I have a common design part in OpenSCAD defined by ca. 15 parameters. Is there a way how to put them to configuration files (or something similar) and choose between them conditionally?
I am looking for something like
type = "wide";
if (type == "narrow")
include <narrow.scad>;
else if (type == "wide">
include <wide.scad>;
else
include <round.scad>;
With file wide.scad containing data like
width = 200;
height = 50;
radius = 7;
etc.
I would like to provide the type parameter from commandline, which is possible via -D, but I cannot find a way how to bind the definition to parameter value.
I don't know of a way to put configurations into separate files, but I have solved a similar problems by putting configurations in a table of key-value pairs like this:
// Rows must be in "asciibetical" order by name.
configs = [
// name width height radius
["narrow", [ 50, 50, 7]],
["round", [ 100, 100, 100]]
["wide", [ 200, 50, 7]],
];
A couple helper functions can find the configuration you want from a table of key-value pairs.
function find_row(key, table, low, high) =
low > high ? undef :
let(i = round_up(mid(low, high)))
table[i][0] == key ? table[i][1] :
table[i][0] < key ? find_row(key, table, i+1, high) :
find_row(key, table, low, i-1);
function find_config(key) =
find_row(key, configs, 0, len(configs) - 1);
To get a configuration:
config = find_config("wide");
assert(!is_undef(config));
Of course, you have to know which parameter is at which index in the configuration. Usually, I immediately unpack them into variables to given them meaningful names.
width = config[0];
height = config[1];
radius = config[2];
This works well enough once you've nailed down the parameters that will be part of a configuration. If the code you're writing it still evolving, it can become tedious to make sure you're using consistent indexes.