From 83fcebf3210b638d9f8248e0007e9f0c9804980a Mon Sep 17 00:00:00 2001 From: "Kartik K. Agaram" Date: Mon, 13 Jul 2015 20:53:41 -0700 Subject: 1778 --- html/045space_surround.cc.html | 90 ++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 90 insertions(+) create mode 100644 html/045space_surround.cc.html (limited to 'html/045space_surround.cc.html') diff --git a/html/045space_surround.cc.html b/html/045space_surround.cc.html new file mode 100644 index 00000000..a01f4094 --- /dev/null +++ b/html/045space_surround.cc.html @@ -0,0 +1,90 @@ + + + + +Mu - 045space_surround.cc + + + + + + + + + + +
+//: So far you can have global variables by not setting default-space, and
+//: local variables by setting default-space. You can isolate variables
+//: between those extremes by creating 'surrounding' spaces.
+//:
+//: (Surrounding spaces are like lexical scopes in other languages.)
+
+:(scenario surrounding_space)
+# location 1 in space 1 refers to the space surrounding the default space, here 20.
+recipe main [
+  10:number <- copy 5:literal  # pretend array
+  20:number <- copy 5:literal  # pretend array
+  default-space:address:array:location <- copy 10:literal
+  0:address:array:location/names:dummy <- copy 20:literal  # later layers will explain the /names: property
+  1:number <- copy 32:literal
+  1:number/space:1 <- copy 33:literal
+]
+# chain space
++mem: storing 20 in location 11
+# store to default-space
++mem: storing 32 in location 12
+# store to chained space
++mem: storing 33 in location 22
+
+//: If you think of a space as a collection of variables with a common
+//: lifetime, surrounding allows managing shorter lifetimes inside a longer
+//: one.
+
+:(replace{} "long long int space_base(const reagent& x)")
+long long int space_base(const reagent& x) {
+  return space_base(x, space_index(x), Current_routine->calls.front().default_space);
+}
+
+long long int space_base(const reagent& x, long long int space_index, long long int base) {
+  if (space_index == 0) {
+    return base;
+  }
+  long long int result = space_base(x, space_index-1, Memory[base+1]);
+  return result;
+}
+
+long long int space_index(const reagent& x) {
+  for (long long int i = /*skip name:type*/1; i < SIZE(x.properties); ++i) {
+    if (x.properties.at(i).first == "space") {
+      assert(SIZE(x.properties.at(i).second) == 1);
+      return to_integer(x.properties.at(i).second.at(0));
+    }
+  }
+  return 0;
+}
+
+:(scenario permit_space_as_variable_name)
+recipe main [
+  space:number <- copy 0:literal
+]
+
+ + + -- cgit 1.4.1-2-gfad0