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//: So far the recipes we define can't run each other. Let's fix that.
:(scenario calling_recipe)
recipe main [
f
]
recipe f [
3:integer <- add 2:literal, 2:literal
]
+mem: storing 4 in location 3
:(scenario return_on_fallthrough)
recipe main [
f
1:integer <- copy 34:literal
2:integer <- copy 34:literal
3:integer <- copy 34:literal
]
recipe f [
4:integer <- copy 34:literal
5:integer <- copy 34:literal
]
+run: instruction main/0
+run: instruction f/0
+run: instruction f/1
+run: instruction main/1
+run: instruction main/2
+run: instruction main/3
:(before "struct routine {")
// Everytime a recipe runs another, we interrupt it and start running the new
// recipe. When that finishes, we continue this one where we left off.
// This requires maintaining a 'stack' of interrupted recipes or 'calls'.
struct call {
recipe_number running_recipe;
size_t running_step_index;
// End call Fields
call(recipe_number r) :running_recipe(r), running_step_index(0) {}
};
typedef stack<call> call_stack;
:(replace{} "struct routine")
struct routine {
call_stack calls;
// End routine Fields
routine(recipe_number r);
bool completed() const;
const vector<instruction>& steps() const;
};
:(code)
routine::routine(recipe_number r) {
calls.push(call(r));
// End routine Constructor
}
//:: now update routine's helpers
:(replace{} "inline size_t& current_step_index()")
inline size_t& current_step_index() {
return Current_routine->calls.top().running_step_index;
}
:(replace{} "inline const string& current_recipe_name()")
inline const string& current_recipe_name() {
return Recipe[Current_routine->calls.top().running_recipe].name;
}
:(replace{} "inline const instruction& current_instruction()")
inline const instruction& current_instruction() {
return Recipe[Current_routine->calls.top().running_recipe].steps[Current_routine->calls.top().running_step_index];
}
:(replace{} "default:" following "End Primitive Recipe Implementations")
default: {
// not a primitive; try to look up the book of recipes
if (Recipe.find(current_instruction().operation) == Recipe.end()) {
raise << "undefined operation " << current_instruction().operation << ": " << current_instruction().name << '\n';
break;
}
Current_routine->calls.push(call(current_instruction().operation));
continue; // not done with caller; don't increment current_step_index()
}
//:: finally, we need to fix the termination conditions for the run loop
:(replace{} "inline bool routine::completed() const")
inline bool routine::completed() const {
return calls.empty();
}
inline const vector<instruction>& routine::steps() const {
return Recipe[calls.top().running_recipe].steps;
}
:(before "Running One Instruction")
// when we reach the end of one call, we may reach the end of the one below
// it, and the one below that, and so on
while (current_step_index() >= Current_routine->steps().size()) {
Current_routine->calls.pop();
if (Current_routine->calls.empty()) return;
// todo: no results returned warning
++current_step_index();
}
:(before "End Includes")
#include <stack>
using std::stack;
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