REPL stands for READ-EVAL-PRINT LOOP: every line you type (READ) (i.e.type than click ⏎) is sent to the interpreter for immediate interpretation (EVAL) and provide feedback (PRINT).
REPL — 交互式解释器环境。
R(read)、E(evaluate)、P(print)、L(loop)
输入值，交互式解释器会读取输入内容并对它求值，再返回结果，并重复此过程。
