Skip to contents

Parameter Manager Base Class

Source: R/parameter_manager.R
params_manager.Rd

params_manager is an R6 base class for managing hierarchical configuration parameters. It supports:

  • Built‑in default settings defined by subclasses

  • Optional overrides via a YAML configuration file

  • Programmatic overrides via named arguments

  • Nested key access using $ syntax or character vectors

The class is designed to be inherited by specialized configuration classes (e.g., for scrapers or API clients) and provides a consistent, validated mechanism for reading, updating, and exporting configuration settings.

Format

An R6::R6Class generator object.

Features

  • YAML read/write support (via the yaml package)

  • Path syntax support: "a$b$c" or c("a","b","c")

  • Nested configuration updating with validation at the top-level key

  • Export of defaults or current configuration to a YAML file

Methods

Public methods

Method new()

Initialize the parameter manager.

This loads configuration using the following precedence:

  1. Defaults defined by the subclass

  2. YAML configuration file (if provided)

  3. Programmatic overrides via ...

Usage

params_manager$new(config_file = NULL, ...)

Arguments

config_file

Optional path to a YAML configuration file.

...

Named overrides applied after defaults and YAML values.

Method print()

Print the current settings

Usage

params_manager$print()

Method load_config()

Loads configuration: defaults < YAML < args

Usage

params_manager$load_config(config_file = NULL, ...)

Arguments

config_file

(Optional) YAML file path.

...

Named overrides to apply last.

Returns

A list with the resulting configuration.

Method get()

Retrieve a configuration value (supports nested paths).

Nested syntax examples:

  • "selenium$host"

  • "robots$check"

  • c("selenium", "port")

Usage

params_manager$get(key)

Arguments

key

A string using $ or a character vector of nested keys.

Returns

The configuration value or NULL if not found.

Method show_config()

Return the complete current configuration as a list.

Usage

params_manager$show_config()

Returns

A named list representing the current configuration.

Method defaults()

Subclasses must override this method to define default settings.

Usage

params_manager$defaults()

Returns

A named list containing default configuration values.

Method write_defaults()

Write default configuration values to a YAML file.

Usage

params_manager$write_defaults(filename)

Arguments

filename

Output file ending in .yaml.

Method export()

Export the current configuration (including overrides) to YAML.

Usage

params_manager$export(filename)

Arguments

filename

Output file ending in .yaml.

Method set()

Updates configuration.

  • If key is a top-level name*, only the specific element is modified.

  • If key is a nested path* (e.g., "x.y" / "x$y" / c("x","y")),

the method updates only that nested value. In both cases, the relevant top-level key is validated via private$.validate().

Usage

params_manager$set(key, val)

Arguments

key

A top-level key or nested path ("a$b$c" or c("a","b","c"))

val

New value to assign.

Returns

The object itself (invisibly).

Method update()

Recursively update configuration values from a (possibly nested) list.

Only top-level keys contained in values are validated.

Usage

params_manager$update(values)

Arguments

values

A named list merged into the current configuration.

Returns

The object itself (invisibly).

Method clone()

The objects of this class are cloneable with this method.

Usage

params_manager$clone(deep = FALSE)

Arguments

deep

Whether to make a deep clone.