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Comment by retrac | Hacker News Reader

Most well-written Lisp code has its structure indicated primarily by the indentation. Some form of offset rule is the most commonly suggested alternative Lisp syntax. It does make the tree structure more obvious:

    define                          (define (pos>? p1 p2)
      pos>? p1 p2                     (or (fx> (pos-row p1) (pos-row p2))
      or                                (and (fx= (pos-row p1) (pos-row p2))   
        fx>                                  (fx> (pos-col p1) (pos-col p2)))))
          pos-row p1
          pos-row p2
        and 
          fx=
            pos-row p1
            pos-row p2
          fx>
            pos-col p1 
            pos-col p2

The left looks a lot like a typical AST for many languages, such as C, shortly after parsing. As the article points out, it's the easy access to this tree-list structure at runtime, that can be easily handled as data by the program itself, that gets Lisp programmers so excited.

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And if anybody is interested in a well developed alternative Lisp syntax in this manner:

https://readable.sourceforge.io/

Unfortunately, as with all standards, there's so many wonderful alternatives to choose from. I rather like Wisp: https://www.draketo.de/software/wisp

I wish all languages had the : operator that Wisp has. It's $ in Haskell. It simply says that what follows to the end of line is wrapped in brackets. So:

  putStrLn $ somefunc $ process val = putStrLn (somefunc (process val))

Like a UNIX pipe, but moving to the left.

Instead of $ they could have used ¢, since it looks more like an opening bracket.

There aren't too many keyboards with a ¢ key included, so I suppose that alone could be a show stopper.

They definitely didn't care about that. No language that uses ` , the most painful common character to write on most non-US keyboards put any consideration into that.

My UK keyboard has it

Not a fair comparison, since most keyboards DO have a US layout.

Outside of the US and a few other English-speaking countries? Not really. In Europe, US keyboards are nowhere to be found (the UK uses a different layout).

It's part of why it's always painful to buy a keyboard west of Oder for me, because Poland use ANSI layout as base, not ISO, at least as an option. After over a decade, even Microsoft finally learnt to default to "Polish (Programmers)" rather than "Polish (214)" keyboard when installing the OS (it was a common pitfall across whole Windows 9x).

Other languages in former Warsaw Pact tend to have "Programmers" layout available as well, because the national standard layouts tended to be designed for typewriters not programming and lack all kinds of characters people need - unless you go trigram route in C/C++.

For what its worth, Common Lisp at least does let you remap ` and such :)

I'm not talking about the physical ISO vs ANSI layouts. I mean the layout in software. It's not even close. Basically noone outside the US and Canada uses it. We're on HN, so obviously someone here will, but outside of this niche? Noone

We have reached Peak Bideshedding

I have always felt SML and F# are basically statically typed Lisps/Schemes without parentheses.

To be consistent, I think the first part should be indented like this:

    define                          
      pos>? p1 
            p2

(p1 and p2 on separate lines)

> The left looks a lot like a typical AST for many languages....

Right, and this is what's meant by the oft-repeated statement "LISP has no syntax." Of course it has syntax in the sense that if you were to go in and delete one of those parens, the whole thing wouldn't compile, but the syntax it does have is 100% regular.

Lisp has quite a bit more syntax, since it has a two stage syntax. The first stage is a syntax for data, called s-expressions. The parentheses are a part of that data syntax. Examples for s-expressions:

  12
  1/3
  rome
  (rome is a city in italy)
  (rome (city . italy) (capital-of italy))
  (rome local-name "Roma")

and more. The s-expression syntax is extensible via reader macros.

Lisp programs then are made out of s-expressions and there is a syntax for Lisp. Additionally the Lisp syntax is extensible via macros.

Example:

  (let ((a 10)
        (b 10))
    (declare (integer a b))
    (+ a b))

Above is a LET expression for spanning a local lexical scope for variables.

The syntax for LET would be (in some kind of EBNF notation):

  let ({var | (var [init-form])}*)
   declaration*
   form*

With then more syntax for DECLARATION, FORM, ...

Who cares? Assembly is regular*, very much so. There is a single control flow construct, in conditional and unconditional flavors. There is a single language construct, of which the single control flow construct is but a special case. Code is Data and Data is Code. Everything is possible.

You don't need regularity or simplicity, you need automation. Programming Languages are tools to under-specify a problem\process\pattern\solution\structure and still get an executable that does something useful, meaning the parts that weren't specified were filled in by the machine (in any way necessary), meaning automation. In other words, "A low level programming language is that which requires attention to the irrelevant", per Alan Perlis.

In that light, lisp's syntax is awful, you're laying down the AST yourself instead of making a parser figuring it out from program text. You're paying precious attention to the extremely irrelevant, the fact that a function's body is nested under its name, the fact that a control construct wraps its code, instead of letting those trivial facts fade into the background of a nicely-designed grammar and actually focus on the code itself.

There is literally 0 need for making code-as-text reflects code-as-tree, Mathematica represents every single language construct as a nested list underneath, and yet it has an extremely rich and pleasant syntax, full of sugar and shortcuts and alternate forms. It can do this because it understands a very fundamental point that lisp syntax fans too often miss : text is irrelevant.

The string "(+ (* 4 10) 2)" is not an S expression, its the textual form of an S expression, the serialized form. You can't do anything useful with it without parsing, the actual S expression is a hierarchical object graph in memory, you can either get it from the text by quoting the text, or immediately evaluate it by entering the text directly into an interpreter (which gets the tree first). In all cases, there is no reason why quoting `while (cond) {exprs}` can't evaluate to the list (while cond (exprs)). You are already parsing the text anyway, quote is nothing but invoking the parser from within a program, so make the textual form convenient to humans while you're at it, a simplistic form benefits no one but the parser (a machine, the very thing that needs to work hard).

Lisp's big idea is just making the compiler's services available through an easy API, this has absolutely nothing to do with its crippled syntax, it can be done by any language of any syntax whatsoever, much better than the 1960s hack lisp fans has stockholm-ed themselves into loving. To the extent it's rarely done in mainstream languages, it reflects the designers' choice.

* : I'm assuming a remotely sane ISA, not the excrement known as x86.

> )))))

You could stack them like this in every language but only in Lisp do people actually do it. Lisps bad habbit of stacking all the parentheses like that is what makes it so hard to read. It is easier to write that way, but it is very hard to understand how many contexts up you just moved.

> Lisps bad habbit of stacking all the parentheses like that is what makes it so hard to read.

How much Lisp have you written/read? Closing parens on separate lines would be a nightmare to read in any real-world code.

Also, what makes Lisp hard to read is lack of familiarity. It's not like C is easy to read for someone who's only ever written Lisp. Lispers don't find Lisp hard to read.

Sounds like a good opportunity to oil up Chesterton’s fence. You may want to consider the possibility that the conventions Lispers have been using for considerably longer than C or whatever language you like to bikeshed style guides in has existed were actually settled on for pragmatic reasons.

You’re not alone though. Many nascent Lispers go through the use reader macros to make Lisp look more like what they’re used to phase.

Not just nascent Lispers. I inherited something like this in a C codebase before (several times, actually, only one that I had to actually edit though):

  #define BEGIN {
  #define END }
  #define INTEGER int
  ...

Yes, they even did it with the types. Made for a weird Pasctran language that the dev was apparently more comfortable with. I think they actually got a C translation of another program almost "for free" doing this. The real thing was they didn't want to write new code and didn't want to learn C, so they subjected everyone after them to this horror.

Moral of the story: If you can't be bothered to learn a language and its conventions, be honest and get another job.

Pasctran is an ancient cult. [1] Some say they're extinct. Others say its practitioners have just gone underground, now that society will no longer tolerate such things done in public. It's everywhere once you start looking though, insidiously contaminating our precious function bodies.

From the source to the original Bourne shell:

    BEGIN
       REG BOOL slash; slash=0;
       WHILE !fngchar(*cs)
       DO    IF *cs++==0
        THEN    IF rflg ANDF slash THEN break; ELSE return(0) FI
        ELIF *cs=='/'
        THEN    slash++;
        FI
       OD
    END

[1] https://research.swtch.com/shmacro

As an old Pascal programmer who never really liked C.... even I have to say NO!!!!

What a horrible thing to do. I've never liked macros, and things like this are part of the reason why.

Not with proper indenting, or rainbow-delimiters/show-paren-mode.

I don't buy that, when you do the same in other languages you get:

    for (var i = 1; i < 101; i++) {
        if (i % 15 == 0) {
          console.log("FizzBuzz");}
        else if (i % 3 == 0) {
          console.log("Fizz");}
        else if (i % 5 == 0) {
          console.log("Buzz");}
        else {
          console.log(i);}}

Why do you think nobody other than lispers writes code like this? Is it really necessary to write code that way? If it is better, why not does nobody else do it? They can also use colored bracers and tooling, while lispers has written code that way forever.

I'm sure a big reason people call lisp a "write only language" is because of this strange convention of stacking all parentheses in a big clump instead of formatting like normal.

Yet, for Python the layout is like above, with indentation being significant:

  for i in range(1, 101):
      if i % 15 == 0:
          print("FizzBuzz")
      elif i % 3 == 0:
          print("Fizz")
      elif i % 5 == 0:
          print("Buzz")
      else:
          print(i)

It does not need the {} pairs then. Now, are we lost because the {} pairs are missing?

In Lisp you need to learn to apply the same idea of indentation being significant:

  (loop for i from 1 upto 100 do
     (cond ((zerop (mod i 15))
            (write-line "FizzBuzz"))
           ((zerop (mod i 3))
            (write-line "Fizz"))      
           ((zerop (mod i 5))
            (write-line "Buzz"))
           (t
            (write-line (princ-to-string  i)))))

Just imagine the grouping parentheses are not there.

The disadvantages of Lisps are basically two:

a) there are more parentheses because of the nested lists being used to write code

b) one now needs to understand when (sin a) is actually code and when it is data.

The advantage of Lisp syntax:

a) code is already a simple nested data structure

b) the indentation&layout of code can be (and often is) computed from the data, while usually in Python the lines and indentation are significant

Do you want Python? Because this is how you get Python.

Joke aside, this is why I never understood this problem. With proper indentation it looks essentially like Python with a generous helping of your-father's-parentheses.

>when you do the same in other languages you get...

Your result should be unsurprising. Lisps have a minimal syntax that naturally entails high levels of nesting: (s-)expressions being used to represent functions, control structures, data, etc.

Why should a particular style convention appropriate for that kind of language necessarily transplant well to JavaScript-- a brace-delimited, Algol-inspired language with a lot of syntax?

I used to feel the same way but lisp gets easier to read with practice, and unless you're writing code in notepad.exe or nano or something, your editor will show you the matching paren.

IMO, because C syntax sucks and makes people actually take time to read and interpret the brackets. In erlang and I think others people don't newline between closing delimiters either. In lisp the brain processes the parens automatically.

Who calls Lisp a "write only language" other than people who don't know Lisp?

There is the classic Minsky quote:

“Anyone could learn Lisp in one day, except that if they already knew Fortran, it would take three days.”

Is it bad that I find that really easy to read?

But why would you care about those trailing parentheses?

Readability. By properly indenting the parentheses and putting them on lines you will at a glance see which contexts you just closed, that is how people format code in every mainstream language.

None of these 'mainstream' languages use a data structure for writing and manipulating code like Lisp. The use of Lisp is thus very different and Lisp programmers find a more compact notation more useful.

> you will at a glance see which contexts you just closed

the text editor does that for me

> how people format code in every mainstream language

Python code formatting looks different from Java code formatting.

Python code:

  for h in range(0, height):
      for w in range(0, width):
          v = bw_image.getpixel((w, h))
  
          if v >= avg:
              bm_image.putpixel((w, h), white)
          else:
              bm_image.putpixel((w, h), black)

Lisp code just looks like that. Only with added parentheses (because Lisp expressions are written as nested lists) and prefix notation:

  (dotimes (h height)
    (dotimes (w width)
      (setf v (get-pixel bw-image w h))

      (if (>= v avg)
          (put-pixel bm-image w h while)
          (put-pixel bm-image w h black))))

Python also formats their parentheses the non lisp way. You typically format things like this:

  data = [
    [1, 2, 3],
    [4, 5, 6],
    [7, 8, 9, [10, 11, 12]]
  ]

Any language that uses closing symbols formats them that way, in Pyhton in Java, in C etc. Lisp is the only example where they don't properly indent closing symbols and instead just put them all together at the last statement.

Yet most Python code is written in the compact form I've showed you, where code indentation is significant. Lisp has the same model: the code indentation is significant. But Lisp has the structure encoded in nested lists. These nested lists are automatically formatted in the same space saving way as Python code. Due to the significant indentation, Python usually can avoid to have grouping characters/symbols.

I see also lots of Python code where data isn't written like you claim...

https://www.programiz.com/python-programming/matrix

With lisp is it not more common to use paredit or similar? I.e. you don’t edit code like in other languages.

As you barf and slurp, you’re interested in the “shape” of code but you ignore the parens.

> but only in Lisp do people actually do it

That is false. Do yourself a favor and run "git grep -F ')))))' in, oh, the root of the Linux kernel tree.

There is a real drawback to stacking more than three or four closing parens like this, without spacing them out: it's hard and in fact impossible to count them at a glance. Not an issue if you have a code editor with auto paren matching, but it can be an annoyance when reading LISP-like code on the web or elsewhere.

> it can be an annoyance when reading LISP-like code

Just mentally collapse any number of consecutive close parens into a thing that reads like "END."

In Interlisp one would write a super parenthesis, which closes all open parentheses, upto an opening [ or the top ( :

  (a (b c (d ]

and also

  (z (a [b c (d]
        [e f (g]]

Nah, you just rely on the indentation to understand the structure, just like every other language.

It's not a bad habit. It's just more practical.

Lisp lists are a data structure. One for example types code&data and computes with an interactive Read Eval Print Loop.

That's what one would write:

  CL-USER 35 > (+ (expt 23 2.4) (sin (* 44 0.23 22)))
  1854.5603

No one would type:

  CL-USER 36 > (+ (expt 23 2.4) (sin (* 44 0.23 22
                                     )
                                )
               )

Also when Lisp deals with s-expressions, the more compact notation is more useful: here Lisp does the layout itself:

  CL-USER 46 > (let ((*PRINT-RIGHT-MARGIN* 30))
                 (pprint '(+ (EXPT 23 2.4) (SIN (* 44 0.23 22)) (COS (+ 12 0.43 19.0)) (TAN (/ 1.4 0.77 3/4)))))

  (+ (EXPT 23 2.4)
     (SIN (* 44 0.23 22))
     (COS (+ 12 0.43 19.0))
     (TAN (/ 1.4 0.77 3/4)))

It's not

  (+ (EXPT 23 2.4
     )
     (SIN (* 44 0.23 22
          )
     )
     (COS (+ 12 0.43 19.0
          )
     )
     (TAN (/ 1.4 0.77 3/4
          )
     )
  )

Above is much harder to read and wastes a huge amount of space on the screen. Imagine that lists of are much longer and deeper nested. Finding the corresponding parentheses is usually done by using the editor (select a whole expression, have blinking or colored parentheses, etc.).

The main difference between Lisp and most other programming languages is that programs are written as a data structure: nested lists. Not only that: they are not static lists, but we can compute with them - that's the main appeal. It's a programming language, where it's easy and common to manipulate lists, even programs as lists. Thus the notation has not only be useful for reading code, but also for input/output by humans and programs. There a compact notation is much more useful, since tools will often create huge amounts of nested lists. For example imagine a macro for some Lisp functionality, like a complex loop expression. The macro expanded code can often be ten times larger as the input expression, yet we may want to see it in a debugger -> write that expression in a compact way.

I let Lisp indent my code and the system-wide standard indentation makes it easier to spot parentheses errors, since all code has the same shape rules.

  (progn
    (case foo
      (var (eval foo)))
    (fn (apply foo args)))

Since all code gets indented during typing, I can easily see that there is one parenthesis too much in the first case clause...

I wouldn't care to see the parentheses aligned and it makes the problem often more difficult to spot:

  (progn
    (case foo
      (var (eval foo
           )
      )
    )
    (fn (apply foo args
        )
    )
  )

I want the expressions to use less vertical space, so that I can see that the opening parentheses of the CASE clauses align. Anything else is just visual clutter.

The standard way is to close inline things inline and close multi-line things on a separate line.

Like this:

  (+ (EXPT 23 2.4)
     (SIN (* 44 0.23 22))
     (COS (+ 12 0.43 19.0))
     (TAN (/ 1.4 0.77 3/4))
  )

Instead of

  (+ (EXPT 23 2.4)
     (SIN (* 44 0.23 22))
     (COS (+ 12 0.43 19.0))
     (TAN (/ 1.4 0.77 3/4)))

It is very common for programmers who are new to Lisp to close their parentheses in the former style. However, it is a crutch that they soon do away with if they stick to the language for any length of time.

There are two reasons why sometimes the parentheses are on a separate line:

  ((paris (french))
   (los-angeles (english spanish))
   )

Something like above would be used if one often adds data clauses to that expression.

Also when there are comments on the last line, then sometimes the expression might be closed on the following like:

  ((paris (french))                 ; city 1
   (los-angeles (english spanish))  ; city 2
   )

Actually that's also wrong, I usually see this rule applied in other languages:

If the opening bracket is on the same line as content, then so is the closing bracket.

By this rule, we have two options:

  (+
     (EXPT 23 2.4)
     (SIN (\* 44 0.23 22))
     (COS (+ 12 0.43 19.0))
     (TAN (/ 1.4 0.77 3/4))
  )

  (+ (EXPT 23 2.4)
     (SIN (\* 44 0.23 22))
     (COS (+ 12 0.43 19.0))
     (TAN (/ 1.4 0.77 3/4)))

The first option has both opening and closing brackets on their own lines, while the second has neither. Note that I consider the function name to be part of the opening bracket since it's distinct from the parameters.

This is consistent with other languages:

  [1, 2, 3]
  f(x, y, z)
  [
    1,
    2,
    3,
  ]
  f(
    x,
    y,
    z
  )

instead of

  [1,
   2,
   3,
  ]
  f(x,
    y,
    z,
   )

Haskell is an odd exception with

    [ x
    , y
    , z
    ]

which looked really weird to me first but I’ve found it to improve legibility a lot. (Of course there’s a reason it’s idiomatic in Haskell and not elsewhere.)

Lisp has lots of multi-line expressions.

That the expression is ended I can see in the typical Lisp expression because of the block structure. The single parentheses does make the layout very cluttered and visually ugly. It gets even worse in typically larger Lisp code or data.

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