S-expressions: Difference between revisions
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=={{header|JavaScript}}==
(for a '''bug-fix''' concerning \" and \n in strings see the [[Talk:S-expressions#JavaScript_version_bugfix_for_%5C%22_and_%5Cn_in_strings|Discussion]])
===Procedural===
<syntaxhighlight lang="javascript">String.prototype.parseSexpr = function() {
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"((data \"quoted data\" 123 4.5)",
" (data (!@# (4.5) \"(more\" \"data)\")))"
]
const [parse, residue] = parseExpr(
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);
return 0 < residue.length
? `Unparsed tokens: ${JSON.stringify(residue)}`
parse.map(serialized).join(" ")
].join("\n\n")) : "Could not be parsed";▼
.join("\n\n")
};
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// An open bracket introduces recursion over
// a sub-expression to define a sub-list.
return "(" === token
const [expr, rest] = parseExpr(ts);
return [xs.concat([expr]), rest.slice(1)];
: [xs.concat(atom(token)), ts];
};
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// atom :: String -> Expr
const atom = s =>
0 < s.length
? isNaN(s)
? "\"'".includes(s[0])
? s.slice(1, -1)
:
▲ ) : parseFloat(s, 10)
▲ ) : "";
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// Brackets and quoted or unquoted atomic strings.
quoteTokens("\"")(s).flatMap(
segment => "\"" !== segment[0]
? segment.replace(/([()])/gu, " $1 ")
.split(/\s+/u)
.filter(Boolean)
);
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// Alternating unquoted and quoted segments.
s => s.split(q).flatMap(
(k, i) => even(i)
? [k]
);
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const t = typeof e;
return "number" === t
? `${e}`
? `"${e}"`
? Array.isArray(e)
? `(${e.map(serialized).join(" ")})`
};
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f => {
const go = x =>
p(x)
? x
: go(f(x));
return go;
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((data "quoted data" 123 4.5) (data (!@# (4.5) "(more" "data)")))</pre>
=={{header|jq}}==
{{works with|jq}}
'''Also works with gojq, the Go implementation of jq'''
[[Category:PEG]]
This entry is based on a Parsing Expression Grammar (PEG) for S-expressions.
The idea is to pass a JSON object `{remainder:_, result:_ }` through a
jq pipeline corresponding to a PEG for S-expressions, consuming the
text in `.remainder` and building up `.result`.
For further details about this approach, see e.g.
[https://github.com/stedolan/jq/wiki/Parsing-Expression-Grammars jq as a PEG Engine].
<syntaxhighlight lang=jq>
# PEG infrastructure
def star(E): ((E | star(E)) // .) ;
### Helper functions:
# Consume a regular expression rooted at the start of .remainder, or emit empty;
# on success, update .remainder and set .match but do NOT update .result
def consume($re):
# on failure, match yields empty
(.remainder | match("^" + $re)) as $match
| .remainder |= .[$match.length :]
| .match = $match.string;
def parse($re):
consume($re)
| .result = .result + [.match] ;
def parseNumber($re):
consume($re)
| .result = .result + [.match|tonumber] ;
def eos: select(.remainder == "");
# whitespace
def ws: consume("[ \t\r\n]*");
def box(E):
((.result = null) | E) as $e
| .remainder = $e.remainder
| .result += [$e.result] # the magic sauce
;
# S-expressions
# Input: a string
# Output: an array representation of the input if it is an S-expression
def SExpression:
def string: consume("\"") | parse("[^\"]") | consume("\"");
def identifier: parse("[^ \t\n\r()]+");
def decimal: parseNumber("[0-9]+([.][0-9]*)?");
def hex: parse("0x[0-9A-Fa-f]+") ;
def number: hex // decimal;
def atom: ws | (string // number // identifier);
def SExpr: ws | consume("[(]") | ws | box(star(atom // SExpr)) | consume("[)]");
{remainder: .} | SExpr | ws | eos | .result;
SExpression
</syntaxhighlight>
'''Invocation:'''
<pre>
cat << EOF |
((data "quoted data" 123 4.5)
(data (!@# (4.5) "(more" "data)")))
EOF
jq -Rsc -f s-expression.jq
</pre>
{{output}}
<pre>
[[["data","\"quoted","data\"",123,4.5],["data",["!@#",[4.5],"\"",["more\"","\"data"],"\""]]]]
</pre>
=={{header|Julia}}==
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=={{header|OCaml}}==
You may be interested
▲You may be interested by [https://realworldocaml.org/v1/en/html/data-serialization-with-s-expressions.html this chapter of the book Real World Ocaml]
The file <code>SExpr.mli</code> containing the interface:
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{{libheader|Wren-pattern}}
{{libheader|Wren-fmt}}
<syntaxhighlight lang="
import "./fmt" for Fmt
var INDENT = 2
| |||