The idea is to build the Layout-branching into the generated Gnuplot script,
based on the number of data columns detected. If there is at least one further
data column, then the "mulitplot" layout will be used to feature this
additional data in a secondary diagram below with aligned axis;
if more than one additional data column is present, all further
visualisation will draw points, using the secondary Y-axis
Moreover, Gnuplot can calculate the linear regresssion line itself,
and the drawing will then be done using an `arrow` command,
defining a function regLine(x) based on the linear model.
- `forElse` belongs to the metaprogramming utils
- have a CSVLine, which is a string with custom appending mechanism
- this in turn allows CSVData to accept arbitrary sized tuples,
by rendering them into CSVLine
The intention is to create a library of convenient building blocks;
providing a visualisation should be as simple as invoking a free function
with CSV data, yet with the ability to tweak some lables or display
variations if desired.
This can be achieved by..
* having a series of ready-made standard visualisations
* expose a function call for each, accepting a data-context builder
* provide secondary convenience shortcuts, which add some of the expected bindings
* notably a shortcut is provided to take the data as CSV-string
* augmented by a wrapper/builder to allow defining data points inline
Deliberately keep it unstructured and add dedicated functions
for each new emerging use case; hopefully some commen usage scheme
will emerge over time.
* Data is to be handed in as an iterator over CSV-strings.
* will have to find out about additional parametrisation on a case-by-case base
Conducted an extended investigation regarding text templating
and the library solutions available and still maintained today.
The conclusion is
* there are some mature and widely used solutions available for C++
* all of these are considered a mismatch for the task at hand,
which is to generate Gnuplot scripts for test data visualisation
Points of contention
* all solutions offer a massive feature set, oriented towards web content generation
* all solutions provide their own structured data type or custom property-tree framework
**Decision** 🠲 better to write a minimalistic templating engine from scratch rather
