Finish basic implementation of garbage collection.

CMakeLists.txt

@@ -8,7 +8,7 @@ project(libabacus)
 
 add_compile_options(-pedantic -Wall)
 
-add_library(abacus STATIC src/lexer.c src/util.c src/table.c src/parser.c src/libabacus.c src/tree.c src/debug.c src/parsetype.c src/reserved.c src/trie.c src/refcount.c src/ref_vec.c src/ref_trie.c src/basetype.c src/value.c src/custom.c src/interpreter.c src/function_list.c src/free_functions.c)
+add_library(abacus STATIC src/lexer.c src/util.c src/table.c src/parser.c src/libabacus.c src/tree.c src/debug.c src/parsetype.c src/reserved.c src/trie.c src/refcount.c src/ref_vec.c src/ref_trie.c src/basetype.c src/value.c src/custom.c src/interpreter.c src/function_list.c src/free_functions.c src/gc.c)
 add_executable(libabacus src/main.c)
 add_executable(interactive src/interactive.c)
 add_subdirectory(external/liblex)
@@ -20,4 +20,4 @@ target_include_directories(libabacus PUBLIC include)
 
 target_link_libraries(abacus lex)
 target_link_libraries(libabacus abacus)
-target_link_libraries(interactive abacus)
+target_link_libraries(interactive abacus m)

include/free_functions.h

@@ -24,6 +24,11 @@ void libab_free_function_list(void* func_list);
  * @param unit the unit to free.
  */
 void libab_free_unit(void* unit);
+/**
+ * Frees a boolean value.
+ * @param b the bool to free.
+ */
+void libab_free_bool(void* b);
 /**
  * Frees a parsetype.
  * @param parsetype the parsetype to free.

include/gc.h

@@ -0,0 +1,56 @@
+#ifndef LIBABACUS_GC_H
+#define LIBABACUS_GC_H
+
+#include "refcount.h"
+#include "gc_functions.h"
+
+/**
+ * Struct used to create an interface
+ * for a set of objects to be collected.
+ */
+struct libab_gc_list_s {
+    /**
+     * The head sentinel node.
+     */
+    struct libab_ref_count_s head_sentinel;
+    /**
+     * The tail sentinel node.
+     */
+    struct libab_ref_count_s tail_sentinel;
+};
+
+typedef struct libab_gc_list_s libab_gc_list;
+
+/**
+ * Initializes a garbage collection tracking list.
+ * @param list the list to initialize.
+ */
+void libab_gc_list_init(libab_gc_list* list);
+/**
+ * Visits the children of the current node, applying the given function to them.
+ * @param ref the reference whose children to visit.
+ * @param visitor the function to call for each child.
+ * @param data the data to pass to the visitor.
+ */
+void libab_gc_visit_children(struct libab_ref_s* ref, libab_visitor_function_ptr visitor, void* data);
+/**
+ * Applies the given visitor function to this reference.
+ */
+void libab_gc_visit(struct libab_ref_s* ref, libab_visitor_function_ptr visitor, void* data);
+/**
+ * Adds the given reference to the given garbage collection list,
+ * and specifies a function used to reach its children.
+ * @param ref the reference whose children to visit.
+ * @param visit_children the function used to reach the chilren of this reference.
+ * @param list the list to which to add the reference.
+ */
+void libab_gc_add(struct libab_ref_s* ref,
+                      libab_visit_function_ptr visit_children,
+                      libab_gc_list* list);
+/**
+ * Performs garbage collection on a given list of container objects/
+ * @param list the list to run collection on.
+ */
+void libab_gc_run(libab_gc_list* list);
+
+#endif

include/gc_functions.h

@@ -0,0 +1,10 @@
+#ifndef LIBABACUS_GC_FUNCTIONS_H
+#define LIBABACUS_GC_FUNCTIONS_H
+
+struct libab_ref_count_s;
+struct libab_ref_s;
+
+typedef void (*libab_visitor_function_ptr)(struct libab_ref_count_s* , void*);
+typedef void (*libab_visit_function_ptr)(void*, libab_visitor_function_ptr, void*);
+
+#endif

include/interpreter.h

@@ -28,6 +28,14 @@ struct libab_interpreter_s {
      * The unit value, which doesn't need more than one instance.
      */
     libab_ref value_unit;
+    /**
+     * The "true" boolean value, which doesn't need more than one instance.
+     */
+    libab_ref value_true;
+    /**
+     * The "false" boolean value, which doesn't need more than one instance.
+     */
+    libab_ref value_false;
 };
 
 typedef enum libab_interpreter_scope_mode_e libab_interpreter_scope_mode;
@@ -73,6 +81,18 @@ libab_result libab_interpreter_run_function(libab_interpreter* intr,
  * @param into the reference into which to store the unit value.
  */
 void libab_interpreter_unit_value(libab_interpreter* intr, libab_ref* into);
+/**
+ * Gets the true value from this interpreter.
+ * @param intr the interpreter from which to get the true value.
+ * @param into the reference into which to store the true value.
+ */
+void libab_interpreter_true_value(libab_interpreter* intr, libab_ref* into);
+/**
+ * Gets the false value from this interpreter.
+ * @param intr the interpreter from which to get the false value.
+ * @param into the reference into which to store the false value.
+ */
+void libab_interpreter_false_value(libab_interpreter* intr, libab_ref* into);
 /**
  * Frees the given interpreter.
  * @param intr the interpreter to free.

include/lexer.h

@@ -60,6 +60,8 @@ enum libab_lexer_token_e {
     TOKEN_OP_PREFIX,
     TOKEN_OP_POSTFIX,
     TOKEN_OP_RESERVED,
+    TOKEN_KW_TRUE,
+    TOKEN_KW_FALSE,
     TOKEN_KW_IF,
     TOKEN_KW_ELSE,
     TOKEN_KW_WHILE,

include/libabacus.h

@@ -9,6 +9,7 @@
 #include "parser.h"
 #include "result.h"
 #include "table.h"
+#include "gc.h"
 
 /**
  * The main struct of libabacus,
@@ -47,6 +48,10 @@ struct libab_s {
      * The number type instance.
      */
     libab_ref type_num;
+    /**
+     * The boolean type instance.
+     */
+    libab_ref type_bool;
     /**
      * The function list type instance.
      */
@@ -55,6 +60,12 @@ struct libab_s {
      * The unit type instance.
      */
     libab_ref type_unit;
+    /**
+     * List of containers references
+     * that should be tracked by the
+     * garbage collector for cycles.
+     */
+    libab_gc_list containers;
 
     /**
      * Internal; the number basetype. This cannot be a static
@@ -144,6 +155,12 @@ libab_result libab_create_type(libab* ab, libab_ref* into, const char* type);
  * @return the num basetype.
  */
 libab_basetype* libab_get_basetype_num(libab* ab);
+/**
+ * Finds and returns the built-in libabacus boolean type.
+ * @param ab the ab instance for which to return a type.
+ * @return the boolean basetype.
+ */
+libab_basetype* libab_get_basetype_bool(libab* ab);
 /**
  * Finds and returns the built-in libabacus function type.
  * @param ab the ab instance for which to return a type.
@@ -169,6 +186,12 @@ libab_basetype* libab_get_basetype_unit(libab* ab);
  * @param into the reference to store the type into.
  */
 void libab_get_type_num(libab* ab, libab_ref* into);
+/**
+ * Get the type of a boolean in this libabacus instance.
+ * @param ab the instance to get the type for.
+ * @param into the reference to store the type into.
+ */
+void libab_get_type_bool(libab* ab, libab_ref* into);
 /**
  * Get the type of the function list in this libabacus instance.
  * @param ab the instance to get the type for.
@@ -188,6 +211,26 @@ void libab_get_type_unit(libab* ab, libab_ref* into);
  * @param into the reference into which to store the unit value.
  */
 void libab_get_unit_value(libab* ab, libab_ref* into);
+/**
+ * Gets the true value form this libab instance.
+ * @param ab the instance to get the true value from.
+ * @param into the reference into which to store the true value.
+ */
+void libab_get_true_value(libab* ab, libab_ref* into);
+/**
+ * Gets the false value form this libab instance.
+ * @param ab the instance to get the false value from.
+ * @param into the reference into which to store the false value.
+ */
+void libab_get_false_value(libab* ab, libab_ref* into);
+/**
+ * Get the boolean value corresponding to val from this
+ * libab instance.
+ * @param ab the instance to get the value from.
+ * @param val the true or false value to represent.
+ * @param into the reference into which to store the value.
+ */
+void libab_get_bool_value(libab* ab, int val, libab_ref* into);
 
 /**
  * Executes the given string of code.

include/refcount.h

@@ -2,6 +2,7 @@
 #define LIBABACUS_REFCOUNT_H
 
 #include "result.h"
+#include "gc_functions.h"
 
 /**
  * A struct for holding
@@ -10,6 +11,10 @@
  * to free the value.
  */
 struct libab_ref_count_s {
+    /**
+     * The value this reference holds.
+     */
+    void* data;
     /**
      * The fucntion to free the value.
      * Can be NULL for no-op.
@@ -25,6 +30,26 @@ struct libab_ref_count_s {
      * that still exist, even to a freed instance.
      */
     int weak;
+    /**
+     * The number of outside references.
+     * This is used for garbage collection.
+     */
+    int gc;
+    /**
+     * Previous pointer for garbage collection
+     * linked list.
+     */
+    struct libab_ref_count_s* prev;
+    /**
+     * Next pointer for garbage collection
+     * linked list.
+     */
+    struct libab_ref_count_s* next;
+    /**
+     * Function used to visit child containers,
+     * used by GC.
+     */
+    libab_visit_function_ptr visit_children;
 };
 
 /**
@@ -44,10 +69,6 @@ struct libab_ref_s {
      * of how many references are pointing to the value.
      */
     struct libab_ref_count_s* count;
-    /**
-     * The value this reference holds.
-     */
-    void* data;
 };
 
 typedef struct libab_ref_s libab_ref;

include/refcount_internal.h

@@ -0,0 +1,8 @@
+#ifndef LIBABACUS_REFCOUNT_INTERNAL_H
+#define LIBABACUS_REFCOUNT_INTERNAL_H
+
+#include "refcount.h"
+
+void libab_ref_count_changed(libab_ref_count* count);
+
+#endif

include/table.h

@@ -94,6 +94,17 @@ libab_table_entry* libab_table_search(libab_table* table, const char* string);
  */
 libab_operator* libab_table_search_operator(libab_table* table,
                                             const char* string, int type);
+/**
+ * Searches for a given string in the table,
+ * returning the entry that holds it only if it is an operator.
+ * @param table the table to search.
+ * @param string the string to search for.
+ * @param type the type of operator to search for (infix, prefix, postfix)
+ * @return the entry, or NULL if it was not found.
+ */
+libab_table_entry* libab_table_search_entry_operator(libab_table* table,
+                                                     const char* string,
+                                                     int type);
 /**
  * Searches for the given basetype in the table, returning a value
  * only if it's a basetype.
@@ -103,6 +114,15 @@ libab_operator* libab_table_search_operator(libab_table* table,
  */
 libab_basetype* libab_table_search_basetype(libab_table* table,
                                             const char* string);
+/**
+ * Searches for the given basetype in the table, returning a table
+ * entry only if it holds a basetype.
+ * @param table to table to search.
+ * @param string the string to search for.
+ * @return the entry holding the basetype, or NULL if it was not found.
+ */
+libab_table_entry* libab_table_search_entry_basetype(libab_table* table,
+                                            const char* string);
 /**
  * Searches for the given value in the table.
  * @param table the table to search.
@@ -112,13 +132,30 @@ libab_basetype* libab_table_search_basetype(libab_table* table,
 void libab_table_search_value(libab_table* table, const char* string,
                               libab_ref* ref);
 /**
- * Searches for the given type parameter in the talb.e
+ * Searches for a value with the given name in the table,
+ * and returns an entry that holds it.
+ * @param table the table to search.
+ * @param string the tabe entry key.
+ * @return the table entry holding the value, or NULL if it was not found.
+ */
+libab_table_entry* libab_table_search_entry_value(libab_table* table,
+                                                  const char* string);
+/**
+ * Searches for the given type parameter in the table.
  * @param table the table to search in.
- * @param string the key ot search for.
+ * @param string the key to search for.
  * @param ref the reference to store the type into.
  */
 void libab_table_search_type_param(libab_table* table, const char* string,
                                    libab_ref* ref);
+/**
+ * Searches for the given type parameter in the table.
+ * @param table the table to search in.
+ * @param string the key to search for.
+ * @return the table entry holding the type parameter, or NULL.
+ */
+libab_table_entry* libab_table_search_entry_type_param(libab_table* table,
+                                                        const char* string);
 /**
  * Stores the given entry in the table under the given key.
  * @param table the table to store the entry into.

include/tree.h

@@ -19,6 +19,8 @@ enum libab_tree_variant_e {
     TREE_POSTFIX_OP,
     TREE_BLOCK,
     TREE_VOID,
+    TREE_TRUE,
+    TREE_FALSE,
     TREE_IF,
     TREE_WHILE,
     TREE_DOWHILE,

include/util.h

@@ -7,6 +7,7 @@
 #include "parsetype.h"
 #include "result.h"
 #include "table.h"
+#include "libabacus.h"
 #include <string.h>
 
 /**
@@ -78,11 +79,12 @@ libab_result libab_instantiate_basetype(libab_basetype* to_instantiate,
                                         libab_ref* into, size_t n, ...);
 /**
  * Creates a new libab_table, and stores it into the given reference.
+ * @param ab the libabacus instance in which the table is being created.
  * @param into the reference to store the table into.
  * @param parent the parent reference to store.
  * @return the result of the instantiation.
  */
-libab_result libab_create_table(libab_ref* into, libab_ref* parent);
+libab_result libab_create_table(libab* ab, libab_ref* into, libab_ref* parent);
 /**
  * Allocates a new reference counted value with the given type and data.
  * @param into the reference to store the allocated data into.
@@ -90,8 +92,8 @@ libab_result libab_create_table(libab_ref* into, libab_ref* parent);
  * @param type the type to give the value.
  * @return the result of necessary allocations.
  */
-libab_result libab_create_value_ref(libab_ref* into, libab_ref* data,
-                                    libab_ref* type);
+libab_result libab_create_value_ref(libab* ab, libab_ref* into, 
+                                    libab_ref* data, libab_ref* type);
 /**
  * Allocates a new reference counted value with the given type and data.
  * @param into the reference to store the allocated data into.
@@ -99,8 +101,8 @@ libab_result libab_create_value_ref(libab_ref* into, libab_ref* data,
  * @param type the type to give the value.
  * @return the result of necessary allocations.
  */
-libab_result libab_create_value_raw(libab_ref* into, void* data,
-                                    libab_ref* type);
+libab_result libab_create_value_raw(libab* ab, libab_ref* into,
+                                    void* data, libab_ref* type);
 /**
  * Allocates a function that uses internal code to run.
  * @param into the reference into which to store the new function.
@@ -109,7 +111,7 @@ libab_result libab_create_value_raw(libab_ref* into, void* data,
  * @param scope the scope in which this function was declared.
  * @return libab_result the result of any necessary allocations.
  */
-libab_result libab_create_function_internal(libab_ref* into,
+libab_result libab_create_function_internal(libab* ab, libab_ref* into,
                                             void (*free_function)(void*),
                                             libab_function_ptr fun,
                                             libab_ref* scope);
@@ -121,7 +123,7 @@ libab_result libab_create_function_internal(libab_ref* into,
  * @param scope the scope in which this function was declared.
  * @return libab_result the result of any necessary allocations.
  */
-libab_result libab_create_function_tree(libab_ref* into,
+libab_result libab_create_function_tree(libab* ab, libab_ref* into,
                                         void (*free_function)(void*),
                                         libab_tree* tree,
                                         libab_ref* scope);
@@ -133,7 +135,7 @@ libab_result libab_create_function_tree(libab_ref* into,
  * @param scope the scope in which this function was declared.
  * @return libab_result the result of any necessary allocations.
  */
-libab_result libab_create_function_behavior(libab_ref* into,
+libab_result libab_create_function_behavior(libab* ab, libab_ref* into,
                                             void (*free_function)(void*),
                                             libab_behavior* behavior,
                                             libab_ref* scope);
@@ -143,7 +145,7 @@ libab_result libab_create_function_behavior(libab_ref* into,
  * @param the function_list type.
  * @return the result of the allocations.
  */
-libab_result libab_create_function_list(libab_ref* into, libab_ref* type);
+libab_result libab_create_function_list(libab* ab, libab_ref* into, libab_ref* type);
 /**
  * Creates a new table entry that holds the given value.
  * @param table the table to store the entry into.
@@ -178,5 +180,12 @@ void* libab_unwrap_value(libab_ref* ref);
  * @return the value at the given index.
  */
 void* libab_unwrap_param(libab_ref_vec* vec, size_t index);
+/**
+ * Sanitizes a string to avoid liblex compilation errors.
+ * @param to the buffer to store the sanitized string to.
+ * @param from the string to sanitize.
+ * @param buffer_size the size of the to buffer.
+ */
+void libab_sanitize(char* to, const char* from, size_t buffer_size);
 
 #endif

src/free_functions.c

@@ -16,6 +16,9 @@ void libab_free_function_list(void* function_list) {
 }
 void libab_free_unit(void* unit) {
 
+}
+void libab_free_bool(void* b) {
+    free(b);
 }
 void libab_free_parsetype(void* parsetype) {
     libab_parsetype_free(parsetype);

src/gc.c

@@ -0,0 +1,103 @@
+#include "gc.h"
+#include "refcount.h"
+#include <stdlib.h>
+#include <stdio.h>
+#include <memory.h>
+#include "refcount_internal.h"
+
+void libab_gc_list_init(libab_gc_list* list) {
+    memset(&list->head_sentinel, 0, sizeof(list->head_sentinel));
+    memset(&list->tail_sentinel, 0, sizeof(list->tail_sentinel));
+    list->head_sentinel.next = &list->tail_sentinel;
+    list->tail_sentinel.prev = &list->head_sentinel;
+}
+
+void _gc_count_visit_children(libab_ref_count* ref, libab_visitor_function_ptr func, void* data) {
+    if(ref->strong && ref->visit_children) ref->visit_children(ref->data, func, data);
+}
+void libab_gc_visit_children(libab_ref* ref, libab_visitor_function_ptr func, void* data) {
+    if(!ref->null) _gc_count_visit_children(ref->count, func, data);
+}
+
+void libab_gc_visit(struct libab_ref_s* ref, libab_visitor_function_ptr visitor, void* data) {
+    if(!ref->null) {
+        visitor(ref->count, data);
+    }
+}
+
+void _libab_gc_list_append(libab_gc_list* list,
+                               libab_ref_count* node) {
+    libab_ref_count* before;
+    if(node->next) node->next->prev = node->prev;
+    if(node->prev) node->prev->next = node->next;
+    before = &list->tail_sentinel;
+    node->next = before;
+    node->prev = before->prev;
+    before->prev->next = node;
+    before->prev = node;
+}
+void libab_gc_add(libab_ref* ref,
+                      libab_visit_function_ptr visit_children,
+                      libab_gc_list* list) {
+    ref->count->visit_children = visit_children;
+    _libab_gc_list_append(list, ref->count);
+}
+
+void _gc_decrement(libab_ref_count* count, void* data) {
+    if(count->visit_children) count->gc--;
+}
+void _gc_save(libab_ref_count* count, void* data) {
+    libab_gc_list* list = data;
+    if(count->visit_children && count->gc >= 0) {
+        count->gc = -1;
+        _libab_gc_list_append(list, count);
+        _gc_count_visit_children(count, _gc_save, data);
+    }
+}
+
+void libab_gc_run(libab_gc_list* list) {
+    libab_gc_list safe;
+    libab_ref_count* head;
+
+    #define ITERATE(CODE) head = list->head_sentinel.next; \
+    while(head != &list->tail_sentinel) { \
+        libab_ref_count* node = head; \
+        CODE;\
+        head = head->next; \
+    }
+
+    libab_gc_list_init(&safe);
+    ITERATE(node->gc = node->weak);
+    ITERATE(_gc_count_visit_children(node, _gc_decrement, NULL));
+    
+    head = list->head_sentinel.next;
+    while(head != &list->tail_sentinel) {
+        if(head->gc > 0) {
+            _gc_save(head, &safe);
+            head = &list->head_sentinel;
+        }
+        head = head->next;
+    }
+
+    ITERATE(
+        node->weak = -1;
+        node->strong = -1;
+        if(node->free_func) node->free_func(node->data);
+    );
+
+    while ((head = list->head_sentinel.next) != &list->tail_sentinel) {
+        head->prev->next = head->next;
+        head->next->prev = head->prev;
+        free(head);
+    }
+
+    if(safe.head_sentinel.next != &safe.tail_sentinel) {
+        list->head_sentinel.next = safe.head_sentinel.next;
+        list->head_sentinel.next->prev = &list->head_sentinel;
+        list->tail_sentinel.prev = safe.tail_sentinel.prev;
+        list->tail_sentinel.prev->next = &list->tail_sentinel;
+    } else {
+        list->head_sentinel.next = &list->tail_sentinel;
+        list->tail_sentinel.prev = &list->head_sentinel;
+    }
+}

src/interactive.c

@@ -7,6 +7,10 @@
 #define TRY(expression)                                                        \
     if (result == LIBAB_SUCCESS)                                               \
         result = expression;
+#define FUNCTION(name)                                                         \
+    libab_result function_##name (libab* ab, libab_ref* scope,                 \
+        libab_ref_vec* params, libab_ref* into)
+    
 #define INTERACTIONS 5
 
 void* impl_parse(const char* string) {
@@ -26,7 +30,7 @@ libab_result create_double_value(libab* ab, double val, libab_ref* into) {
     double* new_double = malloc(sizeof(*new_double));
     if(new_double) {
         *new_double = val;
-        result = libab_create_value_raw(into, new_double, &type_num);
+        result = libab_create_value_raw(ab, into, new_double, &type_num);
         if(result != LIBAB_SUCCESS) {
             free(new_double);
         }
@@ -38,27 +42,69 @@ libab_result create_double_value(libab* ab, double val, libab_ref* into) {
     return result;
 }
 
-libab_result function_atan(libab* ab, libab_ref* scope, libab_ref_vec* params, libab_ref* into) {
+
+FUNCTION(not) {
+    int* left = libab_unwrap_param(params, 0);
+    libab_get_bool_value(ab, !(*left), into);
+    return LIBAB_SUCCESS;
+}
+
+FUNCTION(and) {
+    int* left = libab_unwrap_param(params, 0);
+    int* right = libab_unwrap_param(params, 1);
+    libab_get_bool_value(ab, *left & *right, into);
+    return LIBAB_SUCCESS;
+}
+
+FUNCTION(or) {
+    int* left = libab_unwrap_param(params, 0);
+    int* right = libab_unwrap_param(params, 1);
+    libab_get_bool_value(ab, *left | *right, into);
+    return LIBAB_SUCCESS;
+}
+
+FUNCTION(xor) {
+    int* left = libab_unwrap_param(params, 0);
+    int* right = libab_unwrap_param(params, 1);
+    libab_get_bool_value(ab, *left ^ *right, into);
+    return LIBAB_SUCCESS;
+}
+
+FUNCTION(atan) {
     printf("atan called\n");
     double* val = libab_unwrap_param(params, 0);
     return create_double_value(ab, atan(*val), into);
 }
 
-libab_result function_atan2(libab* ab, libab_ref* scope, libab_ref_vec* params, libab_ref* into) {
+FUNCTION(atan2) {
     printf("atan2 called\n");
     double* left = libab_unwrap_param(params, 0);
     double* right = libab_unwrap_param(params, 1);
     return create_double_value(ab, atan2(*left, *right), into);
 }
 
-libab_result function_print_num(libab* ab, libab_ref* scope, libab_ref_vec* params, libab_ref* into) {
+FUNCTION(equals_num) {
+    double* left = libab_unwrap_param(params, 0);
+    double* right = libab_unwrap_param(params, 1);
+    libab_get_bool_value(ab, *left == *right, into);
+    return LIBAB_SUCCESS;
+}
+
+FUNCTION(print_num) {
     double* param = libab_unwrap_param(params, 0);
     printf("%f\n", *param);
     libab_get_unit_value(ab, into);
     return LIBAB_SUCCESS;
 }
 
-libab_result function_print_unit(libab* ab, libab_ref* scope, libab_ref_vec* params, libab_ref* into) {
+FUNCTION(print_bool) {
+    int* param = libab_unwrap_param(params, 0);
+    printf("%s\n", *param ? "true" : "false");
+    libab_get_unit_value(ab, into);
+    return LIBAB_SUCCESS;
+}
+
+FUNCTION(print_unit) {
     printf("()\n");
     libab_get_unit_value(ab, into);
     return LIBAB_SUCCESS;
@@ -88,12 +134,20 @@ libab_result register_functions(libab* ab) {
     libab_ref difficult_type;
     libab_ref print_num_type;
     libab_ref print_unit_type;
+    libab_ref print_bool_type;
+    libab_ref bool_logic_type;
+    libab_ref bool_not_type;
+    libab_ref equals_num_type;
 
     result = libab_create_type(ab, &trig_type, "(num)->num");
     TRY(libab_create_type(ab, &atan2_type, "(num, num)->num"));
+    TRY(libab_create_type(ab, &equals_num_type, "(num, num)->bool"));
     TRY(libab_create_type(ab, &difficult_type, "((num)->num)->num"));
     TRY(libab_create_type(ab, &print_num_type, "(num)->unit"));
     TRY(libab_create_type(ab, &print_unit_type, "(unit)->unit"));
+    TRY(libab_create_type(ab, &print_bool_type, "(bool)->unit"));
+    TRY(libab_create_type(ab, &bool_logic_type, "(bool,bool)->bool"));
+    TRY(libab_create_type(ab, &bool_not_type, "(bool)->bool"));
 
     TRY(libab_register_function(ab, "atan", &trig_type, function_atan));
     TRY(libab_register_function(ab, "atan2", &atan2_type, function_atan2));
@@ -101,18 +155,32 @@ libab_result register_functions(libab* ab) {
     TRY(libab_register_function(ab, "minus", &atan2_type, function_minus));
     TRY(libab_register_function(ab, "times", &atan2_type, function_times));
     TRY(libab_register_function(ab, "divide", &atan2_type, function_divide));
+    TRY(libab_register_function(ab, "and", &bool_logic_type, function_and));
+    TRY(libab_register_function(ab, "or", &bool_logic_type, function_or));
+    TRY(libab_register_function(ab, "xor", &bool_logic_type, function_xor));
+    TRY(libab_register_function(ab, "not", &bool_not_type, function_not));
+    TRY(libab_register_function(ab, "equals", &equals_num_type, function_equals_num));
     TRY(libab_register_function(ab, "print", &print_num_type, function_print_num));
     TRY(libab_register_function(ab, "print", &print_unit_type, function_print_unit));
+    TRY(libab_register_function(ab, "print", &print_bool_type, function_print_bool));
+    TRY(libab_register_operator_infix(ab, "==", 0, -1, "equals"));
     TRY(libab_register_operator_infix(ab, "+", 0, -1, "plus"));
     TRY(libab_register_operator_infix(ab, "-", 0, -1, "minus"));
     TRY(libab_register_operator_infix(ab, "*", 1, -1, "times"));
     TRY(libab_register_operator_infix(ab, "/", 1, -1, "divide"));
+    TRY(libab_register_operator_infix(ab, "&", 1, -1, "and"));
+    TRY(libab_register_operator_infix(ab, "|", 1, -1, "or"));
+    TRY(libab_register_operator_infix(ab, "^", 1, -1, "xor"));
+    TRY(libab_register_operator_prefix(ab, "!", "not"));
 
     libab_ref_free(&trig_type);
     libab_ref_free(&atan2_type);
     libab_ref_free(&difficult_type);
     libab_ref_free(&print_num_type);
     libab_ref_free(&print_unit_type);
+    libab_ref_free(&print_bool_type);
+    libab_ref_free(&bool_logic_type);
+    libab_ref_free(&bool_not_type);
 
     return result;
 }
@@ -133,6 +201,10 @@ libab_result loop(libab* ab, int interaction_count, libab_ref* scope) {
             printf("Invalid input (error code %d).\n", eval_result);
         } else {
             result = libab_run_function_scoped(ab, "print", scope, &call_into, 1, &eval_into);
+            if(result == LIBAB_BAD_CALL) {
+                printf("(?)\n");
+                result = LIBAB_SUCCESS;
+            }
             libab_ref_free(&call_into);
         }
         libab_ref_free(&eval_into);
@@ -144,6 +216,7 @@ libab_result loop(libab* ab, int interaction_count, libab_ref* scope) {
 int main() {
     libab_result result;
     libab_ref scope;
+    libab_ref test;
     libab ab;
 
     if (libab_init(&ab, impl_parse, impl_free) != LIBAB_SUCCESS) {
@@ -153,10 +226,12 @@ int main() {
 
     result = register_functions(&ab);
     if(result == LIBAB_SUCCESS) {
-        result = libab_create_table(&scope, &ab.table);
+        result = libab_create_table(&ab, &scope, &ab.table);
     }
     if(result == LIBAB_SUCCESS) {
         loop(&ab, INTERACTIONS, &scope);
+        libab_table_search_value(libab_ref_get(&scope), "test", &test);
+        printf("%p\n", libab_ref_get(&test));
         libab_ref_free(&scope);
     }
 

src/interpreter.c

@@ -4,15 +4,52 @@
 #include "free_functions.h"
 #include "reserved.h"
 
+libab_result _create_bool_value(libab* ab, int val, libab_ref* into) {
+    libab_ref type_bool;
+    int* new_bool;
+    libab_result result = LIBAB_SUCCESS;
+
+    libab_get_type_bool(ab, &type_bool);
+    new_bool = malloc(sizeof(*new_bool));
+    if(new_bool) {
+        *new_bool = val;
+        result = libab_create_value_raw(ab, into, new_bool, &type_bool);
+        if(result != LIBAB_SUCCESS) {
+            free(new_bool);
+        }
+    } else {
+        result = LIBAB_MALLOC;
+        libab_ref_null(into);
+    }
+    libab_ref_free(&type_bool);
+    return result;
+}
+
 libab_result libab_interpreter_init(libab_interpreter* intr, libab* ab) {
     libab_result result;
     libab_ref unit_data;
     intr->ab = ab;
+    libab_ref_null(&intr->value_true);
+    libab_ref_null(&intr->value_false);
 
     libab_ref_null(&unit_data);
-    result = libab_create_value_ref(&intr->value_unit, &unit_data, &ab->type_unit);
+    result = libab_create_value_ref(ab, &intr->value_unit, &unit_data, &ab->type_unit);
+    if(result == LIBAB_SUCCESS) {
+        libab_ref_free(&intr->value_true);
+        result = _create_bool_value(ab, 1, &intr->value_true);
+    }
+    if(result == LIBAB_SUCCESS) {
+        libab_ref_free(&intr->value_false);
+        result = _create_bool_value(ab, 0, &intr->value_false);
+    }
     libab_ref_free(&unit_data);
 
+    if(result != LIBAB_SUCCESS) {
+        libab_ref_free(&intr->value_unit);
+        libab_ref_free(&intr->value_true);
+        libab_ref_free(&intr->value_false);
+    }
+
     return result;
 }
 
@@ -38,7 +75,7 @@ libab_result _interpreter_create_num_val(struct interpreter_state* state,
 
     if ((data = state->ab->impl.parse_num(from))) {
         libab_ref_free(into);
-        result = libab_create_value_raw(into, data, &state->ab->type_num);
+        result = libab_create_value_raw(state->ab, into, data, &state->ab->type_num);
 
         if (result != LIBAB_SUCCESS) {
             ((libab_parsetype*)libab_ref_get(&state->ab->type_num))
@@ -429,13 +466,14 @@ libab_result _interpreter_find_match(libab_function_list* function_values,
  * @param type the new type.
  * @param into the reference into which to store the new value.
  */
-libab_result _interpreter_cast_param(libab_ref* param, libab_ref* type,
+libab_result _interpreter_cast_param(libab* ab, libab_ref* param,
+                                     libab_ref* type,
                                      libab_ref_vec* into) {
     libab_result result = LIBAB_SUCCESS;
     libab_value* old_value = libab_ref_get(param);
     libab_ref new_value;
 
-    result = libab_create_value_ref(&new_value, &old_value->data, type);
+    result = libab_create_value_ref(ab, &new_value, &old_value->data, type);
     if (result == LIBAB_SUCCESS) {
         result = libab_ref_vec_insert(into, &new_value);
     }
@@ -451,7 +489,8 @@ libab_result _interpreter_cast_param(libab_ref* param, libab_ref* type,
  * @param into the pre-initialized vector to store the new values into.
  * @return the result of any allocations.
  */
-libab_result _interpreter_cast_params(libab_ref_vec* params,
+libab_result _interpreter_cast_params(libab* ab,
+                                      libab_ref_vec* params,
                                       libab_ref_vec* new_types,
                                       libab_ref_vec* into) {
     libab_result result = LIBAB_SUCCESS;
@@ -463,7 +502,7 @@ libab_result _interpreter_cast_params(libab_ref_vec* params,
         libab_ref_vec_index(params, index, &temp_param);
         libab_ref_vec_index(new_types, index, &temp_type);
 
-        result = _interpreter_cast_param(&temp_param, &temp_type, into);
+        result = _interpreter_cast_param(ab, &temp_param, &temp_type, into);
 
         libab_ref_free(&temp_param);
         libab_ref_free(&temp_type);
@@ -494,7 +533,7 @@ libab_result _interpreter_call_tree(struct interpreter_state* state,
     libab_ref param;
     libab_table* new_scope_raw;
     size_t i;
-    libab_result result = libab_create_table(&new_scope, scope);
+    libab_result result = libab_create_table(state->ab, &new_scope, scope);
 
     if(result == LIBAB_SUCCESS) {
         new_scope_raw = libab_ref_get(&new_scope);
@@ -544,22 +583,24 @@ libab_result _interpreter_call_behavior(struct interpreter_state* state,
  * @param function the function to copy.
  * @param into the reference to store the copy into.
  */
-libab_result _interpreter_copy_function_basic(libab_ref* function,
+libab_result _interpreter_copy_function_basic(libab* ab,
+                                              libab_ref* function,
                                               libab_ref* scope,
                                               libab_ref* into) {
     libab_function* func = libab_ref_get(function);
     void (*free_function)(void*) = function->count->free_func;
-    return libab_create_function_behavior(into, free_function, &func->behavior, scope);
+    return libab_create_function_behavior(ab, into, free_function, &func->behavior, scope);
 }
 
-libab_result _interpreter_copy_function_with_params(libab_ref* function,
+libab_result _interpreter_copy_function_with_params(libab* ab,
+                                                    libab_ref* function,
                                                     libab_ref_vec* params,
                                                     libab_ref* scope,
                                                     libab_ref* into) {
     int index = 0;
     libab_ref param;
     libab_function* func;
-    libab_result result = _interpreter_copy_function_basic(function, scope, into);
+    libab_result result = _interpreter_copy_function_basic(ab, function, scope, into);
     func = libab_ref_get(into);
 
     for(; index < params->size && result == LIBAB_SUCCESS; index++) {
@@ -632,14 +673,14 @@ libab_result _interpreter_partially_apply(struct interpreter_state* state,
 
     value = libab_ref_get(function);
     libab_ref_null(&new_type);
-    result = _interpreter_copy_function_with_params(&value->data, params, scope, &new_function);
+    result = _interpreter_copy_function_with_params(state->ab, &value->data, params, scope, &new_function);
     if(result == LIBAB_SUCCESS) {
         libab_ref_free(&new_type);
         result = _interpreter_copy_type_offset(&value->type, 0, &new_type);
     }
 
     if(result == LIBAB_SUCCESS) {
-        result = libab_create_value_ref(into, &new_function, &new_type);
+        result = libab_create_value_ref(state->ab, into, &new_function, &new_type);
     } else {
         libab_ref_null(into);
     }
@@ -674,10 +715,11 @@ libab_result _interpreter_foreach_insert_param(const libab_ref* param,
     return result;
 }
 
-libab_result _interpreter_create_scope(libab_ref* into,
+libab_result _interpreter_create_scope(libab* ab,
+                                       libab_ref* into,
                                        libab_ref* parent_scope,
                                        libab_ref_trie* param_map) {
-    libab_result result = libab_create_table(into, parent_scope);
+    libab_result result = libab_create_table(ab, into, parent_scope);
     if (result == LIBAB_SUCCESS) {
         result = libab_ref_trie_foreach(param_map, _interpreter_foreach_insert_param, into);
 
@@ -713,7 +755,7 @@ libab_result _interpreter_perform_function_call(struct interpreter_state* state,
     function_type = libab_ref_get(&function_value->type);
     new_params = params->size - function->params.size;
 
-    result = _interpreter_create_scope(&new_scope, &function->scope, param_map);
+    result = _interpreter_create_scope(state->ab, &new_scope, &function->scope, param_map);
 
     if(result != LIBAB_SUCCESS) {
         libab_ref_null(into);
@@ -752,7 +794,7 @@ libab_result _interpreter_cast_and_perform_function_call(
     function = libab_ref_get(&function_value->data);
     result = libab_ref_vec_init_copy(&new_params, &function->params);
     if (result == LIBAB_SUCCESS) {
-        result = _interpreter_cast_params(params, new_types, &new_params);
+        result = _interpreter_cast_params(state->ab, params, new_types, &new_params);
 
         if (result == LIBAB_SUCCESS) {
             result = _interpreter_perform_function_call(state, to_call,
@@ -902,6 +944,7 @@ libab_result _interpreter_call_operator(struct interpreter_state* state,
     libab_ref_vec params;
     libab_ref temp;
 
+    libab_ref_null(into);
     libab_ref_null(&function_value);
     va_start(args, scope);
     result = libab_ref_vec_init(&params);
@@ -935,6 +978,7 @@ libab_result _interpreter_call_operator(struct interpreter_state* state,
         }
 
         if(result == LIBAB_SUCCESS) {
+            libab_ref_free(into);
             result = _interpreter_try_call(state, &function_value, &params, into);
         }
 
@@ -1078,7 +1122,7 @@ libab_result _interpreter_create_function_value(
 
     libab_ref_null(&type);
     libab_ref_null(into);
-    result = libab_create_function_tree(&function, libab_free_function, tree, scope);
+    result = libab_create_function_tree(state->ab, &function, libab_free_function, tree, scope);
 
     if(result == LIBAB_SUCCESS) {
         libab_ref_free(&type);
@@ -1087,7 +1131,7 @@ libab_result _interpreter_create_function_value(
 
     if(result == LIBAB_SUCCESS) {
         libab_ref_free(into);
-        result = libab_create_value_ref(into, &function, &type);
+        result = libab_create_value_ref(state->ab, into, &function, &type);
     }
 
     if(result != LIBAB_SUCCESS) {
@@ -1100,21 +1144,48 @@ libab_result _interpreter_create_function_value(
     return result;
 }
 
+libab_result _interpreter_expect_boolean(struct interpreter_state* state,
+                                         libab_tree* tree, int* into,
+                                         libab_ref* scope,
+                                         libab_interpreter_scope_mode mode) {
+    libab_ref output;
+    libab_result result = _interpreter_run(state, tree, &output, scope, mode);
+    libab_value* value;
+    libab_parsetype* type;
+    if(result == LIBAB_SUCCESS) {
+        value = libab_ref_get(&output);
+        type = libab_ref_get(&value->type);
+
+        if(type->data_u.base != libab_get_basetype_bool(state->ab)) {
+            result = LIBAB_BAD_CALL;
+        }
+
+        if(result == LIBAB_SUCCESS) {
+            *into = *((int*) libab_ref_get(&value->data));
+        }
+    }
+    libab_ref_free(&output);
+    return result;
+}
+
 libab_result _interpreter_run(struct interpreter_state* state, libab_tree* tree,
                               libab_ref* into, libab_ref* scope,
                               libab_interpreter_scope_mode mode) {
+    #define RUN_CHECK(i) _interpreter_expect_boolean(state, \
+        vec_index(&tree->children, i), &value, scope, SCOPE_NORMAL)
+
     libab_result result = LIBAB_SUCCESS;
     libab_ref new_scope;
     int needs_scope = (mode == SCOPE_FORCE) || 
         (mode == SCOPE_NORMAL && libab_tree_has_scope(tree->variant));
 
     if (needs_scope) {
-        result = libab_create_table(&new_scope, scope);
+        result = libab_create_table(state->ab, &new_scope, scope);
         scope = &new_scope;
     }
 
     if (result != LIBAB_SUCCESS) {
-
+        libab_ref_null(into);
     } else if (tree->variant == TREE_BASE || tree->variant == TREE_BLOCK) {
         size_t index = 0;
         libab_get_unit_value(state->ab, into);
@@ -1171,6 +1242,37 @@ libab_result _interpreter_run(struct interpreter_state* state, libab_tree* tree,
                 vec_index(&tree->children, 0),
                 vec_index(&tree->children, 1),
                 into);
+    } else if(tree->variant == TREE_TRUE) {
+        libab_get_true_value(state->ab, into);
+    } else if(tree->variant == TREE_FALSE) {
+        libab_get_false_value(state->ab, into);
+    } else if (tree->variant == TREE_IF) {
+        int value;
+        result = _interpreter_expect_boolean(state,
+                vec_index(&tree->children, 0), &value, scope, SCOPE_NORMAL);
+
+        if(result == LIBAB_SUCCESS) {
+            result = _interpreter_run(state, vec_index(&tree->children,
+                        value ? 1 : 2), into, scope, SCOPE_FORCE);
+        } else {
+            libab_ref_null(into);
+        }
+    } else if(tree->variant == TREE_WHILE) {
+        int value;
+        libab_get_unit_value(state->ab, into);
+        while(result == LIBAB_SUCCESS && (result = RUN_CHECK(0)) == LIBAB_SUCCESS && value) {
+            libab_ref_free(into);
+            result = _interpreter_run(state, vec_index(&tree->children, 1), 
+                                      into, scope, SCOPE_FORCE);
+        }
+    } else if(tree->variant == TREE_DOWHILE) {
+        int value;
+        libab_get_unit_value(state->ab, into);
+        do {
+            libab_ref_free(into);
+            result = _interpreter_run(state, vec_index(&tree->children, 0),
+                                      into, scope, SCOPE_FORCE);
+        } while(result == LIBAB_SUCCESS && (result = RUN_CHECK(1)) == LIBAB_SUCCESS && value);
     } else {
         libab_get_unit_value(state->ab, into);
     }
@@ -1212,7 +1314,7 @@ libab_result libab_interpreter_run_function(libab_interpreter* intr,
                                         function, &function_value);
     if(result == LIBAB_SUCCESS) {
         libab_ref_free(into);
-        _interpreter_try_call(&state, &function_value, params, into);
+        result = _interpreter_try_call(&state, &function_value, params, into);
     }
 
     _interpreter_free(&state);
@@ -1225,6 +1327,16 @@ void libab_interpreter_unit_value(libab_interpreter* intr, libab_ref* into) {
     libab_ref_copy(&intr->value_unit, into);
 }
 
+void libab_interpreter_true_value(libab_interpreter* intr, libab_ref* into) {
+    libab_ref_copy(&intr->value_true, into);
+}
+
+void libab_interpreter_false_value(libab_interpreter* intr, libab_ref* into) {
+    libab_ref_copy(&intr->value_false, into);
+}
+
 void libab_interpreter_free(libab_interpreter* intr) {
     libab_ref_free(&intr->value_unit);
+    libab_ref_free(&intr->value_true);
+    libab_ref_free(&intr->value_false);
 }

src/lexer.c

@@ -10,6 +10,8 @@ libab_result libab_lexer_init(libab_lexer* lexer) {
     const char* words[] = {".",
                            "[a-zA-Z][a-zA-Z0-9_]*",
                            "[0-9]+(\\.[0-9]*)?",
+                           "true",
+                           "false",
                            "if",
                            "else",
                            "while",
@@ -18,9 +20,9 @@ libab_result libab_lexer_init(libab_lexer* lexer) {
                            "fun",
                            "return"};
     libab_lexer_token tokens[] = {
-        TOKEN_CHAR,    TOKEN_ID,        TOKEN_NUM,    TOKEN_KW_IF,
-        TOKEN_KW_ELSE, TOKEN_KW_WHILE,  TOKEN_KW_DO,  TOKEN_KW_ARROW,
-        TOKEN_KW_FUN,  TOKEN_KW_RETURN };
+        TOKEN_CHAR,     TOKEN_ID,       TOKEN_NUM,     TOKEN_KW_TRUE,
+        TOKEN_KW_FALSE, TOKEN_KW_IF,    TOKEN_KW_ELSE, TOKEN_KW_WHILE,
+        TOKEN_KW_DO,    TOKEN_KW_ARROW, TOKEN_KW_FUN,  TOKEN_KW_RETURN};
     const size_t count = sizeof(tokens) / sizeof(libab_lexer_token);
 
     eval_config_init(&lexer->config);

src/libabacus.c

@@ -16,6 +16,8 @@ static libab_basetype _basetype_function = {libab_free_function,
 
 static libab_basetype _basetype_unit = { libab_free_unit, NULL, 0 };
 
+static libab_basetype _basetype_bool = { libab_free_bool, NULL, 0 };
+
 libab_result _prepare_types(libab* ab, void (*free_function)(void*));
 
 libab_result libab_init(libab* ab, void* (*parse_function)(const char*),
@@ -25,16 +27,19 @@ libab_result libab_init(libab* ab, void* (*parse_function)(const char*),
     int interpreter_initialized = 0;
     libab_ref null_ref;
     libab_result result;
+    libab_gc_list_init(&ab->containers);
     libab_ref_null(&null_ref);
     libab_ref_null(&ab->type_num);
+    libab_ref_null(&ab->type_bool);
     libab_ref_null(&ab->type_function_list);
     libab_ref_null(&ab->type_unit);
 
     ab->impl.parse_num = parse_function;
-    result = libab_create_table(&ab->table, &null_ref);
+    result = libab_create_table(ab, &ab->table, &null_ref);
 
     if (result == LIBAB_SUCCESS) {
         libab_ref_free(&ab->type_num);
+        libab_ref_free(&ab->type_bool);
         libab_ref_free(&ab->type_function_list);
         libab_ref_free(&ab->type_unit);
         result = _prepare_types(ab, free_function);
@@ -59,6 +64,7 @@ libab_result libab_init(libab* ab, void* (*parse_function)(const char*),
     if (result != LIBAB_SUCCESS) {
         libab_ref_free(&ab->table);
         libab_ref_free(&ab->type_num);
+        libab_ref_free(&ab->type_bool);
         libab_ref_free(&ab->type_function_list);
         libab_ref_free(&ab->type_unit);
 
@@ -79,16 +85,6 @@ libab_result libab_init(libab* ab, void* (*parse_function)(const char*),
     return result;
 }
 
-void _sanitize(char* to, const char* from, size_t buffer_size) {
-    size_t index = 0;
-    while (*from && index < (buffer_size - 2)) {
-        if (*from == '+' || *from == '*' || *from == '\\')
-            to[index++] = '\\';
-        to[index++] = *(from++);
-    }
-    to[index] = '\0';
-}
-
 void _initialize_behavior(libab_behavior* behavior, libab_ref* type,
                           libab_function_ptr func) {
     behavior->variant = BIMPL_INTERNAL;
@@ -113,7 +109,7 @@ libab_result _register_operator(libab* ab, const char* op,
     }
 
     if (result == LIBAB_SUCCESS) {
-        _sanitize(op_buffer, op, 8);
+        libab_sanitize(op_buffer, op, 8);
         result = libab_convert_lex_result(
             eval_config_add(&ab->lexer.config, op_buffer, TOKEN_OP));
     }
@@ -149,28 +145,29 @@ libab_result libab_register_operator_postfix(libab* ab, const char* op,
     return _register_operator(ab, op, OPERATOR_POSTFIX, 0, 0, function);
 }
 
-libab_result _create_value_function_internal(libab_ref* into, libab_ref* type,
+libab_result _create_value_function_internal(libab* ab, 
+                                             libab_ref* into, libab_ref* type,
                                              libab_function_ptr func, 
                                              libab_ref* scope) {
     libab_ref function_ref;
     libab_result result =
-        libab_create_function_internal(&function_ref, libab_free_function, func, scope);
+        libab_create_function_internal(ab, &function_ref, libab_free_function, func, scope);
     libab_ref_null(into);
     if (result == LIBAB_SUCCESS) {
         libab_ref_free(into);
-        result = libab_create_value_ref(into, &function_ref, type);
+        result = libab_create_value_ref(ab, into, &function_ref, type);
     }
     libab_ref_free(&function_ref);
     return result;
 }
 
-libab_result _create_value_function_list(libab_ref* into, libab_ref* type) {
+libab_result _create_value_function_list(libab* ab, libab_ref* into, libab_ref* type) {
     libab_ref list_ref;
-    libab_result result = libab_create_function_list(&list_ref, type);
+    libab_result result = libab_create_function_list(ab, &list_ref, type);
     libab_ref_null(into);
     if (result == LIBAB_SUCCESS) {
         libab_ref_free(into);
-        result = libab_create_value_ref(into, &list_ref, type);
+        result = libab_create_value_ref(ab, into, &list_ref, type);
     }
     libab_ref_free(&list_ref);
     return result;
@@ -192,7 +189,7 @@ libab_result _libab_register_function_existing(libab* ab,
     } else if (old_type->data_u.base == &_basetype_function) {
         libab_ref new_list;
         result =
-            _create_value_function_list(&new_list, &ab->type_function_list);
+            _create_value_function_list(ab, &new_list, &ab->type_function_list);
         if (result == LIBAB_SUCCESS) {
             libab_function_list* list =
                 libab_ref_get(&((libab_value*)libab_ref_get(&new_list))->data);
@@ -237,7 +234,7 @@ libab_result libab_register_function(libab* ab, const char* name,
     libab_table_entry* existing_entry;
     libab_ref function_value;
     libab_result result =
-        _create_value_function_internal(&function_value, type, func, &ab->table);
+        _create_value_function_internal(ab, &function_value, type, func, &ab->table);
 
     if (result == LIBAB_SUCCESS) {
         existing_entry = libab_table_search_filter(
@@ -282,6 +279,7 @@ libab_result _prepare_types(libab* ab, void (*free_function)(void*)) {
     ab->basetype_num.free_function = free_function;
 
     libab_ref_null(&ab->type_num);
+    libab_ref_null(&ab->type_bool);
     libab_ref_null(&ab->type_function_list);
     libab_ref_null(&ab->type_unit);
 
@@ -291,6 +289,12 @@ libab_result _prepare_types(libab* ab, void (*free_function)(void*)) {
             libab_instantiate_basetype(&ab->basetype_num, &ab->type_num, 0);
     }
 
+    if (result == LIBAB_SUCCESS) {
+        libab_ref_free(&ab->type_bool);
+        result =
+            libab_instantiate_basetype(&_basetype_bool, &ab->type_bool, 0);
+    }
+
     if (result == LIBAB_SUCCESS) {
         libab_ref_free(&ab->type_function_list);
         result = libab_instantiate_basetype(&_basetype_function_list,
@@ -306,6 +310,10 @@ libab_result _prepare_types(libab* ab, void (*free_function)(void*)) {
         result = libab_register_basetype(ab, "num", &ab->basetype_num);
     }
 
+    if(result == LIBAB_SUCCESS) {
+        result = libab_register_basetype(ab, "bool", &_basetype_bool);
+    }
+
     if (result == LIBAB_SUCCESS) {
         result = libab_register_basetype(ab, "function", &_basetype_function);
     }
@@ -321,9 +329,11 @@ libab_result _prepare_types(libab* ab, void (*free_function)(void*)) {
 
     if (result != LIBAB_SUCCESS) {
         libab_ref_free(&ab->type_num);
+        libab_ref_free(&ab->type_bool);
         libab_ref_free(&ab->type_function_list);
         libab_ref_free(&ab->type_unit);
         libab_ref_null(&ab->type_num);
+        libab_ref_null(&ab->type_bool);
         libab_ref_null(&ab->type_function_list);
         libab_ref_null(&ab->type_unit);
     }
@@ -350,6 +360,8 @@ libab_result libab_create_type(libab* ab, libab_ref* into, const char* type) {
 
 libab_basetype* libab_get_basetype_num(libab* ab) { return &ab->basetype_num; }
 
+libab_basetype* libab_get_basetype_bool(libab* ab) { return &_basetype_bool; }
+
 libab_basetype* libab_get_basetype_function(libab* ab) {
     return &_basetype_function;
 }
@@ -366,6 +378,10 @@ void libab_get_type_num(libab* ab, libab_ref* into) {
     libab_ref_copy(&ab->type_num, into);
 }
 
+void libab_get_type_bool(libab* ab, libab_ref* into) {
+    libab_ref_copy(&ab->type_bool, into);
+}
+
 void libab_get_type_function_list(libab* ab, libab_ref* into) {
     libab_ref_copy(&ab->type_function_list, into);
 }
@@ -378,6 +394,18 @@ void libab_get_unit_value(libab* ab, libab_ref* into) {
     libab_interpreter_unit_value(&ab->intr, into);
 }
 
+void libab_get_true_value(libab* ab, libab_ref* into) {
+    libab_interpreter_true_value(&ab->intr, into);
+}
+
+void libab_get_false_value(libab* ab, libab_ref* into) {
+    libab_interpreter_false_value(&ab->intr, into);
+}
+
+void libab_get_bool_value(libab* ab, int val, libab_ref* into) {
+    val ? libab_get_true_value(ab, into) : libab_get_false_value(ab, into);
+}
+
 libab_result _create_tree(libab* ab, const char* string, libab_tree** into) {
     libab_result result = LIBAB_SUCCESS;
     ll tokens;
@@ -490,12 +518,16 @@ libab_result libab_run_tree_scoped(libab* ab, libab_tree* tree, libab_ref* scope
 }
 
 libab_result libab_free(libab* ab) {
+    libab_result result = LIBAB_SUCCESS;
     libab_table_free(libab_ref_get(&ab->table));
     libab_ref_free(&ab->table);
     libab_ref_free(&ab->type_num);
+    libab_ref_free(&ab->type_bool);
     libab_ref_free(&ab->type_function_list);
     libab_ref_free(&ab->type_unit);
     libab_parser_free(&ab->parser);
     libab_interpreter_free(&ab->intr);
-    return libab_lexer_free(&ab->lexer);
+    result = libab_lexer_free(&ab->lexer);
+    libab_gc_run(&ab->containers);
+    return result;
 }

src/parser.c

@@ -406,6 +406,38 @@ libab_result _parse_void(struct parser_state* state, libab_tree** store_into) {
     return result;
 }
 
+libab_result _parse_true(struct parser_state* state, libab_tree** store_into) {
+    libab_result result = _parser_consume_type(state, TOKEN_KW_TRUE);
+    if(result == LIBAB_SUCCESS) {
+        if ((*store_into = malloc(sizeof(**store_into)))) {
+            (*store_into)->variant = TREE_TRUE;
+        } else {
+            result = LIBAB_MALLOC;
+        }
+    }
+
+    if(result != LIBAB_SUCCESS) {
+        *store_into = NULL;
+    }
+    return result;
+}
+
+libab_result _parse_false(struct parser_state* state, libab_tree** store_into) {
+    libab_result result = _parser_consume_type(state, TOKEN_KW_FALSE);
+    if(result == LIBAB_SUCCESS) {
+        if ((*store_into = malloc(sizeof(**store_into)))) {
+            (*store_into)->variant = TREE_FALSE;
+        } else {
+            result = LIBAB_MALLOC;
+        }
+    }
+
+    if(result != LIBAB_SUCCESS) {
+        *store_into = NULL;
+    }
+    return result;
+}
+
 libab_result _parse_if(struct parser_state* state, libab_tree** store_into) {
     libab_result result = LIBAB_SUCCESS;
     libab_tree* condition = NULL;
@@ -736,6 +768,10 @@ libab_result _parse_atom(struct parser_state* state, libab_tree** store_into) {
         result = _parse_fun(state, store_into);
     } else if (_parser_is_type(state, TOKEN_KW_RETURN)) {
         result = _parse_return(state, store_into);
+    } else if (_parser_is_type(state, TOKEN_KW_TRUE)) {
+        result = _parse_true(state, store_into);
+    } else if (_parser_is_type(state, TOKEN_KW_FALSE)) {
+        result = _parse_false(state, store_into);
     } else {
         result = LIBAB_UNEXPECTED;
     }
@@ -1019,11 +1055,13 @@ libab_result _parse_expression(struct parser_state* state,
 
             while (result == LIBAB_SUCCESS && op_stack.tail &&
                    _parser_match_is_op(op_stack.tail->data)) {
+                libab_lexer_match* other_token = op_stack.tail->data;
+                if(other_token->type == TOKEN_OP_INFIX) {
                     _parser_find_operator_infix(state, op_stack.tail->data,
                             &other_operator);
+                }
 
-                if (((libab_lexer_match*)op_stack.tail->data)->type ==
-                        TOKEN_OP_PREFIX ||
+                if (other_token->type == TOKEN_OP_PREFIX ||
                     (operator.associativity == - 1 &&
                      operator.precedence <= other_operator.precedence) ||
                     (operator.associativity == 1 &&

src/refcount.c

@@ -7,10 +7,13 @@ libab_result libab_ref_new(libab_ref* ref, void* data,
     libab_result result = LIBAB_SUCCESS;
     ref->null = 0;
     ref->strong = 1;
-    ref->data = data;
     if ((ref->count = malloc(sizeof(*(ref->count))))) {
+        ref->count->data = data;
         ref->count->strong = ref->count->weak = 1;
         ref->count->free_func = free_func;
+        ref->count->visit_children = NULL;
+        ref->count->prev = NULL;
+        ref->count->next = NULL;
     } else {
         result = LIBAB_MALLOC;
     }
@@ -23,10 +26,12 @@ void _libab_ref_changed(libab_ref* ref) {
     if (ref->count->strong == 0) {
         ref->count->strong--;
         if (ref->count->free_func) {
-            ref->count->free_func(ref->data);
+            ref->count->free_func(ref->count->data);
         }
     }
     if (ref->count->weak == 0) {
+        if(ref->count->prev) ref->count->prev->next = ref->count->next;
+        if(ref->count->next) ref->count->next->prev = ref->count->prev;
         free(ref->count);
     }
 }
@@ -67,7 +72,7 @@ void libab_ref_data_free(void* data) { free(data); }
 void* libab_ref_get(const libab_ref* ref) {
     void* to_return = NULL;
     if (!ref->null && ref->count->strong > 0) {
-        to_return = ref->data;
+        to_return = ref->count->data;
     }
     return to_return;
 }

src/refcount_internal.c

@@ -0,0 +1,16 @@
+#include "refcount_internal.h"
+#include <stdlib.h>
+
+void libab_ref_count_changed(libab_ref_count* count) {
+    if (count->strong == 0) {
+        count->strong--;
+        if (count->free_func) {
+            count->free_func(count->data);
+        }
+    }
+    if (count->weak == 0) {
+        if(count->prev) count->prev->next = count->next;
+        if(count->next) count->next->prev = count->prev;
+        free(count);
+    }
+}

src/reserved.c

@@ -1,6 +1,20 @@
 #include "reserved.h"
 #include "string.h"
 #include "util.h"
+#include "value.h"
+#include "libabacus.h"
+
+libab_result _update_entry(libab_table* table, const char* name, libab_ref* value) {
+    libab_result result = LIBAB_SUCCESS;
+    libab_table_entry* value_entry = libab_table_search_entry_value(table, name);
+    if(value_entry) {
+        libab_ref_free(&value_entry->data_u.value);
+        libab_ref_copy(value, &value_entry->data_u.value);
+    } else {
+        result = libab_put_table_value(table, name, value);
+    }
+    return result;
+}
 
 libab_result _behavior_assign(libab* ab, libab_ref* scope, 
                               libab_tree* left, libab_tree* right,
@@ -10,7 +24,7 @@ libab_result _behavior_assign(libab* ab, libab_ref* scope,
     if(left->variant == TREE_ID) {
         result = libab_run_tree_scoped(ab, right, scope, into);
         if(result == LIBAB_SUCCESS) {
-            result = libab_put_table_value(libab_ref_get(scope), left->string_value, into);
+            result = _update_entry(libab_ref_get(scope), left->string_value, into);
         }
 
         if(result != LIBAB_SUCCESS) {
@@ -27,12 +41,85 @@ libab_result _behavior_assign(libab* ab, libab_ref* scope,
     return result;
 }
 
-static const libab_reserved_operator libab_reserved_operators[] = {{
+libab_result _expect_boolean(libab* ab, libab_ref* scope,
+                          libab_tree* to_run, int* into) {
+    libab_result result = LIBAB_SUCCESS;
+    libab_ref output;
+    libab_value* value;
+    libab_parsetype* type;
+
+    result = libab_run_tree_scoped(ab, to_run, scope, &output);
+    if(result == LIBAB_SUCCESS) {
+        value = libab_ref_get(&output);
+        type = libab_ref_get(&value->type);
+        if(type->data_u.base != libab_get_basetype_bool(ab)) {
+            result = LIBAB_BAD_CALL;
+        } else {
+            *into = *((int*) libab_ref_get(&value->data));
+        }
+    }
+    libab_ref_free(&output);
+    return result;
+}
+
+libab_result _behavior_land(libab* ab, libab_ref* scope,
+                            libab_tree* left, libab_tree* right,
+                            libab_ref* into) {
+    libab_result result = LIBAB_SUCCESS;
+    int temp;
+    result = _expect_boolean(ab, scope, left, &temp);
+    if(result == LIBAB_SUCCESS && temp) {
+        result = _expect_boolean(ab, scope, right, &temp);
+    }
+
+    if(result == LIBAB_SUCCESS) {
+        libab_get_bool_value(ab, temp, into);
+    } else {
+        libab_ref_null(into);
+    }
+
+    return result;
+}
+
+libab_result _behavior_lor(libab* ab, libab_ref* scope,
+                           libab_tree* left, libab_tree* right,
+                           libab_ref* into) {
+    libab_result result = LIBAB_SUCCESS;
+    int temp = 0;
+    result = _expect_boolean(ab, scope, left, &temp);
+    if(result == LIBAB_SUCCESS && !temp) {
+        result = _expect_boolean(ab, scope, right, &temp);
+    }
+
+    if(result == LIBAB_SUCCESS) {
+        libab_get_bool_value(ab, temp, into);
+    } else {
+        libab_ref_null(into);
+    }
+
+    return result;
+}
+
+static const libab_reserved_operator libab_reserved_operators[] = {
+    {
         "=", /* Assignment */
         0,   /* Lowest precedence */
         1,   /* Right associative, a = b = 6 should be a = (b = 6) */
         _behavior_assign
-}};
+    },
+    {
+        "&&", /* Logical and */
+        0,    /* Low precedence */
+        -1,   /* Left associative. */
+        _behavior_land
+    },
+    {
+        "||", /* Logical or */
+        0,    /* Low precedence */
+        -1,   /* Left associative. */
+        _behavior_lor
+    },
+};
 
 static const size_t element_count =
     sizeof(libab_reserved_operators) / sizeof(libab_reserved_operator);
@@ -48,20 +135,24 @@ const libab_reserved_operator* libab_find_reserved_operator(const char* name) {
 
 libab_result libab_register_reserved_operators(libab_lexer* lexer) {
     libab_result result = LIBAB_SUCCESS;
+    char buffer[16];
     size_t i;
     for (i = 0; i < element_count && result == LIBAB_SUCCESS; i++) {
+        libab_sanitize(buffer, libab_reserved_operators[i].op, 16);
         result = libab_convert_lex_result(eval_config_add(
-            &lexer->config, libab_reserved_operators[i].op, TOKEN_OP_RESERVED));
+            &lexer->config, buffer, TOKEN_OP_RESERVED));
     }
     return result;
 }
 
 libab_result libab_remove_reserved_operators(libab_lexer* lexer) {
     libab_result result = LIBAB_SUCCESS;
+    char buffer[16];
     size_t i;
     for (i = 0; i < element_count && result == LIBAB_SUCCESS; i++) {
+        libab_sanitize(buffer, libab_reserved_operators[i].op, 16);
         result = libab_convert_lex_result(eval_config_remove(
-            &lexer->config, libab_reserved_operators[i].op, TOKEN_OP_RESERVED));
+            &lexer->config, buffer, TOKEN_OP_RESERVED));
     }
     return result;
 }

src/table.c

@@ -54,6 +54,12 @@ int libab_table_compare_type_param(const void* left, const void* right) {
 
 libab_operator* libab_table_search_operator(libab_table* table,
                                             const char* string, int type) {
+    libab_table_entry* entry =
+        libab_table_search_entry_operator(table, string, type);
+    return entry ? &entry->data_u.op : NULL;
+}
+libab_table_entry* libab_table_search_entry_operator(libab_table* table,
+                                                     const char* string, int type) {
     libab_table_entry* entry = NULL;
     if (type == OPERATOR_PREFIX) {
         entry = libab_table_search_filter(table, string, NULL,
@@ -65,37 +71,52 @@ libab_operator* libab_table_search_operator(libab_table* table,
         entry = libab_table_search_filter(table, string, NULL,
                                           libab_table_compare_op_postfix);
     }
-    return entry ? &entry->data_u.op : NULL;
+    return entry;
 }
 
 libab_basetype* libab_table_search_basetype(libab_table* table,
                                             const char* string) {
-    libab_table_entry* entry = libab_table_search_filter(
-        table, string, NULL, libab_table_compare_basetype);
+    libab_table_entry* entry =
+        libab_table_search_entry_basetype(table, string);
     return entry ? entry->data_u.basetype : NULL;
 }
+libab_table_entry* libab_table_search_entry_basetype(libab_table* table,
+                                                     const char* string) {
+    return libab_table_search_filter(table, string, NULL, 
+                                     libab_table_compare_basetype);
+}
 
 void libab_table_search_value(libab_table* table, const char* string,
                               libab_ref* ref) {
-    libab_table_entry* entry = libab_table_search_filter(
-        table, string, NULL, libab_table_compare_value);
+    libab_table_entry* entry =
+        libab_table_search_entry_value(table, string);
     if (entry) {
         libab_ref_copy(&entry->data_u.value, ref);
     } else {
         libab_ref_null(ref);
     }
 }
+libab_table_entry* libab_table_search_entry_value(libab_table* table,
+                                                  const char* string) {
+    return libab_table_search_filter(table, string, NULL,
+                                     libab_table_compare_value);
+}
 
 void libab_table_search_type_param(libab_table* table, const char* string,
                                    libab_ref* ref) {
-    libab_table_entry* entry = libab_table_search_filter(
-        table, string, NULL, libab_table_compare_type_param);
+    libab_table_entry* entry =
+        libab_table_search_entry_type_param(table, string);
     if (entry) {
         libab_ref_copy(&entry->data_u.type_param, ref);
     } else {
         libab_ref_null(ref);
     }
 }
+libab_table_entry* libab_table_search_entry_type_param(libab_table* table,
+                                                       const char* string) {
+    return libab_table_search_filter(
+        table, string, NULL, libab_table_compare_type_param);
+}
 
 libab_result libab_table_put(libab_table* table, const char* string,
                              libab_table_entry* entry) {

src/util.c

@@ -2,6 +2,7 @@
 #include "value.h"
 #include <stdarg.h>
 #include <stdlib.h>
+#include <stdio.h>
 #include "free_functions.h"
 
 libab_result libab_convert_lex_result(liblex_result to_convert) {
@@ -186,7 +187,31 @@ libab_result libab_instantiate_basetype(libab_basetype* to_instantiate,
     return result;
 }
 
-libab_result libab_create_table(libab_ref* into, libab_ref* parent) {
+void _gc_visit_table_entry(libab_table_entry* entry, libab_visitor_function_ptr visitor, void* data) {
+    if (entry->variant == ENTRY_VALUE) {
+        libab_gc_visit(&entry->data_u.value, visitor, data);
+    }
+}
+
+void _gc_visit_table_trie(libab_trie_node* parent, libab_visitor_function_ptr visitor, void* data) {
+    ll_node* head;
+    if(parent == NULL) return;
+    head = parent->values.head;
+    _gc_visit_table_trie(parent->child, visitor, data);
+    _gc_visit_table_trie(parent->next, visitor, data);
+    while(head != NULL) {
+        _gc_visit_table_entry(head->data, visitor, data);
+        head = head->next;
+    }
+}
+
+void _gc_visit_table_children(void* parent, libab_visitor_function_ptr visitor, void* data) {
+    libab_table* table = parent;
+    libab_gc_visit(&table->parent, visitor, data);
+    _gc_visit_table_trie(table->trie.head, visitor, data);
+}
+
+libab_result libab_create_table(libab* ab, libab_ref* into, libab_ref* parent) {
     libab_table* table;
     libab_result result = LIBAB_SUCCESS;
     if ((table = malloc(sizeof(*table)))) {
@@ -203,12 +228,19 @@ libab_result libab_create_table(libab_ref* into, libab_ref* parent) {
 
     if (result != LIBAB_SUCCESS) {
         libab_ref_null(into);
+    } else {
+        libab_gc_add(into, _gc_visit_table_children, &ab->containers);
     }
     return result;
 }
 
-libab_result libab_create_value_ref(libab_ref* into, libab_ref* data,
-                                    libab_ref* type) {
+void _gc_visit_value_children(void* val, libab_visitor_function_ptr visitor, void* data) {
+    libab_value* value = val;
+    libab_gc_visit(&value->data, visitor, data);
+}
+
+libab_result libab_create_value_ref(libab* ab, libab_ref* into, 
+                                    libab_ref* data, libab_ref* type) {
     libab_value* value;
     libab_result result = LIBAB_SUCCESS;
     if ((value = malloc(sizeof(*value)))) {
@@ -224,12 +256,14 @@ libab_result libab_create_value_ref(libab_ref* into, libab_ref* data,
 
     if (result != LIBAB_SUCCESS) {
         libab_ref_null(into);
+    } else {
+        libab_gc_add(into, _gc_visit_value_children, &ab->containers);
     }
     return result;
 }
 
-libab_result libab_create_value_raw(libab_ref* into, void* data,
-                                    libab_ref* type) {
+libab_result libab_create_value_raw(libab* ab, libab_ref* into,
+                                    void* data, libab_ref* type) {
     libab_value* value;
     libab_result result = LIBAB_SUCCESS;
 
@@ -249,12 +283,19 @@ libab_result libab_create_value_raw(libab_ref* into, void* data,
     if (result != LIBAB_SUCCESS) {
         libab_ref_null(into);
         free(value);
+    } else {
+        libab_gc_add(into, _gc_visit_value_children, &ab->containers);
     }
 
     return result;
 }
 
-libab_result libab_create_function_internal(libab_ref* into,
+void _gc_visit_function_children(void* function, libab_visitor_function_ptr visitor, void* data) {
+    libab_function* func = function;
+    libab_gc_visit(&func->scope, visitor, data);
+}
+
+libab_result libab_create_function_internal(libab* ab, libab_ref* into,
                                             void (*free_function)(void*),
                                             libab_function_ptr fun,
                                             libab_ref* scope) {
@@ -277,12 +318,14 @@ libab_result libab_create_function_internal(libab_ref* into,
     if (result != LIBAB_SUCCESS) {
         libab_ref_null(into);
         free(new_function);
+    } else {
+        libab_gc_add(into, _gc_visit_function_children, &ab->containers);
     }
 
     return result;
 }
 
-libab_result libab_create_function_tree(libab_ref* into,
+libab_result libab_create_function_tree(libab* ab, libab_ref* into,
                                         void (*free_function)(void*),
                                         libab_tree* tree,
                                         libab_ref* scope) {
@@ -305,12 +348,14 @@ libab_result libab_create_function_tree(libab_ref* into,
     if (result != LIBAB_SUCCESS) {
         libab_ref_null(into);
         free(new_function);
+    } else {
+        libab_gc_add(into, _gc_visit_function_children, &ab->containers);
     }
 
     return result;
 }
 
-libab_result libab_create_function_behavior(libab_ref* into,
+libab_result libab_create_function_behavior(libab* ab, libab_ref* into,
                                             void (*free_function)(void*),
                                             libab_behavior* behavior,
                                             libab_ref* scope) {
@@ -333,12 +378,14 @@ libab_result libab_create_function_behavior(libab_ref* into,
     if(result != LIBAB_SUCCESS) {
         libab_ref_null(into);
         free(new_function);
+    } else {
+        libab_gc_add(into, _gc_visit_function_children, &ab->containers);
     }
 
     return result;
 }
 
-libab_result libab_create_function_list(libab_ref* into, libab_ref* type) {
+libab_result libab_create_function_list(libab* ab, libab_ref* into, libab_ref* type) {
     libab_function_list* list;
     libab_result result = LIBAB_SUCCESS;
 
@@ -360,6 +407,8 @@ libab_result libab_create_function_list(libab_ref* into, libab_ref* type) {
     if (result != LIBAB_SUCCESS) {
         libab_ref_null(into);
         free(list);
+    } else {
+        libab_gc_add(into, _gc_visit_function_children, &ab->containers);
     }
 
     return result;
@@ -416,3 +465,15 @@ void* libab_unwrap_param(libab_ref_vec* vec, size_t index) {
     libab_ref_free(&temp);
     return data;
 }
+
+void libab_sanitize(char* to, const char* from, size_t buffer_size) {
+    size_t index = 0;
+    while (*from && index < (buffer_size - 2)) {
+        if (*from == '+' || *from == '*' || *from == '\\' ||
+                *from == '|' || *from == '[' || *from == ']' || *from == '(' ||
+                *from == ')')
+            to[index++] = '\\';
+        to[index++] = *(from++);
+    }
+    to[index] = '\0';
+}