Go: Functions that satisfy interfaces

I ran across this while sifting through the http package:

// The HandlerFunc type is an adapter to allow the use of
// ordinary functions as HTTP handlers. If f is a function
// with the appropriate signature, HandlerFunc(f) is a
// Handler that calls f.
type HandlerFunc func(ResponseWriter, *Request)

// ServeHTTP calls f(w, r).
func (f HandlerFunc) ServeHTTP(w ResponseWriter, r *Request) {
    f(w, r)

A function that satisfies http.HandlerFunc will also automatically get a function-on-a-function (who knew) that makes it look like a struct that satisfies the http.Handler interface as well.

I had looked for a footnote about this in the section on function declarations in the Go language specification but was not successful. The receiver is little more than just a repositioned first-argument. There’s nothing that says “MUST be a struct or a func”.


Add Timestamps to Your Bash History

Put this in your profile script (.bashrc):

export HISTTIMEFORMAT="%d/%m/%y %T "

I also find it helpful to increase the size of my command-line history:

export HISTFILESIZE=10000
export HISTSIZE=10000

The first controls how many are stored. The second controls how many are kept in memory. You can also tweak it to hold an actual unlimited number if you so wish.

Git: Get the Latest Commits in a Repository

Sometimes you have a large repository (many commits, many branches) and it either might be an old clone or you might be operating out of a secondary branch and not aware of which branch has the majority of activity. You can do a git-log that displays all commits without respect to the current branch and order them by parents before children, in descending commit-timestamp (as opposed to author-timestamp) order.

This prints the top five:

$ git log -5 --all --date-order