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Could parentheses be a reason Lisp is hard to read?

#python #lisp #syntax #language

Many in the communities of Lisp-style languages (Lisp, Clojure etc.) seem to discount parentheses being a reason for people not adopting Lisp. (It must only be the unfamiliarity of FP! You get used to the parentheses, and see past them!) Even though newcomers frequently complain about all the parentheses (of Lisp S-expressions), and several people have attempted to make an indentation-based Lisp (I-expressions, T-expressions aka. Sweet expressions, Cirru, Wisp, etc.). So there must be something to it, or..?

Shared from perplexity.ai :

—-

Reasons why developers might find heavily nested parentheses in Lisp harder to read, and how the Python equivalent addresses that issue.

1. Visual Clutter

Lisp Example:

(defun complex-calculation (x y z)
  (+ (* (- x y) (/ z 2)) (sqrt (abs (- (* x x) (* y y))))))
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Why it's hard to read in Lisp:

The parentheses dominate the visual space, making it difficult to focus on the actual logic of the computation. You have to mentally parse which parentheses belong to which operation, and this can be overwhelming in more complex expressions.

Python Example:

def complex_calculation(x, y, z):
    return (x - y) * (z / 2) + math.sqrt(abs(x**2 - y**2))
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Why Python is clearer:

Python uses operator precedence and infix notation (+, -, *, /) instead of prefix notation (+, *, etc.). This reduces the need for explicit grouping with parentheses. The mathematical operators are familiar and visually intuitive, making the expression easier to read at a glance.

2. Lack of Visual Cues

Lisp Example:

(if (and (> x 0) ( 0 and y  a b)
      (+ (- a (* b c)) (/ (+ a b) c))
      (- (* a b) (/ (- b c) a))))
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Why it's hard to read in Lisp:

With multiple levels of parentheses nested within an if statement, it becomes difficult to match opening and closing parentheses at a glance. Misplacing or omitting just one parenthesis can lead to errors that are hard to debug.

Python Example:

def nested_function(a, b, c):
    if a > b:
        return (a - (b * c)) + ((a + b) / c)
    else:
        return (a * b) - ((b - c) / a)
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Why Python is clearer:

Python uses indentation and blocks instead of parentheses for structure. The logical separation between the if and else branches is clear. Parentheses are only used for grouping where necessary, making them easier to match visually.

5. Reduced Readability

Lisp Example:

(loop for i from 0 to 10
      when (evenp i)
        collect (list i (expt 2 i))
      else
        collect (list i (1+ i)))
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Why it's hard to read in Lisp:

The combination of nested parentheses and keywords like collect makes it harder to follow what’s happening at each step of the loop. The logic is compact but not immediately intuitive because everything is expressed as nested expressions.

Python Example:

result = []
for i in range(11):
    if i % 2 == 0:
        result.append([i, 2**i])
    else:
        result.append([i, i+1])
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Why Python is clearer:

Python's loop syntax separates each part of the logic into distinct lines (for, if, else). The use of indentation makes it easy to see what happens under each condition without needing to mentally parse nested constructs.

6. Limited Expression of Precedence

Lisp Example:

(setq result (+ (* 2 (- 5 3)) (/ 10 (+ 2 3))))
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Why it's hard to read in Lisp:

In Lisp's prefix notation, every operator requires explicit grouping with parentheses. This makes it harder to intuitively understand operator precedence because there’s no visual shorthand like infix operators provide.

Python Example:

result = 2 * (5 - 3) + 10 / (2 + 3)
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Why Python is clearer:

Python uses standard mathematical notation with infix operators (+, -, *, /) that inherently express precedence rules without requiring extra grouping symbols. This makes the expression more natural and easier for most developers to understand.

7. Indentation Challenges

Lisp Example:

(defun process-data (data)
  (let ((processed
          (remove-if
            #'null
            (mapcar
              #'(lambda (item)
                  (when (valid-item-p item)
                    (transform-item item)))
              data))))
    (sort processed #'item-compare)))
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Why it's hard to read in Lisp:

Proper indentation is critical here because it’s the only way to visually separate different parts of the code. Without clear indentation or if indentation is inconsistent, it becomes nearly impossible to follow what’s happening at each level of nesting.

Python Example:

def process_data(data):
    processed = [transform_item(item) for item in data if valid_item(item)]
    return sorted(processed, key=item_compare)
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Why Python is clearer:

Python enforces consistent indentation as part of its syntax rules. This ensures that code blocks are visually distinct and easy to follow without relying on parentheses or other delimiters.

Conclusion

In each case:

  • Lisp's reliance on heavy nesting and uniform syntax creates challenges related to readability, cognitive load, and debugging.
  • Python addresses these issues by using features like indentation, infix operators, keywords (if, for), and breaking logic into smaller steps. This comparison highlights why many developers perceive Lisp's syntax as harder to read while appreciating Python's more structured approach!

Answer from Perplexity: https://www.perplexity.ai/search/8f98d153-997c-4cca-8236-2ea8c2149ca6?utm_source=copy_output

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