Merge branch 'concept/ast-design' into 47-add-tests

src/ast/ast.c

@@ -0,0 +1,165 @@
+
+#include <ast/ast.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/log.h>
+
+struct AST_Node_t *AST_new_node(enum AST_SyntaxElement_t kind, const char* value) {
+  DEBUG("creating new AST node: %d \"%s\"", kind, value);
+
+  struct AST_Node_t *node = malloc(sizeof(struct AST_Node_t));
+
+  if (node == NULL) {
+    PANIC("failed to allocate AST node");
+  }
+
+  // init to discrete state
+  node->parent = NULL;
+  node->children = NULL;
+  node->child_count = 0;
+  node->kind = kind;
+  node->value = value;
+
+  return node;
+}
+
+const char* AST_node_to_string(struct AST_Node_t* node) {
+  DEBUG("converting AST node to string: %p", node);
+
+  const char* string = "unknown";
+
+  switch (node->kind) {
+    case AST_Expression:
+      string = "expression";
+      break;
+    case AST_Statement:
+      string = "statement";
+      break;
+    case AST_Branch:
+      string = "if";
+      break;
+    case AST_IntegerLiteral:
+      string = node->value;
+      break;
+    case AST_OperatorAdd:
+      string = "+";
+      break;
+  }
+
+  return string;
+}
+
+void AST_push_node(struct AST_Node_t *owner, struct AST_Node_t *child) {
+  DEBUG("Adding new node %p to %p", child, owner);
+
+  // if there are no children for now
+  if (owner->child_count == 0) {
+    DEBUG("Allocating new children array");
+    owner->children = malloc(sizeof(struct AST_Node_t *));
+
+  } else {
+    DEBUG("Rellocating old children array");
+    const size_t size = sizeof(struct AST_Node_t *) * (owner->child_count + 1);
+    owner->children = realloc(owner->children, size);
+  }
+
+  if (owner->children == NULL) {
+    PANIC("failed to allocate children array of AST node");
+  }
+
+  owner->children[owner->child_count++] = child;
+}
+
+struct AST_Node_t *AST_get_node(struct AST_Node_t *owner, size_t idx) {
+  DEBUG("retrvieng node %d from %p", idx, owner);
+
+  if (owner == NULL) {
+    PANIC("AST owner node is NULL");
+  }
+
+  if (owner->children == NULL) {
+    PANIC("AST owner node has no children");
+  }
+
+  struct AST_Node_t *child = owner->children[idx];
+
+  if (child == NULL) {
+    PANIC("child node is NULL");
+  }
+
+  return child;
+}
+
+void AST_delete_node(struct AST_Node_t *node) {
+  DEBUG("Deleting AST node: %p", node);
+
+  if (node == NULL) {
+    PANIC("Node to free is NULL");
+  }
+
+  if (node->children == NULL) {
+    return;
+  }
+
+  for (size_t i = 0; i < node->child_count; i++) {
+    AST_delete_node(node->children[i]);
+  }
+}
+
+static void __AST_visit_nodes_recurse2(struct AST_Node_t *root,
+                                       void (*for_each)(struct AST_Node_t *node,
+                                                        size_t depth),
+                                       size_t depth) {
+  DEBUG("Recursive visit of %p at %d with %p", root, depth, for_each);
+
+  (for_each)(root, depth);
+
+  for (size_t i = 0; i < root->child_count; i++) {
+    __AST_visit_nodes_recurse2(root->children[i], for_each, depth + 1);
+  }
+}
+
+void AST_visit_nodes_recurse(struct AST_Node_t *root,
+                             void (*for_each)(struct AST_Node_t *node,
+                                              size_t depth)) {
+  DEBUG("Starting recursive visit of %p with %p", root, for_each);
+  __AST_visit_nodes_recurse2(root, for_each, 0);
+}
+
+static void __AST_fprint_graphviz_node_definition(FILE* stream, struct AST_Node_t* node) {
+  DEBUG("Printing graphviz definition of %p", node);
+
+  fprintf(stream, "\tnode%p [label=\"%s\"]\n", (void*) node, AST_node_to_string(node));
+
+  if (node->children == NULL) {
+    return;
+  }
+
+  for (size_t i = 0; i < node->child_count; i++) {
+    __AST_fprint_graphviz_node_definition(stream, node->children[i]);
+  }
+}
+
+static void __AST_fprint_graphviz_node_connection(FILE* stream, struct AST_Node_t* node) {
+  DEBUG("Printing graphviz connection of %p", node);
+
+  if (node->children == NULL) {
+    return;
+  }
+
+  for (size_t i = 0; i < node->child_count; i++) {
+    fprintf(stream, "\tnode%p -- node%p\n", (void*) node, (void*) node->children[i]);
+    __AST_fprint_graphviz_node_connection(stream, node->children[i]);
+  }
+}
+
+void AST_fprint_graphviz(FILE* stream, struct AST_Node_t* root) {
+  DEBUG("Starting print of graphviz graph of %p", root);
+
+  fprintf(stream, "graph {\n");
+
+  __AST_fprint_graphviz_node_definition(stream, root);
+  __AST_fprint_graphviz_node_connection(stream, root);
+
+  fprintf(stream, "}\n");
+}

src/ast/ast.h

@@ -0,0 +1,56 @@
+
+#ifndef _AST_H_
+#define _AST_H_
+
+#include <stdio.h>
+
+// Syntax elements which are stored in a syntax tree
+enum AST_SyntaxElement_t {
+  AST_Statement,
+  AST_Expression,
+  AST_Branch,
+  AST_OperatorAdd,
+  AST_IntegerLiteral
+};
+
+struct AST_Node_t {
+  // parent node that owns this node
+  struct AST_Node_t *parent;
+
+  // type of AST node: if, declration, ...
+  enum AST_SyntaxElement_t kind;
+  // optional value: integer literal, string literal, ...
+  const char* value;
+
+  // number of child nodes ownd by this node
+  // length of children array
+  size_t child_count;
+  // variable amount of child nodes
+  struct AST_Node_t **children;
+};
+
+// return a string representation of the nodes type and its value
+// does not take into account its children or parent
+const char* AST_node_to_string(struct AST_Node_t* node);
+
+// create a new initialized (empty) node
+struct AST_Node_t *AST_new_node(enum AST_SyntaxElement_t kind, const char* value);
+
+void AST_delete_node(struct AST_Node_t *);
+
+// add a new child node
+void AST_push_node(struct AST_Node_t *owner, struct AST_Node_t *child);
+
+// get a specific child node
+struct AST_Node_t *AST_get_node(struct AST_Node_t *owner, size_t idx);
+
+// visit this and all of its child nodes calling the given function
+// for every node
+void AST_visit_nodes_recurse(struct AST_Node_t *root,
+                             void (*for_each)(struct AST_Node_t *node,
+                                              size_t depth));
+
+// print a graphviz diagram of the supplied node (as root node) into stream
+void AST_fprint_graphviz(FILE* stream, struct AST_Node_t* node);
+
+#endif

src/main.c

@@ -1,6 +1,7 @@
+#include <ast/ast.h>
+#include <stdio.h>
 #include <stdlib.h>
 #include <sys/log.h>
-#include <yacc/parser.tab.h>
 
 #define LOG_LEVEL LOG_LEVEL_DEBUG
 
@@ -65,13 +66,26 @@ int main(int argc, char *argv[]) {
 
     FILE *file = fopen(filename, "r");
 
-    if (NULL == file)
+    struct AST_Node_t* node = AST_new_node(AST_Branch, NULL);
-    {
-        PANIC("File couldn't be opened!");
-    }
-    yyin = file;
 
-    yyparse();
+    struct AST_Node_t* child = AST_new_node(AST_OperatorAdd, NULL);
+    AST_push_node(child, AST_new_node(AST_IntegerLiteral, "43"));
+    AST_push_node(child, AST_new_node(AST_IntegerLiteral, "9"));
+
+    AST_push_node(node, child);
+    AST_push_node(node, AST_new_node(AST_Expression, NULL));
+    AST_push_node(node, AST_new_node(AST_Expression, NULL));
+
+    FILE* out = fopen("ast.gv", "w+");
+    // convert this file        ^^^^^^
+    // to an svg with: `dot -Tsvg ast.gv > graph.svg`
+
+    AST_fprint_graphviz(out, node);
+
+    AST_delete_node(node);
+
+    fflush(out);
+    fclose(out);
 
     return 0;
 }