//: 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 # pretend array
20:number <- copy 5 # pretend array
default-space:address:array:location <- copy 10
0:address:array:location/names:dummy <- copy 20 # later layers will explain the /names: property
1:number <- copy 32
1:number/space:1 <- copy 33
]
# 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") {
if (SIZE(x.properties.at(i).second) != 1)
raise << current_recipe_name() << ": /space metadata should take exactly one value in " << x.original_string << '\n' << end();
return to_integer(x.properties.at(i).second.at(0));
}
}
return 0;
}
:(scenario permit_space_as_variable_name)
recipe main [
space:number <- copy 0
]