Walking values with pattern constraints

[verdverm]

Given the API in cue.Value with the Walk and Fields functions, and also using a custom walk function as in #862

is it possible to discover the constraint side of a pattern constraint in the following? (for labels and other)

#Other: {
    foo: string
    bar: number
}

thing: {
    name: string
    labels: [string]: string
    other: [string]: #Other
}

Does one need to go to the AST for the ability to walk into thing.labels and thing.other?

[myitcv]

Something like this will probably get you what you want (again, apologies for the delay in replying to this)

exec go mod tidy
exec go run main.go

-- go.mod --
module mod.com

go 1.16

require cuelang.org/go v0.4.0
-- main.go --
package main

import (
	"fmt"

	"cuelang.org/go/cue"
	"cuelang.org/go/cue/cuecontext"
	"cuelang.org/go/cue/load"
)

func main() {
	ctx := cuecontext.New()
	bps := load.Instances([]string{"."}, nil)
	v := ctx.BuildInstance(bps[0])

	thing_labels_any := v.LookupPath(cue.MakePath(cue.Str("thing"), cue.Str("labels"), cue.AnyString))
	thing_other_any := v.LookupPath(cue.MakePath(cue.Str("thing"), cue.Str("other"), cue.AnyString))

	fmt.Printf("thing_labels_any: %v\n", thing_labels_any)
	fmt.Printf("thing_other_any: %v\n", thing_other_any)
}
-- x.cue --
package x

#Other: {
	foo: string
	bar: number
}

thing: {
	name: string
	labels: [string]: string
	other: [string]:  #Other
}

Gives:

> exec go run main.go
[stdout]
thing_labels_any: string
thing_other_any: {
        foo: string
        bar: number
}

[cueckoo]

This discussion has been migrated to cue-lang/cue#895.

For more details about CUE's migration to a new home, please see cue-lang/cue#1078.