//: A Mu program is a book of 'recipes' (functions)
:(before "End Globals")
//: Each recipe is stored at a specific page number, or ordinal.
map<recipe_ordinal, recipe> Recipe;
//: You can also refer to each recipe by its name.
map<string, recipe_ordinal> Recipe_ordinal;
recipe_ordinal Next_recipe_ordinal = 1;

//: Ordinals are like numbers, except you can't do arithmetic on them. Ordinal
//: 1 is not less than 2, it's just different. Phone numbers are ordinals;
//: adding two phone numbers is meaningless. Here each recipe does something
//: incommensurable with any other recipe.
:(after "Types")
typedef int recipe_ordinal;

:(before "End Types")
// Recipes are lists of instructions. To perform or 'run' a recipe, the
// computer runs its instructions.
struct recipe {
  recipe_ordinal ordinal;
  string name;
  vector<instruction> steps;
  // End recipe Fields
  recipe();
};

:(before "struct recipe")
// Each instruction is either of the form:
//   product1, product2, product3, ... <- operation ingredient1, ingredient2, ingredient3, ...
// or just a single 'label' starting with a non-alphanumeric character
//   +label
// Labels don't do anything, they're just named locations in a recipe.
struct instruction {
  bool is_label;
  string label;  // only if is_label
  string name;  // only if !is_label
  string original_string;  // for error messages
  recipe_ordinal operation;  // get(Recipe_ordinal, name)
  vector<reagent> ingredients;  // only if !is_label
  vector<reagent> products;  // only if !is_label
  // End instruction Fields
  instruction();
  void clear();
  bool is_empty();
};

:(before "struct instruction")
// Ingredients and products are a single species -- a reagent. Reagents refer
// either to numbers or to locations in memory along with 'type' tags telling
// us how to interpret them. They also can contain arbitrary other lists of
// properties besides types, but we're getting ahead of ourselves.
struct reagent {
  string original_string;
  string name;
  type_tree* type;
  vector<pair<string, string_tree*> > properties;  // can't be a map because the string_tree sometimes needs to be NULL, which can be confusing
  double value;
  bool initialized;
  // End reagent Fields
  reagent(const string& s);
  reagent() :type(NULL), value(0), initialized(false) {}
  reagent(type_tree* t) :type(t), value(0), initialized(false) {}
  ~reagent();
  void clear();
  reagent(const reagent& original);
  reagent& operator=(const reagent& original);
  void set_value(double v) { value = v;  initialized = true; }
};

:(before "struct reagent")
// Types can range from a simple type ordinal, to arbitrarily complex trees of
// type parameters, like (map (address array character) (list number))
struct type_tree {
  bool atom;
  string name;  // only if atom
  type_ordinal value;  // only if atom
  type_tree* left;  // only if !atom
  type_tree* right;  // only if !atom
  ~type_tree();
  type_tree(const type_tree& original);
  // atomic type ordinal
  explicit type_tree(string name);
  type_tree(string name, type_ordinal v) :atom(true), name(name), value(v), left(NULL), right(NULL) {}
  // tree of type ordinals
  type_tree(type_tree* l, type_tree* r) :atom(false), value(0), left(l), right(r) {}
  type_tree& operator=(const type_tree& original);
  bool operator==(const type_tree& other) const;
  bool operator!=(const type_tree& other) const { return !operator==(other); }
  bool operator<(const type_tree& other) const;
  bool operator>(const type_tree& other) const { return other.operator<(*this); }
};

struct string_tree {
  bool atom;
  string value;  // only if atom
  string_tree* left;  // only if !atom
  string_tree* right;  // only if !atom
  ~string_tree();
  string_tree(const string_tree& original);
  // atomic string
  explicit string_tree(string v) :atom(true), value(v), left(NULL), right(NULL) {}
  // tree of strings
  string_tree(string_tree* l, string_tree* r) :atom(false), left(l), right(r) {}
};

// End type_tree Definition
:(code)
type_tree::type_tree(string name) :atom(true), name(name), value(get(Type_ordinal, name)), left(NULL), right(NULL) {}

:(before "End Globals")
// Locations refer to a common 'memory'. Each location can store a number.
map<int, double> Memory;
:(before "End Reset")
Memory.clear();

:(after "Types")
// Mu types encode how the numbers stored in different parts of memory are
// interpreted. A location tagged as a 'character' type will interpret the
// value 97 as the letter 'a', while a different location of type 'number'
// would not.
//
// Unlike most computers today, Mu stores types in a single big table, shared
// by all the Mu programs on the computer. This is useful in providing a
// seamless experience to help understand arbitrary Mu programs.
typedef int type_ordinal;
:(before "End Globals")
map<string, type_ordinal> Type_ordinal;
map<type_ordinal, type_info> Type;
type_ordinal Next_type_ordinal = 1;
type_ordinal Number_type_ordinal = 0;
type_ordinal Boolean_type_ordinal = 0;
type_ordinal Character_type_ordinal = 0;
type_ordinal Address_type_ordinal = 0;
type_ordinal Array_type_ordinal = 0;
:(code)
void setup_types() {
  Type.clear();  Type_ordinal.clear();
  put(Type_ordinal, "literal", 0);
  Next_type_ordinal = 1;
  // Mu Types Initialization
  Number_type_ordinal = put(Type_ordinal, "number", Next_type_ordinal++);
  get_or_insert(Type, Number_type_ordinal).name = "number";
  put(Type_ordinal, "location", Number_type_ordinal);  // synonym of number for addresses we'll never look up
  Address_type_ordinal = put(Type_ordinal, "address", Next_type_ordinal++);
  get_or_insert(Type, Address_type_ordinal).name = "address";
  Boolean_type_ordinal = put(Type_ordinal, "boolean", Next_type_ordinal++);
  get_or_insert(Type, Boolean_type_ordinal).name = "boolean";
  Character_type_ordinal = put(Type_ordinal, "character", Next_type_ordinal++);
  get_or_insert(Type, Character_type_ordinal).name = "character";
  // Array types are a special modifier to any other type. For example,
  // array:number or array:address:boolean.
  Array_type_ordinal = put(Type_ordinal, "array", Next_type_ordinal++);
  get_or_insert(Type, Array_type_ordinal).name = "array";
  // End Mu Types Initialization
}
void teardown_types() {
  for (map<type_ordinal, type_info>::iterator p = Type.begin();  p != Type.end();  ++p) {
    for (int i = 0;  i < SIZE(p->second.elements);  ++i)
      p->second.elements.clear();
  }
  Type_ordinal.clear();
}
:(before "End One-time Setup")
setup_types();
atexit(teardown_types);

:(before "End Types")
// You can construct arbitrary new types. New types are either 'containers'
// with multiple 'elements' of other types, or 'exclusive containers' containing
// one of multiple 'variants'. (These are similar to C structs and unions,
// respectively, though exclusive containers implicitly include a tag element
// recording which variant they should be interpreted as.)
//
// For example, storing bank balance and name for an account might require a
// container, but if bank accounts may be either for individuals or groups,
// with different properties for each, that may require an exclusive container
// whose variants are individual-account and joint-account containers.
enum kind_of_type {
  PRIMITIVE,
  CONTAINER,
  EXCLUSIVE_CONTAINER
};

struct type_info {
  string name;
  kind_of_type kind;
  vector<reagent> elements;
  // End type_info Fields
  type_info() :kind(PRIMITIVE) {
    // End type_info Constructor
  }
};

enum primitive_recipes {
  IDLE = 0,
  COPY,
  // End Primitive Recipe Declarations
  MAX_PRIMITIVE_RECIPES,
};
:(code)
//: It's all very well to construct recipes out of other recipes, but we need
//: to know how to do *something* out of the box. For the following
//: recipes there are only codes, no entries in the book, because Mu just knows
//: what to do for them.
void setup_recipes() {
  Recipe.clear();  Recipe_ordinal.clear();
  put(Recipe_ordinal, "idle", IDLE);
  // Primitive Recipe Numbers
  put(Recipe_ordinal, "copy", COPY);
  // End Primitive Recipe Numbers
}
//: We could just reset the recipe table after every test, but that gets slow
//: all too quickly. Instead, initialize the common stuff just once at
//: startup. Later layers will carefully undo each test's additions after
//: itself.
:(before "End One-time Setup")
setup_recipes();
assert(MAX_PRIMITIVE_RECIPES < 200);  // level 0 is primitives; until 199
Next_recipe_ordinal = 200;
put(Recipe_ordinal, "main", Next_recipe_ordinal++);
// Load Mu Prelude
// End Mu Prelude
:(before "End Commandline Parsing")
assert(Next_recipe_ordinal < 1000);  // recipes being tested didn't overflow into test space
:(before "End Reset")
Next_recipe_ordinal = 1000;  // consistent new numbers for each test

//: One final detail: tests can modify our global tables of recipes and types,
//: so we need some way to clean up after each test is done so it doesn't
//: influence later ones.
:(before "End Globals")
map<string, recipe_ordinal> Recipe_ordinal_snapshot;
map<recipe_ordinal, recipe> Recipe_snapshot;
map<string, type_ordinal> Type_ordinal_snapshot;
map<type_ordinal, type_info> Type_snapshot;
:(before "End One-time Setup")
save_snapshots();
:(before "End Reset")
restore_snapshots();

:(code)
void save_snapshots() {
  Recipe_ordinal_snapshot = Recipe_ordinal;
  Recipe_snapshot = Recipe;
  Type_ordinal_snapshot = Type_ordinal;
  Type_snapshot = Type;
  // End save_snapshots
}

void restore_snapshots() {
  Recipe = Recipe_snapshot;
  Recipe_ordinal = Recipe_ordinal_snapshot;
  restore_non_recipe_snapshots();
}
// when running sandboxes in the edit/ app we'll want to restore everything except recipes defined in the app
void restore_non_recipe_snapshots() {
  Type_ordinal = Type_ordinal_snapshot;
  Type = Type_snapshot;
  // End restore_snapshots
}

//:: Helpers

:(code)
recipe::recipe() {
  ordinal = -1;
  // End recipe Constructor
}

instruction::instruction() :is_label(false), operation(IDLE) {
  // End instruction Constructor
}
void instruction::clear() {
  is_label=false;
  label.clear();
  name.clear();
  operation=IDLE;
  ingredients.clear();
  products.clear();
  original_string.clear();
  // End instruction Clear
}
bool instruction::is_empty() { return !is_label && name.empty(); }

// Reagents have the form <name>:<type>:<type>:.../<property>/<property>/...
reagent::reagent(const string& s) :original_string(s), type(NULL), value(0), initialized(false) {
  // Parsing reagent(string s)
  istringstream in(s);
  in >> std::noskipws;
  // name and type
  istringstream first_row(slurp_until(in, '/'));
  first_row >> std::noskipws;
  name = slurp_until(first_row, ':');
  string_tree* type_names = parse_property_list(first_row);
  // End Parsing Reagent Type Property(type_names)
  type = new_type_tree(type_names);
  delete type_names;
  // special cases
  if (is_integer(name) && type == NULL)
    type = new type_tree("literal");
  if (name == "_" && type == NULL)
    type = new type_tree("literal");
  // other properties
  slurp_properties(in, properties);
  // End Parsing reagent
}

void slurp_properties(istream& in, vector<pair<string, string_tree*> >& out) {
  while (has_data(in)) {
    istringstream row(slurp_until(in, '/'));
    row >> std::noskipws;
    string key = slurp_until(row, ':');
    string_tree* value = parse_property_list(row);
    out.push_back(pair<string, string_tree*>(key, value));
  }
}

string_tree* parse_property_list(istream& in) {
  skip_whitespace_but_not_newline(in);
  if (!has_data(in)) return NULL;
  string_tree* first = new string_tree(slurp_until(in, ':'));
  if (!has_data(in)) return first;
  string_tree* rest = parse_property_list(in);
  if (!has_data(in) && rest->atom)
    return new string_tree(first, new string_tree(rest, NULL));
  return new string_tree(first, rest);
}
:(before "End Unit Tests")
void test_parse_property_list_atom() {
  istringstream in("a");
  string_tree* x = parse_property_list(in);
  CHECK(x->atom);
  delete x;
}
void test_parse_property_list_list() {
  istringstream in("a:b");
  string_tree* x = parse_property_list(in);
  CHECK(!x->atom);
  CHECK(x->left->atom);
  CHECK_EQ(x->left->value, "a");
  CHECK(!x->right->atom);
  CHECK(x->right->left->atom);
  CHECK_EQ(x->right->left->value, "b");
  CHECK(x->right->right == NULL);
  delete x;
}

:(code)
type_tree* new_type_tree(const string_tree* properties) {
  if (!properties) return NULL;
  if (properties->atom) {
    const string& type_name = properties->value;
    int value = 0;
    if (contains_key(Type_ordinal, type_name))
      value = get(Type_ordinal, type_name);
    else if (is_integer(type_name))  // sometimes types will contain literal integers, like for the size of an array
      value = 0;
    else if (properties->value == "->")  // used in recipe types
      value = 0;
    else
      value = -1;  // should never happen; will trigger errors later
    return new type_tree(type_name, value);
  }
  return new type_tree(new_type_tree(properties->left),
                       new_type_tree(properties->right));
}

//: avoid memory leaks for the type tree

reagent::reagent(const reagent& other) {
  original_string = other.original_string;
  name = other.name;
  value = other.value;
  initialized = other.initialized;
  for (int i = 0;  i < SIZE(other.properties);  ++i) {
    properties.push_back(pair<string, string_tree*>(other.properties.at(i).first, copy(other.properties.at(i).second)));
  }
  type = copy(other.type);
  // End reagent Copy Constructor
}

type_tree::type_tree(const type_tree& original) {
  atom = original.atom;
  name = original.name;
  value = original.value;
  left = copy(original.left);
  right = copy(original.right);
}

type_tree& type_tree::operator=(const type_tree& original) {
  atom = original.atom;
  name = original.name;
  value = original.value;
  if (left) delete left;
  left = copy(original.left);
  if (right) delete right;
  right = copy(original.right);
  return *this;
}

bool type_tree::operator==(const type_tree& other) const {
  if (atom != other.atom) return false;
  if (atom)
    return name == other.name && value == other.value;
  return (left == other.left || *left == *other.left)
      && (right == other.right || *right == *other.right);
}

// only constraint we care about: if a < b then !(b < a)
bool type_tree::operator<(const type_tree& other) const {
  if (atom != other.atom) return atom > other.atom;  // atoms before non-atoms
  if (atom) return value < other.value;
  // first location in one that's missing in the other makes that side 'smaller'
  if (left && !other.left) return false;
  if (!left && other.left) return true;
  if (right && !other.right) return false;
  if (!right && other.right) return true;
  // now if either pointer is unequal neither side can be null
  // if one side is equal that's easy
  if (left == other.left || *left == *other.left) return right && *right < *other.right;
  if (right == other.right || *right == *other.right) return left && *left < *other.left;
  // if the two sides criss-cross, pick the side with the smaller lhs
  if ((left == other.right || *left == *other.right)
      && (right == other.left || *right == *other.left))
    return *left < *other.left;
  // now the hard case: both sides are not equal
  // make sure we stay consistent between (a < b) and (b < a)
  // just return the side with the smallest of the 4 branches
  if (*left < *other.left && *left < *other.right) return true;
  if (*right < *other.left && *right < *other.right) return true;
  return false;
}
:(before "End Unit Tests")
// These unit tests don't always use valid types.
void test_compare_atom_types() {
  reagent a("a:address"), b("b:boolean");
  CHECK(*a.type < *b.type);
  CHECK(!(*b.type < *a.type));
}
void test_compare_equal_atom_types() {
  reag<style>pre { line-height: 125%; }
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td.linenos .special { color: #000000; background-color: #ffffc0; padding-left: 5px; padding-right: 5px; }
span.linenos.special { color: #000000; background-color: #ffffc0; padding-left: 5px; padding-right: 5px; }
.highlight .hll { background-color: #ffffcc }
.highlight .c { color: #888888 } /* Comment */
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.highlight .k { color: #008800; font-weight: bold } /* Keyword */
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.highlight .c1 { color: #888888 } /* Comment.Single */
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.highlight .gd { color: #000000; background-color: #ffdddd } /* Generic.Deleted */
.highlight .ge { font-style: italic } /* Generic.Emph */
.highlight .ges { font-weight: bold; font-style: italic } /* Generic.EmphStrong */
.highlight .gr { color: #aa0000 } /* Generic.Error */
.highlight .gh { color: #333333 } /* Generic.Heading */
.highlight .gi { color: #000000; background-color: #ddffdd } /* Generic.Inserted */
.highlight .go { color: #888888 } /* Generic.Output */
.highlight .gp { color: #555555 } /* Generic.Prompt */
.highlight .gs { font-weight: bold } /* Generic.Strong */
.highlight .gu { color: #666666 } /* Generic.Subheading */
.highlight .gt { color: #aa0000 } /* Generic.Traceback */
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.highlight .kn { color: #008800; font-weight: bold } /* Keyword.Namespace */
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.highlight .kt { color: #888888; font-weight: bold } /* Keyword.Type */
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.highlight .na { color: #336699 } /* Name.Attribute */
.highlight .nb { color: #003388 } /* Name.Builtin */
.highlight .nc { color: #bb0066; font-weight: bold } /* Name.Class */
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.highlight .nd { color: #555555 } /* Name.Decorator */
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.highlight .nf { color: #0066bb; font-weight: bold } /* Name.Function */
.highlight .nl { color: #336699; font-style: italic } /* Name.Label */
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.highlight .py { color: #336699; font-weight: bold } /* Name.Property */
.highlight .nt { color: #bb0066; font-weight: bold } /* Name.Tag */
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.highlight .fm { color: #0066bb; font-weight: bold } /* Name.Function.Magic */
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.highlight .vm { color: #336699 } /* Name.Variable.Magic */
.highlight .il { color: #0000DD; font-weight: bold } /* Literal.Number.Integer.Long */</style><div class="highlight"><pre><span></span><span class="kn">package</span><span class="w"> </span><span class="nx">commands</span>

<span class="kn">import</span><span class="w"> </span><span class="p">(</span>
<span class="w">	</span><span class="s">&quot;fmt&quot;</span>
<span class="w">	</span><span class="s">&quot;strconv&quot;</span>

<span class="w">	</span><span class="s">&quot;git.sr.ht/~sircmpwn/aerc/widgets&quot;</span>
<span class="p">)</span>

<span class="kd">type</span><span class="w"> </span><span class="nx">NextPrevTab</span><span class="w"> </span><span class="kd">struct</span><span class="p">{}</span>

<span class="kd">func</span><span class="w"> </span><span class="nx">init</span><span class="p">()</span><span class="w"> </span><span class="p">{</span>
<span class="w">	</span><span class="nx">register</span><span class="p">(</span><span class="nx">NextPrevTab</span><span class="p">{})</span>
<span class="p">}</span>

<span class="kd">func</span><span class="w"> </span><span class="p">(</span><span class="nx">NextPrevTab</span><span class="p">)</span><span class="w"> </span><span class="nx">Aliases</span><span class="p">()</span><span class="w"> </span><span class="p">[]</span><span class="kt">string</span><span class="w"> </span><span class="p">{</span>
<span class="w">	</span><span class="k">return</span><span class="w"> </span><span class="p">[]</span><span class="kt">string</span><span class="p">{</span><span class="s">&quot;next-tab&quot;</span><span class="p">,</span><span class="w"> </span><span class="s">&quot;prev-tab&quot;</span><span class="p">}</span>
<span class="p">}</span>

<span class="kd">func</span><span class="w"> </span><span class="p">(</span><span class="nx">NextPrevTab</span><span class="p">)</span><span class="w"> </span><span class="nx">Complete</span><span class="p">(</span><span class="nx">aerc</span><span class="w"> </span><span class="o">*</span><span class="nx">widgets</span><span class="p">.</span><span class="nx">Aerc</span><span class="p">,</span><span class="w"> </span><span class="nx">args</span><span class="w"> </span><span class="p">[]</span><span class="kt">string</span><span class="p">)</span><span class="w"> </span><span class="p">[]</span><span class="kt">string</span><span class="w"> </span><span class="p">{</span>
<span class="w">	</span><span class="k">return</span><span class="w"> </span><span class="kc">nil</span>
<span class="p">}</span>

<span class="kd">func</span><span class="w"> </span><span class="p">(</span><span class="nx">NextPrevTab</span><span class="p">)</span><span class="w"> </span><span class="nx">Execute</span><span class="p">(</span><span class="nx">aerc</span><span class="w"> </span><span class="o">*</span><span class="nx">widgets</span><span class="p">.</span><span class="nx">Aerc</span><span class="p">,</span><span class="w"> </span><span class="nx">args</span><span class="w"> </span><span class="p">[]</span><span class="kt">string</span><span class="p">)</span><span class="w"> </span><span class="kt">error</span><span class="w"> </span><span class="p">{</span>
<span class="w">	</span><span class="k">if</span><span class="w"> </span><span class="nb">len</span><span class="p">(</span><span class="nx">args</span><span class="p">)</span><span class="w"> </span><span class="p">&gt;</span><span class="w"> </span><span class="mi">2</span><span class="w"> </span><span class="p">{</span>
<span class="w">		</span><span class="k">return</span><span class="w"> </span><span class="nx">nextPrevTabUsage</span><span class="p">(</span><span class="nx">args</span><span class="p">[</span><span class="mi">0</span><span class="p">])</span>
<span class="w">	</span><span class="p">}</span>
<span class="w">	</span><span class="kd">var</span><span class="w"> </span><span class="p">(</span>
<span class="w">		</span><span class="nx">n</span><span class="w">   </span><span class="kt">int</span><span class="w"> </span><span class="p">=</span><span class="w"> </span><span class="mi">1</span>
<span class="w">		</span><span class="nx">err</span><span class="w"> </span><span class="kt">error</span>
<span class="w">	</span><span class="p">)</span>
<span class="w">	</span><span class="k">if</span><span class="w"> </span><span class="nb">len</span><span class="p">(</span><span class="nx">args</span><span class="p">)</span><span class="w"> </span><span class="p">&gt;</span><span class="w"> </span><span class="mi">1</span><span class="w"> </span><span class="p">{</span>
<span class="w">		</span><span class="nx">n</span><span class="p">,</span><span class="w"> </span><span class="nx">err</span><span class="w"> </span><span class="p">=</span><span class="w"> </span><span class="nx">strconv</span><span class="p">.</span><span class="nx">Atoi</span><span class="p">(</span><span class="nx">args</span><span class="p">[</span><span class="mi">1</span><span class="p">])</span>
<span class="w">		</span><span class="k">if</span><span class="w"> </span><span class="nx">err</span><span class="w"> </span><span class="o">!=</span><span class="w"> </span><span class="kc">nil</span><span class="w"> </span><span class="p">{</span>
<span class="w">			</span><span class="k">return</span><span class="w"> </span><span class="nx">nextPrevTabUsage</span><span class="p">(</span><span class="nx">args</span><span class="p">[</span><span class="mi">0</span><span class="p">])</span>
<span class="w">		</span><span class="p">}</span>
<span class="w">	</span><span class="p">}</span>
<span class="w">	</span><span class="k">for</span><span class="w"> </span><span class="p">;</span><span class="w"> </span><span class="nx">n</span><span class="w"> </span><span class="p">&gt;</span><span class="w"> </span><span class="mi">0</span><span class="p">;</span><span class="w"> </span><span class="nx">n</span><span class="o">--</span><span class="w"> </span><span class="p">{</span>
<span class="w">		</span><span class="k">if</span><span class="w"> </span><span class="nx">args</span><span class="p">[</span><span class="mi">0</span><span class="p">]</span><span class="w"> </span><span class="o">==</span><span class="w"> </span><span class="s">&quot;prev-tab&quot;</span><span class="w"> </span><span class="p">{</span>
<span class="w">			</span><span class="nx">aerc</span><span class="p">.</span><span class="nx">PrevTab</span><span class="p">()</span>
<span class="w">		</span><span class="p">}</span><span class="w"> </span><span class="k">else</span><span class="w"> </span><span class="p">{</span>
<span class="w">			</span><span class="nx">aerc</span><span class="p">.</span><span class="nx">NextTab</span><span class="p">()</span>
<span class="w">		</span><span class="p">}</span>
<span cla