elisp: Motion by Indent
31.17.6 Indentation-Based Motion Commands
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These commands, primarily for interactive use, act based on the
indentation in the text.
-- Command: back-to-indentation
This command moves point to the first non-whitespace character in
the current line (which is the line in which point is located). It
returns ‘nil’.
-- Command: backward-to-indentation &optional arg
This command moves point backward ARG lines and then to the first
nonblank character on that line. It returns ‘nil’. If ARG is
omitted or ‘nil’, it defaults to 1.
-- Command: forward-to-indentation &optional arg
This command moves point forward ARG lines and then to the first
nonblank character on that line. It returns ‘nil’. If ARG is
omitted or ‘nil’, it defaults to 1.