memory available");
       exit(1);
     }
 
-    tlhash_insert_symbol(global_names, symbol);
+    stack = stack->next;
   }
+
+  // The variable is not declared
+  printf("Error in function %s: Variable %s is not defined\n", function->name, identifier->data);
+  exit(1);
 }
 
 void
-bind_names ( symbol_t *function, node_t *root )
+bind_string(node_t *node)
+{
+  if (node->type != STRING_DATA) {
+    printf("Error in bind_string: Illegal node type %d\n", node->type);
+    exit(1);
+  }
+
+  if (string_list == NULL) {
+    string_list = calloc(stringc + 1, sizeof(char*));
+  } else {
+    string_list = realloc(string_list, (stringc + 1)*sizeof(char*));
+  }
+  if (string_list == NULL) {
+    printf("Error in bind_string: Couldn't realloc string array with size %d\n", stringc+1);
+  }
+  string_list[stringc] = node->data;
+  size_t *count = malloc(sizeof(size_t));
+  *count = stringc;
+  node->data = (void*) count;
+  stringc++;
+}
+
+void
+bind_expression(symbol_t *function, node_t *expression, struct scope_stack *stack)
+{
+  if (expression->type == IDENTIFIER_DATA) {
+    bind_variable(function, expression, stack);
+  } else if (expression->type == STRING_DATA) {
+    bind_string(expression);
+  } else if (expression->type == NUMBER_DATA) {
+    // Ignore
+  } else if (expression->type == EXPRESSION || expression->type == RELATION) {
+    if (expression->data == NULL) {
+      bind_variable(function, expression->children[0], stack);
+
+      for (int i = 0; i < expression->children[1]->n_children; i++) {
+	node_t *child = expression->children[1]->children[i];
+
+	if (child->type == IDENTIFIER_DATA) {
+	  bind_variable(function, child, stack);
+	} else if (child->type == EXPRESSION) {
+	  bind_expression(function, child, stack);
+	}
+      }
+    } else {
+      for (int i = 0; i < expression->n_children; i++) {
+	bind_expression(function, expression->children[i], stack);
+      }
+    }
+  } else {
+    printf("Error in bind_expression: Illegal node type %d\n", expression->type);
+    exit(1);
+  }
+}
+
+void
+bind_statement(symbol_t *function, node_t *node, struct scope_stack *stack)
+{
+  if (node->type == ASSIGNMENT_STATEMENT) {
+    bind_variable(function, node->children[0], stack);
+    bind_expression(function, node->children[1], stack);
+  } else if (node->type == PRINT_STATEMENT) {
+    for (int i = 0; i < node->n_children; i++) {
+      bind_expression(function, node->children[i], stack);
+    }
+  } else if (node->type == IF_STATEMENT || node->type == WHILE_STATEMENT) {
+    bind_expression(function, node->children[0], stack);
+
+    // The if statement can have two sub-statements, the if and the else.
+    // The while statement only has one, but the logic is the same
+    for (int i = 1; i < node->n_children; i++) {
+      if (node->children[i]->type == BLOCK) {
+	bind_scope(function, node->children[i], stack);
+      } else {
+	bind_statement(function, node->children[i], stack);
+      }
+    }
+  } else if (node->type == RETURN_STATEMENT) {
+    bind_expression(function, node->children[0], stack);
+  }
+}
+
+void
+bind_scope ( symbol_t *function, node_t *root, struct scope_stack *parent_stack )
 {
   // Go through variable list, add to local scope
-  // Go through rest of function
-  // Replace variable references with pointers to the symbol table
-  // put strings in the symbol table, and increment root->data = stringc
+  node_t *statement_list;
+  int seq = tlhash_size(function->locals);
+
+  struct scope_stack *stack = malloc(sizeof(struct scope_stack));
+  stack->next = parent_stack;
+  stack->scope = malloc(sizeof(tlhash_t));
+  if (tlhash_init(stack->scope, 1) != TLHASH_SUCCESS) {
+    printf("Couldn't initialize stack\n");
+    exit(1);
+  }
+
+  if (root->n_children == 2) {
+    node_t *variable_list = root->children[0];
+    statement_list = root->children[1];
+
+    for (int i = 0; i < variable_list->n_children; i++) {
+      for (int j = 0; j < variable_list->children[i]->children[0]->n_children; j++) {
+	node_t *variable = variable_list->children[i]->children[0]->children[j];
+	symbol_t *variable_symbol = malloc(sizeof(symbol_t));
+	variable_symbol->name = variable->data;
+	variable_symbol->type = SYM_LOCAL_VAR;
+	variable_symbol->node = variable;
+	variable_symbol->seq = seq++;
+
+	// Insert into the global table with an unique key
+	tlhash_insert_local_symbol(function->locals, variable_symbol, function->name, seq);
+	// Insert into the global table with the name as the key
+	tlhash_insert_symbol(stack->scope, variable_symbol);
+      }
+    }
+  } else {
+    statement_list = root->children[0];
+  }
+
+  for (int i = 0; i < statement_list->n_children; i++) {
+    bind_statement(function, statement_list->children[i], stack);
+  }
+
+  tlhash_finalize(stack->scope);
+  free(stack->scope);
+  free(stack);
+}
+
+void
+bind_names ( symbol_t *function, node_t *root )
+{
+  struct scope_stack *global_stack = malloc(sizeof(struct scope_stack));
+  struct scope_stack *stack = malloc(sizeof(struct scope_stack));
+
+  global_stack->next = NULL;
+  global_stack->scope = global_names;
+  stack->next = global_stack;
+  stack->scope = malloc(sizeof(tlhash_t));
+  if (tlhash_init(stack->scope, 1) != TLHASH_SUCCESS) {
+    printf("Couldn't initialize stack\n");
+    exit(1);
+  }
+
+  // Insert the function parameters into the symbol table
+  for (int i = 0; i < function->nparms; i++) {
+    node_t *parameter = root->children[1]->children[i];
+    symbol_t *parameter_symbol = malloc(sizeof(symbol_t));
+    parameter_symbol->name = parameter->data;
+    parameter_symbol->type = SYM_PARAMETER;
+    parameter_symbol->node = parameter;
+    parameter_symbol->seq = i;
+
+    // Insert into the global table with an unique key
+    tlhash_insert_local_symbol(function->locals, parameter_symbol, function->name, i);
+    // Insert into the global table with the name as the key
+    tlhash_insert_symbol(stack->scope, parameter_symbol);
+  }
+
+  bind_scope(function, root->children[2], stack);
+
+  tlhash_finalize(stack->scope);
+  free(stack->scope);
+  free(stack);
+  free(global_stack);
 }
 
 void
 destroy_symtab ( void )
 {
+  for (int i = 0; i < stringc; i++) {
+    free(string_list[i]);
+  }
+  free(string_list);
+
+  symbol_t **values = calloc(tlhash_size(global_names), sizeof(symbol_t*));
+  tlhash_values(global_names, values);
+
+  if (values != NULL) {
+    for (int i = 0; i < tlhash_size(global_names); i++) {
+      symbol_t *symbol = values[i];
+
+      if (symbol->locals != NULL) {
+	symbol_t **local_values = calloc(tlhash_size(symbol->locals), sizeof(symbol_t*));
+	tlhash_values(symbol->locals, local_values);
+
+	if (local_values != NULL) {
+	  for (int i = 0; i < tlhash_size(symbol->locals); i++) {
+	    symbol_t *local_symbol = local_values[i];
+	    free(local_symbol);
+	  }
+	}
+
+	free(local_values);
+	tlhash_finalize(symbol->locals);
+	free(symbol->locals);
+      }
+
+      free(symbol);
+    }
+  }
+  free(values);
+  tlhash_finalize(global_names);
+  free(global_names);
 }
diff --git a/vsl_programs/euclid.tree b/vsl_programs/euclid.tree
index b812cea..960eb7d 100644
--- a/vsl_programs/euclid.tree
+++ b/vsl_programs/euclid.tree
@@ -82,3 +82,53 @@
        IDENTIFIER_DATA(a)
      RETURN_STATEMENT
       IDENTIFIER_DATA(g)
+String table:
+0: "Greatest common divisor of"
+1: "and"
+2: "is"
+3: "and"
+4: "are relative primes"
+-- 
+Globals:
+gcd: function 1:
+	3 local variables, 2 are parameters:
+	g: local var 2
+	b: parameter 1
+	a: parameter 0
+euclid: function 0:
+	2 local variables, 2 are parameters:
+	b: parameter 1
+	a: parameter 0
+-- 
+Linked parameter 0 ('a')
+Linked parameter 0 ('a')
+Linked parameter 0 ('a')
+Linked parameter 1 ('b')
+Linked parameter 1 ('b')
+Linked parameter 1 ('b')
+Linked function 1 ('gcd')
+Linked parameter 0 ('a')
+Linked parameter 1 ('b')
+Linked string 0
+Linked parameter 0 ('a')
+Linked string 1
+Linked parameter 1 ('b')
+Linked string 2
+Linked function 1 ('gcd')
+Linked parameter 0 ('a')
+Linked parameter 1 ('b')
+Linked parameter 0 ('a')
+Linked string 3
+Linked parameter 1 ('b')
+Linked string 4
+Linked parameter 1 ('b')
+Linked local var 2 ('g')
+Linked function 1 ('gcd')
+Linked parameter 1 ('b')
+Linked parameter 0 ('a')
+Linked parameter 0 ('a')
+Linked parameter 1 ('b')
+Linked parameter 1 ('b')
+Linked local var 2 ('g')
+Linked parameter 0 ('a')
+Linked local var 2 ('g')
diff --git a/vsl_programs/lexical.tree b/vsl_programs/lexical.tree
index 16fa2cf..6597a7c 100644
--- a/vsl_programs/lexical.tree
+++ b/vsl_programs/lexical.tree
@@ -116,3 +116,81 @@
          IDENTIFIER_DATA(a)
      RETURN_STATEMENT
       NUMBER_DATA(0)
+String table:
+0: "Hello, world!"
+1: ""
+2: "Hello, \"world\"!"
+3: "+"
+4: ":="
+5: "-"
+6: ":="
+7: "+ (-"
+8: ") :="
+9: "*"
+10: ":="
+11: "/"
+12: ":="
+13: "Skip..."
+-- 
+Globals:
+main: function 0:
+	3 local variables, 0 are parameters:
+	a_2: local var 2
+	_a1: local var 1
+	a: local var 0
+-- 
+Linked string 0
+Linked string 1
+Linked string 2
+Linked local var 1 ('_a1')
+Linked local var 2 ('a_2')
+Linked local var 0 ('a')
+Linked local var 1 ('_a1')
+Linked local var 2 ('a_2')
+Linked local var 1 ('_a1')
+Linked string 3
+Linked local var 2 ('a_2')
+Linked string 4
+Linked local var 0 ('a')
+Linked local var 0 ('a')
+Linked local var 1 ('_a1')
+Linked local var 2 ('a_2')
+Linked local var 1 ('_a1')
+Linked string 5
+Linked local var 2 ('a_2')
+Linked string 6
+Linked local var 0 ('a')
+Linked local var 0 ('a')
+Linked local var 1 ('_a1')
+Linked local var 2 ('a_2')
+Linked local var 1 ('_a1')
+Linked string 7
+Linked local var 2 ('a_2')
+Linked string 8
+Linked local var 0 ('a')
+Linked local var 0 ('a')
+Linked local var 1 ('_a1')
+Linked local var 2 ('a_2')
+Linked local var 1 ('_a1')
+Linked string 9
+Linked local var 2 ('a_2')
+Linked string 10
+Linked local var 0 ('a')
+Linked local var 0 ('a')
+Linked local var 1 ('_a1')
+Linked local var 2 ('a_2')
+Linked local var 1 ('_a1')
+Linked string 11
+Linked local var 2 ('a_2')
+Linked string 12
+Linked local var 0 ('a')
+Linked local var 0 ('a')
+Linked local var 0 ('a')
+Linked local var 0 ('a')
+Linked local var 0 ('a')
+Linked local var 0 ('a')
+Linked local var 0 ('a')
+Linked local var 0 ('a')
+Linked local var 0 ('a')
+Linked string 13
+Linked local var 0 ('a')
diff --git a/vsl_programs/newton.tree b/vsl_programs/newton.tree
index 5b3dc7b..aa3ba1e 100644
--- a/vsl_programs/newton.tree
+++ b/vsl_programs/newton.tree
@@ -57,3 +57,34 @@
         EXPRESSION_LIST
          IDENTIFIER_DATA(n)
          IDENTIFIER_DATA(next)
+String table:
+0: "The square root of"
+1: "is"
+-- 
+Globals:
+improve: function 1:
+	3 local variables, 2 are parameters:
+	next: local var 2
+	estimate: parameter 1
+	n: parameter 0
+newton: function 0:
+	1 local variables, 1 are parameters:
+	n: parameter 0
+-- 
+Linked string 0
+Linked parameter 0 ('n')
+Linked string 1
+Linked function 1 ('improve')
+Linked parameter 0 ('n')
+Linked local var 2 ('next')
+Linked parameter 1 ('estimate')
+Linked parameter 1 ('estimate')
+Linked parameter 1 ('estimate')
+Linked parameter 0 ('n')
+Linked parameter 1 ('estimate')
+Linked local var 2 ('next')
+Linked parameter 1 ('estimate')
+Linked local var 2 ('next')
+Linked function 1 ('improve')
+Linked parameter 0 ('n')
+Linked local var 2 ('next')
diff --git a/vsl_programs/prec.tree b/vsl_programs/prec.tree
index 90b4862..7633fcc 100644
--- a/vsl_programs/prec.tree
+++ b/vsl_programs/prec.tree
@@ -18,3 +18,13 @@
       NUMBER_DATA(-2)
      RETURN_STATEMENT
       NUMBER_DATA(0)
+String table:
+-- 
+Globals:
+unary_minus_precedence: function 0:
+	2 local variables, 0 are parameters:
+	b: local var 1
+	a: local var 0
+-- 
+Linked local var 0 ('a')
+Linked local var 1 ('b')
diff --git a/vsl_programs/prime.tree b/vsl_programs/prime.tree
index 563de03..91a849a 100644
--- a/vsl_programs/prime.tree
+++ b/vsl_programs/prime.tree
@@ -69,3 +69,34 @@
        STRING_DATA("is a prime factor")
      RETURN_STATEMENT
       NUMBER_DATA(0)
+String table:
+0: "is a prime factor"
+-- 
+Globals:
+factor: function 1:
+	3 local variables, 1 are parameters:
+	r: local var 2
+	f: local var 1
+	n: parameter 0
+main: function 0:
+	0 local variables, 0 are parameters:
+-- 
+Linked function 1 ('factor')
+Linked local var 1 ('f')
+Linked parameter 0 ('n')
+Linked parameter 0 ('n')
+Linked local var 1 ('f')
+Linked parameter 0 ('n')
+Linked local var 1 ('f')
+Linked local var 1 ('f')
+Linked local var 1 ('f')
+Linked local var 1 ('f')
+Linked local var 2 ('r')
+Linked function 1 ('factor')
+Linked local var 1 ('f')
+Linked local var 2 ('r')
+Linked function 1 ('factor')
+Linked parameter 0 ('n')
+Linked local var 1 ('f')
+Linked parameter 0 ('n')
+Linked string 0
diff --git a/vsl_programs/simplify.tree b/vsl_programs/simplify.tree
index c1d9499..d047cdc 100644
--- a/vsl_programs/simplify.tree
+++ b/vsl_programs/simplify.tree
@@ -34,3 +34,24 @@
          IDENTIFIER_DATA(d)
      RETURN_STATEMENT
       NUMBER_DATA(0)
+String table:
+0: "a="
+-- 
+Globals:
+simplify: function 0:
+	2 local variables, 2 are parameters:
+	f: parameter 1
+	e: parameter 0
+d: global variable
+c: global variable
+b: global variable
+a: global variable
+-- 
+Linked global var 'a'
+Linked string 0
+Linked global var 'a'
+Linked global var 'a'
+Linked global var 'b'
+Linked function 0 ('simplify')
+Linked global var 'c'
+Linked global var 'd'