.Dd December  2, 2020
.Dt HOT-TIPS 7
.Os "Causal Agency"
.
.Sh NAME
.Nm hot tips
.Nd from my files
.
.Sh DESCRIPTION
This is a short list of tips
from my configuration files and code
that might be useful.
.
.Ss Shell
.Bl -tag -width Ds
.It CDPATH=:~
This is useful if you sometimes type,
for example,
.Ql cd src/bin
wanting to go to
.Pa ~/src/bin
but you aren't in
.Pa ~ .
If the path doesn't exist
in the current directory,
.Ic cd
will try it in
.Pa ~
as well.
.
.It alias ls='LC_COLLATE=C ls'
This makes it so that
.Xr ls 1
lists files in ASCIIbetical order,
which puts capitalized names like
.Pa README
and
.Pa Makefile
first.
.
.It git config --global commit.verbose true
Not shell but close enough.
This makes it so the entire diff is shown
below the usual summary
in the editor for a
.Xr git-commit(1)
message.
Useful for doing a quick review
of what you're committing.
.El
.
.Ss (neo)vim
.Bl -tag -width Ds
.It set inccommand=nosplit
This is the only
.Xr nvim 1
feature I really care about
aside from the improved defaults.
This provides a live preview of what a
.Ic :s
substitution command will do.
It makes it much easier to
write complex substitutions.
.
.It nmap <leader>s vip:sort<CR>
This mapping sorts the lines of a paragraph,
or block of text separated by blank lines.
I use this a lot to sort
#include directives.
.
.It nmap <leader>S $vi{:sort<CR>
Similar to the last mapping,
this one sorts lines inside braces.
I use this to sort
switch statement cases
or array initializers.
.
.It nmap <leader>a m':0/^#include <<CR>:nohlsearch<CR>O#include <
I use this mapping to add new
#include directives,
usually followed by
.Ic <leader>s
and
.Ic ''
to sort them
and return to where I was.
.
.It nmap <leader>d :0delete<CR>:0read !date +'.Dd \e%B \e%e, \e%Y'<CR>
I use this to replace the first line of
.Xr mdoc 7
files with the current date.
.El
.
.Ss C
.Bl -tag -width Ds
.It #define Q(...) #__VA_ARGS__
This is what I've started using
to quote things like SQL statements
or HTML fragments in C.
Anything that happens to be valid C tokens,
which is most code,
can be quoted this way.
You can embed (matched) quotes
without having to escape them.
Whitespace gets collapsed,
so you can write nicely formatted multi-line SQL
that doesn't mess up your debug logging,
for example.
.Bd -literal -offset indent
const char *sql = Q(
	INSERT OR IGNORE INTO names (nick, user, host)
	VALUES (:nick, :user, :host);
);
.Ed
.
.It #define BIT(x) x##Bit, x = 1 << x##Bit, x##Bit_ = x##Bit
I use this macro to declare bitflag enums.
It takes advantage of
auto-incrementing enum items
so you don't need to set the values manually.
You also get constants
for both the bit index
and the flag value
for each item.
.Bd -literal -offset indent
enum Attr {
	BIT(Bold),
	BIT(Reverse),
	BIT(Italic),
	BIT(Underline),
};
.Ed
.Pp
For example,
defines
.Sy ItalicBit = 2
and
.Sy Italic = 1 << 2 .
Ignore the extraneous constants.
.
.It typedef int FnType(const char *str, size_t len);
You can just typedef function types!
It annoys me more than it probably should
that everyone writes ugly
function pointer typedefs.
Just stick
.Sy typedef
on the front of a function declaration
and use
.Vt FnType * .
.El
.
.Sh AUTHORS
.Mt june@causal.agency