Wrap reflect.Type.ConvertibleTo calls with Go/TinyGo implementations

[kenshaw]

Enable package to be usable with TinyGo.

Changes calls to reflect.Type.ConvertibleTo in decode.go to Go/TinyGo specific implementations. Basic examples work, but (some) unit tests fail as conversions to interface{} do not currently work in TinyGo.

Otherwise, all other functionality I've tested now appears to work properly: highlighted error output, cmd/ycat, the README.md examples, etc.

As an example, both Go and TinyGo are now able to use this package vis-a-vis this example taken from README.md:

package main

import (
	"fmt"
	"strings"

	"github.com/goccy/go-yaml"
)

func main() {
	yml := `
store:
  book:
    - author: john
      price: 10
    - author: ken
      price: 12
  bicycle:
    color: red
    price: 19.95
`
	path, err := yaml.PathString("$.store.book[*].author")
	if err != nil {
		//...
	}
	var authors []string
	if err := path.Read(strings.NewReader(yml), &authors); err != nil {
		//...
	}
	fmt.Println(authors)
}

Output:

ken@ken-desktop:~/g$ go run main.go
[john ken]
ken@ken-desktop:~/g$ tinygo run main.go
[john ken]
ken@ken-desktop:~/g$

(previously the tinygo run would panic)

Before submitting your PR, please confirm the following.

• Describe the purpose for which you created this PR.
• Create test code that corresponds to the modification

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Additional details and impacted files

@@           Coverage Diff           @@
##           master     #522   +/-   ##
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  Coverage   79.71%   79.72%           
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  Files          18       19    +1     
  Lines        6374     6376    +2     
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+ Hits         5081     5083    +2     
  Misses        986      986           
  Partials      307      307           

[kenshaw]

Hi, humbly requesting that this be added, as I have some command-line utilities that I'm switching over to to building with tinygo, and would like to use this package for YAML parsing.

Thanks in advance, and really appreciate the work on this package! Especially now that it has zero dependencies!

[goccy]

Thank you for your contribution.

Is there any public information regarding the lack of support for reflect.Type.ConvertibleTo in TinyGo ?
Additionally, if we include TinyGo as a build target, ensuring that it can be continuously built with TinyGo will be required, so we need to consider the maintenance cost.

[kenshaw]

Appreciate the quick response. I'm happy to contribute to the CI/CD build workflow if necessary, but I would not suggest making TinyGo as a major compatibility target and/or "supported".

For those using TinyGo, they are most likely already aware of TinyGo's limitations, and know they are working with subset of Go to begin with. As such, they likely would appreciate any functionality/support, and they will likely test their code code sufficiently enough.

The request for this to be merge is because it doesn't affect regular Go in any fashion, but at least enables using the package with TinyGo. It's worth noting that the API used in the actual conv_tinygo.go is Go's standard, public reflect API, it's actually possible to build/compile this path with regular Go, if one were so inclined (it just wouldn't work in all scenarios).

This PR is just a helpful workaround for those who are using TinyGo, as otherwise TinyGo's reflect package panics when calling the ConvertibleTo directly. Hopefully in some future release of TinyGo they will get ConvertibleTo (and the rest of the reflect package and standard library) working, and at that point this change would be revertible to just the standard API.

[kenshaw]

I've rebased the commit to the latest master. Would appreciate any feedback on what would be necessary to get this added to the source tree. Happy to do any work necessary to get this accepted. Thanks!