add a json test and get it running

there are a few areas where we fail (decimal usage, and formatting complex numbers)
so those specific lines are commented out.

The changes in src were necessary to get the test to run to completion with -n.
Finally, we skip the test when -x is present because pypa doesn't parse unicode
literals correctly.

src/asm_writing/rewriter.h

@@ -123,7 +123,7 @@ template <class T> class LocMap {
 private:
     static const int N_REGS = 16;
     static const int N_XMM = 16;
-    static const int N_SCRATCH = 16;
+    static const int N_SCRATCH = 32;
     static const int N_STACK = 16;
 
     T map_reg[N_REGS];

src/codegen/irgen/irgenerator.cpp

@@ -1863,6 +1863,8 @@ private:
 
                     // Currently we represent 'undef's as 'i16 undef'
                     val = emitter.getBuilder()->CreateIntToPtr(val, g.llvm_value_type_ptr);
+                } else if (var->getType() == CLOSURE) {
+                    ptr = emitter.getBuilder()->CreateBitCast(ptr, g.llvm_closure_type_ptr->getPointerTo());
                 } else {
                     assert(val->getType() == g.llvm_value_type_ptr);
                 }

test/tests/json_test.py

+# skip-if: '-x' in EXTRA_JIT_ARGS
+
+from StringIO import StringIO
+import json
+
+# encoding basic python object hierarchies
+print 1, json.dumps("")
+print 2, json.dumps(['foo', {'bar': ('baz', None, 1.0, 2)}])
+print 3, json.dumps("\"foo\bar")
+print 4, json.dumps(u'\u1234')
+print 5, json.dumps('\\')
+print 6, json.dumps({"c": 0, "b": 0, "a": 0}, sort_keys=True)
+io = StringIO()
+json.dump(['streaming API'], io)
+print 7, io.getvalue()
+
+# compact encoding
+print 8, json.dumps([1,2,3,{'4': 5, '6': 7}], sort_keys=True, separators=(',',':'))
+
+# pretty printing
+print 9, json.dumps({'4': 5, '6': 7}, sort_keys=True, indent=4, separators=(',', ': '))
+
+# decoding json
+
+print 10, json.loads('["foo", {"bar":["baz", null, 1.0, 2]}]')
+print 11, json.loads('"\\"foo\\bar"')
+io = StringIO('["streaming API"]')
+print 12, json.load(io)
+
+# specializing json object decoding
+def as_complex(dct):
+    if '__complex__' in dct:
+        return complex(dct['real'], dct['imag'])
+    return dct
+
+# disable this part for now.  pyston formats the real/imaginary parts as floats always, but cpython
+# formats them as integers if they are.  i.e. (1+2j) in cpython vs (1.0+2.0j) in pyston.
+#print 13, json.loads('{"__complex__": true, "real": 1, "imag": 2}', object_hook=as_complex)
+
+# Pyston doesn't support the decimal module yet
+#import decimal
+#print type(json.loads('1.1', parse_float=decimal.Decimal))
+
+# extending JSONEncoder
+
+class ComplexEncoder(json.JSONEncoder):
+    def default(self, obj):
+        if isinstance(obj, complex):
+            return [obj.real, obj.imag]
+        # Let the base class default method raise the TypeError
+        return json.JSONEncoder.default(self, obj)
+
+print 14, json.dumps(complex(2, 1), cls=ComplexEncoder)
+print 15, ComplexEncoder().encode(complex(2, 1))
+print 16, list(ComplexEncoder().iterencode(complex(2, 1)))
+