Hook Field Defaults

[robcxyz]

Hook Field Defaults

Allow flexible ways to declare hook field defaults

• Proposal Status: implemented

• Issue Number: 237

• Proposal Doc: hook-field-defaults.md

Overview

Declarative hook default values should be parsed for hook calls.

<-:

  literal: val

  literal_compact->: input

  literal_expanded:

    ->: input

  field:

    type: str

    default: foo

  field_default_compact:

    type: str

    default->: input  

  field_default_expanded:

    type: str

    default:

      ->: input

Ways to implement

1. Macro + type handler

   • Rewrites the input in expanded form

   • When 'default' key is a dict, create a special dict type that can be parsed later in the absense of a supplied input.

   • Can't parse right away as we don't know if this is a user supplied variable

   • Don't know the type either so it either needs to be supplied (normally with default key, you don't need to give type) or it is set as Any until the default dict is parsed.

   • Needs to be done when we compile the hook

<-:

  # from

  literal_compact->: input

  # to

  literal_compact:

    default:

      ->: input

  # from

  literal_expanded:

    ->: input

  # to

  literal_expand:

    default:

      ->: input

  # This is an issue because the default has no type

  # from

  field_default_compact:

    type: str

    default->: input  

  # to

  field_default_compact2:

    type: str

    default:  

      ->: input

Calling tackle externally

• Before we had an extra context being passed into the tackle hook call which made sense as we didn't have specific variables to populate a hook's strongly typed interface.

Issues

1. For the prompt hooks, the msg without the message field is the key which in this case the default, not what we want

This is probably not an issue as the default is just the key that refs the value. Not the key that is actually in the dict

• Options

  • We can catch the issue in the hook itself

    • Wouldn't take much work to check if the key is default and then look the parent key but then all keys called default would have the erroneous behaviour

  • When we interpret the special dict, we can run another macro to rewrite the value back to the original key

    • Could write directly to the proper context

    • ??? What context?