Hi,

I took a cursory look at the Printf package. You should send #printf:
to the format string, with the data to be formatted as the arguments.
There are some examples on the class side of FormatString. Your
example could be written as:
'%6.2e' printf: 12.343434 resulting in: ' 12.34'.

String understands #format: which is the basic string interpolation
method in Squeak, but it doesn't do any number formatting. The same
formatting as above could be achieved with methods already in the
trunk like this:
(12.343434 printShowingMaxDecimalPlaces: 2) padded: #left to: 6 with:
Character space

Maybe there is a more concise way?

HTH, Balázs