Boolean Expressions


True values
1
("a", "b")     A list with elements
" "            Whitespace is true
"hello"        Strings are true
"00"           A string with multiple zeros
False values
0         The number zero
( )       An empty list
""        Null string (empty string)
"0"       A string containing a single zero; the only string of non-zero
          length that's false

undef     An undefined symbol