The Lisp Curse (2011)

Re:The Lisp Curse (2011) by rol on Thursday February 25, 2016 @05:23PM (#11178315)

If you have Quicklisp[1] installed you can install the "infix" package and get infix notation in Common Lisp[2]:

    $ sbcl
    This is SBCL 1.2.4.debian, an implementation of ANSI Common Lisp.
    More information about SBCL is available at <http://www.sbcl.org/>.
    
    > (ql:quickload 'infix)
    ; Loading package
    (INFIX)
    > #i(1 + 1)            ; addition
    
    2
    > #i(2^^128)           ; exponentiation
    
    340282366920938463463374607431768211456
    > (defun factorial (x)
         #i(if x == 0 then
              1
            else
              x * factorial(x-1)))       ; infix function call
    
    FACTORIAL
    > (factorial 5)
    
    120
    > #i(factorial(5) / factorial(6))
    
    1/6
    > '#i((a + b) * (c + d))      ; Put a ' before the #i() to see what code is generated
    
    (* (+ A B)
       (+ C D))

[1] - https://www.quicklisp.org/beta/ [2] - Don't know if there is a similar package for Scheme.

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Re:The Lisp Curse (2011) by jrapdx3 on Thursday February 25, 2016 @11:21PM (#11179774)

> Don't know if there is a similar package for Scheme.

I have to agree with others in the thread that infix in Lisp/Scheme is not the convention, and IMO an awkward fit. Don't recall encountering infix in any published/shared code I've seen, it may exist, but to learn Scheme becoming comfortable with s-expr notation is definitely necessary.

However, there is SRFI 105[0] which describes "curly infix expressions". It's implemented in Guile 2.x, possibly available in a few others but evidently not had a lot of uptake among Schemes.

[0] http://srfi.schemers.org/srfi-105/srfi-105.html

Edit: added URL

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Re:The Lisp Curse (2011) by adwf on Thursday February 25, 2016 @06:34PM (#11178736)

I wouldn't recommend using infix libraries if you really want to get into Common Lisp though. They're a bit of a crutch for people coming from other languages, but that's it.

Pretty much the whole language is based on Polish notation. The sooner you realise that + - * / are just function names like any other, the better you'll do.

For example:

  (+ 1 2 3)

  in plain symbols is just:

  (function parameter parameter parameter)
  
  But if I were to write my own addition function:

  (addition 1 2 3)

  it would also be:

  (function parameter parameter parameter)

  and so is:

  (http-request "http://www.google.com")

  (function parameter)

If you use infix notation, you're writing half your code in a competely different semantic to the other half. I can't imagine it helping people really get a proper grasp of how Common Lisp works.

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