proto-expand

Proto 'planilla' expander

The code in this module is used to preprocess a process definition (A.K.A. Protocol) and expand it to a flattened format.

Motivation

SWAR version 1.x doesn't support arrays so every value needs to be a scalar. The current workaround is to expand an array as a set of scalar values using a postfix number.

So instead of having an array x you will have n scalars:

x_1 x_2 ... x_n

To be able to do that you need to know n beforehand. This limit the workaround to cases where n is fixed.

This module was created to solve that problem

Payload Management

Given the data to initialize a process in a standard json format, for example:

const initialPayload = {
    "a": 10,
    "b": "xxx",
    "tires": [
        {"pressure": 36},
        {"pressure": 36},
        {"pressure": 40},
        {"pressure": 40}
    ],
    "doors": [
        {"width": 10},
        {"width": 10},
    ]
}

The data can be transformed in a flatten version of the payload for example:

flattenPayload(initialPayload)

Will return

const result = {
    "a": 10,
    "b": "xxx",
    "pressure_1": 36,
    "pressure_2": 36,
    "pressure_3": 40,
    "pressure_4": 40,
    "width_1": 10,
    "width_2": 10
};

Also check payload.ts for additional functions to operate Payloads

Process (a.k.a. Protocol) parsing and expansion

As of today a Protocol is just a set of activities each one containing a set of instructions

Appropriate Classes Activity and Instructions are created to represent this concepts. A protocol definition is just an Array<Activity>

A simple end to end example of expansion will be like this:

// Extract the `Dimensions` from the `Payload`
const dimensions: Dimensions = extractDimensions(payload)

// Parse a Protocol definition (This assume a big string as defined in a proto file today)

const activities: Array<Activity> = parseProtoString("A proto file loaded in a string")

// Expand the variables

const expandedActivities: Array<Activity> = expandAllActivities(activities, dimensions)

// Convert the array back to a big `string`

const bigString = exportToString(expandedActivities)