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Clojure uses a number of special characters such as
^String #(xyz ...)%&#_(some form here)>!and many more. How can I search for documentation for these special characters, given that Google et al mostly ignore special characters in web pages and search strings?
744
->> is the "thread-last" macro. It evaluates one form and passes it as the last argument into the next form. Your code is the equivalent of: (reduce str (interpose ", " (map :subject scenes)))
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. It has no value.
List is a structure used to store a collection of data items. In Clojure, the List implements the ISeq interface. Lists are created in Clojure by using the list function.
def is a special form that associates a symbol (x) in the current namespace with a value (7). This linkage is called a var . 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.
This question and others have raised an important topic: it can often be difficult and frustrating to find documentation on special characters used in Clojure source code.
The first place to look is the Clojure docs themselves. There is even a special page devoted to this topic:
Many of the special characters are known as Reader Literals, which also have a documentation page:
You can also find hints regarding special chars & their usage on:
Finally, the search engine SymbolHound.com can search for special symbols that Google & others ignore. For example, consider this Clojure code:
(defn lines
"Given an open reader, return a lazy sequence of lines"
[^java.io.BufferedReader reader]
(take-while identity (repeatedly #(.readLine reader))))
How could we search for the meaning of ^java.io.BufferedReader on the 3rd line? If we go to SymbolHound and use the search string clojure ^ we get back:
270 results found for clojure ^
and many more answers.
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They're all described here:
https://clojure.org/guides/weird_characters
You can also add more by contributing:
https://clojure.org/community/contributing_site
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