Hanging Semi-colons and commas Auto-newline insertion Clean-ups

4.1.4: Other electric commands

A few other keys also provide electric behavior. For example # (c-electric-pound) is electric when typed as the first non-whitespace character on a line. In this case, the variable c-electric-pound-behavior is consulted for the electric behavior. This variable takes a list value, although the only element currently defined is alignleft, which tells this command to force the `#' character into column zero. This is useful for entering C preprocessor macro definitions.

Stars and slashes (i.e. * and /, c-electric-star and c-electric-slash respectively) are also electric under certain circumstances. If a star is inserted as the second character of a C style block comment on a comment-only line, then the comment delimiter is indented as defined by c-offsets-alist. A comment-only line is defined as a line which contains only a comment, as in:

void spam( int i ) 
{
        // this is a comment-only line...
    if( i == 7 )                             // but this is not
    {
        dosomething(i);
    }
}

Likewise, if a slash is inserted as the second slash in a C++ style line comment (also only on a comment-only line), then the line is indented as defined by c-offsets-alist.

Less-than and greater-than signs (c-electric-lt-gt) are also electric, but only in C++ mode. Hitting the second of two < or > keys re-indents the line if it is a C++ style stream operator.

Hanging Semi-colons and commas

Auto-newline insertion

Clean-ups