On 1/11/22 22:15, Adriano dos Santos Fernandes wrote:
Hi!
Currently sub routines cannot access the outer (main routine/block)
variables, parameters and cursors - #4769.
There is some details to make that happen safely.
Currently a variable cannot have its value changed while its being used.
var = var + <expression>
Not clear - you provide some proposition and right after it a sample
disproving it.
No expression can reset var.
As soon we let sub routines change outer variables, that will be possible.
Currently VariableNode just returns a descriptor pointing to the
variable's impure_value present in the variable declaration.
To make outer access safe, variables accessed in outer scope would be
flagged and its VariableNode (even in the main routine/block) should
copy the value to its own impure_value. It will be a bit slower, but I
don't see a problem.
What worried me more is how to represent things in BLR. A simple
approach would be to have blr_outer_variable.
But it is not only variables.
There is also parameters, fields, dbkeys, cursor statements.
What seems for me the way to go is to implement single blr_outer_map
that maps main routine's things to sub routines in they own number space.
blr_outer_map,
blr_outer_map_variable,
0,0,
3,0
It maps main's variable 0,0 to this sub routine's 3,0, so it can access
with blr_variable, 3,0.
blr_outer_map,
blr_outer_map_cursor,
1,0,
2,0
Maps main's cursor 1,0 to this sub routine's 2,0, so it can access with
blr_cursor_stmt, 2,0.
Comments?
Provided mapping always begins with blr_outer_map do we really need
blr_outer_map_variable, blr_outer_map_cursor, etc. BLR codes? Is not it
enough to take into an account blr_outer_map before and use existing
blr_variable, etc.?
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