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Marshal() (type)

Converts structured memory into a structured file format (eg for stdio)

Description

This is a function you would write when programming a Murex data-type. The marshal function takes in a Go (golang) type or struct and returns a byte slice of a “string” representation of that format (eg in JSON) or an error.

This marshaller is then registered to Murex inside an init() function and Murex builtins can use that marshaller via the MarshalData() API.

Usage

Registering Marshal() (for writing builtin data-types)

// To avoid data races, this should only happen inside func init()
lang.Marshallers[ /* your type name */ ] = /* your readIndex func */

Using an existing marshaller (eg inside a builtin command)

// See documentation on lang.MarshalData for more details
b, err := lang.MarshalData(p, dataType, data)

Examples

Defining a marshaller for a murex data-type

package example

import (
    "encoding/json"

    "github.com/lmorg/murex/lang"
)

func init() {
    // Register data-type
    lang.Marshallers["json"] = marshal
}

// Describe marshaller
func marshal(p *lang.Process, v interface{}) ([]byte, error) {
    if p.Stdout.IsTTY() {
        // If STDOUT is a TTY (ie not pipe, text file or other destination other
        // than a terminal) then output JSON in an indented, human readable,
        // format....
        return json.MarshalIndent(v, "", "    ")
    }

    // ....otherwise we might as well output it in a minified format
    return json.Marshal(v)
}

Parameters

1. *lang.Process: Process’s runtime state. Typically expressed as the variable p
2. interface{}: data you wish to marshal

See Also

• apis/Unmarshal() (type): Converts a structured file format into structured memory
• apis/lang.MarshalData() (system API): Converts structured memory into a Murex data-type (eg for stdio)
• apis/lang.UnmarshalData() (system API): Converts a Murex data-type into structured memory

This document was generated from lang/define_marshal_doc.yaml.