ECHO: "Normal variables"
ECHO: true
ECHO: false
ECHO: true
WARNING: Ignoring unknown variable 'a', in file isundef-test.scad, line 8.
ECHO: undef
ECHO: "hallo"
ECHO: undef
ECHO: "Test with scopes"
ECHO: false
ECHO: true
ECHO: true
ECHO: true
WARNING: Ignoring unknown variable 'd', in file isundef-test.scad, line 21.
ECHO: undef
ECHO: "Special variables"
ECHO: true
ECHO: false
ECHO: true
WARNING: Ignoring unknown variable '$a', in file isundef-test.scad, line 30.
ECHO: undef
ECHO: 132465
ECHO: undef
ECHO: "constants resulting in true"
ECHO: true
ECHO: "constants resulting in false"
ECHO: false
ECHO: false
ECHO: "constants resulting in undef"
WARNING: is_undef() number of parameters does not match, in file isundef-test.scad, line 42
ECHO: undef
WARNING: is_undef() number of parameters does not match, in file isundef-test.scad, line 43
ECHO: undef
WARNING: is_undef() number of parameters does not match, in file isundef-test.scad, line 44
ECHO: undef
ECHO: "functions resulting in true"
WARNING: len() number of parameters does not match, in file isundef-test.scad, line 47
ECHO: true
WARNING: is_undef() number of parameters does not match, in file isundef-test.scad, line 48
ECHO: true
ECHO: "functions resulting in false"
ECHO: false
ECHO: false
