More on 'mk' (plan9)

The following is a valid mk-file (with basically the same syntax as a makefile):

% cat mkfile

MKSHELL=bash

dinosaur:

        for i in a b c; do

            echo $i;

            echo next...;

        done

MKSHELL=rc

target:

        for(i in a b c) {

            echo $i

            echo next...

        }

MKSHELL=./wrap-python

foo:

        import sys

        for i in range(3):

          sys.stdout.write('Whoa!\n')

MKSHELL=./wrap-perl

bar:

        use Cwd;

        for my $i (1..3) {

            print getcwd() . "\n";

        }

% cat wrap-perl

#!/bin/sh

echo $*

exec perl

(The wrappers are needed only because mk passes '-e' to the MKSHELL program.)

Not only does it make sh easier to use than with 'make', but it also allows the recipes to be written in any language.  (If you use SHELL in 'make', each line is a separate invocation.)  If you want, you can use multiple languages within the same mk-file.  You have to admit that's pretty cool.

As for rc, because of complications with readline and command-history, I can't yet advocate it for an interactive shell.  Oh, well.