caar as (define (caar x) (car (car x)))

-> (disassemble (lambda (x) (caar x)))
       0: 488b4808                       (mov rcx (mem64+ rax #x8))
       4: 48894bf8                       (mov (mem64+ rbx #x-8) rcx)
       8: 488b4810                       (mov rcx (mem64+ rax #x10))
       c: 48894bf0                       (mov (mem64+ rbx #x-10) rcx)
      10: 4883c3f0                       (add rbx #xfffffffffffffff0)
      14: 48895bf8                       (mov (mem64+ rbx #x-8) rbx)
      18: 488b13                         (mov rdx (mem64+ rbx))
      1b: 488b5218                       (mov rdx (mem64+ rdx #x18))
      1f: 488b4208                       (mov rax (mem64+ rdx #x8))
      23: 4885c0                         (test rax rax)
      26: 0f845cdcac05                   (jz (+ rip #x5acdc5c))
      2c: 4889c6                         (mov rsi rax)
      2f: 488b4310                       (mov rax (mem64+ rbx #x10))
      33: 48895b10                       (mov (mem64+ rbx #x10) rbx)
      37: 488943f8                       (mov (mem64+ rbx #x-8) rax)
      3b: 4883c3f8                       (add rbx #xfffffffffffffff8)
      3f: e9338cad05                     (jmp (+ rip #x5ad8c33))

caar built-in

-> (disassemble (lambda (x) (caar x)))
       0: 488943f8                       (mov (mem64+ rbx #x-8) rax)
       4: 4883c3f8                       (add rbx #xfffffffffffffff8)
       8: 488b4308                       (mov rax (mem64+ rbx #x8))
       c: 4889c2                         (mov rdx rax)
       f: f6c001                         (test al #x1)
      12: 0f8405000000                   (jz (+ rip #x5))
      18: e8a524ac08                     (call (+ rip #x8ac24a5))
      1d: 66833841                       (cmp (mem16+ rax) #x41)
      21: 0f85f1ffffff                   (jnz (+ rip #x-f))
      27: 488b4008                       (mov rax (mem64+ rax #x8))
      2b: f6c001                         (test al #x1)
      2e: 0f85e4ffffff                   (jnz (+ rip #x-1c))
      34: 66833841                       (cmp (mem16+ rax) #x41)
      38: 0f85daffffff                   (jnz (+ rip #x-26))
      3e: 488b4008                       (mov rax (mem64+ rax #x8))
      42: 4c8b75c8                       (mov r14 (mem64+ rbp #x-38))
      46: 4883c428                       (add rsp #x28)
      4a: 415d                           (pop r13)
      4c: 415c                           (pop r12)
      4e: 5b                             (pop rbx)
      4f: 5d                             (pop rbp)
      50: c3                             (ret)

gistfile1.txt

-> (disassemble (lambda (x) (car (car x))))
       0: 488943f8                       (mov (mem64+ rbx #x-8) rax)
       4: 4883c3f8                       (add rbx #xfffffffffffffff8)
       8: 488b4308                       (mov rax (mem64+ rbx #x8))
       c: f6c001                         (test al #x1)
       f: 0f8405000000                   (jz (+ rip #x5))
      15: e8a6fccb01                     (call (+ rip #x1cbfca6))
      1a: 66833841                       (cmp (mem16+ rax) #x41)
      1e: 0f85f1ffffff                   (jnz (+ rip #x-f))
      24: 488b4008                       (mov rax (mem64+ rax #x8))
      28: f6c001                         (test al #x1)
      2b: 0f8405000000                   (jz (+ rip #x5))
      31: e88afccb01                     (call (+ rip #x1cbfc8a))
      36: 66833841                       (cmp (mem16+ rax) #x41)
      3a: 0f85f1ffffff                   (jnz (+ rip #x-f))
      40: 488b4008                       (mov rax (mem64+ rax #x8))
      44: 4c8b75c8                       (mov r14 (mem64+ rbp #x-38))
      48: 4883c428                       (add rsp #x28)
      4c: 415d                           (pop r13)
      4e: 415c                           (pop r12)
      50: 5b                             (pop rbx)
      51: 5d                             (pop rbp)
      52: c3                             (ret)