https://github.com/akkartik/mu/blob/master/026call.cc

      1 //: So far the recipes we define can't run each other. Let's fix that.
      2
      3 :(scenario calling_recipe)
      4 def main [
      5   f
      6 ]
      7 def f [
      8   3:num <- add 2, 2
      9 ]
     10 +mem: storing 4 in location 3
     11
     12 :(scenario return_on_fallthrough)
     13 def main [
     14   f
     15   1:num <- copy 0
     16   2:num <- copy 0
     17   3:num <- copy 0
     18 ]
     19 def f [
     20   4:num <- copy 0
     21   5:num <- copy 0
     22 ]
     23 +run: f
     24 # running f
     25 +run: {4: "number"} <- copy {0: "literal"}
     26 +run: {5: "number"} <- copy {0: "literal"}
     27 # back out to main
     28 +run: {1: "number"} <- copy {0: "literal"}
     29 +run: {2: "number"} <- copy {0: "literal"}
     30 +run: {3: "number"} <- copy {0: "literal"}
     31
     32 :(before "struct routine {")
     33 // Everytime a recipe runs another, we interrupt it and start running the new
     34 // recipe. When that finishes, we continue this one where we left off.
     35 // This requires maintaining a 'stack' of interrupted recipes or 'calls'.
     36 struct call {
     37   recipe_ordinal running_recipe;
     38   int running_step_index;
     39   // End call Fields
     40   call(recipe_ordinal r) { clear(r, 0); }
     41   call(recipe_ordinal r, int index) { clear(r, index); }
     42   void clear(recipe_ordinal r, int index) {
     43     running_recipe = r;
     44     running_step_index = index;
     45     // End call Constructor
     46   }
     47   ~call() {
     48     // End call Destructor
     49   }
     50 };
     51 typedef list<call> call_stack;
     52
     53 :(replace{} "struct routine")
     54 struct routine {
     55   call_stack calls;
     56   // End routine Fields
     57   routine(recipe_ordinal r);
     58   bool completed() const;
     59   const vector<instruction>& steps() const;
     60 };
     61 :(code)
     62 routine::routine(recipe_ordinal r) {
     63   if (Trace_stream) {
     64     ++Trace_stream->callstack_depth;
     65     trace("trace") << "new routine; incrementing callstack depth to " << Trace_stream->callstack_depth << end();
     66     assert(Trace_stream->callstack_depth < 9000);  // 9998-101 plus cushion
     67   }
     68   calls.push_front(call(r));
     69   // End routine Constructor
     70 }
     71
     72 //:: now update routine's helpers
     73
     74 //: macro versions for a slight speedup
     75
     76 :(delete{} "int& current_step_index()")
     77 :(delete{} "recipe_ordinal currently_running_recipe()")
     78 :(delete{} "const string& current_recipe_name()")
     79 :(delete{} "const recipe& current_recipe()")
     80 :(delete{} "const instruction& current_instruction()")
     81
     82 :(before "End Includes")
     83 #define current_call() Current_routine->calls.front()
     84 #define current_step_index() current_call().running_step_index
     85 #define currently_running_recipe() current_call().running_recipe
     86 #define current_recipe() get(Recipe, currently_running_recipe())
     87 #define current_recipe_name() current_recipe().name
     88 #define to_instruction(call) get(Recipe, (call).running_recipe).steps.at((call).running_step_index)
     89 #define current_instruction() to_instruction(current_call())
     90
     91 //: function versions for debugging
     92
     93 :(code)
     94 //? :(before "End Globals")
     95 //? bool Foo2 = false;
     96 //? :(code)
     97 //? call& current_call() {
     98 //?   if (Foo2) cerr << __FUNCTION__ << '\n';
     99 //?   return Current_routine->calls.front();
    100 //? }
    101 //? :(replace{} "int& current_step_index()")
    102 //? int& current_step_index() {
    103 //?   assert(!Current_routine->calls.empty());
    104 //?   if (Foo2) cerr << __FUNCTION__ << '\n';
    105 //?   return current_call().running_step_index;
    106 //? }
    107 //? :(replace{} "recipe_ordinal currently_running_recipe()")
    108 //? recipe_ordinal currently_running_recipe() {
    109 //?   assert(!Current_routine->calls.empty());
    110 //?   if (Foo2) cerr << __FUNCTION__ << '\n';
    111 //?   return current_call().running_recipe;
    112 //? }
    113 //? :(replace{} "const string& current_recipe_name()")
    114 //? const string& current_recipe_name() {
    115 //?   assert(!Current_routine->calls.empty());
    116 //?   if (Foo2) cerr << __FUNCTION__ << '\n';
    117 //?   return get(Recipe, current_call().running_recipe).name;
    118 //? }
    119 //? :(replace{} "const recipe& current_recipe()")
    120 //? const recipe& current_recipe() {
    121 //?   assert(!Current_routine->calls.empty());
    122 //?   if (Foo2) cerr << __FUNCTION__ << '\n';
    123 //?   return get(Recipe, current_call().running_recipe);
    124 //? }
    125 //? :(replace{} "const instruction& current_instruction()")
    126 //? const instruction& current_instruction() {
    127 //?   assert(!Current_routine->calls.empty());
    128 //?   if (Foo2) cerr << __FUNCTION__ << '\n';
    129 //?   return to_instruction(current_call());
    130 //? }
    131 //? :(code)
    132 //? const instruction& to_instruction(const call& call) {
    133 //?   return get(Recipe, call.running_recipe).steps.at(call.running_step_index);
    134 //? }
    135
    136 :(code)
    137 void dump_callstack() {
    138   if (!Current_routine) return;
    139   if (Current_routine->calls.size() <= 1) return;
    140   for (call_stack::const_iterator p = ++Current_routine->calls.begin();  p != Current_routine->calls.end();  ++p)
    141     raise << "  called from " << get(Recipe, p->running_recipe).name << ": " << to_original_string(to_instruction(*p)) << '\n' << end();
    142 }
    143
    144 :(after "Defined Recipe Checks")
    145 // not a primitive; check that it's present in the book of recipes
    146 if (!contains_key(Recipe, inst.operation)) {
    147   raise << maybe(get(Recipe, r).name) << "undefined operation in '" << to_original_string(inst) << "'\n" << end();
    148   break;
    149 }
    150 :(replace{} "default:" following "End Primitive Recipe Implementations")
    151 default: {
    152   if (contains_key(Recipe, current_instruction().operation)) {  // error already raised in Checks above
    153     // not a primitive; look up the book of recipes
    154     if (Trace_stream) {
    155       ++Trace_stream->callstack_depth;
    156       trace("trace") << "incrementing callstack depth to " << Trace_stream->callstack_depth << end();
    157       assert(Trace_stream->callstack_depth < 9000);  // 9998-101 plus cushion
    158     }
    159     const call& caller_frame = current_call();
    160     Current_routine->calls.push_front(call(to_instruction(caller_frame).operation));
    161     finish_call_housekeeping(to_instruction(caller_frame), ingredients);
    162     // not done with caller
    163     write_products = false;
    164     fall_through_to_next_instruction = false;
    165     // End Non-primitive Call(caller_frame)
    166   }
    167 }
    168 :(code)
    169 void finish_call_housekeeping(const instruction& call_instruction, const vector<vector<double> >& ingredients) {
    170   // End Call Housekeeping
    171 }
    172
    173 :(scenario calling_undefined_recipe_fails)
    174 % Hide_errors = true;
    175 def main [
    176   foo
    177 ]
    178 +error: main: undefined operation in 'foo'
    179
    180 :(scenario calling_undefined_recipe_handles_missing_result)
    181 % Hide_errors = true;
    182 def main [
    183   x:num <- foo
    184 ]
    185 +error: main: undefined operation in 'x:num <- foo'
    186
    187 //:: finally, we need to fix the termination conditions for the run loop
    188
    189 :(replace{} "bool routine::completed() const")
    190 bool routine::completed() const {
    191   return calls.empty();
    192 }
    193
    194 :(replace{} "const vector<instruction>& routine::steps() const")
    195 const vector<instruction>& routine::steps() const {
    196   assert(!calls.empty());
    197   return get(Recipe, calls.front().running_recipe).steps;
    198 }
    199
    200 :(after "Running One Instruction")
    201 // when we reach the end of one call, we may reach the end of the one below
    202 // it, and the one below that, and so on
    203 while (current_step_index() >= SIZE(Current_routine->steps())) {
    204   // Falling Through End Of Recipe
    205   if (Trace_stream) {
    206     trace("trace") << "fall-through: exiting " << current_recipe_name() << "; decrementing callstack depth from " << Trace_stream->callstack_depth << end();
    207     --Trace_stream->callstack_depth;
    208     assert(Trace_stream->callstack_depth >= 0);
    209   }
    210   Current_routine->calls.pop_front();
    211   if (Current_routine->calls.empty()) goto stop_running_current_routine;
    212   // Complete Call Fallthrough
    213   // todo: fail if no products returned
    214   ++current_step_index();
    215 }
    216
    217 :(before "End Primitive Recipe Declarations")
    218 _DUMP_CALL_STACK,
    219 :(before "End Primitive Recipe Numbers")
    220 put(Recipe_ordinal, "$dump-call-stack", _DUMP_CALL_STACK);
    221 :(before "End Primitive Recipe Checks")
    222 case _DUMP_CALL_STACK: {
    223   break;
    224 }
    225 :(before "End Primitive Recipe Implementations")
    226 case _DUMP_CALL_STACK: {
    227   dump(Current_routine->calls);
    228   break;
    229 }
    230 :(code)
    231 void dump(const call_stack& calls) {
    232   for (call_stack::const_reverse_iterator p = calls.rbegin(); p != calls.rend(); ++p)
    233     cerr << get(Recipe, p->running_recipe).name << ":" << p->running_step_index << " -- " << to_string(to_instruction(*p)) << '\n';
    234 }