Parsing slice data to map failed

[dong50252409]

• Go version: 1.23.4
• BurntSushi/[email protected]

I want to map the data to the collect structure when parsing the ImportExtension field, so that I can quickly determine whether the table is supported at runtime. Unfortunately, I have tried a lot of methods and cannot call back the UnmarshalText method during parsing. What should I do? I can't parse the data through the UnmarshalTOML implementation interface because I actually have a lot of configuration

Example:

package main

import (
	"github.com/BurntSushi/toml"
	"log"
)

type collect struct {
	Set map[string]any
}

type contacts struct {
	Source             string
	ImportExtension    collect
}

func (c *collect) UnmarshalText(v []byte) error {
	// It won't be called here
	return nil
}

func main() {
	blob := `
		source = "./samples/"
		import_extension = ["csv", "xlsx"]
	`
	var c contacts
	_, err := toml.Decode(blob, &c)
	if err != nil {
		log.Fatal(err)
	}

}

[qdongxu]

What is the X problem you want to resolve? It's unusual to request to parse a slice into a map.

[arp242]

You need to use struct tags to map the ImportExtension field to the import_extension value.

UnmarshalText is only called for strings, not arrays. You want UnmarshalTOML.

Putting that together:

package main

import (
	"fmt"

	"github.com/BurntSushi/toml"
)

type contacts struct {
	Source          string  `toml:"source"`
	ImportExtension collect `toml:"import_extension"`
}

type collect struct {
	Set map[string]any
}

func (c *collect) UnmarshalTOML(v any) error {
	fmt.Printf("UnmarshalTOML: %#v\n", v)
	return nil
}

func main() {
	var c contacts
	_, err := toml.Decode(`
		source = "./samples/"
		import_extension = ["csv", "xlsx"]
	`, &c)
	fmt.Println(err)
	fmt.Println(c)
}

Outputs:

UnmarshalTOML: []interface {}{"csv", "xlsx"}
<nil>
{./samples/ {map[]}}