Initial data commit

Task/S-expressions/JavaScript/s-expressions-1.js

@@ -0,0 +1,38 @@
+String.prototype.parseSexpr = function() {
+	var t = this.match(/\s*("[^"]*"|\(|\)|"|[^\s()"]+)/g)
+	for (var o, c=0, i=t.length-1; i>=0; i--) {
+		var n, ti = t[i].trim()
+		if (ti == '"') return
+		else if (ti == '(') t[i]='[', c+=1
+		else if (ti == ')') t[i]=']', c-=1
+		else if ((n=+ti) == ti) t[i]=n
+		else t[i] = '\'' + ti.replace('\'', '\\\'') + '\''
+		if (i>0 && ti!=']' && t[i-1].trim()!='(' ) t.splice(i,0, ',')
+		if (!c) if (!o) o=true; else return
+	}
+	return c ? undefined : eval(t.join(''))
+}
+
+Array.prototype.toString = function() {
+	var s=''; for (var i=0, e=this.length; i<e; i++) s+=(s?' ':'')+this[i]
+	return '('+s+')'
+}
+
+Array.prototype.toPretty = function(s) {
+	if (!s) s = ''
+	var r = s + '(<br>'
+	var s2 = s + Array(6).join('&nbsp;')
+	for (var i=0, e=this.length; i<e; i+=1) {
+		var ai = this[i]
+		r += ai.constructor != Array ? s2+ai+'<br>' : ai.toPretty(s2)
+	}
+	return r + s + ')<br>'
+}
+
+var str = '((data "quoted data" 123 4.5)\n (data (!@# (4.5) "(more" "data)")))'
+document.write('text:<br>', str.replace(/\n/g,'<br>').replace(/ /g,'&nbsp;'), '<br><br>')
+var sexpr = str.parseSexpr()
+if (sexpr === undefined)
+	document.write('Invalid s-expr!', '<br>')
+else
+	document.write('s-expr:<br>', sexpr, '<br><br>', sexpr.constructor != Array ? '' : 'pretty print:<br>' + sexpr.toPretty())

Task/S-expressions/JavaScript/s-expressions-2.js

@@ -0,0 +1,138 @@
+(() => {
+    "use strict";
+
+    // ------------------ S-EXPRESSIONS ------------------
+    const main = () => {
+        const expr = [
+            "((data \"quoted data\" 123 4.5)",
+            "  (data (!@# (4.5) \"(more\" \"data)\")))"
+        ].join("\n");
+
+        const [parse, residue] = parseExpr(
+            tokenized(expr)
+        );
+
+        return 0 < residue.length ? (
+            `Unparsed tokens: ${JSON.stringify(residue)}`
+        ) : 0 < parse.length ? ([
+            JSON.stringify(parse, null, 2),
+            "Reserialized from parse:",
+            parse.map(serialized).join(" ")
+        ].join("\n\n")) : "Could not be parsed";
+    };
+
+    // ---------------- EXPRESSION PARSER ----------------
+
+    // parseExpr [String] -> ([Expr], [String])
+    const parseExpr = tokens =>
+        // A tuple of (parsed trees, residual tokens)
+        // derived from a list of tokens.
+        until(finished)(readToken)([
+            [], tokens
+        ]);
+
+
+    // finished :: ([Expr], [String]) -> Bool
+    const finished = ([, tokens]) =>
+        // True if no tokens remain, or the next
+        // closes a sub-expression.
+        0 === tokens.length || ")" === tokens[0];
+
+
+    // readToken :: ([Expr], [String]) -> ([Expr], [String])
+    const readToken = ([xs, tokens]) => {
+        // A tuple of enriched expressions and
+        // depleted tokens.
+        const [token, ...ts] = tokens;
+
+        // 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)];
+        })() : ")" === token ? (
+            [xs, token]
+        ) : [xs.concat(atom(token)), ts];
+    };
+
+    // ------------------- ATOM PARSER -------------------
+
+    // atom :: String -> Expr
+    const atom = s =>
+        0 < s.length ? (
+            isNaN(s) ? (
+                "\"'".includes(s[0]) ? (
+                    s.slice(1, -1)
+                ) : {
+                    name: s
+                }
+            ) : parseFloat(s, 10)
+        ) : "";
+
+
+    // ------------------ TOKENIZATION -------------------
+
+    // tokenized :: String -> [String]
+    const tokenized = s =>
+        // Brackets and quoted or unquoted atomic strings.
+        quoteTokens("\"")(s).flatMap(
+            segment => "\"" !== segment[0] ? (
+                segment.replace(/([()])/gu, " $1 ")
+                .split(/\s+/u)
+                .filter(Boolean)
+            ) : [segment]
+        );
+
+
+    // quoteTokens :: Char -> String -> [String]
+    const quoteTokens = q =>
+        // Alternating unquoted and quoted segments.
+        s => s.split(q).flatMap(
+            (k, i) => even(i) ? (
+                Boolean(k) ? (
+                    [k]
+                ) : []
+            ) : [`${q}${k}${q}`]
+        );
+
+    // ------------------ SERIALIZATION ------------------
+
+    // serialized :: Expr -> String
+    const serialized = e => {
+        const t = typeof e;
+
+        return "number" === t ? (
+            `${e}`
+        ) : "string" === t ? (
+            `"${e}"`
+        ) : "object" === t ? (
+            Array.isArray(e) ? (
+                `(${e.map(serialized).join(" ")})`
+            ) : e.name
+        ) : "?";
+    };
+
+
+    // --------------------- GENERIC ---------------------
+
+    // even :: Int -> Bool
+    const even = n =>
+        // True if 2 is a factor of n.
+        0 === n % 2;
+
+
+    // until :: (a -> Bool) -> (a -> a) -> a -> a
+    const until = p =>
+        // The value resulting from repeated applications
+        // of f to the seed value x, terminating when
+        // that result returns true for the predicate p.
+        f => {
+            const go = x =>
+                p(x) ? x : go(f(x));
+
+            return go;
+        };
+
+    return main();
+})();