What is Colon in Clojure?

What is Colon in Clojure?

The double colon is there to fully qualify keywords with your current namespace. This is intended to avoid name clashes for keywords which are meaningful for different libraries. Without fully qualified keywords you might accidentally overwrite some values in a map and break compatibility with a library.

What are Symbols in Clojure?

In Common Lisp, a “symbol” is a location in memory, a place where data can be stored. The “value” of a symbol is the data stored at that location in memory. In Clojure, a “symbol” is just a name.

Is Clojure better than Common Lisp?

Common lisp comparatively faster than Clojure as it uses compilers like SBCL which makes common lisp faster than C programming or any other low-level programming language and it also provides a variety of different libraries for different concepts that can be included in the program for easy execution.

What does FN mean in Clojure?

Function Literals. An anonymous function is a function without a name. In Clojure these can be defined in two ways, fn and the literal #(… ​) . Creating a function with defn immediately binds it to a name, fn just creates a function.

What does cons do in Clojure?

Note that Cons objects in Clojure are different from cons cells in other Lisps — in most Lisps, a “cons” is just an object which holds 2 pointers to other arbitrary objects. So you can use cons cells to build trees, and so on. A Clojure Cons takes an arbitrary Object as head, and an ISeq as tail.

Why should I use Clojure?

Clojure is being used extensively for processing large volumes of data. It is very well suited to data mining/commercial-AI (ie: Runa) and large scale predictions (aka WeatherBill). Clojure’s concurrency story really helps in these data heavy domains where parallel processing is simply the only answer.

Is clojure a Scheme?

Clojure was designed for concurrency. As a result, Scheme has a reputation of being minimal and elegant, Common Lisp of being powerful and paradigm-agnostic (functional, OO, whatever), and Clojure of favoring functional programming.

Is clojure Common Lisp?

Clojure is a dialect of Lisp, and shares with Lisp the code-as-data philosophy and a powerful macro system. On the other hand, Common Lisp is detailed as “The modern, multi-paradigm, high-performance, compiled, ANSI-standardized descendant of the long-running family of Lisp programming languages”.

What is lazy sequence in Clojure?

Lazy sequences are produced by functions. Such functions either use the clojure. clojure. core/lazy-seq accepts one or more forms that produce a sequence of nil (when the sequence is fully realized) and returns a seqable data structure that invokes the body the first time the value is needed and then caches the result.

Is Clojure any good?

Clojure is especially suited to concurrency tasks. It was built from the ground up to be an awesome language for concurrency, and it’s STM system is fantastic. If you need to do some hardcore concurrency related stuff, Clojure might be especially suited to that task.

What types of data does CL Clojure support?

Clojure also supports the Java syntax for octal (prefix 0 ), hexadecimal (prefix 0x) and arbitrary radix (prefix with base then r) integers. Ratios are provided as their own type combining a numerator and denominator. Floating point values are read as double-precision 64-bit floats, or arbitrary precision with an M suffix.

What are the different types of symbols in Clojure?

There are three special symbols that are read as different types – nil is the null value, and true and false are the boolean values. Symbols that start with a leading colon are called keywords. Keywords always evaluate to themselves and are frequently used as enumerated values or attribute names in Clojure.

How do I define VARs in Clojure?

In most actual Clojure code, vars should refer to either a constant value or a function, but it’s common to define and re-define them for convenience when working at the REPL. Note the return value above is #’user/x – that’s the literal representation for a var: #’ followed by the namespaced symbol. user is the default namespace.

How can I force arbitrary precision in Clojure?

A trailing N can be used to force arbitrary precision. Clojure also supports the Java syntax for octal (prefix 0 ), hexadecimal (prefix 0x) and arbitrary radix (prefix with base then r) integers. Ratios are provided as their own type combining a numerator and denominator.