//////////////////////////////////////////////////////////////////////
// LibFile: common.scad
//   Common functions used in argument processing.
//   To use, include this line at the top of your file:
//   ```
//   use <BOSL2/std.scad>
//   ```
//////////////////////////////////////////////////////////////////////


// Section: Handling `undef`s.


// Function: is_def()
// Usage:
//   is_def(v)
// Description:
//   Returns true if `v` is not `undef`.  False if `v==undef`.
function is_def(v) = !is_undef(v);


// Function: default()
// Description:
//   Returns the value given as `v` if it is not `undef`.
//   Otherwise, returns the value of `dflt`.
// Arguments:
//   v = Value to pass through if not `undef`.
//   dflt = Value to return if `v` *is* `undef`.
function default(v,dflt=undef) = is_undef(v)? dflt : v;


// Function: first_defined()
// Description:
//   Returns the first item in the list that is not `undef`.
//   If all items are `undef`, or list is empty, returns `undef`.
// Arguments:
//   v = The list whose items are being checked.
//   recursive = If true, sublists are checked recursively for defined values.  The first sublist that has a defined item is returned.
function first_defined(v,recursive=false,_i=0) =
	_i<len(v) && (
		is_undef(v[_i]) || (
			recursive &&
			is_list(v[_i]) &&
			is_undef(first_defined(v[_i],recursive=recursive))
		)
	)? first_defined(v,recursive=recursive,_i=_i+1) : v[_i];


// Function: num_defined()
// Description: Counts how many items in list `v` are not `undef`.
function num_defined(v,_i=0,_cnt=0) = _i>=len(v)? _cnt : num_defined(v,_i+1,_cnt+(is_undef(v[_i])? 0 : 1));


// Function: any_defined()
// Description:
//   Returns true if any item in the given array is not `undef`.
// Arguments:
//   v = The list whose items are being checked.
//   recursive = If true, any sublists are evaluated recursively.
function any_defined(v,recursive=false) = first_defined(v,recursive=recursive) != undef;


// Function: all_defined()
// Description:
//   Returns true if all items in the given array are not `undef`.
// Arguments:
//   v = The list whose items are being checked.
//   recursive = If true, any sublists are evaluated recursively.
function all_defined(v,recursive=false) = max([for (x=v) is_undef(x)||(recursive&&is_list(x)&&!all_defined(x))? 1 : 0])==0;


// Section: Argument Helpers


// Function: get_radius()
// Usage:
//   get_radius([r1], [r], [d1], [d], [dflt]);
// Description:
//   Given various radii and diameters, returns the most specific radius.
//   If a diameter is most specific, returns half its value, giving the radius.
//   If no radii or diameters are defined, returns the value of dflt.
//   Value specificity order is r1, d1, r, d, then dflt
// Arguments:
//   r1 = Most specific radius.
//   d1 = Most specific diameter.
//   r = Most general radius.
//   d = Most general diameter.
//   dflt = Value to return if all other values given are `undef`.
function get_radius(r1=undef, r=undef, d1=undef, d=undef, dflt=undef) = (
	!is_undef(r1)? r1 :
	!is_undef(d1)? d1/2 :
	!is_undef(r)? r :
	!is_undef(d)? d/2 :
	dflt
);


// Function: scalar_vec3()
// Usage:
//   scalar_vec3(v, [dflt]);
// Description:
//   If `v` is a scalar, and `dflt==undef`, returns `[v, v, v]`.
//   If `v` is a scalar, and `dflt!=undef`, returns `[v, dflt, dflt]`.
//   If `v` is a vector, returns the first 3 items, with any missing values replaced by `dflt`.
//   If `v` is `undef`, returns `undef`.
// Arguments:
//   v = Value to return vector from.
//   dflt = Default value to set empty vector parts from.
function scalar_vec3(v, dflt=undef) =
	is_undef(v)? undef :
	is_list(v)? [for (i=[0:2]) default(v[i], default(dflt, 0))] :
	!is_undef(dflt)? [v,dflt,dflt] : [v,v,v];


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