Why am I getting an invalid syntax error in Python REPL right after IF statement?

Question

I think this is perfectly valid.

if False:
    print(1)
print(2)

However, it gives me an invalid syntax error in Python REPL.

Why is it?

On Python 3.6.5 (x64), Windows 10 RS4

Answer 1

As pointed out by user2357112, this behaviour is explained in https://docs.python.org/3/tutorial/introduction.html#first-steps-towards-programming,

The body of the loop is indented: indentation is Python’s way of grouping statements. At the interactive prompt, you have to type a tab or space(s) for each indented line. In practice you will prepare more complicated input for Python with a text editor; all decent text editors have an auto-indent facility. When a compound statement is entered interactively, it must be followed by a blank line to indicate completion (since the parser cannot guess when you have typed the last line). Note that each line within a basic block must be indented by the same amount.