when configuring a new algorithm
While the previous behaviour of defaulting to a static value makes
sense for things like numeric parameters, this is a very rare use
case for map layer parameters. For better new user experience we can
default instead to showing model inputs for these parameter types.
This allows a range of new possibilities, including:
- models with static outputs for child algorithms, e.g. always saving
a child algorithm's output to a geopackage or postgres layer
- models with expression based output values for child algorithms, e.g.
generating an automatic file name based on today's date and saving
outputs to that file
data defined buttons for model child algorithms
The context was not previously exposed, so users would not have
been aware that they can utilise all the variables and functions
available to parameters within child algorithms.
for pre-calculated expressions
Correctly exposes ALL the variables and functions available for use
in pre-calculated expressions so that users actually know they can
use these in their models!
