diff --git a/.github/workflows/build-check-sdk.yaml b/.github/workflows/build-check-sdk.yaml
index 10a4811..b17b734 100644
--- a/.github/workflows/build-check-sdk.yaml
+++ b/.github/workflows/build-check-sdk.yaml
@@ -2,7 +2,7 @@ name: "Build check gemstone in SDK"
 run-name: SDK build check to ${{ inputs.deploy_target }} by @${{ github.actor }}
 on: [push, pull_request]
 env:
-  SDK: 0.2.2-alpine-3.19.1
+  SDK: 0.2.3-alpine-3.19.1
 jobs:
   build-check-sdk:
     runs-on: ubuntu-latest
diff --git a/CMakeLists.txt b/CMakeLists.txt
index 824b3d4..12e8c66 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -21,6 +21,9 @@ project(gemstone
     DESCRIPTION "programming language compiler"
     LANGUAGES C)
 
+set(CMAKE_C_STANDARD 23)
+set(CMAKE_C_STANDARD_REQUIRED TRUE)
+
 set(GEMSTONE_TEST_DIR ${PROJECT_SOURCE_DIR}/tests)
 set(GEMSTONE_BINARY_DIR ${PROJECT_SOURCE_DIR}/bin)
 
diff --git a/Dockerfile b/Dockerfile
index 09e34b6..a8c2f7f 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,6 +1,6 @@
-FROM servostar/gemstone:sdk-0.2.2-alpine-3.19.1
+FROM servostar/gemstone:sdk-0.2.3-alpine-3.19.1
 LABEL authors="servostar"
-LABEL version="0.2.2"
+LABEL version="0.2.3"
 LABEL description="docker image for setting up the build pipeline on SDK"
 LABEL website="https://github.com/Servostar/gemstone"
 
diff --git a/sdk/Dockerfile b/sdk/Dockerfile
index 1a6a677..aae7438 100644
--- a/sdk/Dockerfile
+++ b/sdk/Dockerfile
@@ -1,11 +1,11 @@
 FROM alpine:3.19.1
 LABEL authors="servostar"
-LABEL version="0.2.2"
+LABEL version="0.2.3"
 LABEL description="base image for building the gemstone programming language compiler"
 LABEL website="https://github.com/Servostar/gemstone"
 
 # install dependencies
-RUN apk add build-base gcc make cmake bison flex git python3
+RUN apk add build-base gcc make cmake bison flex git python3 graphviz
 
 # create user for build
 RUN adduser --disabled-password lorang
diff --git a/src/ast/ast.c b/src/ast/ast.c
new file mode 100644
index 0000000..233e8da
--- /dev/null
+++ b/src/ast/ast.c
@@ -0,0 +1,274 @@
+
+#include <ast/ast.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/log.h>
+#include <assert.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);
+  assert(kind < AST_ELEMENT_COUNT);
+
+  struct AST_Node_t *node = malloc(sizeof(struct AST_Node_t));
+
+  if (node == NULL) {
+    PANIC("failed to allocate AST node");
+  }
+
+  assert(node != NULL);
+
+  // init to discrete state
+  node->parent = NULL;
+  node->children = NULL;
+  node->child_count = 0;
+  node->kind = kind;
+  node->value = value;
+
+  return node;
+}
+
+static const char* lookup_table[AST_ELEMENT_COUNT] = { "__UNINIT__" };
+
+void AST_init() {
+  DEBUG("initializing global syntax tree...");
+
+  INFO("filling lookup table...");
+
+  lookup_table[AST_Stmt] = "stmt";
+  lookup_table[AST_Expr] = "expr";
+
+  lookup_table[AST_Add] = "+";
+  lookup_table[AST_Sub] = "-";
+  lookup_table[AST_Mul] = "*";
+  lookup_table[AST_Div] = "/";
+
+  lookup_table[AST_BitAnd] = "&";
+  lookup_table[AST_BitOr] = "|";
+  lookup_table[AST_BitXor] = "^";
+  lookup_table[AST_BitNot] = "!";
+
+  lookup_table[AST_Eq] = "==";
+  lookup_table[AST_Less] = "<";
+  lookup_table[AST_Greater] = ">";
+
+  lookup_table[AST_BoolAnd] = "&&";
+  lookup_table[AST_BoolOr] = "||";
+  lookup_table[AST_BoolXor] = "^^";
+  lookup_table[AST_BoolNot] = "!!";
+
+  lookup_table[AST_While] = "while";
+  lookup_table[AST_If] = "if";
+  lookup_table[AST_IfElse] = "else if";
+  lookup_table[AST_Else] = "else";
+
+  lookup_table[AST_Decl] = "decl";
+  lookup_table[AST_Assign] = "assign";
+  lookup_table[AST_Def] = "def";
+
+  lookup_table[AST_Typedef] = "typedef";
+  lookup_table[AST_Box] = "box";
+  lookup_table[AST_Fun] = "fun";
+
+  lookup_table[AST_Typecast] = "cast";
+  lookup_table[AST_Transmute] = "as";
+  lookup_table[AST_Condition] = "condition";
+}
+
+const char* AST_node_to_string(const struct AST_Node_t* node) {
+  DEBUG("converting AST node to string: %p", node);
+  assert(node != NULL);
+
+  const char* string;
+
+  switch(node->kind) {
+    case AST_Int:
+    case AST_Float:
+    case AST_String:
+    case AST_Ident:
+    case AST_Macro:
+    case AST_Import:
+    case AST_Call:
+      string = node->value;
+      break;
+    default:
+      string = lookup_table[node->kind];
+  }
+
+  assert(string != NULL);
+
+  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);
+  assert(owner != NULL);
+  assert(child != NULL);
+
+  // 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");
+  }
+
+  assert(owner->children != NULL);
+
+  owner->children[owner->child_count++] = child;
+}
+
+struct AST_Node_t *AST_get_node(struct AST_Node_t *owner, const size_t idx) {
+  DEBUG("retrvieng node %d from %p", idx, owner);
+  assert(owner != NULL);
+  assert(owner->children != NULL);
+  assert(idx < owner->child_count);
+
+  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;
+}
+
+struct AST_Node_t* AST_remove_child(struct AST_Node_t* owner, const size_t idx) {
+  assert(owner != NULL);
+  assert(owner->children != NULL);
+  assert(idx < owner->child_count);
+
+  struct AST_Node_t* child = owner->children[idx];
+
+  child->parent = NULL;
+
+  owner->child_count--;
+
+  // shift back every following element by one
+  for (size_t i = idx; i < owner->child_count; i++) {
+    owner->children[i] = owner->children[i + 1];
+  }
+
+  return child;
+}
+
+struct AST_Node_t* AST_detach_child(struct AST_Node_t* owner, const struct AST_Node_t* child) {
+  assert(owner != NULL);
+  assert(child != NULL);
+  assert(owner->children != NULL);
+
+  for (size_t i = 0; i < owner->child_count; i++) {
+    if (owner->children[i] == child) {
+      return AST_remove_child(owner, i);
+    }
+  }
+
+  PANIC("Child to detach not a child of parent");
+}
+
+void AST_delete_node(struct AST_Node_t *node) {
+  assert(node != NULL);
+
+  DEBUG("Deleting AST node: %p", node);
+
+  if (node->children == NULL) {
+    return;
+  }
+
+  if (node->parent != NULL) {
+    const struct AST_Node_t* child = AST_detach_child(node->parent, node);
+    assert(child == node);
+  }
+
+  for (size_t i = 0; i < node->child_count; i++) {
+    // prevent detach of children node
+    node->children[i]->parent = NULL;
+    AST_delete_node(node->children[i]);
+  }
+
+  free(node->children);
+  free(node);
+}
+
+static void AST_visit_nodes_recurse2(struct AST_Node_t *root,
+                                       void (*for_each)(struct AST_Node_t *node,
+                                                        size_t depth),
+                                       const size_t depth) {
+  DEBUG("Recursive visit of %p at %d with %p", root, depth, for_each);
+
+  assert(root != NULL);
+
+  (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);
+
+  assert(root != NULL);
+  assert(for_each != NULL);
+
+  AST_visit_nodes_recurse2(root, for_each, 0);
+}
+
+static void AST_fprint_graphviz_node_definition(FILE* stream, const struct AST_Node_t* node) {
+  DEBUG("Printing graphviz definition of %p", node);
+
+  assert(stream != NULL);
+  assert(node != NULL);
+
+  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, const struct AST_Node_t* node) {
+  DEBUG("Printing graphviz connection of %p", node);
+
+  assert(stream != NULL);
+  assert(node != NULL);
+
+  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, const struct AST_Node_t* root) {
+  DEBUG("Starting print of graphviz graph of %p", root);
+
+  assert(stream != NULL);
+  assert(root != NULL);
+
+  fprintf(stream, "graph {\n");
+
+  AST_fprint_graphviz_node_definition(stream, root);
+  AST_fprint_graphviz_node_connection(stream, root);
+
+  fprintf(stream, "}\n");
+}
diff --git a/src/ast/ast.h b/src/ast/ast.h
new file mode 100644
index 0000000..5129765
--- /dev/null
+++ b/src/ast/ast.h
@@ -0,0 +1,200 @@
+
+#ifndef _AST_H_
+#define _AST_H_
+
+#include <stdio.h>
+
+/**
+ * @brief The type of a AST node
+ * @attention The last element is not to be used in the AST
+ *            as it is used as a lazy way to get the total number of available
+ *            variants of this enum.
+ */
+enum AST_SyntaxElement_t {
+  AST_Stmt = 0,
+  AST_Expr,
+  // Literals
+  AST_Int,
+  AST_Float,
+  AST_String,
+  // Control flow
+  AST_While,
+  AST_If,
+  AST_IfElse,
+  AST_Else,
+  AST_Condition,
+  // Variable management
+  AST_Decl,
+  AST_Assign,
+  AST_Def,
+  AST_Ident,
+  // Arithmetic operators
+  AST_Add,
+  AST_Sub,
+  AST_Mul,
+  AST_Div,
+  // Bitwise operators
+  AST_BitAnd,
+  AST_BitOr,
+  AST_BitXor,
+  AST_BitNot,
+  // Boolean operators
+  AST_BoolAnd,
+  AST_BoolOr,
+  AST_BoolXor,
+  AST_BoolNot,
+  // Logical operators
+  AST_Eq,
+  AST_Greater,
+  AST_Less,
+  // Casts
+  AST_Typecast,   // type cast
+  AST_Transmute,  // reinterpret cast
+  AST_Call,       // function call
+  AST_Macro,      // builtin functions: lineno(), filename(), ...
+  // Defintions
+  AST_Typedef,
+  AST_Box,
+  AST_Fun,
+  AST_Import,
+  // amount of variants
+  // in this enum
+  AST_ELEMENT_COUNT
+};
+
+/**
+ * @brief A single node which can be joined with other nodes like a graph.
+ * Every node can have one ancestor (parent) but multiple (also none) children.
+ * Nodes have two properties:
+ *  - kind: The type of the node. Such as AST_Expr, AST_Add, ...
+ *  - value: A string representing an optional value. Can be a integer literal for kind AST_int
+ */
+struct AST_Node_t {
+  // parent node that owns this node
+  struct AST_Node_t *parent;
+
+  // type of AST node: if, declaration, ...
+  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;
+};
+
+/**
+ * Shorthand type for a single AST node
+ */
+typedef struct AST_Node_t* AST_NODE_PTR;
+
+/**
+ * @brief Initalize the global state of this module. Required for some functionality to work correctly.
+ */
+void AST_init(void);
+
+/**
+ * @brief Returns the string representation of the supplied node
+ * @attention The retuned pointer is not to be freed as it may either be a statically stored string or
+ *            used by the node after this function call.
+ * @param node to return string representation of
+ * @return string represenation of the node
+ */
+[[maybe_unused]]
+[[gnu::nonnull(1)]]
+const char* AST_node_to_string(const struct AST_Node_t* node);
+
+/**
+ * @brief Create a new node struct on the system heap. Initializes the struct with the given values.
+ *        All other fields are set to either NULL or 0. No allocation for children array is preformed.
+*  @attention parameter value can be NULL in case no value can be provided for the node
+ * @param kind the type of this node
+ * @param value an optional value for this node
+ * @return
+ */
+[[maybe_unused]]
+[[nodiscard("pointer must be freed")]]
+[[gnu::returns_nonnull]]
+struct AST_Node_t *AST_new_node(enum AST_SyntaxElement_t kind, const char* value);
+
+/**
+ * @brief Deallocate this node and all of its children.
+ * @attention This function will detach this node from its parent if one is present
+ *            Use of the supplied node after this call is undefined behavior
+ * @param node The node to deallocate
+ */
+[[maybe_unused]]
+[[gnu::nonnull(1)]]
+void AST_delete_node(struct AST_Node_t * node);
+
+/**
+ * @brief Add a new child node to a parent node
+ * @attention This can reallocate the children array
+ * @param owner node to add a child to
+ * @param child node to be added as a child
+ */
+[[maybe_unused]]
+[[gnu::nonnull(1), gnu::nonnull(2)]]
+void AST_push_node(struct AST_Node_t *owner, struct AST_Node_t *child);
+
+/**
+ * @brief Remove the specified child from the owner.
+ * @attention The parent of the removed node is set to NULL.
+ *            The returned pointer is still valid. It must be freed at some pointer later.
+ * @param owner Node to remove the child from
+ * @param idx the index of the child to remove
+ * @return a pointer to the child which was removed
+ */
+[[maybe_unused]]
+[[nodiscard("pointer must be freed")]]
+[[gnu::nonnull(1)]]
+struct AST_Node_t* AST_remove_child(struct AST_Node_t* owner, size_t idx);
+
+/**
+ * @brief Detach a child from its parent. This involves removing the child from its parent
+ *        and marking the parent of the child as NULL.
+ * @attention The returned pointer is still valid. It must be freed at some pointer later.
+ * @param owner the owner to remove the child from
+ * @param child the child to detach
+ * @return a pointer to child detached
+ */
+[[nodiscard("pointer must be freed")]]
+[[gnu::nonnull(1), gnu::nonnull(1)]]
+struct AST_Node_t* AST_detach_child(struct AST_Node_t* owner, const struct AST_Node_t* child);
+
+/**
+ * @brief Return a pointer to the n-th child of a node
+ * @attention Pointer to childen nodes will never change.
+ *            However, the index a node is stored within a parent can change
+ *            if a child of lower index is removed, thus reducing the childrens index by one.
+ * @param owner the parent node which owns the children
+ * @param idx the index of the child to get a pointer to
+ * @return a pointer to the n-th child of the owner node
+ */
+[[maybe_unused]]
+[[gnu::nonnull(1)]]
+struct AST_Node_t *AST_get_node(struct AST_Node_t *owner, size_t idx);
+
+/**
+ * @brief Execute a function for every child, grandchild, ... and the supplied node as topmost ancestor
+ * @param root the root to recursively execute a function for
+ * @param for_each the function to execute
+ */
+[[maybe_unused]]
+[[gnu::nonnull(1), gnu::nonnull(2)]]
+void AST_visit_nodes_recurse(struct AST_Node_t *root,
+                             void (*for_each)(struct AST_Node_t *node,
+                                              size_t depth));
+
+/**
+ * @brief Prints a graphviz graph of the node and all its ancestors.
+ * @param stream The stream to print to. Can be a file, stdout, ...
+ * @param node the topmost ancestor
+ */
+[[maybe_unused]]
+[[gnu::nonnull(1), gnu::nonnull(2)]]
+void AST_fprint_graphviz(FILE* stream, const struct AST_Node_t* node);
+
+#endif
diff --git a/src/main.c b/src/main.c
index 38cf9c9..03ab6b9 100644
--- a/src/main.c
+++ b/src/main.c
@@ -1,77 +1,71 @@
+#include <ast/ast.h>
 #include <stdlib.h>
 #include <sys/log.h>
 #include <yacc/parser.tab.h>
 
 #define LOG_LEVEL LOG_LEVEL_DEBUG
 
-extern FILE* yyin;
+extern FILE *yyin;
 
 /**
  * @brief Log a debug message to inform about beginning exit procedures
- * 
+ *
  */
-void notify_exit(void)
-{
-    DEBUG("Exiting gemstone...");
-}
+void notify_exit(void) { DEBUG("Exiting gemstone..."); }
 
 /**
  * @brief Closes File after compiling.
- * 
+ *
  */
 
-void close_file(void)
-{
-    if (NULL != yyin)
-    {
-        fclose(yyin);
-    }
+void close_file(void) {
+  if (NULL != yyin) {
+    fclose(yyin);
+  }
 }
 
 /**
  * @brief Run compiler setup here
- * 
+ *
  */
-void setup(void)
-{
-    // setup preample
+void setup(void) {
+  // setup preample
 
-    log_init();
-    DEBUG("starting gemstone...");
+  log_init();
+  DEBUG("starting gemstone...");
 
-    #if LOG_LEVEL <= LOG_LEVEL_DEBUG
-    atexit(&notify_exit);
-    #endif
+#if LOG_LEVEL <= LOG_LEVEL_DEBUG
+  atexit(&notify_exit);
+#endif
 
-    // actual setup
-    
-    DEBUG("finished starting up gemstone...");
+  // actual setup
+  AST_init();
+
+  DEBUG("finished starting up gemstone...");
 }
 
 int main(int argc, char *argv[]) {
 
-    setup();
-    atexit(close_file);
-    
-    // Check for file input as argument
-    if (2 != argc)
-    {
-        INFO("Usage: %s <filename>\n", argv[0]);
-        PANIC("No File could be found");
-    }
-    
-    // filename as first argument
-    char *filename = argv[1];
+  setup();
+  atexit(close_file);
 
-    FILE *file = fopen(filename, "r");
+  // Check for file input as argument
+  if (2 != argc) {
+    INFO("Usage: %s <filename>\n", argv[0]);
+    PANIC("No File could be found");
+  }
 
-    if (NULL == file)
-    {
-        PANIC("File couldn't be opened!");
-    }
-    yyin = file;
-    
-    yyparse();
+  // filename as first argument
+  char *filename = argv[1];
 
-    return 0;
+  FILE *file = fopen(filename, "r");
+
+  if (NULL == file) {
+    PANIC("File couldn't be opened!");
+  }
+  yyin = file;
+
+  yyparse();
+
+  return 0;
 }
diff --git a/src/sys/log.c b/src/sys/log.c
index e3a7cd6..0aeab5f 100644
--- a/src/sys/log.c
+++ b/src/sys/log.c
@@ -3,6 +3,7 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <sys/log.h>
+#include <assert.h>
 
 static struct Logger_t {
     FILE** streams;
@@ -11,13 +12,15 @@ static struct Logger_t {
 
 void log_init(void)
 {
+    assert(LOG_DEFAULT_STREAM != NULL);
     log_register_stream(LOG_DEFAULT_STREAM);
 }
 
 void log_register_stream(FILE* restrict stream)
 {
-    if (stream == NULL)
-        PANIC("stream to register is NULL");
+    // replace runtime check with assertion
+    // only to be used in debug target
+    assert(stream != NULL);
 
     if (GlobalLogger.stream_count == 0)
     {
@@ -57,7 +60,7 @@ static void vflogf(
     vfprintf(stream, format, args);
 }
 
-void __logf(
+void syslog_logf(
     const char* restrict level,
     const char* restrict file,
     const unsigned long line,
@@ -78,7 +81,7 @@ void __logf(
     va_end(args);
 }
 
-void __panicf(
+void syslog_panicf(
     const char* restrict file,
     const unsigned long line,
     const char* restrict func,
@@ -95,7 +98,7 @@ void __panicf(
     exit(EXIT_FAILURE);
 }
 
-void __fatalf(
+void syslog_fatalf(
     const char* restrict file,
     const unsigned long line,
     const char* restrict func,
diff --git a/src/sys/log.h b/src/sys/log.h
index aa18c88..6b8991d 100644
--- a/src/sys/log.h
+++ b/src/sys/log.h
@@ -2,7 +2,6 @@
 #define _SYS_ERR_H_
 
 #include <stdio.h>
-#include <string.h>
 
 #define LOG_DEFAULT_STREAM stderr
 
@@ -35,14 +34,14 @@
  *        This macro will print debug information to stderr and call abort() to
  *        performa a ungracefull exit. No clean up possible.
  */
-#define PANIC(format, ...) __panicf(__FILE_NAME__, __LINE__, __func__, format"\n", ##__VA_ARGS__)
+#define PANIC(format, ...) syslog_panicf(__FILE_NAME__, __LINE__, __func__, format"\n", ##__VA_ARGS__)
 
 /**
  * @brief Panic is used in cases where the process is in an invalid or undefined state.
  *        This macro will print debug information to stderr and call exit() to
  *        initiate a gracefull exit, giving the process the opportunity to clean up.
  */
-#define FATAL(format, ...) __fatalf(__FILE_NAME__, __LINE__, __func__, format"\n", ##__VA_ARGS__)
+#define FATAL(format, ...) syslog_fatalf(__FILE_NAME__, __LINE__, __func__, format"\n", ##__VA_ARGS__)
 
 /*
 Standard log macros. These will not terminate the application.
@@ -57,7 +56,7 @@ will not print.
 #define __LOG(level, priority, format, ...) \
     do { \
         if (LOG_LEVEL <= priority) \
-            __logf(level, __FILE_NAME__, __LINE__, __func__, format, ##__VA_ARGS__); \
+            syslog_logf(level, __FILE_NAME__, __LINE__, __func__, format, ##__VA_ARGS__); \
     } while(0)
 
 /**
@@ -70,10 +69,11 @@ will not print.
  * @param format the format to print following args in
  * @param ... 
  */
-void __logf(
+[[gnu::nonnull(1), gnu::nonnull(2), gnu::nonnull(4)]]
+void syslog_logf(
     const char* restrict level,
     const char* restrict file,
-    const unsigned long line,
+    unsigned long line,
     const char* restrict func,
     const char* restrict format,
     ...);
@@ -87,9 +87,11 @@ void __logf(
  * @param format the format to print following args in
  * @param ... 
  */
-void __panicf(
+[[noreturn]]
+[[gnu::nonnull(1), gnu::nonnull(3), gnu::nonnull(4)]]
+void syslog_panicf(
     const char* restrict file,
-    const unsigned long line,
+    unsigned long line,
     const char* restrict func,
     const char* restrict format,
     ...);
@@ -103,9 +105,11 @@ void __panicf(
  * @param format the format to print following args in
  * @param ... 
  */
-void __fatalf(
+[[noreturn]]
+[[gnu::nonnull(1), gnu::nonnull(3), gnu::nonnull(4)]]
+void syslog_fatalf(
     const char* restrict file,
-    const unsigned long line,
+    unsigned long line,
     const char* restrict func,
     const char* restrict format,
     ...);
@@ -121,6 +125,7 @@ void log_init(void);
  * 
  * @param stream 
  */
+[[gnu::nonnull(1)]]
 void log_register_stream(FILE* restrict stream);
 
 #endif /* _SYS_ERR_H_ */
diff --git a/tests/CMakeLists.txt b/tests/CMakeLists.txt
index ab8afdc..b5c1111 100644
--- a/tests/CMakeLists.txt
+++ b/tests/CMakeLists.txt
@@ -7,4 +7,5 @@ set(CTEST_BINARY_DIRECTORY ${PROJECT_BINARY_DIR}/tests)
 # Provide test to run here or include another CMakeLists.txt
 
 add_subdirectory(logging)
-add_subdirectory(input_file)
\ No newline at end of file
+add_subdirectory(input_file)
+add_subdirectory(ast)
\ No newline at end of file
diff --git a/tests/ast/CMakeLists.txt b/tests/ast/CMakeLists.txt
new file mode 100644
index 0000000..455130b
--- /dev/null
+++ b/tests/ast/CMakeLists.txt
@@ -0,0 +1,51 @@
+include(CTest)
+
+include_directories(${PROJECT_SOURCE_DIR}/src)
+
+# ------------------------------------------------------- #
+# CTEST 1
+# test building the syntax tree
+
+add_executable(ast_build_tree
+        ${PROJECT_SOURCE_DIR}/src/ast/ast.c
+        ${PROJECT_SOURCE_DIR}/src/sys/log.c
+        build_tree.c)
+set_target_properties(ast_build_tree
+        PROPERTIES
+        OUTPUT_NAME "build_tree"
+        RUNTIME_OUTPUT_DIRECTORY ${GEMSTONE_BINARY_DIR}/tests/ast)
+add_test(NAME ast_build_tree
+        WORKING_DIRECTORY ${PROJECT_SOURCE_DIR}
+        COMMAND python ${GEMSTONE_TEST_DIR}/ast/test_ast.py check_build_tree)
+
+# ------------------------------------------------------- #
+# CTEST 2
+# test node to string output
+
+add_executable(ast_print_node
+        ${PROJECT_SOURCE_DIR}/src/ast/ast.c
+        ${PROJECT_SOURCE_DIR}/src/sys/log.c
+        print_node.c)
+set_target_properties(ast_print_node
+        PROPERTIES
+        OUTPUT_NAME "print_node"
+        RUNTIME_OUTPUT_DIRECTORY ${GEMSTONE_BINARY_DIR}/tests/ast)
+add_test(NAME ast_print_node
+        WORKING_DIRECTORY ${PROJECT_SOURCE_DIR}
+        COMMAND python ${GEMSTONE_TEST_DIR}/ast/test_ast.py check_print_node)
+
+# ------------------------------------------------------- #
+# CTEST 3
+# test graphviz output
+
+add_executable(ast_graphviz
+        ${PROJECT_SOURCE_DIR}/src/ast/ast.c
+        ${PROJECT_SOURCE_DIR}/src/sys/log.c
+        print_graphviz.c)
+set_target_properties(ast_graphviz
+        PROPERTIES
+        OUTPUT_NAME "print_graphviz"
+        RUNTIME_OUTPUT_DIRECTORY ${GEMSTONE_BINARY_DIR}/tests/ast)
+add_test(NAME ast_graphviz
+        WORKING_DIRECTORY ${PROJECT_SOURCE_DIR}
+        COMMAND python ${GEMSTONE_TEST_DIR}/ast/test_ast.py check_print_graphviz)
diff --git a/tests/ast/build_tree.c b/tests/ast/build_tree.c
new file mode 100644
index 0000000..dec7b85
--- /dev/null
+++ b/tests/ast/build_tree.c
@@ -0,0 +1,40 @@
+//
+// Created by servostar on 5/7/24.
+//
+
+#include <ast/ast.h>
+#include <sys/log.h>
+
+void generate_statement(const AST_NODE_PTR stmt) {
+    const AST_NODE_PTR add = AST_new_node(AST_Add, NULL);
+
+    AST_push_node(add, AST_new_node(AST_Int, "3"));
+    AST_push_node(add, AST_new_node(AST_Int, "6"));
+
+    AST_push_node(stmt, add);
+}
+
+void generate_branch(const AST_NODE_PTR stmt) {
+    const AST_NODE_PTR branch = AST_new_node(AST_If, NULL);
+    const AST_NODE_PTR gt = AST_new_node(AST_Greater, NULL);
+
+    AST_push_node(branch, gt);
+
+    AST_push_node(gt, AST_new_node(AST_Float, "2.3"));
+    AST_push_node(gt, AST_new_node(AST_Float, "0.79"));
+
+    AST_push_node(stmt, branch);
+
+    generate_statement(branch);
+}
+
+int main(void) {
+
+    const AST_NODE_PTR root = AST_new_node(AST_Stmt, NULL);
+
+    generate_branch(root);
+
+    AST_delete_node(root);
+
+    return 0;
+}
diff --git a/tests/ast/gen_graph.c b/tests/ast/gen_graph.c
new file mode 100644
index 0000000..186d571
--- /dev/null
+++ b/tests/ast/gen_graph.c
@@ -0,0 +1,32 @@
+//
+// Created by servostar on 5/7/24.
+//
+
+#include <ast/ast.h>
+#include <sys/log.h>
+
+int main(void) {
+
+    struct AST_Node_t* node = AST_new_node(AST_If, NULL);
+
+    struct AST_Node_t* child = AST_new_node(AST_Add, NULL);
+    AST_push_node(child, AST_new_node(AST_Int, "43"));
+    AST_push_node(child, AST_new_node(AST_Int, "9"));
+
+    AST_push_node(node, child);
+    AST_push_node(node, AST_new_node(AST_Expr, NULL));
+    AST_push_node(node, AST_new_node(AST_Expr, 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;
+}
diff --git a/tests/ast/print_graphviz.c b/tests/ast/print_graphviz.c
new file mode 100644
index 0000000..6df64b4
--- /dev/null
+++ b/tests/ast/print_graphviz.c
@@ -0,0 +1,54 @@
+//
+// Created by servostar on 5/8/24.
+//
+
+#include <ast/ast.h>
+#include <sys/log.h>
+
+void generate_statement(const AST_NODE_PTR stmt) {
+    const AST_NODE_PTR add = AST_new_node(AST_Add, NULL);
+
+    AST_push_node(add, AST_new_node(AST_Int, "3"));
+    AST_push_node(add, AST_new_node(AST_Int, "6"));
+
+    AST_push_node(stmt, add);
+}
+
+void generate_branch(const AST_NODE_PTR stmt) {
+    const AST_NODE_PTR branch = AST_new_node(AST_If, NULL);
+    const AST_NODE_PTR gt = AST_new_node(AST_Greater, NULL);
+
+    AST_push_node(branch, gt);
+
+    AST_push_node(gt, AST_new_node(AST_Float, "2.3"));
+    AST_push_node(gt, AST_new_node(AST_Float, "0.79"));
+
+    AST_push_node(stmt, branch);
+
+    generate_statement(branch);
+}
+
+int main(void) {
+
+    AST_init();
+
+    const AST_NODE_PTR root = AST_new_node(AST_Stmt, NULL);
+
+    generate_branch(root);
+
+    FILE* output = fopen("tmp/graph.gv", "w");
+
+    if (output == NULL) {
+        PANIC("unable to open file");
+    }
+
+    AST_fprint_graphviz(output, root);
+
+    fflush(output);
+
+    fclose(output);
+
+    AST_delete_node(root);
+
+    return 0;
+}
diff --git a/tests/ast/print_node.c b/tests/ast/print_node.c
new file mode 100644
index 0000000..38e8a41
--- /dev/null
+++ b/tests/ast/print_node.c
@@ -0,0 +1,23 @@
+//
+// Created by servostar on 5/7/24.
+//
+
+#include <ast/ast.h>
+
+int main(void) {
+
+    AST_init();
+
+    const AST_NODE_PTR node = AST_new_node(0, "value");
+
+    for (size_t i = 0; i < AST_ELEMENT_COUNT; i++) {
+        // set kind
+        node->kind = i;
+        // print symbol
+        printf("%ld %s\n", i, AST_node_to_string(node));
+    }
+
+    AST_delete_node(node);
+
+    return 0;
+}
diff --git a/tests/ast/test_ast.py b/tests/ast/test_ast.py
new file mode 100644
index 0000000..0f9b757
--- /dev/null
+++ b/tests/ast/test_ast.py
@@ -0,0 +1,126 @@
+import subprocess
+import sys
+import logging
+from logging import info, error
+import os
+
+BIN_DIR = "bin/tests/ast/"
+
+
+def run_check_build_tree():
+    info("started check tree build...")
+
+    p = subprocess.run(BIN_DIR + "build_tree", capture_output=True, text=True)
+
+    info("checking exit code...")
+
+    # check exit code
+    assert p.returncode == 0
+
+
+def run_check_print_node():
+    info("started check node print...")
+
+    p = subprocess.run(BIN_DIR + "print_node", capture_output=True, text=True)
+
+    info("checking exit code...")
+
+    # check exit code
+    assert p.returncode == 0
+
+    assert """0 stmt
+1 expr
+2 value
+3 value
+4 value
+5 while
+6 if
+7 else if
+8 else
+9 condition
+10 decl
+11 assign
+12 def
+13 value
+14 +
+15 -
+16 *
+17 /
+18 &
+19 |
+20 ^
+21 !
+22 &&
+23 ||
+24 ^^
+25 !!
+26 ==
+27 >
+28 <
+29 cast
+30 as
+31 value
+32 value
+33 typedef
+34 box
+35 fun
+36 value
+""" == p.stdout
+
+
+def run_check_print_graphviz():
+    info("started check print graphviz...")
+
+    info("creating temporary folder...")
+
+    if not os.path.exists("tmp"):
+        os.mkdir("tmp")
+
+    info("cleaning temporary folder...")
+
+    if os.path.exists("tmp/graph.gv"):
+        os.remove("tmp/graph.gv")
+
+    if os.path.exists("tmp/graph.svg"):
+        os.remove("tmp/graph.svg")
+
+    p = subprocess.run(BIN_DIR + "print_graphviz", capture_output=True, text=True)
+
+    info("checking exit code...")
+
+    # check exit code
+    assert p.returncode == 0
+
+    info("converting gv to svg...")
+
+    p = subprocess.run(["dot", "-Tsvg", "tmp/graph.gv", "-otmp/graph.svg"])
+
+    info("checking exit code...")
+    assert p.returncode == 0
+
+    info("checking svg output...")
+    with open("tmp/graph.svg", "r") as file:
+        string = "".join(file.readlines())
+        assert "2.3" in string
+        assert "0.79" in string
+        assert "stmt" in string
+        assert "if" in string
+
+
+if __name__ == "__main__":
+    logging.basicConfig(level=logging.INFO)
+
+    target = sys.argv[1]
+
+    info(f"starting ast test suite with target: {target}")
+
+    match target:
+        case "check_build_tree":
+            run_check_build_tree()
+        case "check_print_node":
+            run_check_print_node()
+        case "check_print_graphviz":
+            run_check_print_graphviz()
+        case _:
+            error(f"unknown target: {target}")
+            exit(1)