fixed bug with being to aggressive

- Is now more flexible
- Added resolve constant relations

exercises/04/vslc/src/tree.c

@@ -12,6 +12,10 @@ tree_print(node_t* root, stem head);
 
 static void destroy_subtree ( node_t *discard );
 
+static void prune_children(node_t **simplified, node_t *root);
+static void resolve_constant_expressions(node_t **simplified, node_t *root);
+static void flatten(node_t **simplified, node_t *root);
+
 
 /* External interface */
 void
@@ -154,18 +158,71 @@ destroy_subtree ( node_t *discard )
     }
 }
 
+
+static void
+flatten(node_t **simplified, node_t *root)
+{
+    /* This will flatten left-expanded lists */
+    if (!root)
+        return;
+
+    /* Do this recursivly */
+    for (int i = 0; i < root->n_children; i++)
+        flatten(&root->children[i], root->children[i]);
+
+    node_t **new_children, *result = root;
+    switch (root->type)
+    {
+    case GLOBAL_LIST:
+    case STATEMENT_LIST:
+    case PRINT_LIST:
+    case EXPRESSION_LIST:
+    case VARIABLE_LIST:
+    case DECLARATION_LIST:
+        // Check if node have more than two children
+        if (root->n_children < 2)
+            break;
+        
+        result = root->children[0];
+        result->n_children++;
+
+        // Realloc the array of children to the new size 
+        if (!(new_children = realloc(result->children, result->n_children * sizeof(node_t*))))
+            break;
+        // if successs, insert the new array
+        result->children = new_children;
+
+        // Insert child at the end
+        result->children[result->n_children - 1] = root->children[1];
+
+        node_finalize(root);
+        break;
+    }
+
+    *simplified = result;
+}
+
+
 static void
 prune_children(node_t **simplified, node_t *root) 
 {
     if (!root)
         return;
 
+    /* Do this recursivly */
+    for (int i = 0; i < root->n_children; i++)
+        prune_children(&root->children[i], root->children[i]);
+
     node_t *result = root;
     switch (root->type)
     {
+    case PROGRAM:
     case GLOBAL:
     //case ARGUMENT_LIST:     // For this to work, need to change order of operations
     //case PARAMETER_LIST:    // For this to work, need to change order of operations
+    //case VARIABLE_LIST:
+    //case EXPRESSION_LIST:
+    case DECLARATION:
     case STATEMENT:
     case PRINT_ITEM:
     case PRINT_STATEMENT:
@@ -189,6 +246,10 @@ resolve_constant_expressions(node_t **simplified, node_t *root)
     if (!root)
         return;
 
+    /* Do this recursivly */
+    for (int i = 0; i < root->n_children; i++)
+        resolve_constant_expressions(&root->children[i], root->children[i]);
+    
     if (root->type != EXPRESSION)
         return;
     
@@ -239,6 +300,7 @@ resolve_constant_expressions(node_t **simplified, node_t *root)
 
             switch (*(char*)root->data)
             {
+            /* Assignments */
             case '|': *lhs |= *rhs; break;
             case '^': *lhs ^= *rhs; break;
             case '&': *lhs &= *rhs; break;
@@ -258,57 +320,80 @@ resolve_constant_expressions(node_t **simplified, node_t *root)
     *simplified = result;
 }
 
+
 static void
-flatten(node_t **simplified, node_t *root)
+resolve_constant_relations( node_t** simplified, node_t* root)
 {
-    /* This will flatten left-expanded lists */
     if (!root)
         return;
 
-    node_t **new_children, *result = root;
-    switch (root->type)
-    {
-    case GLOBAL_LIST:
-    case STATEMENT_LIST:
-    case PRINT_LIST:
-    case EXPRESSION_LIST:
-    case VARIABLE_LIST:
-    case DECLARATION_LIST:
-        // Check if node have more than two children
-        if (root->n_children < 2)
-            break;
+    /* Do this recursivly */
+    for (int i = 0; i < root->n_children; i++)
+        resolve_constant_relations(&root->children[i], root->children[i]);
+    
+    if (root->type != RELATION)//|| root->type != RELATION)
+        return;
+
+    node_t *result = root;
+
+    if (root->n_children != 2)
+        return;
+
+    // Both children must be constant numbers
+    if (root->children[0]->type != NUMBER_DATA ||
+        root->children[1]->type != NUMBER_DATA)
+        return;
+
+    // Check if children does not contain null pointers
+    if (!root->children[0]->data)
+        return;
+    if (!root->children[1]->data)
+        return;
+
+    // Check if data field is not null pointer
+    if (!root->data)
+        return;
 
     result = root->children[0];
-        result->n_children++;
+    int64_t
+        *lhs = result->data,
+        *rhs = root->children[1]->data;
 
-        // Realloc the array of children to the new size 
-        if (!(new_children = realloc(result->children, result->n_children * sizeof(node_t*))))
-            break;
-        // if successs, insert the new array
-        result->children = new_children;
-
-        // Insert child at the end
-        result->children[result->n_children - 1] = root->children[1];
-
-        node_finalize(root);
-        break;
+    switch (*(char*)root->data)
+    {
+    /* Relations */
+    case '=': *lhs = (*lhs == *rhs); break;
+    case '<': *lhs = (*lhs <  *rhs); break;
+    case '>': *lhs = (*lhs >  *rhs); break;
     }
 
+    node_finalize(root->children[1]);
+    node_finalize(root);
+
     *simplified = result;
 }
 
+
 static void
 simplify_tree ( node_t **simplified, node_t *root )
 {
     if (!root) 
         return;
 
-    for (int i = 0; i < root->n_children; i++)
-        simplify_tree(&root->children[i], root->children[i]);
+    //for (int i = 0; i < root->n_children; i++)
+    //    simplify_tree(&root->children[i], root->children[i]);
 
+    /*  
+        Each of  the functions do their operations recursivly.
+        This opens up for a lot more flexibility, like removing 
+        variable list after it is flatten
+    */
+    flatten(&root, root);
     prune_children(&root, root);
     resolve_constant_expressions(&root, root);
-    flatten(&root, root);
+
+    // The following is experimental, will resolve the constant relations
+    resolve_constant_relations(&root, root);
 
     *simplified = root;
 }