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Questions tagged [s-expression]

S-expressions are a notation for nested list or tree-structured data, popularized by the Lisp programming language.

In computing, s-expressions, sexprs or sexps (for "symbolic expression") are a notation for nested list (tree-structured) data, invented for and popularized by the programming language which uses them for source code as well as data.

Source: Wikipedia

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Lisp: list vs S-expression

I'm new to Lisp. I encountered 2 terms "list" and "S-expression". I just can't distinguish between them. Are they just synonyms in Lisp?
Dagang
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Why are most S-Expression languages dynamically typed?

How come most Lisps and Schemes are dynamically typed? Does static typing not mix with some of their common features?
keiter
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Do you know of a language with Static Type checking where Code is Data?

Can you name languages with static type checking (like Java) and where code is data (like in LISP)? I mean both things in one language.
Dzmitry Lahoda
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What advantage does common lisp reader macros have that Clojure does not have?

I have been using Clojure alot recently but I still don't understand what functionality I do not get that common lisp reader macros provide. Can explain explain this to me in simple terms?
yazz.com
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How do I manipulate parse trees?

I've been playing around with natural language parse trees and manipulating them in various ways. I've been using Stanford's Tregex and Tsurgeon tools but the code is a mess and doesn't fit in well with my mostly Python environment (those tools are…
guidoism
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Why are s-expressions not used compared to JSON and XML?

Why are s-expressions popularized by Lisp not considered as an option relative to JSON and XML? Is there some defect to them that made the Lisp s-expression never catch on?
user782220
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Parsing S-Expressions in Python

Are there any python modules available for parsing and manipulating symbolic expressions in Python similar to how Lisp expressions are evaluated?
adinsa
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Building Lisp/Scheme-like parse tree with flex/bison

I was trying to parse simple Lisp/scheme-like code E.g. (func a (b c d) ) and build a tree from it, I could do the parsing in C without using bison (i.e, using only flex to return tokens and building the tree with recursion). But, with bison…
Ani
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Is there a C# utility for matching patterns in (syntactic parse) trees?

I'm working on a Natural Language Processing (NLP) project in which I use a syntactic parser to create a syntactic parse tree out of a given sentence. Example Input: I ran into Joe and Jill and then we went shopping Example Output: [TOP [S [S [NP…
Gilad Gat
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Slurpage and barfage in Clojure

I am using vim-sexp and vim-sexp-mappings-for-regular-people plugins for editing Clojure files. I don't quite understand what slurp and barf commands do exactly. I tried playing with them, and it seems that they insert/remove forms at the…
siphiuel
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Is there something similar to Nokogiri for parsing Ruby code?

Nokogiri is awesome. I can do things like #css('.bla') which will return the first matching element. Right now we need to do some parsing of Ruby source code - finding all methods within a class etc. We're using the ruby_parser gem, but all it does…
Suan
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Write C as s-expressions

I want to write C in s-expressions and use compile-time macros. Does anybody know of anything that does this? It should translate the s-expressions into standard C.
Ollie Saunders
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How to construct a named list (a SEXP) to be returned from the C function called with .Call()?

I call C code via .Call("foo", ), where foo calls other C functions, computes the result and returns it. The result is a list of length 3 and I would like to name this list. To this end, foo does this: /* Construct result list from variables…
Marius Hofert
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How to safely read untrusted Clojure code (not just some serialized data)?

(def evil-code (str "(" (slurp "/mnt/src/git/clj/clojure/src/clj/clojure/core.clj") ")" )) (def r (read-string evil-code )) Works, but unsafe (def r (clojure.edn/read-string evil-code)) RuntimeException Map literal must contain an even number of…
Vi.
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What are improper lists for?

This is a follow-up of my previous question: Why do we need nil? Clearly, proper lists are used most of the time. But what is the purpose of an improper list?
day
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