1769 - routines can now have global variables

1 files changed, 54 insertions, 0 deletions

diff --git a/047global.cc b/047global.cc
new file mode 100644
index 00000000..1ab77eec
--- /dev/null
+++ b/047global.cc
@@ -0,0 +1,54 @@
+// 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:literal
+  20:number <- copy 5:literal
+  # actual start of this recipe
+  default-space:address:array:location <- copy 10:literal
+  1:number <- copy 23:literal
+  global-space:address:array:location <- copy 20:literal
+  1:number/space:global <- copy 24:literal
+]
++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") {
+    assert(scalar(data));
+    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 << "routine has no global space\n" << die();
+    return Current_routine->global_space;
+  }
+
+:(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.at(0) == "global";
+  }
+  return false;
+}