Martijn Dwars martijndwars

This document explains some aspects of Spoofax that we got questions about. It also describes some common mistakes and pitfalls. Finally, it describes Spoofax' internals more in-depth, with the goal of clarifying some of its behaviour.

Disambiguation tests. Disambiguation tests are tests of the form test ... [[1+2+3]] parse to [[(1+2)+3]]. SPT will parse both fragments and compare the ASTs. A common mistake is to introduce a constructor when parsing parenthesized expressions, e.g. Exp.Parens = <(<Exp>)>. When you make this mistake, the AST for the second fragment will contain Parens nodes and hence be different from the AST for the first fragment.

The solution is to not introduce a constructor. This is semantically cleaner anyway, as a Parens node does not convey any semantic content (remember: the AST is a tree, not a string, and as such it already encodes what you would otherwise achieve by adding parenthesis). Spoofax will show an error "Missing bracket attribute or constructor name" whi

	crypto = require 'crypto'

	class RC4
	constructor: (@key, drop) ->
	@cipher = crypto.createCipher 'rc4', key
	if drop > 0
	this.cipher.update new Buffer drop

	encrypt: (data) ->
	@cipher.update data

	p <- 1/2;
	u <- 2;
	d <- 1/u;
	r <- 1/4;

	v <- function(n, s) {
	if (n == 3) {
	return(pmax(s-10, 0));
	}

	object OptionValue {
	val N = 2
	val u: Double = 2
	val d: Double = 1/u

	def main(args: Array[String]): Unit = {
	println(v(0,4,(s: Double) => 0.0 max (4.0-s)))
	}

	def v(n: Double, s: Double, g: Double => Double): Double =

	/**
	* Given a length m and elements xs, generate all combinations of length m
	* from the elements in xs.
	*
	* @type (int, List(a)) -> List(List(a))
	*/
	combinations:
	(0, _) -> [[]]

	combinations:

	module names

	namespaces

	Global

	binding rules

	Class(c, _):
	defines Global c

	import java.security.PublicKey;

	public class Encrypted {
	private final PublicKey publicKey;
	private final byte[] salt;
	private final byte[] ciphertext;

	public Encrypted(final PublicKey publicKey, final byte[] salt, final byte[] ciphertext) {
	this.publicKey = publicKey;
	this.salt = salt;

	org.metaborg.core.analysis.AnalysisException: Analysis for eclipse:///MiniJava/tests/lab6/constraints/main-class/main-class-instantiation.spt failed
	at org.metaborg.spoofax.core.analysis.legacy.StrategoAnalyzer.analyze(StrategoAnalyzer.java:203) ~[org.metaborg.spoofax.core_2.0.0.20160612-002403-master.jar:na]
	at org.metaborg.spoofax.core.analysis.legacy.StrategoAnalyzer.analyze(StrategoAnalyzer.java:99) ~[org.metaborg.spoofax.core_2.0.0.20160612-002403-master.jar:na]
	at org.metaborg.spoofax.core.analysis.legacy.StrategoAnalyzer.analyze(StrategoAnalyzer.java:1) ~[org.metaborg.spoofax.core_2.0.0.20160612-002403-master.jar:na]
	at org.metaborg.core.analysis.AnalysisService.analyze(AnalysisService.java:27) ~[org.metaborg.core_2.0.0.20160612-002403-master.jar:na]
	at org.metaborg.spoofax.core.analysis.SpoofaxAnalysisService.analyze(SpoofaxAnalysisService.java:17) ~[org.metaborg.spoofax.core_2.0.0.20160612-002403-master.jar:na]
	at org.metaborg.spoofax.core.analysis.SpoofaxAnalysisService.analyze(SpoofaxAnalysis

	### Keybase proof

	I hereby claim:

	* I am martijndwars on github.
	* I am martijndwars (https://keybase.io/martijndwars) on keybase.
	* I have a public key ASCjzLNxLHlexZfNDGu9sVMBtIxE-kax2HPwmJh5rPWDtgo

	To claim this, I am signing this object:

	$(function () {
	if ('serviceWorker' in navigator) {
	navigator.serviceWorker.register('/sw.js').then(initialiseState);
	} else {
	console.warn('Service workers are not supported in this browser.');
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	function initialiseState() {
	if (!('showNotification' in ServiceWorkerRegistration.prototype)) {