Add openStructOption & structOption

[GTrunSec]

The field type must be included within the {...} structAttrs.
If the field type exists within {...} structAttrs

contrast with:

(openStruct "option" {a = string; b = int; c = attrs any;}) {a = "x"; b = 5; c = {}; d = "5";}
{ a = "x"; b = 5; c = { ... }; d = "5"; }

(openStruct "option" {a = string; b = int; c = attrs any;}) {a = "x"; b = 5; d = "5";}
 expected 'option'-struct, but found:
 missing required attrs<any> field 'c'

(openStructOption "option" {a = string; b = int; c = attrs any;}) {a = "x"; b = 5; d = "5";}
{ a = "x"; b = 5; d = "5"; }

[GTrunSec]

fix the error output of either

/*
  (struct {name = string;}) { addr = "xxx"; }
  =>
    expected 'anon'-struct, but found:
    missing required string field 'name'
    unexpected struct field 'addr

  (struct {age = string;}) { addr = "xxx"; }
   =>
    expected 'anon'-struct, but found:
    missing required int field 'age'
    unexpected struct field 'addr'


  either (struct {name = string;}) (struct { age = int; }) { addr = "xxx"; }
  =>
      expected type 'either<anon, anon>', but value '{
        addr = "xxx";
      }' is of type 'set'
 

after

(either (struct {name = string;}) (struct { age = int; })) { addr = "xxx"; }
=>
expected type 'either<anon, anon>', but found:
       missing required string field 'name'
       unexpected struct field 'addr'

       expected type 'either<anon, anon>', but found:
       missing required int field 'age'
       unexpected struct field 'addr'

[blaggacao]

Would an option struct not better pe composed of a strict with option type?

[blaggacao]

I fail to grok how hasAttr n def translates to the concept of "should ignore". Could you find a more suitable name?

[blaggacao]

This is somewhat redundant, because it's already checked in one branch of shouldIgnore.

Maybe it's just the naming that confuses me here 😊

Ideally, the redundant branches could be unified.

Edit: for clarity I suggest you do a plain 3-branch case (if else) statement (ignored/hasattr/else)

[blaggacao]

I parse this name as an "option for a struct", but it rather is a "struct with all elements being optional".