exploded out the source code

.gitignore

@@ -14,3 +14,5 @@ stats.ods
 bin/
 typescript
 .main.c.swp
+.build-cache/
+__pycache__

avl/avl.c

@@ -0,0 +1,596 @@
+/*****************************************************************************
+
+    avl.c - Source code for the AVL-tree library.
+
+    Copyright (C) 1998  Michael H. Buselli <cosine@cosine.org>
+    Copyright (C) 2000-2002  Wessel Dankers <wsl@nl.linux.org>
+
+    This library is free software; you can redistribute it and/or
+    modify it under the terms of the GNU Lesser General Public
+    License as published by the Free Software Foundation; either
+    version 2.1 of the License, or (at your option) any later version.
+
+    This library is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+    Lesser General Public License for more details.
+
+    You should have received a copy of the GNU Lesser General Public
+    License along with this library; if not, write to the Free Software
+    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307  USA
+
+    Augmented AVL-tree. Original by Michael H. Buselli <cosine@cosine.org>.
+
+    Modified by Wessel Dankers <wsl@nl.linux.org> to add a bunch of bloat to
+    the sourcecode, change the interface and squash a few bugs.
+    Mail him if you find new bugs.
+
+*****************************************************************************/
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <errno.h>
+
+#include "avl.h"
+
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wconversion"
+
+static void avl_rebalance(avl_tree_t *, avl_node_t *);
+
+#ifdef AVL_COUNT
+#define NODE_COUNT(n)  ((n) ? (n)->count : 0)
+#define L_COUNT(n)     (NODE_COUNT((n)->left))
+#define R_COUNT(n)     (NODE_COUNT((n)->right))
+#define CALC_COUNT(n)  (L_COUNT(n) + R_COUNT(n) + 1)
+#endif
+
+#ifdef AVL_DEPTH
+#define NODE_DEPTH(n)  ((n) ? (n)->depth : 0)
+#define L_DEPTH(n)     (NODE_DEPTH((n)->left))
+#define R_DEPTH(n)     (NODE_DEPTH((n)->right))
+#define CALC_DEPTH(n)  ((L_DEPTH(n)>R_DEPTH(n)?L_DEPTH(n):R_DEPTH(n)) + 1)
+#endif
+
+#ifndef AVL_DEPTH
+/* Also known as ffs() (from BSD) */
+static int lg(unsigned int u) {
+	int r = 1;
+	if(!u) return 0;
+	if(u & 0xffff0000) { u >>= 16; r += 16; }
+	if(u & 0x0000ff00) { u >>= 8; r += 8; }
+	if(u & 0x000000f0) { u >>= 4; r += 4; }
+	if(u & 0x0000000c) { u >>= 2; r += 2; }
+	if(u & 0x00000002) r++;
+	return r;
+}
+#endif
+
+static int avl_check_balance(avl_node_t *avlnode) {
+#ifdef AVL_DEPTH
+	int d;
+	d = R_DEPTH(avlnode) - L_DEPTH(avlnode);
+	return d<-1?-1:d>1?1:0;
+#else
+/*	int d;
+ *	d = lg(R_COUNT(avlnode)) - lg(L_COUNT(avlnode));
+ *	d = d<-1?-1:d>1?1:0;
+ */
+#ifdef AVL_COUNT
+	int pl, r;
+
+	pl = lg(L_COUNT(avlnode));
+	r = R_COUNT(avlnode);
+
+	if(r>>pl+1)
+		return 1;
+	if(pl<2 || r>>pl-2)
+		return 0;
+	return -1;
+#else
+#error No balancing possible.
+#endif
+#endif
+}
+
+#ifdef AVL_COUNT
+unsigned int avl_count(const avl_tree_t *avltree) {
+	return NODE_COUNT(avltree->top);
+}
+
+avl_node_t *avl_at(const avl_tree_t *avltree, unsigned int index) {
+	avl_node_t *avlnode;
+	unsigned int c;
+
+	avlnode = avltree->top;
+
+	while(avlnode) {
+		c = L_COUNT(avlnode);
+
+		if(index < c) {
+			avlnode = avlnode->left;
+		} else if(index > c) {
+			avlnode = avlnode->right;
+			index -= c+1;
+		} else {
+			return avlnode;
+		}
+	}
+	return NULL;
+}
+
+unsigned int avl_index(const avl_node_t *avlnode) {
+	avl_node_t *next;
+	unsigned int c;
+
+	c = L_COUNT(avlnode);
+
+	while((next = avlnode->parent)) {
+		if(avlnode == next->right)
+			c += L_COUNT(next) + 1;
+		avlnode = next;
+	}
+
+	return c;
+}
+#endif
+
+int avl_search_closest(const avl_tree_t *avltree, const void *item, avl_node_t **avlnode) {
+	avl_node_t *node;
+	avl_compare_t cmp;
+	int c;
+
+	if(!avlnode)
+		avlnode = &node;
+
+	node = avltree->top;
+
+	if(!node)
+		return *avlnode = NULL, 0;
+
+	cmp = avltree->cmp;
+
+	for(;;) {
+		c = cmp(item, node->item);
+
+		if(c < 0) {
+			if(node->left)
+				node = node->left;
+			else
+				return *avlnode = node, -1;
+		} else if(c > 0) {
+			if(node->right)
+				node = node->right;
+			else
+				return *avlnode = node, 1;
+		} else {
+			return *avlnode = node, 0;
+		}
+	}
+}
+
+/*
+ * avl_search:
+ * Return a pointer to a node with the given item in the tree.
+ * If no such item is in the tree, then NULL is returned.
+ */
+avl_node_t *avl_search(const avl_tree_t *avltree, const void *item) {
+	avl_node_t *node;
+	return avl_search_closest(avltree, item, &node) ? NULL : node;
+}
+
+avl_tree_t *avl_init_tree(avl_tree_t *rc, avl_compare_t cmp, avl_freeitem_t freeitem) {
+	if(rc) {
+		rc->head = NULL;
+		rc->tail = NULL;
+		rc->top = NULL;
+		rc->cmp = cmp;
+		rc->freeitem = freeitem;
+	}
+	return rc;
+}
+
+avl_tree_t *avl_alloc_tree(avl_compare_t cmp, avl_freeitem_t freeitem) {
+	return avl_init_tree(malloc(sizeof(avl_tree_t)), cmp, freeitem);
+}
+
+void avl_clear_tree(avl_tree_t *avltree) {
+	avltree->top = avltree->head = avltree->tail = NULL;
+}
+
+void avl_free_nodes(avl_tree_t *avltree) {
+	avl_node_t *node, *next;
+	avl_freeitem_t freeitem;
+
+	freeitem = avltree->freeitem;
+
+	for(node = avltree->head; node; node = next) {
+		next = node->next;
+		if(freeitem)
+			freeitem(node->item);
+		free(node);
+	}
+	
+	avl_clear_tree(avltree);
+}
+
+/*
+ * avl_free_tree:
+ * Free all memory used by this tree.  If freeitem is not NULL, then
+ * it is assumed to be a destructor for the items referenced in the avl_
+ * tree, and they are deleted as well.
+ */
+void avl_free_tree(avl_tree_t *avltree) {
+	avl_free_nodes(avltree);
+	free(avltree);
+}
+
+static void avl_clear_node(avl_node_t *newnode) {
+	newnode->left = newnode->right = NULL;
+	#ifdef AVL_COUNT
+	newnode->count = 1;
+	#endif
+	#ifdef AVL_DEPTH
+	newnode->depth = 1;
+	#endif
+}
+
+avl_node_t *avl_init_node(avl_node_t *newnode, void *item) {
+	if(newnode) {
+/*		avl_clear_node(newnode); */
+		newnode->item = item;
+	}
+	return newnode;
+}
+
+avl_node_t *avl_insert_top(avl_tree_t *avltree, avl_node_t *newnode) {
+	avl_clear_node(newnode);
+	newnode->prev = newnode->next = newnode->parent = NULL;
+	avltree->head = avltree->tail = avltree->top = newnode;
+	return newnode;
+}
+
+avl_node_t *avl_insert_before(avl_tree_t *avltree, avl_node_t *node, avl_node_t *newnode) {
+	if(!node)
+		return avltree->tail
+			? avl_insert_after(avltree, avltree->tail, newnode)
+			: avl_insert_top(avltree, newnode);
+
+	if(node->left)
+		return avl_insert_after(avltree, node->prev, newnode);
+
+	avl_clear_node(newnode);
+
+	newnode->next = node;
+	newnode->parent = node;
+
+	newnode->prev = node->prev;
+	if(node->prev)
+		node->prev->next = newnode;
+	else
+		avltree->head = newnode;
+	node->prev = newnode;
+
+	node->left = newnode;
+	avl_rebalance(avltree, node);
+	return newnode;
+}
+
+avl_node_t *avl_insert_after(avl_tree_t *avltree, avl_node_t *node, avl_node_t *newnode) {
+	if(!node)
+		return avltree->head
+			? avl_insert_before(avltree, avltree->head, newnode)
+			: avl_insert_top(avltree, newnode);
+
+	if(node->right)
+		return avl_insert_before(avltree, node->next, newnode);
+
+	avl_clear_node(newnode);
+
+	newnode->prev = node;
+	newnode->parent = node;
+
+	newnode->next = node->next;
+	if(node->next)
+		node->next->prev = newnode;
+	else
+		avltree->tail = newnode;
+	node->next = newnode;
+
+	node->right = newnode;
+	avl_rebalance(avltree, node);
+	return newnode;
+}
+
+avl_node_t *avl_insert_node(avl_tree_t *avltree, avl_node_t *newnode) {
+	avl_node_t *node;
+
+	if(!avltree->top)
+		return avl_insert_top(avltree, newnode);
+
+	switch(avl_search_closest(avltree, newnode->item, &node)) {
+		case -1:
+			return avl_insert_before(avltree, node, newnode);
+		case 1:
+			return avl_insert_after(avltree, node, newnode);
+	}
+
+	return NULL;
+}
+
+/*
+ * avl_insert:
+ * Create a new node and insert an item there.
+ * Returns the new node on success or NULL if no memory could be allocated.
+ */
+avl_node_t *avl_insert(avl_tree_t *avltree, void *item) {
+	avl_node_t *newnode;
+
+	newnode = avl_init_node(malloc(sizeof(avl_node_t)), item);
+	if(newnode) {
+		if(avl_insert_node(avltree, newnode))
+			return newnode;
+		free(newnode);
+		errno = EEXIST;
+	}
+	return NULL;
+}
+
+/*
+ * avl_unlink_node:
+ * Removes the given node.  Does not delete the item at that node.
+ * The item of the node may be freed before calling avl_unlink_node.
+ * (In other words, it is not referenced by this function.)
+ */
+void avl_unlink_node(avl_tree_t *avltree, avl_node_t *avlnode) {
+	avl_node_t *parent;
+	avl_node_t **superparent;
+	avl_node_t *subst, *left, *right;
+	avl_node_t *balnode;
+
+	if(avlnode->prev)
+		avlnode->prev->next = avlnode->next;
+	else
+		avltree->head = avlnode->next;
+
+	if(avlnode->next)
+		avlnode->next->prev = avlnode->prev;
+	else
+		avltree->tail = avlnode->prev;
+
+	parent = avlnode->parent;
+
+	superparent = parent
+		? avlnode == parent->left ? &parent->left : &parent->right
+		: &avltree->top;
+
+	left = avlnode->left;
+	right = avlnode->right;
+	if(!left) {
+		*superparent = right;
+		if(right)
+			right->parent = parent;
+		balnode = parent;
+	} else if(!right) {
+		*superparent = left;
+		left->parent = parent;
+		balnode = parent;
+	} else {
+		subst = avlnode->prev;
+		if(subst == left) {
+			balnode = subst;
+		} else {
+			balnode = subst->parent;
+			balnode->right = subst->left;
+			if(balnode->right)
+				balnode->right->parent = balnode;
+			subst->left = left;
+			left->parent = subst;
+		}
+		subst->right = right;
+		subst->parent = parent;
+		right->parent = subst;
+		*superparent = subst;
+	}
+
+	avl_rebalance(avltree, balnode);
+}
+
+void *avl_delete_node(avl_tree_t *avltree, avl_node_t *avlnode) {
+	void *item = NULL;
+	if(avlnode) {
+		item = avlnode->item;
+		avl_unlink_node(avltree, avlnode);
+		if(avltree->freeitem)
+			avltree->freeitem(item);
+		free(avlnode);
+	}
+	return item;
+}
+
+void *avl_delete(avl_tree_t *avltree, const void *item) {
+	return avl_delete_node(avltree, avl_search(avltree, item));
+}
+
+avl_node_t *avl_fixup_node(avl_tree_t *avltree, avl_node_t *newnode) {
+	avl_node_t *oldnode = NULL, *node;
+
+	if(!avltree || !newnode)
+		return NULL;
+
+	node = newnode->prev;
+	if(node) {
+		oldnode = node->next;
+		node->next = newnode;
+	} else {
+		avltree->head = newnode;
+	}
+
+	node = newnode->next;
+	if(node) {
+		oldnode = node->prev;
+		node->prev = newnode;
+	} else {
+		avltree->tail = newnode;
+	}
+
+	node = newnode->parent;
+	if(node) {
+		if(node->left == oldnode)
+			node->left = newnode;
+		else
+			node->right = newnode;
+	} else {
+		oldnode = avltree->top;
+		avltree->top = newnode;
+	}
+
+	return oldnode;
+}
+
+/*
+ * avl_rebalance:
+ * Rebalances the tree if one side becomes too heavy.  This function
+ * assumes that both subtrees are AVL-trees with consistant data.  The
+ * function has the additional side effect of recalculating the count of
+ * the tree at this node.  It should be noted that at the return of this
+ * function, if a rebalance takes place, the top of this subtree is no
+ * longer going to be the same node.
+ */
+void avl_rebalance(avl_tree_t *avltree, avl_node_t *avlnode) {
+	avl_node_t *child;
+	avl_node_t *gchild;
+	avl_node_t *parent;
+	avl_node_t **superparent;
+
+	parent = avlnode;
+
+	while(avlnode) {
+		parent = avlnode->parent;
+
+		superparent = parent
+			? avlnode == parent->left ? &parent->left : &parent->right
+			: &avltree->top;
+
+		switch(avl_check_balance(avlnode)) {
+		case -1:
+			child = avlnode->left;
+			#ifdef AVL_DEPTH
+			if(L_DEPTH(child) >= R_DEPTH(child)) {
+			#else
+			#ifdef AVL_COUNT
+			if(L_COUNT(child) >= R_COUNT(child)) {
+			#else
+			#error No balancing possible.
+			#endif
+			#endif
+				avlnode->left = child->right;
+				if(avlnode->left)
+					avlnode->left->parent = avlnode;
+				child->right = avlnode;
+				avlnode->parent = child;
+				*superparent = child;
+				child->parent = parent;
+				#ifdef AVL_COUNT
+				avlnode->count = CALC_COUNT(avlnode);
+				child->count = CALC_COUNT(child);
+				#endif
+				#ifdef AVL_DEPTH
+				avlnode->depth = CALC_DEPTH(avlnode);
+				child->depth = CALC_DEPTH(child);
+				#endif
+			} else {
+				gchild = child->right;
+				avlnode->left = gchild->right;
+				if(avlnode->left)
+					avlnode->left->parent = avlnode;
+				child->right = gchild->left;
+				if(child->right)
+					child->right->parent = child;
+				gchild->right = avlnode;
+				if(gchild->right)
+					gchild->right->parent = gchild;
+				gchild->left = child;
+				if(gchild->left)
+					gchild->left->parent = gchild;
+				*superparent = gchild;
+				gchild->parent = parent;
+				#ifdef AVL_COUNT
+				avlnode->count = CALC_COUNT(avlnode);
+				child->count = CALC_COUNT(child);
+				gchild->count = CALC_COUNT(gchild);
+				#endif
+				#ifdef AVL_DEPTH
+				avlnode->depth = CALC_DEPTH(avlnode);
+				child->depth = CALC_DEPTH(child);
+				gchild->depth = CALC_DEPTH(gchild);
+				#endif
+			}
+		break;
+		case 1:
+			child = avlnode->right;
+			#ifdef AVL_DEPTH
+			if(R_DEPTH(child) >= L_DEPTH(child)) {
+			#else
+			#ifdef AVL_COUNT
+			if(R_COUNT(child) >= L_COUNT(child)) {
+			#else
+			#error No balancing possible.
+			#endif
+			#endif
+				avlnode->right = child->left;
+				if(avlnode->right)
+					avlnode->right->parent = avlnode;
+				child->left = avlnode;
+				avlnode->parent = child;
+				*superparent = child;
+				child->parent = parent;
+				#ifdef AVL_COUNT
+				avlnode->count = CALC_COUNT(avlnode);
+				child->count = CALC_COUNT(child);
+				#endif
+				#ifdef AVL_DEPTH
+				avlnode->depth = CALC_DEPTH(avlnode);
+				child->depth = CALC_DEPTH(child);
+				#endif
+			} else {
+				gchild = child->left;
+				avlnode->right = gchild->left;
+				if(avlnode->right)
+					avlnode->right->parent = avlnode;
+				child->left = gchild->right;
+				if(child->left)
+					child->left->parent = child;
+				gchild->left = avlnode;
+				if(gchild->left)
+					gchild->left->parent = gchild;
+				gchild->right = child;
+				if(gchild->right)
+					gchild->right->parent = gchild;
+				*superparent = gchild;
+				gchild->parent = parent;
+				#ifdef AVL_COUNT
+				avlnode->count = CALC_COUNT(avlnode);
+				child->count = CALC_COUNT(child);
+				gchild->count = CALC_COUNT(gchild);
+				#endif
+				#ifdef AVL_DEPTH
+				avlnode->depth = CALC_DEPTH(avlnode);
+				child->depth = CALC_DEPTH(child);
+				gchild->depth = CALC_DEPTH(gchild);
+				#endif
+			}
+		break;
+		default:
+			#ifdef AVL_COUNT
+			avlnode->count = CALC_COUNT(avlnode);
+			#endif
+			#ifdef AVL_DEPTH
+			avlnode->depth = CALC_DEPTH(avlnode);
+			#endif
+		}
+		avlnode = parent;
+	}
+}
+
+#pragma GCC diagnostic pop

avl/avl.h

@@ -0,0 +1,186 @@
+/*****************************************************************************
+
+    avl.h - Source code for the AVL-tree library.
+
+    Copyright (C) 1998  Michael H. Buselli <cosine@cosine.org>
+    Copyright (C) 2000-2002  Wessel Dankers <wsl@nl.linux.org>
+
+    This library is free software; you can redistribute it and/or
+    modify it under the terms of the GNU Lesser General Public
+    License as published by the Free Software Foundation; either
+    version 2.1 of the License, or (at your option) any later version.
+
+    This library is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+    Lesser General Public License for more details.
+
+    You should have received a copy of the GNU Lesser General Public
+    License along with this library; if not, write to the Free Software
+    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307  USA
+
+    Augmented AVL-tree. Original by Michael H. Buselli <cosine@cosine.org>.
+
+    Modified by Wessel Dankers <wsl@nl.linux.org> to add a bunch of bloat to
+    the sourcecode, change the interface and squash a few bugs.
+    Mail him if you find new bugs.
+
+*****************************************************************************/
+
+#ifndef _AVL_H
+#define _AVL_H
+
+/* We need either depths, counts or both (the latter being the default) */
+#if !defined(AVL_DEPTH) && !defined(AVL_COUNT)
+#define AVL_DEPTH
+#define AVL_COUNT
+#endif
+
+/* User supplied function to compare two items like strcmp() does.
+ * For example: cmp(a,b) will return:
+ *   -1  if a < b
+ *    0  if a = b
+ *    1  if a > b
+ */
+typedef int (*avl_compare_t)(const void *, const void *);
+
+/* User supplied function to delete an item when a node is free()d.
+ * If NULL, the item is not free()d.
+ */
+typedef void (*avl_freeitem_t)(void *);
+
+typedef struct avl_node_t {
+	struct avl_node_t *next;
+	struct avl_node_t *prev;
+	struct avl_node_t *parent;
+	struct avl_node_t *left;
+	struct avl_node_t *right;
+	void *item;
+#ifdef AVL_COUNT
+	unsigned int count;
+#endif
+#ifdef AVL_DEPTH
+	unsigned char depth;
+#endif
+} avl_node_t;
+
+typedef struct avl_tree_t {
+	avl_node_t *head;
+	avl_node_t *tail;
+	avl_node_t *top;
+	avl_compare_t cmp;
+	avl_freeitem_t freeitem;
+} avl_tree_t;
+
+/* Initializes a new tree for elements that will be ordered using
+ * the supplied strcmp()-like function.
+ * Returns the value of avltree (even if it's NULL).
+ * O(1) */
+extern avl_tree_t *avl_init_tree(avl_tree_t *avltree, avl_compare_t, avl_freeitem_t);
+
+/* Allocates and initializes a new tree for elements that will be
+ * ordered using the supplied strcmp()-like function.
+ * Returns NULL if memory could not be allocated.
+ * O(1) */
+extern avl_tree_t *avl_alloc_tree(avl_compare_t, avl_freeitem_t);
+
+/* Frees the entire tree efficiently. Nodes will be free()d.
+ * If the tree's freeitem is not NULL it will be invoked on every item.
+ * O(n) */
+extern void avl_free_tree(avl_tree_t *);
+
+/* Reinitializes the tree structure for reuse. Nothing is free()d.
+ * Compare and freeitem functions are left alone.
+ * O(1) */
+extern void avl_clear_tree(avl_tree_t *);
+
+/* Free()s all nodes in the tree but leaves the tree itself.
+ * If the tree's freeitem is not NULL it will be invoked on every item.
+ * O(n) */
+extern void avl_free_nodes(avl_tree_t *);
+
+/* Initializes memory for use as a node. Returns NULL if avlnode is NULL.
+ * O(1) */
+extern avl_node_t *avl_init_node(avl_node_t *avlnode, void *item);
+
+/* Insert an item into the tree and return the new node.
+ * Returns NULL and sets errno if memory for the new node could not be
+ * allocated or if the node is already in the tree (EEXIST).
+ * O(lg n) */
+extern avl_node_t *avl_insert(avl_tree_t *, void *item);
+
+/* Insert a node into the tree and return it.
+ * Returns NULL if the node is already in the tree.
+ * O(lg n) */
+extern avl_node_t *avl_insert_node(avl_tree_t *, avl_node_t *);
+
+/* Insert a node in an empty tree. If avlnode is NULL, the tree will be
+ * cleared and ready for re-use.
+ * If the tree is not empty, the old nodes are left dangling.
+ * O(1) */
+extern avl_node_t *avl_insert_top(avl_tree_t *, avl_node_t *avlnode);
+
+/* Insert a node before another node. Returns the new node.
+ * If old is NULL, the item is appended to the tree.
+ * O(lg n) */
+extern avl_node_t *avl_insert_before(avl_tree_t *, avl_node_t *old, avl_node_t *new);
+
+/* Insert a node after another node. Returns the new node.
+ * If old is NULL, the item is prepended to the tree.
+ * O(lg n) */
+extern avl_node_t *avl_insert_after(avl_tree_t *, avl_node_t *old, avl_node_t *new);
+
+/* Deletes a node from the tree. Returns immediately if the node is NULL.
+ * The item will not be free()d regardless of the tree's freeitem handler.
+ * This function comes in handy if you need to update the search key.
+ * O(lg n) */
+extern void avl_unlink_node(avl_tree_t *, avl_node_t *);
+
+/* Deletes a node from the tree. Returns immediately if the node is NULL.
+ * If the tree's freeitem is not NULL, it is invoked on the item.
+ * If it is, returns the item.
+ * O(lg n) */
+extern void *avl_delete_node(avl_tree_t *, avl_node_t *);
+
+/* Searches for an item in the tree and deletes it if found.
+ * If the tree's freeitem is not NULL, it is invoked on the item.
+ * If it is, returns the item.
+ * O(lg n) */
+extern void *avl_delete(avl_tree_t *, const void *item);
+
+/* If exactly one node is moved in memory, this will fix the pointers
+ * in the tree that refer to it. It must be an exact shallow copy.
+ * Returns the pointer to the old position.
+ * O(1) */
+extern avl_node_t *avl_fixup_node(avl_tree_t *, avl_node_t *new);
+
+/* Searches for a node with the key closest (or equal) to the given item.
+ * If avlnode is not NULL, *avlnode will be set to the node found or NULL
+ * if the tree is empty. Return values:
+ *   -1  if the returned node is smaller
+ *    0  if the returned node is equal or if the tree is empty
+ *    1  if the returned node is greater
+ * O(lg n) */
+extern int avl_search_closest(const avl_tree_t *, const void *item, avl_node_t **avlnode);
+
+/* Searches for the item in the tree and returns a matching node if found
+ * or NULL if not.
+ * O(lg n) */
+extern avl_node_t *avl_search(const avl_tree_t *, const void *item);
+
+#ifdef AVL_COUNT
+/* Returns the number of nodes in the tree.
+ * O(1) */
+extern unsigned int avl_count(const avl_tree_t *);
+
+/* Searches a node by its rank in the list. Counting starts at 0.
+ * Returns NULL if the index exceeds the number of nodes in the tree.
+ * O(lg n) */
+extern avl_node_t *avl_at(const avl_tree_t *, unsigned int);
+
+/* Returns the rank of a node in the list. Counting starts at 0.
+ * O(lg n) */
+extern unsigned int avl_index(const avl_node_t *);
+#endif
+
+#endif

cmdln/free.c

@@ -0,0 +1,11 @@
+
+#include <debug.h>
+
+#include "free.h"
+
+void free_cmdln_flags(
+    struct cmdln_flags* flags)
+{
+    TODO;
+}
+

cmdln/free.h

@@ -0,0 +1,5 @@
+
+struct cmdln_flags;
+
+void free_cmdln_flags(
+    struct cmdln_flags* flags);

cmdln/print_usage.c

@@ -0,0 +1,9 @@
+
+#include <debug.h>
+
+#include "print_usage.h"
+
+void print_usage()
+{
+    TODO;
+}

cmdln/print_usage.h

@@ -0,0 +1,3 @@
+
+void print_usage(void);
+

cmdln/process.c

@@ -0,0 +1,254 @@
+
+#include <debug.h>
+
+#include <memory/smalloc.h>
+
+#include "struct.h"
+#include "process.h"
+#include "print_usage.h"
+
+static struct option long_options[] = {
+    {"print-all-and-quit",       no_argument, NULL, 't'},
+    {"command",            required_argument, NULL, 'c'},
+    {"operators",          required_argument, NULL, 'o'},
+    {"print-stats",              no_argument, NULL, 'm'},
+    {"help",                     no_argument, NULL, 'h'},
+    {0, 0, 0, 0}
+};
+
+struct cmdln_flags* process_cmdln_flags(
+    int argc,
+    char* const* argv)
+{
+    ENTER;
+    
+    const char* command = NULL;
+    
+    bool unset_operators = true;
+    struct operators selected_operators = {};
+    
+    bool unset_print_with_color = true;
+    bool print_with_color;
+    
+    bool print_all_and_quit = false;
+    bool print_stats = false;
+    
+    for (int opt, idx;
+            (opt = getopt_long(argc, argv, "tc:o:mh", long_options, &idx)) != -1;)
+    {
+        switch (opt)
+        {
+            case 't':
+            {
+                print_all_and_quit = true;
+                break;
+            }
+            
+            case 'c':
+            {
+                command = optarg;
+                break;
+            }
+            
+            case 'o':
+            {
+                TODO;
+                break;
+            }
+            
+            case 'm':
+            {
+                TODO;
+                break;
+            }
+            
+            case 'h':
+            {
+                print_usage();
+                exit(0);
+                break;
+            }
+            
+            default:
+            {
+                print_usage();
+                exit(1);
+                break;
+            }
+        }
+    }
+    
+    if (unset_operators)
+    {
+        selected_operators.not = true;
+        selected_operators.or = true;
+        selected_operators.and = true;
+    }
+    
+    if (unset_print_with_color)
+    {
+        if (isatty(1))
+        {
+            print_with_color = true;
+        }
+        else
+        {
+            print_with_color = false;
+        }
+    }
+    
+    struct cmdln_flags* flags = smalloc(sizeof(*flags));
+    
+    flags->command = command;
+    flags->selected_operators = selected_operators;
+    flags->print_with_color = print_with_color;
+    flags->print_stats = print_stats;
+    flags->print_all_and_quit = print_all_and_quit;
+    
+    EXIT;
+    return flags;
+}
+
+#if 0
+
+static void parse_args(int argc, char* const* argv)
+{
+    bool unset_operators = true;
+
+    print_with_color = isatty(1);
+
+    for (int opt; (opt = getopt(argc, argv, "tpyqmvc:eEo:C:B")) != -1; ) switch (opt)
+    {
+        case 't':
+            print_truthtable = true;
+            break;
+
+        case 'p':
+            print_all_and_quit = true;
+            break;
+
+        case 'y':
+            assume_yes = true;
+            break;
+
+        case 'q':
+            quiet = true;
+            break;
+
+        case 'm':
+            print_stats = true;
+            break;
+
+        case 'v':
+            verbose = true;
+            break;
+
+        case 'c':
+            command = optarg;
+            break;
+
+        case 'E':
+            use_operators.ternary = true;
+            // fallthrough
+
+        case 'e':
+        {
+            use_operators.not = true;
+            use_operators.or = true;
+            use_operators.and = true;
+
+            use_operators.orn = true;
+            use_operators.nor = true;
+
+            use_operators.andn = true;
+            use_operators.nand = true;
+
+            use_operators. xor = true;
+            use_operators.nxor = true;
+
+            unset_operators = false;
+            break;
+        }
+
+        case 'o':
+        {
+            unset_operators = false;
+
+            for (char* moving; (moving = strtok_r(NULL, ",", &optarg)); )
+            {
+                if (!strcmp(moving, "not") || !strcmp(moving, "!"))
+                    use_operators.not = true;
+                else if (!strcmp(moving, "or") || !strcmp(moving, "||"))
+                    use_operators.or = true;
+                else if (!strcmp(moving, "orn") || !strcmp(moving, "|!"))
+                    use_operators.orn = true;
+                else if (!strcmp(moving, "nor") || !strcmp(moving, "!|"))
+                    use_operators.nor = true;
+                else if (!strcmp(moving, "and") || !strcmp(moving, "&&"))
+                    use_operators.and = true;
+                else if (!strcmp(moving, "andn") || !strcmp(moving, "&!"))
+                    use_operators.andn = true;
+                else if (!strcmp(moving, "nand") || !strcmp(moving, "!&"))
+                    use_operators.nand = true;
+                else if (!strcmp(moving, "xor") || !strcmp(moving, "!="))
+                    use_operators.xor = true;
+                else if (!strcmp(moving, "nxor") || !strcmp(moving, "=="))
+                    use_operators.nxor = true;
+                else if (!strcmp(moving, "lt") || !strcmp(moving, "<"))
+                    use_operators.lt = true;
+                else if (!strcmp(moving, "lte") || !strcmp(moving, "<="))
+                    use_operators.lte = true;
+                else if (!strcmp(moving, "gt") || !strcmp(moving, ">"))
+                    use_operators.gt = true;
+                else if (!strcmp(moving, "gte") || !strcmp(moving, ">="))
+                    use_operators.gte = true;
+                else if (!strcmp(moving, "ternary") || !strcmp(moving, "?:"))
+                    use_operators.ternary = true;
+                else
+                {
+                    assert(!"TODO");
+                }
+            }
+            break;
+        }
+
+        case 'C':
+        {
+            if (!strcmp(optarg, "yes") || !strcmp(optarg, "on"))
+                print_with_color = true;
+            else if (!strcmp(optarg, "no") || !strcmp(optarg, "off"))
+                print_with_color = false;
+            else if (!strcmp(optarg, "auto"))
+                print_with_color = isatty(1);
+            else
+            {
+                assert(!"TODO");
+            }
+
+            break;
+        }
+
+        case 'B':
+        {
+            force_rebuild = true;
+
+            break;
+        }
+
+        default:
+        {
+            printf("Unknown option '%c'!" "\n", opt);
+            exit(1);
+            break;
+        }
+    }
+
+    if (unset_operators)
+    {
+        use_operators.not = true;
+        use_operators.or = true;
+        use_operators.and = true;
+    }
+}
+
+#endif

cmdln/process.h

@@ -0,0 +1,4 @@
+
+struct cmdln_flags* process_cmdln_flags(
+    int argc,
+    char* const* argv);

cmdln/struct.h

@@ -0,0 +1,54 @@
+
+#include <stdbool.h>
+
+#include <structs/operators.h>
+
+struct cmdln_flags
+{
+    const char* command;
+    
+    struct operators selected_operators;
+    
+    bool print_stats;
+    bool print_all_and_quit;
+    
+    bool print_with_color;
+    
+    bool verbose;
+};
+
+#if 0
+
+bool print_all_and_quit = false;
+
+const char* command = NULL;
+
+struct {
+    bool not;
+
+    bool or, orn, nor;
+
+    bool and, andn, nand;
+
+    bool xor, nxor;
+
+    bool lt, lte, gt, gte;
+
+    bool ternary;
+} use_operators;
+
+bool print_truthtable = false;
+
+bool assume_yes = false;
+
+bool verbose = false;
+
+bool print_with_color = false;
+
+bool print_stats = false;
+
+bool force_rebuild = false;
+
+bool quiet = false;
+
+#endif

debug.c

@@ -0,0 +1,4 @@
+
+#ifdef DEBUG_BUILD_TYPE
+int debug_depth;
+#endif

debug.h

@@ -0,0 +1,46 @@
+
+#ifdef DEBUG_BUILD_TYPE
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <getopt.h>
+#include <assert.h>
+#include <stdbool.h>
+#include <inttypes.h>
+#include <limits.h>
+#include <string.h>
+
+struct string;
+struct scope;
+struct expression;
+struct cmdln_flags;
+struct avl_tree_t;
+struct truthtable_set;
+
+extern int debug_depth;
+
+#include <typedefs/truthtable_t.h>
+
+#include <memory/smalloc.h>
+
+#include <string/inc.h>
+
+#define ENTER \
+    printf("%*s" "%s():" "\n", debug_depth++, "", __PRETTY_FUNCTION__);
+
+#define TODO \
+    assert(!"TODO");
+    
+#define CHECK \
+    assert(!"CHECK");
+    
+#define EXIT \
+    printf("%*s" "return; // from %s" "\n", debug_depth--, "", __PRETTY_FUNCTION__);
+
+#endif
+
+#ifdef RELEASE_BUILD_TYPE
+#define ENTER ;
+#define TODO ;
+#endif
+

defines/M.h

@@ -0,0 +1,2 @@
+
+#define M (0b1111111111111111)

defines/N.h

@@ -0,0 +1 @@
+#define N (65536)

defines/W.h

@@ -0,0 +1 @@
+#define W 0b0101010101010101

defines/X.h

@@ -0,0 +1 @@
+#define X 0b0011001100110011

defines/Y.h

@@ -0,0 +1 @@
+#define Y 0b0000111100001111

defines/Z.h

@@ -0,0 +1 @@
+#define Z 0b0000000011111111

expression/and/free.c

@@ -0,0 +1,11 @@
+
+#include <debug.h>
+
+#include "free.h"
+
+void free_and_expression(
+    struct expression* super)
+{
+    TODO;
+}
+

expression/and/free.h

@@ -0,0 +1,5 @@
+
+struct expression;
+
+void free_and_expression(
+    struct expression* super);

expression/and/inheritance.c

@@ -0,0 +1,11 @@
+
+#include "inheritance.h"
+#include "print.h"
+#include "free.h"
+
+struct expression_inheritance and_expression_inheritance =
+{
+    .print = and_expression_print,
+    .free = free_and_expression,
+};
+

expression/and/inheritance.h

@@ -0,0 +1,5 @@
+
+#include "../inheritance.h"
+
+extern struct expression_inheritance and_expression_inheritance;
+

expression/and/new.c

@@ -0,0 +1,27 @@
+
+#include <debug.h>
+
+#include "../new.h"
+#include "../inc.h"
+
+#include "inheritance.h"
+#include "struct.h"
+#include "new.h"
+
+struct expression* new_and_expression(
+    int cost,
+    struct expression* left,
+    struct expression* right)
+{
+    struct and_expression* this =
+        (void*) new_expression(
+            /* inheritance: */ &and_expression_inheritance,
+            /* cost: */ cost,
+            /* size: */ sizeof(*this));
+    
+    this->left  = inc_expression(left);
+    this->right = inc_expression(right);
+    
+    return (void*) this;
+}
+

expression/and/new.h

@@ -0,0 +1,5 @@
+
+struct expression* new_and_expression(
+    int cost,
+    struct expression* left,
+    struct expression* right);

expression/and/print.c

@@ -0,0 +1,16 @@
+
+#include <debug.h>
+
+#include "../print.h"
+
+#include "struct.h"
+#include "print.h"
+
+void and_expression_print(
+    struct expression* super)
+{
+    struct and_expression* this = (void*) super;
+    
+    printf("("), expression_print(this->left), printf(" && "), expression_print(this->right), printf(")");
+}
+

expression/and/print.h

@@ -0,0 +1,3 @@
+
+void and_expression_print(
+    struct expression* super);

expression/and/struct.h

@@ -0,0 +1,12 @@
+
+#include "../struct.h"
+
+struct and_expression
+{
+    struct expression super;
+    
+    struct expression* left;
+    
+    struct expression* right;
+};
+

expression/free.c

@@ -0,0 +1,25 @@
+
+#include <debug.h>
+
+#include "inheritance.h"
+#include "struct.h"
+#include "free.h"
+
+void free_expression(
+    struct expression* this)
+{
+    if (this)
+    {
+        if (!--this->refcount)
+        {
+            assert(this);
+            
+            assert(this->inheritance);
+            
+            assert(this->inheritance->free);
+            
+            free(this);
+        }
+    }
+}
+

expression/free.h

@@ -0,0 +1,3 @@
+
+void free_expression(
+    struct expression* this);

expression/inc.c

@@ -0,0 +1,17 @@
+
+#include <debug.h>
+
+#include "struct.h"
+#include "inc.h"
+
+struct expression* inc_expression(
+    struct expression* this)
+{
+    if (this)
+    {
+        this->refcount++;
+    }
+    
+    return this;
+}
+

expression/inc.h

@@ -0,0 +1,3 @@
+
+struct expression* inc_expression(
+    struct expression* this);

expression/inheritance.h

@@ -0,0 +1,12 @@
+
+struct expression;
+
+struct expression_inheritance
+{
+    void (*print)(
+        struct expression*);
+    
+    void (*free)(
+        struct expression*);
+};
+

expression/literal/free.c

@@ -0,0 +1,11 @@
+
+#include <debug.h>
+
+#include "free.h"
+
+void free_literal_expression(
+    struct expression* super)
+{
+    TODO;
+}
+

expression/literal/free.h

@@ -0,0 +1,3 @@
+
+void free_literal_expression(
+    struct expression* super);

expression/literal/inheritance.c

@@ -0,0 +1,11 @@
+
+#include "inheritance.h"
+#include "print.h"
+#include "free.h"
+
+struct expression_inheritance literal_expression_inheritance =
+{
+    .print = literal_expression_print,
+    .free = free_literal_expression,
+};
+

expression/literal/inheritance.h

@@ -0,0 +1,5 @@
+
+#include "../inheritance.h"
+
+extern struct expression_inheritance literal_expression_inheritance;
+

expression/literal/new.c

@@ -0,0 +1,26 @@
+
+#include <debug.h>
+
+#include "../new.h"
+
+#include "inheritance.h"
+#include "struct.h"
+#include "new.h"
+
+struct expression* new_literal_expression(
+    int cost, bool value)
+{
+    ENTER;
+    
+    struct literal_expression* this =
+        (void*) new_expression(
+            /* inheritance: */ &literal_expression_inheritance,
+            /* cost: */ cost,
+            /* size: */ sizeof(*this));
+    
+    this->value = value;
+    
+    EXIT;
+    return (void*) this;
+}
+

expression/literal/new.h

@@ -0,0 +1,4 @@
+
+struct expression* new_literal_expression(
+    int cost,
+    bool is_one);

expression/literal/print.c

@@ -0,0 +1,21 @@
+
+#include <debug.h>
+
+#include "struct.h"
+#include "print.h"
+
+void literal_expression_print(
+    struct expression* super)
+{
+    struct literal_expression* this = (void*) super;
+    
+    if (this->value)
+    {
+        printf("1");
+    }
+    else
+    {
+        printf("0");
+    }
+}
+

expression/literal/print.h

@@ -0,0 +1,3 @@
+
+void literal_expression_print(
+    struct expression* super);

expression/literal/struct.h

@@ -0,0 +1,10 @@
+
+#include "../struct.h"
+
+struct literal_expression
+{
+    struct expression super;
+    
+    bool value;
+};
+

expression/new.c

@@ -0,0 +1,22 @@
+
+#include <debug.h>
+
+#include "struct.h"
+#include "new.h"
+
+struct expression* new_expression(
+    const struct expression_inheritance* inheritance,
+    int cost,
+    size_t size)
+{
+    struct expression* this = smalloc(size);
+    
+    this->inheritance = inheritance;
+    
+    this->cost = cost;
+    
+    this->refcount = 1;
+    
+    return this;
+}
+

expression/new.h

@@ -0,0 +1,7 @@
+
+struct expression_inheritance;
+
+struct expression* new_expression(
+    const struct expression_inheritance* inheritance,
+    int cost,
+    size_t size);

expression/not/free.c

@@ -0,0 +1,11 @@
+
+#include <debug.h>
+
+#include "free.h"
+
+void free_not_expression(
+    struct expression* super)
+{
+    TODO;
+}
+

expression/not/free.h

@@ -0,0 +1,5 @@
+
+struct expression;
+
+void free_not_expression(
+    struct expression* super);

expression/not/inheritance.c

@@ -0,0 +1,11 @@
+
+#include "inheritance.h"
+#include "print.h"
+#include "free.h"
+
+struct expression_inheritance not_expression_inheritance =
+{
+    .print = not_expression_print,
+    .free = free_not_expression,
+};
+

expression/not/inheritance.h

@@ -0,0 +1,5 @@
+
+#include "../inheritance.h"
+
+extern struct expression_inheritance not_expression_inheritance;
+

expression/not/new.c

@@ -0,0 +1,25 @@
+
+#include <debug.h>
+
+#include "../new.h"
+#include "../inc.h"
+
+#include "inheritance.h"
+#include "struct.h"
+#include "new.h"
+
+struct expression* new_not_expression(
+    int cost,
+    struct expression* inner)
+{
+    struct not_expression* this =
+        (void*) new_expression(
+            /* inheritance: */ &not_expression_inheritance,
+            /* cost: */ cost,
+            /* size: */ sizeof(*this));
+    
+    this->inner = inc_expression(inner);
+    
+    return (void*) this;
+}
+

expression/not/new.h

@@ -0,0 +1,4 @@
+
+struct expression* new_not_expression(
+    int cost,
+    struct expression* subexpression);

expression/not/print.c

@@ -0,0 +1,16 @@
+
+#include <debug.h>
+
+#include "../print.h"
+
+#include "struct.h"
+#include "print.h"
+
+void not_expression_print(
+    struct expression* super)
+{
+    struct not_expression* this = (void*) super;
+    
+    printf("(!"), expression_print(this->inner), printf(")");
+}
+

expression/not/print.h

@@ -0,0 +1,3 @@
+
+void not_expression_print(
+    struct expression* super);

expression/not/struct.h

@@ -0,0 +1,10 @@
+
+#include "../struct.h"
+
+struct not_expression
+{
+    struct expression super;
+    
+    struct expression* inner;
+};
+

expression/or/free.c

@@ -0,0 +1,11 @@
+
+#include <debug.h>
+
+#include "free.h"
+
+void free_or_expression(
+    struct expression* super)
+{
+    TODO;
+}
+

expression/or/free.h

@@ -0,0 +1,5 @@
+
+struct expression;
+
+void free_or_expression(
+    struct expression* super);

expression/or/inheritance.c

@@ -0,0 +1,11 @@
+
+#include "inheritance.h"
+#include "print.h"
+#include "free.h"
+
+struct expression_inheritance or_expression_inheritance =
+{
+    .print = or_expression_print,
+    .free = free_or_expression,
+};
+

expression/or/inheritance.h

@@ -0,0 +1,5 @@
+
+#include "../inheritance.h"
+
+extern struct expression_inheritance or_expression_inheritance;
+

expression/or/new.c

@@ -0,0 +1,27 @@
+
+#include <debug.h>
+
+#include "../new.h"
+#include "../inc.h"
+
+#include "inheritance.h"
+#include "struct.h"
+#include "new.h"
+
+struct expression* new_or_expression(
+    int cost,
+    struct expression* left,
+    struct expression* right)
+{
+    struct or_expression* this =
+        (void*) new_expression(
+            /* inheritance: */ &or_expression_inheritance,
+            /* cost: */ cost,
+            /* size: */ sizeof(*this));
+    
+    this->left  = inc_expression(left);
+    this->right = inc_expression(right);
+    
+    return (void*) this;
+}
+

expression/or/new.h

@@ -0,0 +1,5 @@
+
+struct expression* new_or_expression(
+    int cost,
+    struct expression* left,
+    struct expression* right);

expression/or/print.c

@@ -0,0 +1,16 @@
+
+#include <debug.h>
+
+#include "../print.h"
+
+#include "struct.h"
+#include "print.h"
+
+void or_expression_print(
+    struct expression* super)
+{
+    struct or_expression* this = (void*) super;
+    
+    printf("("), expression_print(this->left), printf(" || "), expression_print(this->right), printf(")");
+}
+

expression/or/print.h

@@ -0,0 +1,3 @@
+
+void or_expression_print(
+    struct expression* super);

expression/or/struct.h

@@ -0,0 +1,12 @@
+
+#include "../struct.h"
+
+struct or_expression
+{
+    struct expression super;
+    
+    struct expression* left;
+    
+    struct expression* right;
+};
+

expression/print.c

@@ -0,0 +1,17 @@
+
+#include <debug.h>
+
+#include "inheritance.h"
+#include "struct.h"
+#include "print.h"
+
+void expression_print(
+    struct expression* this)
+{
+    assert(this);
+    assert(this->inheritance);
+    assert(this->inheritance->print);
+    
+    (this->inheritance->print)(this);
+}
+

expression/print.h

@@ -0,0 +1,5 @@
+
+struct expression;
+
+void expression_print(
+    struct expression* this);

expression/struct.h

@@ -0,0 +1,12 @@
+
+struct expression_inheritance;
+
+struct expression
+{
+    const struct expression_inheritance* inheritance;
+    
+    int cost;
+    
+    unsigned refcount;
+};
+

expression/unreachable/free.c

@@ -0,0 +1,11 @@
+
+#include <debug.h>
+
+#include "free.h"
+
+void free_unreachable_expression(
+    struct expression* super)
+{
+    TODO;
+}
+

expression/unreachable/free.h

@@ -0,0 +1,3 @@
+
+void free_unreachable_expression(
+    struct expression* super);

expression/unreachable/inheritance.c

@@ -0,0 +1,11 @@
+
+#include "inheritance.h"
+#include "print.h"
+#include "free.h"
+
+struct expression_inheritance unreachable_expression_inheritance =
+{
+    .print = unreachable_expression_print,
+    .free = free_unreachable_expression,
+};
+

expression/unreachable/inheritance.h

@@ -0,0 +1,5 @@
+
+#include "../inheritance.h"
+
+extern struct expression_inheritance unreachable_expression_inheritance;
+

expression/unreachable/new.c

@@ -0,0 +1,23 @@
+
+#include <debug.h>
+
+#include "../new.h"
+
+#include "inheritance.h"
+#include "struct.h"
+#include "new.h"
+
+struct expression* new_unreachable_expression(void)
+{
+    ENTER;
+    
+    struct unreachable_expression* this =
+        (void*) new_expression(
+            /* inheritance: */ &unreachable_expression_inheritance,
+            /* cost: */ INT_MAX,
+            /* size: */ sizeof(*this));
+    
+    EXIT;
+    return (void*) this;
+}
+

expression/unreachable/new.h

@@ -0,0 +1,2 @@
+
+struct expression* new_unreachable_expression(void);

expression/unreachable/print.c

@@ -0,0 +1,11 @@
+
+#include <debug.h>
+
+#include "print.h"
+
+void unreachable_expression_print(
+    struct expression* super)
+{
+    TODO;
+}
+

expression/unreachable/print.h

@@ -0,0 +1,3 @@
+
+void unreachable_expression_print(
+    struct expression* super);

expression/unreachable/struct.h

@@ -0,0 +1,8 @@
+
+#include "../struct.h"
+
+struct unreachable_expression
+{
+    struct expression super;
+};
+

expression/variable/free.c

@@ -0,0 +1,11 @@
+
+#include <debug.h>
+
+#include "free.h"
+
+void free_variable_expression(
+    struct expression* super)
+{
+    TODO;
+}
+

expression/variable/free.h

@@ -0,0 +1,3 @@
+
+void free_variable_expression(
+    struct expression* super);

expression/variable/inheritance.c

@@ -0,0 +1,11 @@
+
+#include "inheritance.h"
+#include "print.h"
+#include "free.h"
+
+struct expression_inheritance variable_expression_inheritance =
+{
+    .print = variable_expression_print,
+    .free = free_variable_expression,
+};
+

expression/variable/inheritance.h

@@ -0,0 +1,5 @@
+
+#include "../inheritance.h"
+
+extern struct expression_inheritance variable_expression_inheritance;
+

expression/variable/new.c

@@ -0,0 +1,27 @@
+
+#include <debug.h>
+
+#include "../new.h"
+
+#include "inheritance.h"
+#include "struct.h"
+#include "new.h"
+
+struct expression* new_variable_expression(
+    int cost,
+    struct string* name)
+{
+    ENTER;
+    
+    struct variable_expression* this =
+        (void*) new_expression(
+            /* inheritance: */ &variable_expression_inheritance,
+            /* cost: */ cost,
+            /* size: */ sizeof(*this));
+    
+    this->name = inc_string(name);
+    
+    EXIT;
+    return (void*) this;
+}
+

expression/variable/new.h

@@ -0,0 +1,4 @@
+
+struct expression* new_variable_expression(
+    int cost,
+    struct string* name);

expression/variable/print.c

@@ -0,0 +1,16 @@
+
+#include <debug.h>
+
+#include <string/print.h>
+
+#include "struct.h"
+#include "print.h"
+
+void variable_expression_print(
+    struct expression* super)
+{
+    struct variable_expression* this = (void*) super;
+    
+    string_print(this->name);
+}
+

expression/variable/print.h

@@ -0,0 +1,3 @@
+
+void variable_expression_print(
+    struct expression* super);

expression/variable/struct.h

@@ -0,0 +1,10 @@
+
+#include "../struct.h"
+
+struct variable_expression
+{
+    struct expression super;
+    
+    struct string* name;
+};
+

flake.nix

@@ -25,10 +25,13 @@
           pkgs.mkShell {
             buildInputs = with pkgs; [
               gcc
-              gnumake
               readline.dev
               python3
             ];
+            
+            shellHook = ''
+              export PATH="$PWD:$PATH"
+            '';
           };
           packages.default = pkgs.stdenv.mkDerivation rec {
             pname = "4-variable-simplifier";

main.c

@@ -1,4 +1,18 @@
 
+#include <assert.h>
+#include <debug.h>
+
+#include <cmdln/struct.h>
+#include <cmdln/process.h>
+#include <cmdln/free.h>
+
+#include <scope/new.h>
+#include <scope/free.h>
+
+#include <simplifications/new.h>
+#include <simplifications/free.h>
+
+#if 0
 #include <math.h>
 #include <string.h>
 #include <stdint.h>
@@ -14,8 +28,6 @@
 #include <readline/readline.h>
 #include <readline/history.h>
 
-#define argv0 program_invocation_name
-
 #ifdef ZDEBUG
 #define zprintf(fmt, ...) \
     printf(fmt, ## __VA_ARGS__);
@@ -23,186 +35,6 @@
 #define zprintf(...);
 #endif
 
-bool print_all_and_quit = false;
-
-const char* command = NULL;
-
-struct {
-    bool not;
-
-    bool or, orn, nor;
-
-    bool and, andn, nand;
-
-    bool xor, nxor;
-
-    bool lt, lte, gt, gte;
-
-    bool ternary;
-} use_operators;
-
-bool print_truthtable = false;
-
-bool assume_yes = false;
-
-bool verbose = false;
-
-bool print_with_color = false;
-
-bool print_stats = false;
-
-bool force_rebuild = false;
-
-bool quiet = false;
-
-static void parse_args(int argc, char* const* argv)
-{
-    bool unset_operators = true;
-
-    print_with_color = isatty(1);
-
-    for (int opt; (opt = getopt(argc, argv, "tpyqmvc:eEo:C:B")) != -1; ) switch (opt)
-    {
-        case 't':
-            print_truthtable = true;
-            break;
-
-        case 'p':
-            print_all_and_quit = true;
-            break;
-
-        case 'y':
-            assume_yes = true;
-            break;
-
-        case 'q':
-            quiet = true;
-            break;
-
-        case 'm':
-            print_stats = true;
-            break;
-
-        case 'v':
-            verbose = true;
-            break;
-
-        case 'c':
-            command = optarg;
-            break;
-
-        case 'E':
-            use_operators.ternary = true;
-            // fallthrough
-
-        case 'e':
-        {
-            use_operators.not = true;
-            use_operators.or = true;
-            use_operators.and = true;
-
-            use_operators.orn = true;
-            use_operators.nor = true;
-
-            use_operators.andn = true;
-            use_operators.nand = true;
-
-            use_operators. xor = true;
-            use_operators.nxor = true;
-
-            unset_operators = false;
-            break;
-        }
-
-        case 'o':
-        {
-            unset_operators = false;
-
-            for (char* moving; (moving = strtok_r(NULL, ",", &optarg)); )
-            {
-                if (!strcmp(moving, "not") || !strcmp(moving, "!"))
-                    use_operators.not = true;
-                else if (!strcmp(moving, "or") || !strcmp(moving, "||"))
-                    use_operators.or = true;
-                else if (!strcmp(moving, "orn") || !strcmp(moving, "|!"))
-                    use_operators.orn = true;
-                else if (!strcmp(moving, "nor") || !strcmp(moving, "!|"))
-                    use_operators.nor = true;
-                else if (!strcmp(moving, "and") || !strcmp(moving, "&&"))
-                    use_operators.and = true;
-                else if (!strcmp(moving, "andn") || !strcmp(moving, "&!"))
-                    use_operators.andn = true;
-                else if (!strcmp(moving, "nand") || !strcmp(moving, "!&"))
-                    use_operators.nand = true;
-                else if (!strcmp(moving, "xor") || !strcmp(moving, "!="))
-                    use_operators.xor = true;
-                else if (!strcmp(moving, "nxor") || !strcmp(moving, "=="))
-                    use_operators.nxor = true;
-                else if (!strcmp(moving, "lt") || !strcmp(moving, "<"))
-                    use_operators.lt = true;
-                else if (!strcmp(moving, "lte") || !strcmp(moving, "<="))
-                    use_operators.lte = true;
-                else if (!strcmp(moving, "gt") || !strcmp(moving, ">"))
-                    use_operators.gt = true;
-                else if (!strcmp(moving, "gte") || !strcmp(moving, ">="))
-                    use_operators.gte = true;
-                else if (!strcmp(moving, "ternary") || !strcmp(moving, "?:"))
-                    use_operators.ternary = true;
-                else
-                {
-                    assert(!"TODO");
-                }
-            }
-            break;
-        }
-
-        case 'C':
-        {
-            if (!strcmp(optarg, "yes") || !strcmp(optarg, "on"))
-                print_with_color = true;
-            else if (!strcmp(optarg, "no") || !strcmp(optarg, "off"))
-                print_with_color = false;
-            else if (!strcmp(optarg, "auto"))
-                print_with_color = isatty(1);
-            else
-            {
-                assert(!"TODO");
-            }
-
-            break;
-        }
-
-        case 'B':
-        {
-            force_rebuild = true;
-
-            break;
-        }
-
-        default:
-        {
-            printf("Unknown option '%c'!" "\n", opt);
-            exit(1);
-            break;
-        }
-    }
-
-    if (unset_operators)
-    {
-        use_operators.not = true;
-        use_operators.or = true;
-        use_operators.and = true;
-    }
-}
-
-#define W 0b0101010101010101
-#define X 0b0011001100110011
-#define Y 0b0000111100001111
-#define Z 0b0000000011111111
-#define M 0b1111111111111111
-
-#define N (65536)
-
 enum kind {
     ek_unreachable,
 
@@ -1442,15 +1274,18 @@ uint16_t evaluate(const char* text)
 
     return truthtable;
 }
+#endif
 
 int main(int argc, char* const* argv)
 {
-    parse_args(argc, argv);
+    ENTER;
-
+    
-    get_simplifications();
+    struct cmdln_flags* flags = process_cmdln_flags(argc, argv);
-
+    
-    if (print_all_and_quit)
+    if (flags->print_all_and_quit)
     {
+        TODO;
+        #if 0
         for (int i = 0; i < N; i++)
         {
             int cost = lookup[i].cost;
@@ -1460,9 +1295,12 @@ int main(int argc, char* const* argv)
                 printf("0b%016b: [%2i]: ", i, cost), print(i, 0), puts("");
             }
         }
+        #endif
     }
-    else if (print_stats)
+    else if (flags->print_stats)
     {
+        TODO;
+        #if 0
         printf("statistics:" "\n");
 
         uintmax_t total_cost = 0;
@@ -1515,9 +1353,18 @@ int main(int argc, char* const* argv)
         {
             puts("everything unreachable: no statistics to give");
         }
+        #endif
     }
-    else if (command)
+    else if (flags->command)
     {
+        struct scope* scope = new_scope();
+        
+        struct simplifications* simplifications = new_simplifications(
+            /* operators: */ &flags->selected_operators,
+            /* scope: */ scope);
+        
+        TODO;
+        #if 0
         uint16_t truthtable = evaluate(command);
 
         if (print_truthtable)
@@ -1534,9 +1381,16 @@ int main(int argc, char* const* argv)
             // printf("%2i: ", lookup[truthtable].cost), print(truthtable, 0), puts("");
             print(truthtable, 0), puts("");
         }
+        #endif
+        
+        free_simplifications(simplifications);
+        
+        free_scope(scope);
     }
     else
     {
+        TODO;
+        #if 0
         if (!quiet)
         {
             puts("Use C-style syntax for boolean operators and expressions.");
@@ -1544,8 +1398,7 @@ int main(int argc, char* const* argv)
             puts("Extended operators: nor is '!|', orn is '|!', nand is '!&', andn is '&!'.");
             puts("Comparison operators are also suppported.");
         }
-
+        
-
         for (char* line; (line = readline(">>> ")); free(line))
         {
             if (!*line) continue;
@@ -1567,12 +1420,14 @@ int main(int argc, char* const* argv)
             {
                 // printf("%2i: ", lookup[truthtable].cost);
                 printf("        ");
-
+                print(truthtable, 0), puts("");
-				print(truthtable, 0), puts("");
             }
         }
+        #endif
     }
 
+    free_cmdln_flags(flags);
+
     return 0;
 }