Why is the cursor not visually positioned on the first column when it is on the first column of an indented line?

Question

I inserted the program below in both the original vi and nvi. The indented lines are indented using a single tab.

#include <stdio.h>

int main(void)
{
    puts("Hello world!");
    return 0;
}

When I try to position the cursor on the first column of an indented line (5G0), this is what happens:

The cursor is not visually on the first column! This screenshot is from nvi, but exactly the same behavior appears in original vi. If I try to move the cursor to the left using h, nvi warns: Already in the first column.

What is the reason for this behavior? Is there a way to make the cursor appear in the first visual column when it is on the first column of an indented line?

Answer 1

Hard tab is a single character. Eight spaces are displayed on screen but they are not a part of a buffer. Just like those trailing spaces after line ends.

In Vim if you want the cursor to move through all non-existent chars one by one you have to set virtualedit option to "all" value. In nvi, AFAIU, you just can't.

Answer 2

Instead of using "0" to go the first character in the line, you can use "^" to move to the first non-blank character in the line.