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Description
In many data-intensive applications, we need sentinel values that signal "nothing interesting here." That's normally handled in ordinary Python via None and the Optional type. Here is an example of what I would like:
from lpython import (i32, dataclass)
@dataclass
class FullFormValue:
list_i32 : Optional[list[i32]]
string : Optional[str]
foo : dict[str, FullFormValue]
ttype : FullFormValue = FullFormValue(None, 'dimensions')
contents : FullFormValue = FullFormValue([1, 2], None)
foo = {'ttype' : ttype,
'contents': contents}Instead, I have to do something like the following:
from lpython import (i32, dataclass)
@dataclass
class FullFormValue:
list_i32 : list[i32]
string : str
foo : dict[str, FullFormValue]
DEAD_LIST : list[i32] = [-1] # Issue 2039 forces non-empty sentinel
DEAD_STRING : str = '' # would prefer None but we don't have Optional
ttype : FullFormValue = FullFormValue(DEAD_LIST, 'dimensions')
contents : FullFormValue = FullFormValue([1, 2], DEAD_STRING)
foo = {'ttype' : ttype,
'contents': contents}