---
variables:
default-value: ""
required-value:
required: true
value: ${default-value}
commands:
example: echo required-value = ${required-value}
# The example2/pre command will run before "garden example2" aborts
# due to the empty required-value.
example2/pre: echo "default-value = ${default-value}"
example2<: example2/pre
example2: echo ${required-value}
...