ECHO: "a number is a number:"
ECHO: true
ECHO: true
ECHO: true
ECHO: "inf is a number:"
ECHO: true
ECHO: true
ECHO: "nan is not a number:"
ECHO: false
ECHO: false
ECHO: "resulting in false:"
ECHO: false
ECHO: false
ECHO: false
ECHO: false
ECHO: false
ECHO: "resulting in warnings:"
WARNING: is_num() number of parameters does not match: expected 1, found 3 in file isnum-test.scad, line 22
ECHO: undef
WARNING: is_num() number of parameters does not match: expected 1, found 0 in file isnum-test.scad, line 23
ECHO: undef
