Merge pull request #864 from null-a/check-extra-args-at-sample

More sample/dist arg checks

scripts/distHeader

@@ -33,7 +33,7 @@ var helpers = {
 };
 
 var t = _.mapValues({
-  ctor: 'var <%= name %> = function(params) { return util.jsnew(dists.<%= name %>, params); };',
+  ctor: 'var <%= name %> = dists.make<%= name %>;',
   helper: [
     'var <% print(downcaseInitial(name)) %> = function(<% print(fnParams(params)) %>) {',
     '  var params = util.isObject(arg0) ? arg0 : {<% print(args2Obj(params)) %>};',

src/dists.ad.js

@@ -1646,6 +1646,26 @@ var distributions = {
   Delta: Delta
 };
 
+// For each distribution type, we create a WebPPL function that
+// creates instances of that type. We include the argument check here
+// to avoid the expensive slicing of arguments that would be required
+// if it were anywhere else. e.g. In the WebPPL distribution header or
+// in the distribution's JS constructor.
+
+var wpplFns = _.chain(distributions)
+    .mapValues(function(ctor) {
+      return function(s, k, a, params) {
+        if (arguments.length > 4) {
+          throw new Error('Too many arguments. Distributions take at most one argument.');
+        }
+        return k(s, new ctor(params));
+      };
+    })
+    .mapKeys(function(ctor, name) {
+      return 'make' + name;
+    })
+    .value();
+
 module.exports = _.assign({
   // rng
   betaSample: betaSample,
@@ -1664,4 +1684,4 @@ module.exports = _.assign({
   squishToProbSimplex: squishToProbSimplex,
   isDist: isDist,
   metadata: metadata
-}, distributions);
+}, distributions, wpplFns);

src/header.js

@@ -84,6 +84,14 @@ module.exports = function(env) {
     if (!dists.isDist(dist)) {
       throw new Error('sample() expected a distribution but received \"' + JSON.stringify(dist) + '\".');
     }
+    for (var name in options) {
+      if (name !== 'guide' &&
+          name !== 'driftKernel' &&
+          name !== 'noAutoGuide' &&
+          name !== 'reparam') {
+        throw new Error('Unknown option "' + name + '" passed to sample.');
+      }
+    }
     return env.coroutine.sample(s, k, a, dist, options);
   };
 

src/util.js

@@ -297,10 +297,6 @@ function jsthrow(obj) {
   throw obj;
 }
 
-function jsnew(ctor, arg) {
-  return new ctor(arg);
-}
-
 // Equivalent to Number.isInteger(), which isn't available in the
 // version of phantom.js used on Travis at the time of writing.
 function isInteger(x) {
@@ -404,7 +400,6 @@ module.exports = {
   warn: warn,
   resetWarnings: resetWarnings,
   error: error,
-  jsnew: jsnew,
   jsthrow: jsthrow,
   isInteger: isInteger,
   isObject: isObject,