READ(str): return reader.read_str(str)
-pair?(ast): return ... // true if non-empty sequence
quasiquote(ast): return ... // quasiquote
macro?(ast, env): return ... // true if macro call
'sequential? sequential?,
'cons: (a) -> concat([a[0]], a[1]),
'concat: (a) -> reduce(concat, [], a),
+ 'vec: (l) -> l converted to vector,
'nth: (a) -> a[0][a[1]] OR raise "nth: index out of range",
'first: (a) -> a[0][0] OR nil,
'rest: (a) -> a[0][1..] OR list(),