Override

Overrides let you change config values on the fly at compose time without editing YAML files. In this vignette, we use one base config file for every example:

author:
  given: Vincent
  family: Arel-Bundock
numeric: 2

A copy of this config file is distributed with the hydraR package. It is stored in a local directory that we can identify with system.file().

system.file("examples", package = "hydraR")

[1] "/path/to/R/library/hydraR/examples"

To avoid repeating the full config directory path and config name every time we call compose(), we set global options once at the start.

library(hydraR)
options(
  hydraR.compose.config_path = system.file("examples", package = "hydraR"),
  hydraR.compose.config_name = "minimal"
)

No Overrides

cfg <- compose()
print(cfg)

## author:
##   given: Vincent
##   family: Arel-Bundock
## numeric: 2

Replace: key=value

cfg <- compose(
  overrides = c("numeric=3", "author.given=Alice")
)
print(cfg)

## author:
##   given: Alice
##   family: Arel-Bundock
## numeric: 3

Add: +key=value

cfg <- compose(
  overrides = c("+experiment.name=baseline", "+experiment.seed=42")
)
print(cfg)

## author:
##   given: Vincent
##   family: Arel-Bundock
## numeric: 2
## experiment:
##   name: baseline
##   seed: 42

Upsert: ++key=value

Upsert means update a value if the key exists, or insert it if the key does not exist.

cfg <- compose(
  overrides = c("++numeric=5", "++experiment.tag=trial")
)
print(cfg)

## author:
##   given: Vincent
##   family: Arel-Bundock
## numeric: 5
## experiment:
##   tag: trial

Remove: ~key

cfg <- compose(
  overrides = c("~author.family")
)
print(cfg)

## author:
##   given: Vincent
## numeric: 2

Combine Multiple Overrides

cfg <- compose(
  overrides = c(
    "numeric=4",
    "+experiment.name=stress",
    "++author.middle=A.",
    "~author.family"
  )
)
print(cfg)

## author:
##   given: Vincent
##   middle: A.
## numeric: 4
## experiment:
##   name: stress