Adjust indentation of current line.
Equivalent to RET followed by TAB (
The basic indentation command is TAB, which gives the current
line the correct indentation as determined from the previous lines. The
function that TAB runs depends on the major mode; it is
lisp-indent-line in Lisp mode,
c-indent-line in C mode,
etc. These functions understand different syntaxes for different
languages, but they all do about the same thing. TAB in any
programming language major mode inserts or deletes whitespace at the
beginning of the current line, independent of where point is in the
line. If point is inside the whitespace at the beginning of the line,
TAB leaves it at the end of that whitespace; otherwise, TAB
leaves point fixed with respect to the characters around it.
Use C-q TAB to insert a tab at point.
When entering a large amount of new code, use LFD
newline-and-indent), which is equivalent to a RET followed
by a TAB. LFD creates a blank line, then gives it the
TAB indents the second and following lines of the body of a parenthetical grouping each under the preceding one; therefore, if you alter one line’s indentation to be nonstandard, the lines below tend to follow it. This is the right behavior in cases where the standard result of TAB does not look good.
Remember that Emacs assumes that an open-parenthesis, open-brace, or other opening delimiter at the left margin (including the indentation routines) is the start of a function. You should therefore never have an opening delimiter in column zero that is not the beginning of a function, not even inside a string. This restriction is vital for making the indentation commands fast. See Defuns, for more information on this behavior.