nuts-foundation/nuts-node

/*
 * Nuts node
 * Copyright (C) 2022 Nuts community
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <https://www.gnu.org/licenses/>.
 *
 */

package jsonld

import (
    "errors"
    "fmt"
)

// Scalar represents a JSON-LD scalar (string, number, true or false)
type Scalar interface {
    fmt.Stringer
    // Value returns the underlying value (string, float, true or false)
    Value() interface{}
}

// StringScalar is the string version of a Scalar
type StringScalar string

func (ss StringScalar) String() string {
    return string(ss)
}

func (ss StringScalar) Value() interface{} {
    return string(ss)
}

// BoolScalar is the boolean version of a Scalar
type BoolScalar bool

func (bs BoolScalar) String() string {
    if bs {
        return "true"
    }
    return "false"
}

func (bs BoolScalar) Value() interface{} {
    return bool(bs)
}

// Float64Scalar is the float64 version of a Scalar
type Float64Scalar float64

func (fs Float64Scalar) String() string {
    return fmt.Sprintf("%f", float64(fs))
}

func (fs Float64Scalar) Value() interface{} {
    return float64(fs)
}

// ErrInvalidValue is returned when an invalid value is parsed
var ErrInvalidValue = errors.New("invalid value")

// ParseScalar returns a Scalar based on an interface value. It returns ErrInvalidValue for unsupported values.
func ParseScalar(value interface{}) (Scalar, error) {
    switch castValue := value.(type) {
    case bool:
        return BoolScalar(castValue), nil
    case string:
        return StringScalar(castValue), nil
    case float64:
        return Float64Scalar(castValue), nil
    }

    return nil, ErrInvalidValue
}

// MustParseScalar returns a Scalar based on an interface value. It panics when the value is not supported.
func MustParseScalar(value interface{}) Scalar {
    s, err := ParseScalar(value)
    if err != nil {
        panic(err)
    }
    return s
}