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ReadMap() (type)

Treat data type as a key/value structure and read its contents

Description

This is a function you would write when programming a Murex data-type.

It’s called by builtins to allow them to read data structures one key/value pair at a time.

The purpose of this function is to allow builtins to support sequential reads (where possible) and also create a standard interface for builtins, thus allowing them to be data-type agnostic.

Usage

Registering your ReadMap()

// To avoid confusion, this should only happen inside func init()
stdio.RegisterReadMap(/* your type name */, /* your readMap func */)

Examples

Example ReadMap() function:

package json

import (
    "github.com/lmorg/murex/config"
    "github.com/lmorg/murex/lang"
    "github.com/lmorg/murex/lang/stdio"
    "github.com/lmorg/murex/lang/types"
    "github.com/lmorg/murex/utils/json"
)

func readMap(read stdio.Io, _ *config.Config, callback func(*stdio.Map)) error {
    // Create a marshaller function to pass to ArrayWithTypeTemplate
    marshaller := func(v interface{}) ([]byte, error) {
        return json.Marshal(v, read.IsTTY())
    }

    return lang.MapTemplate(types.Json, marshaller, json.Unmarshal, read, callback)
}

Detail

There isn’t (yet) a template read function for types to call. However that might follow in a future release of Murex.

Parameters

1. stdio.Io: stream to read from (eg stdin)
2. *config.Config: scoped config (eg your data type might have configurable parsing rules)
3. func(key, value string, last bool): callback function: key and value of map plus boolean which is true if last element in row (eg reading from tables rather than key/values)

See Also

• apis/ReadArray() (type): Read from a data type one array element at a time
• apis/ReadArrayWithType() (type): Read from a data type one array element at a time and return the elements contents and data type
• apis/ReadIndex() (type): Data type handler for the index, [, builtin
• apis/ReadNotIndex() (type): Data type handler for the bang-prefixed index, ![, builtin
• apis/WriteArray() (type): Write a data type, one array element at a time

This document was generated from lang/stdio/interface_doc.yaml.