Distinction between inputs and parameters

[m-wierzba]

This a concern initially raised by @mih:

I was struggling a bit with the distinction between inputs and parameters (also in the make API). Both are inputs to a computation. I guess an input is a file dependency, whereas a parameter is a non-file information dependency.

I cannot provide a recommendation for better names -- just going on record that this causes mental friction for me.

Suggestions by @christian-monch:

• variable
• template-variable
• script-variable

[christian-monch]

I was mainly going with the nomenclature of datalad run when using input and output. We could use something else for the input to the script variable, i.e. for parameter.

I am a little hesitant to call it anything with variable though, usually "variable" refers to a variable in the script, e.g. participant_label, and "parameter" refers to the value that is passed to the variable.