1 files changed, 83 insertions, 0 deletions
diff --git a/046global.cc b/046global.cc
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+++ b/046global.cc
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+// So far we have local variables, and we can nest local variables of short
+// lifetimes inside longer ones. Now let's support 'global' variables that
+// last for the life of a routine. If we create multiple routines they won't
+// have access to each other's globals.
+
+:(scenario global_space)
+recipe main [
+  # pretend arrays; in practice we'll use new
+  10:number <- copy 5
+  20:number <- copy 5
+  # actual start of this recipe
+  global-space:address:array:location <- copy 20/unsafe
+  default-space:address:array:location <- copy 10/unsafe
+  1:number <- copy 23
+  1:number/space:global <- copy 24
+]
++mem: storing 23 in location 12
++mem: storing 24 in location 22
+
+//: to support it, create another special variable called global space
+:(before "End Disqualified Reagents")
+if (x.name == "global-space")
+  x.initialized = true;
+:(before "End is_special_name Cases")
+if (s == "global-space") return true;
+
+//: writes to this variable go to a field in the current routine
+:(before "End routine Fields")
+long long int global_space;
+:(before "End routine Constructor")
+global_space = 0;
+:(after "void write_memory(reagent x, vector<double> data)")
+  if (x.name == "global-space") {
+    if (!scalar(data)
+        || !x.type
+        || x.type->value != get(Type_ordinal, "address")
+        || !x.type->right
+        || x.type->right->value != get(Type_ordinal, "array")
+        || !x.type->right->right
+        || x.type->right->right->value != get(Type_ordinal, "location")
+        || x.type->right->right->right) {
+      raise_error << maybe(current_recipe_name()) << "'global-space' should be of type address:array:location, but tried to write " << to_string(data) << '\n' << end();
+    }
+    if (Current_routine->global_space)
+      raise_error << "routine already has a global-space; you can't over-write your globals" << end();
+    Current_routine->global_space = data.at(0);
+    return;
+  }
+
+//: now marking variables as /space:global looks them up inside this field
+:(after "long long int space_base(const reagent& x)")
+  if (is_global(x)) {
+    if (!Current_routine->global_space)
+      raise_error << "routine has no global space\n" << end();
+    return Current_routine->global_space;
+  }
+
+//: for now let's not bother giving global variables names.
+//: don't want to make them too comfortable to use.
+
+:(scenario global_space_with_names)
+% Hide_errors = true;
+recipe main [
+  global-space:address:array:location <- new location:type, 10
+  x:number <- copy 23
+  1:number/space:global <- copy 24
+]
+# don't complain about mixing numeric addresses and names
+$error: 0
+
+:(after "bool is_numeric_location(const reagent& x)")
+  if (is_global(x)) return false;
+
+//: helpers
+
+:(code)
+bool is_global(const reagent& x) {
+  for (long long int i = /*skip name:type*/1; i < SIZE(x.properties); ++i) {
+    if (x.properties.at(i).first == "space")
+      return x.properties.at(i).second && x.properties.at(i).second->value == "global";
+  }
+  return false;
+}