Jade mixin used in "each"/"for" loop gives JS_Parse_Error

Jade mixin used in "each"/"for" loop gives JS_Parse_Error

Title: Jade mixin used in "each"/"for" loop gives JS_Parse_Error
Question: What is the root cause of -and fix for- the error being thrown
by this code?
Goal: Use Jade's 'mixin' capability with its 'each' iteration construct to
populate the view with data stored in an array.
Background: Assuming the issue is with syntax for iteration, I've tried
many permutations ('each'|'for'; commas|no commas;
(placeholder|expression) interpolation, escaped|unescaped; varying the
whitespace)... and even prayer. I am all out of ideas.
Code:
The Jade view (file named "mixin_with_args.jade" placed in $APP_ROOT/views/):
heroes = [
{name: 'Fooman', role: 'captain'},
{name: 'Barman', role: 'entertainer'},
{name: 'Napman', role: 'hacker'},
{name: 'Zipman', role: 'collector'}
]
mixin heroes_list(hero)
if hero.role == 'captain'
li Captain #{hero.name}
else
li #{hero.name}
ul
each hero in heroes
+heroes_list(hero)
The express.js server "app.js" (placed in $APP_ROOT):
var express = require('express');
var routes = require('./routes');
var user = require('./routes/user');
var http = require('http');
var path = require('path');
var app = express();
// all environments
app.set('port', process.env.PORT || 3000);
app.set('views', __dirname + '/views');
app.set('view engine', 'jade');
app.use(express.favicon());
app.use(express.logger({ format: ':remote-addr :method :url' }));
app.use(express.bodyParser());
app.use(express.static('./public'));
app.use(app.router);
app.locals.pretty = true;
app.use(express.errorHandler({ dumpExceptions: true , showStack: true }));
app.get('/', function(req, res) {
res.render('mixin_with_args', {
});
});
http.createServer(app).listen(app.get('port'), function(){
console.log('Express server listening on port ' + app.get('port'));
});
Error message and stack trace are:
500 Unexpected token: punc ()) (line: 4, col: 15, pos: 185) Error at new
JS_Parse_Error
(/Users/lucky/myapp/node_modules/jade/node_modules/with/node_modules/uglify-js/lib/parse.js:196:18)
at js_error
(/Users/lucky/myapp/node_modules/jade/node_modules/with/node_modules/uglify-js/lib/parse.js:204:11)
at croak
(/Users/lucky/myapp/node_modules/jade/node_modules/with/node_modules/uglify-js/lib/parse.js:636:9)
at token_error
(/Users/lucky/myapp/node_modules/jade/node_modules/with/node_modules/uglify-js/lib/parse.js:644:9)
at unexpected
(/Users/lucky/myapp/node_modules/jade/node_modules/with/node_modules/uglify-js/lib/parse.js:650:9)
at expr_atom
(/Users/lucky/myapp/node_modules/jade/node_modules/with/node_modules/uglify-js/lib/parse.js:1119:13)
at maybe_unary
(/Users/lucky/myapp/node_modules/jade/node_modules/with/node_modules/uglify-js/lib/parse.js:1287:19)
at expr_ops
(/Users/lucky/myapp/node_modules/jade/node_modules/with/node_modules/uglify-js/lib/parse.js:1322:24)
at maybe_conditional
(/Users/lucky/myapp/node_modules/jade/node_modules/with/node_modules/uglify-js/lib/parse.js:1327:20)
at maybe_assign
(/Users/lucky/myapp/node_modules/jade/node_modules/with/node_modules/uglify-js/lib/parse.js:1351:20)
at new JS_Parse_Error
(/Users/lucky/myapp/node_modules/jade/node_modules/with/node_modules/uglify-js/lib/parse.js:196:18)
at js_error
(/Users/lucky/myapp/node_modules/jade/node_modules/with/node_modules/uglify-js/lib/parse.js:204:11)
at croak
(/Users/lucky/myapp/node_modules/jade/node_modules/with/node_modules/uglify-js/lib/parse.js:636:9)
at token_error
(/Users/lucky/myapp/node_modules/jade/node_modules/with/node_modules/uglify-js/lib/parse.js:644:9)
at unexpected
(/Users/lucky/myapp/node_modules/jade/node_modules/with/node_modules/uglify-js/lib/parse.js:650:9)
at expr_atom
(/Users/lucky/myapp/node_modules/jade/node_modules/with/node_modules/uglify-js/lib/parse.js:1119:13)
at maybe_unary
(/Users/lucky/myapp/node_modules/jade/node_modules/with/node_modules/uglify-js/lib/parse.js:1287:19)
at expr_ops
(/Users/lucky/myapp/node_modules/jade/node_modules/with/node_modules/uglify-js/lib/parse.js:1322:24)
at maybe_conditional
(/Users/lucky/myapp/node_modules/jade/node_modules/with/node_modules/uglify-js/lib/parse.js:1327:20)
at maybe_assign
(/Users/lucky/myapp/node_modules/jade/node_modules/with/node_modules/uglify-js/lib/parse.js:1351:20)