One of the basic ideas when editing Lisp text is, that you can select a list by (double-) clicking on the parentheses (or by using a key command when the cursor is inside the expression or on the parentheses). Then you can cut/copy the expression and paste it …

In Lisp and other languages that use S-expressions for syntax, the parentheses are primarily for the benefit of the compiler, while layout and indentation (which are ignored by the compiler) are for the benefit of programmers.

2015年2月17日 · In other languages, not Lisps, parenthesis are normally used to group operators and so are optional in many cases. But in Lisp parenthesis are always meaningful. There may not be extra or optional parenthesis. Most often parenthesis around expression mean function or macro application:

Making a gross simplification, the parentheses in most parts of a Lisp program are delimiting arguments passed to functions—just like in C-like languages—and not delimiting statement blocks. For the same reasons we tend to keep the parentheses bounding a function call in C close around the arguments, so too do we do the same in Lisp, with ...

When people are first exposed to Lisp, they often find the use of parentheses strange and annoying. Why are the parentheses there? Is it bad design, a feature that could easily be removed or reduced? Or is there some good reason Lisp is full of parentheses, and other programming languages are not?

Parentheses in Lisp. Every parenthesis in an S-expression has significance. (a b c) is different from (a (b c)) or ((a b) c). To call a zero-argument function, put its name in parentheses: (read) But not ((read)) The empty list can be denoted ( ) or NIL. Parentheses should always be balanced. (+ 3 (* 4 5) is an incomplete S-expression.

The key to formatting Lisp code is to indent it properly. The indentation should reflect the structure of the code so that you don't need to count parentheses to see what goes with what. In general, each new level of nesting gets indented a bit more, and, if line breaks are necessary, items at the same level of nesting are lined up.

This library defines a face named parenthesis used just for parentheses. The originally intended purpose of this face is to make parentheses less visible in Lisp code by dimming them. We lispers probably don’t need to be constantly made aware of the existence of the parentheses.

Lisp code is meant to be simple and elegant; if you find yourself staring into an impenetrable confusion of parenthesis-chaos, your code is too complex for you to manage. Using techniques for decomposition and refactoring also presented in this book, you will learn how to write beautiful and elegant programs as well as the Common Lisp language ...

2025年2月7日 · “So many parentheses! I can’t read it. Why don’t they just use braces like other languages?” What these people fail to understand is that the Lisp “syntax” is actually the parse tree for the code. That means, among other things, that those parentheses—or some similar symbol—is absolutely necessary.