simple_config - JSON Configuration for Eiffel

Overview

simple_config provides easy JSON-based configuration for Eiffel applications with dot-notation access and environment variable support.

Part of the Simple Eiffel ecosystem.

Quick Start

Installation

Set the environment variable:
```
export SIMPLE_EIFFEL=/d/prod
```

Add to your ECF file:

<library name="simple_config" location="$SIMPLE_EIFFEL/simple_config/simple_config.ecf"/>

config.json

{
    "database": {
        "host": "localhost",
        "port": 5432,
        "name": "mydb"
    },
    "features": {
        "debug": true,
        "cache_size": 1024
    }
}

Usage

local
    config: SIMPLE_CONFIG
do
    create config.make_with_file ("config.json")

    -- Dot notation access
    print (config.string_value ("database.host"))
    print (config.integer_value ("database.port"))
    print (config.boolean_value ("features.debug"))

    -- With defaults and env vars
    port := config.integer_value_or_env ("database.port", "DB_PORT", 5432)
end

Key Features

Dot Notation

Access nested values: "database.host" navigates JSON structure.

Environment Fallback

Config values can fall back to environment variables.

Type-Safe Access

String, integer, boolean, real, and array accessors.

File Merging

Merge multiple config files for environment overrides.

API Summary

Loading

Feature	Description
`make`	Create empty config
`make_with_file (path)`	Load from JSON file
`load`	Reload from file
`merge_file (path)`	Merge another config

String Access

Feature	Description
`string_value (key)`	Get string
`string_value_or_default (key, default)`	Get with default
`string_value_or_env (key, env_var)`	Get from config or env

Other Types

Feature	Description
`integer_value (key)`	Get integer
`boolean_value (key)`	Get boolean
`real_value (key)`	Get real/double
`string_list (key)`	Get string array
`section (key)`	Get nested section

Modification

Feature	Description
`set_string (key, value)`	Set string value
`set_integer (key, value)`	Set integer value
`set_boolean (key, value)`	Set boolean value
`save`	Save to file
`save_to (path)`	Save to new file

Documentation

User Guide - Complete tutorial with examples
API Reference - Full API with contracts
Architecture - Internal design and rationale
Cookbook - Ready-to-use recipes and patterns