The Little PHPer - 1. Toys

Scheme	PHP [Source Code]
atom	non-array ^[1]
`atom` `(quote atom)`	`'atom'`
`1492`	`1492`
`*abc$`	`'*abc$'`
list ^[2]	array ^[3]
`(atom)` `(quote (atom))`	`['atom']`
`(atom turkey or)`	`['atom', 'turkey', 'or']`
`((atom, turkey) or)`	`[['atom', 'turkey'], 'or']`
`(((how) are) ((you) (doing so)) far)`	`[[['how'], 'are'] [['you'], ['doing', 'so']], 'far']`
`()`	`[]`
`(() () ())`	`[[], [], []]`
`car`	`function car ($l) {return $l[0]; }`
`cdr` ^[4]	`function cdr ($l) {return array_slice($l, 1); }`
`cons`	`function cons ($s, $l) {return array_merge([$s], $l); }`
`null?`	`function is_nulll ($l) {return [] === $l; }`
`atom?`	`function is_atom ($s) {return ! is_array($s); }`
`eq?`	`function is_eq ($s1, $s2) {return $s1 === $s2; }`