At 4:20 PM -0400 7/6/02, Brian Keefer wrote:
>I'd like to try my project out on any other Smalltalk, and the SqueakSCII
>rift is the second problem I ran up against.
>
>What is the history behind Squeak's use of _ ? <grandpa>Back in the days
>of the Great Depression, a colon was considered a waste of perfectly good
>periods. But nowadays, you kids waste perfectly good ellipses...</grandpa>

Smalltalk-72 used a number of characters that weren't standard ASCII. 
By Smalltalk-80, these had been eliminated from the syntax, but two 
slightly 'odd' characters remained. These were the up-arrow, used to 
signify a value to be returned, and the left-arrow, used to signify 
assignment. These characters were defined in ASCII-1963, but in 
ASCII-1967 their codes were reused for the circumflex  ^ and the 
underscore _.[1] Smalltalk-80's fonts, though, had arrow glyphs for 
those codes, as in ASCII-1963.

Squeak is directly based on Smalltalk-80, so its assignment operator 
is the left arrow, which appears in most non-Squeak fonts as an 
underscore. At some point, Squeak started also accepting := as an 
alternate assignment operator.

-Martin

[1] http://www.wps.com/texts/codes/#LEFT