Alexandre Ferrieux$Revision: 1.3 $Tcl binary

This TIP proposes to add a %b specifier to the format and scan commands for working with integers in base-2 representation.

The format and scan commands already have decimal, hexadecimal, and octal support, but people wanting binary today resort to a hack, namely going hexadecimal first and then string mapping the hex digits to their four-bits binary representations. We also already have the "0b" notation as input for expr. This lack is inelegant.

This TIP proposes to reuse the existing binary representation machinery to expose a new %b specifier: CWZvcm1hdCAlYiA1CT0+IDEwMQ==CXNjYW4gMDAwMTAxICViIHg7c2V0IHg=CT0+IDU= The good properties of the existing code make the addition really painless, in that it automagically combines with the size (l,ll), width (digits), and prefix (#) modifiers: CWZvcm1hdCAlIzA2YiA1CT0+IDBiMDEwMQ==CWZvcm1hdCAlbGxiIFtleHByIHsoMioqNzItMSkvN31dCTEwMDEwMDEwMDEwMDEwMDEwMDEwMDEwMDEwMDEwMDEwMDEwMDEwMDEwMDEwMDEwMDEwMDEwMDEwMDEwMDEwMDEwMDEwMDE=

That is really low-hanging fruit. All the pieces are in place, it's just a matter of exposition. The binary representation is a nice pedagogic tool, and having it handy (rather than with a hack) is a bonus.

See Patch 2368084 [].

This document has been placed in the public domain.