Treat parsed option values differently by option type.

There is a vexingly large world of possible option types, each with its own quirks of how it interfaces with new inputs as they come in: values can be
- overridden (default)
- concatenated (allowMultiple)
- flattened (allowMultiple that accepts list inputs)
- disappear into additional flag inputs (expansion flags)
Or some combination of the above, in the case of flags with implicit dependencies and wrapper options.

Begin removing the error-prone treatment of all option types with conditional branches. This model of the different options will make it much easier to isolate the option-type specific logic with the command-line parsing logic. Flags that affect other flags (implicit requirements, expansions, and wrappers) will be migrated in a later change.

This CL does not change flag parsing semantics, just migrates the current parsing logic to the new class structure.

RELNOTES: None.
PiperOrigin-RevId: 169239182

0 files changed, 0 insertions, 0 deletions