Reuse existing megaparsec parsers

[dcastro]

Clarification and motivation

The Web API reimplements some parsing logic to parse things like Filter (see the instance FromHttpApiData Filter).

We should reuse the same parsers we used in the CLI modules.

Additionally, the logic to parse a QualifiedPath is duplicated in FromHttpApiData (QualifiedPath path) and in CLI.Parser.readQualifiedEntryPath. We should try to have a single mkQualifiedPath function that is reused in the FromHttpApiData instance and in the CLI parser.

Acceptance criteria

• The parsing logic is not duplicated.

[Kariel-Myrr]

Where we should store mk.... functions? We just importing parsers From CLI.Parser into other pkg? Or we should make some upper logic file?

[dcastro]

Where we should store mk.... functions?

The mkQualifiedPath functions should live next to the QualifiedPath type (similar to how mkPath lives next to Path).

We just importing parsers From CLI.Parser into other pkg?

Preferably, yes.

Though we might run into some issues. For example, right now we have:

• the Filter type defined in CLI.Types
• the parser parseFilter defined in CLI.Parser
• instance FromHttpApiData Filter defined in CLI.Types

Reusing parseFilter to implement instance FromHttpApiData Filter would create a cyclic dependency between the two modules (CLI.Parser depends on CLI.Types, CLI.Types depends on CLI.Parser). To avoid this cyclic dep, we should move parseFilter to CLI.Types.