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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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building s-expression with boost::proto

I'm trying to build s-expression objects using boost::proto with the following terminals: typedef proto::terminal< const char* >::type string_term_t; typedef proto::terminal< uint32_t >::type uint32_term_t; typedef…
lurscher
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Non-intrusive extension of Rcpp with Rcpp::traits::Exporter

I am writing an Rcpp package with classes containing base Rcpp objects that are non-intrusively exported to C++ types (see Extending Rcpp by Eddelbuettel and Francois, and this helpful vignette by coatless). What this means is that if I have a class…
zdebruine
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`Rcpp::wrap` and `Rcpp::as` for external classes that use Rcpp namespace classes

How can Rcpp::wrap and Rcpp::as methods be written for classes that contain an Rcpp class? For example, the following .cpp file compiles using sourceCpp(): #include namespace Rcpp { class myVector { public: NumericVector data; …
zdebruine
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Why does my Prolog S-expression tokenizer fail on its base case?

To learn some Prolog (I'm using GNU Prolog) and grok its parsing abilities, I am starting by writing a Lisp (or S-expression, if I'm being exact) tokenizer, which given a set of tokens like ['(', 'f', 'o', 'o', ')'] should produce ['(', 'foo', ')'].…
Caspian Ahlberg
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What's causing my OCaml S-expression parser to fail?

I am working on making a Lisp interpreter in OCaml. I naturally started with the front-end. So far I have an S-expression parsing algorithm that works most of the time. For both simple S-expressions like (a b) and ((a b) (c d)) my function,…
Caspian Ahlberg
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How to select successive words backwards with `C-M-SPC` (`mark-sexp`)?

I tried to select three successive words using C-M-SPC SPC SPC. The quick brown fox jumps over the lazy dog Repeating SPC selects additional words in a forward direction. How can I do the same thing in a backward direction, e.g. starting after lazy…
AbstProcDo
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Why doesn't this clojure code using go blocks work?

(defn ff [t] (let [ch (chan 5)] (map (fn [i] (println i)) t) (go (>! ch 0)))) (ff [1 2 3 4 5]) The mapping function body isn't being executed. If I remove the go block in the last line, it works as expected. This function gives…
saga
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turn lisp command to nested lists in python

I am building a lisp parser in python 3.7. Imagine I have this list program as a string "(begin (define r 10) (* pi (* r r)))" which I tokenize using: def tokenize(string): return string.replace('(', ' ( ').replace(')', ' )…
Tytire Recubans
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Declare s-expressions types in TypeScript

TypeScript client communicates with server using s-expressions, encoded as JSON. For simplicity let's assume that expression alphabet consist of one terminator function 'rx' which accepts string as parameter and functions 'and', 'or' which accept…
Andrew Lanin
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How to highlight region enclosed by parentheses in vim?

Is there a way to automatically highlight the region enclosed by parentheses when the cursor goes over that region? Take the following text as an example: (define (example x) (cond ((string? x) (display x)) (else (error "Bad"…
Flux
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How do I use Jane Street's Sexplib's pretty-printer functions?

I'm a new OCaml-learner, and I'm trying to print some S-expressions, using Jane Street's Sexplib (included with Core): let rec print_source ?(channel = stdout) sexps = let formatter = Format.formatter_of_out_channel channel in Sexp.pp_hum…
ELLIOTTCABLE
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Parse lists which can contain parentheses with ANTLR4

Lets say I want to create a grammar that is similar to Lisp where all expressions are between open and close parentheses. For example: (+ 1 2) I also want the grammar to be able to parse the string ('(def foo)) to a parse tree which is similar to…
tymm
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How to represent a simple document as an s-exp?

I'm trying to understand how to express a simple document in an s-expression. Here's what I mean. Let's say I have this simple html structure:

Document Title

Paragraph with some text.

Paragraph with some bold…

fraxture
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emacs: Evaluate buffer contents as an s-expression?

Suppose I have an emacs buffer which contains the following text: '(1 2 3) I would like to evaluate the contents of this buffer as a lisp exprerssion (an s-expression). If I invoke (eval (buffer-string)), the result simply gets evaluated as the…
HippoMan
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How to Match Parenthesis to Parse a S-Expression?

I am trying to create a function that does the following: Assuming that the code input is "(a 1 2 (b 3 4 5 (c 6) |7) 8 9)" where the pipe | symbol is the position of the cursor, the function returns: a String "b 3 4 5 (c 6) 7" representing the code…
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