SPUG: interpolating into a string variable

[Michael R. Wolf]

m3047 at inwa.net (Fred Morris) writes:

> Let's say we have a string variable. In practice it's read in from a file,
> but it could be a constant. And what we want to do is force interpolation
> into it before we use it for something like... ooooh, a regex. So,
> something like this:
>
>
>     my $foo_str = 'foo';
>
>     my $expr = 'a $foo_str happens here';
>
>     my $interpolated_expr = something magic happens to $expr;
>
> and then if you print "$interpolated_expr\n"; you would get
>
>     a foo happens here

For readability, I always liked sprintf

    my $foo_str = 'useful use of sprintf';

    my $fmt = "a %s happens here";
    my $interpolated_expr = sprintf($fmt, $foo_str);

    print $interpolated_expr;

yeilds this output

a useful use of sprintf happens here
    
================================================================

I've seen the fat comma used to enhance readability (for some
definitions of enhance and readability), though it does not change the
semantics in this case.

    my $interpolated_expr = sprintf($fmt => $foo_str);


-- 
Michael R. Wolf
    All mammals learn by playing!
        MichaelRWolf at att.net