Re: [stack] a constructive-concatenative language

----- Original Message ----- 
From: "William Tanksley, Jr" <[email protected]>
To: <[email protected]>

>> I do have to admit, however, that I've been considering a language
>> which is structured similarly to APL/J.  The idea that you read from
>> left to right, but evaluate from right to left is very appealing to
>> me, particularly from an applicative point of view.  So far as I can
>> tell, the only core primitives in the language would be function
>> definition (=), and the McCarthy conditional construct (a->b;c), and
>> function application (a(b)).  

what you've described is just iverson's "direct definition" restriction
of APL.  a direct definition is an expression

    f = expression

or

    f = condition:expression-if-true:expression-if-false

"alpha" and "omega" are arguments to f.  using x and y for these:

    diff = x>y:x-y:y-x

some large APL systems have been written using only direct definition.