A quick sample to understand my situation:
static Interpreter ParseInterpreter = new Interpreter();
...
var func = ParseInterpreter.Parse("ctx.SomeProp", new Parameter("ctx", typeof(???1)).Compile<Func<???2, object>>;
...
var token = JToken.Parse(s);
dynamic dToken = token;
var obj = func(dToken);
In other words, is there a way to pass some dynamic parameter to Parse method and then get a functor which accepts such parameters?
You can directly use the Lambda class returned by the Parse method, and not call the Compile function:
var interpreter = new Interpreter()
string expression = "ctx.SomeProp";
Lambda parsedExpression = interpreter.Parse(expression, new Parameter("ctx", typeof(object)));
var token = JToken.Parse(s);
var result = parsedExpression.Invoke(token);
I have not tested exactly your code but for example I have a test like this that works correctly:
dynamic dyn = new ExpandoObject();
dyn.Foo = "bar";
var interpreter = new Interpreter()
.SetVariable("dyn", (object)dyn);
Assert.AreEqual(dyn.Foo, interpreter.Eval("dyn.Foo"));
Consider that this only works on .NET 4.x, on .NET Standard/Core dynamics are not supported.
Related
I using bind variable to do a batch update using below code
`var balanceUpdate = dslContext.batch(
dslContext.update(BALANCE)
.set(BALANCE.BALANCE, (BigDecimal) null)
.where(BALANCE.ID.eq((String) null)));
balances.forEach(balance -> {
balanceUpdate.bind(
balance.getAmount()
balance.Id);
});
int[] execute = balanceUpdate.execute();
`
Above code work well, but now i want to use bind with array of arguments like
var balanceUpdate = dslContext.batch(
dslContext.update(BALANCE)
.set(BALANCE.BALANCE, (BigDecimal) null)
.where(BALANCE.ID.eq((String) null)));
var arguments = balances.stream()
.map(balance ->
new Object[] {
balance.getAmount(),
balance.Id
}).collect(Collectors.toList());
int[] execute = balanceUpdate.bind(arguments).execute();
I get exception
java.lang.ArrayStoreException: arraycopy: element type mismatch: can not cast one of the elements of java.lang.Object[] to the type of the destination array, java.math.BigDecimal
at org.jooq_3.14.4.ORACLE12C.debug(Unknown Source)
at java.base/java.util.Arrays.copyOf(Arrays.java:3722)
at org.jooq.tools.Convert.convertArray(Convert.java:357)
at org.jooq.tools.Convert.convertArray(Convert.java:345)
at org.jooq.tools.Convert$ConvertAll.from(Convert.java:603)
at org.jooq.tools.Convert.convert0(Convert.java:392)
at org.jooq.tools.Convert.convert(Convert.java:384)
at org.jooq.tools.Convert.convert(Convert.java:458)
at org.jooq.tools.Convert.convertArray(Convert.java:363)
at org.jooq.tools.Convert.convertArray(Convert.java:345)
at org.jooq.tools.Convert$ConvertAll.from(Convert.java:614)
at org.jooq.tools.Convert.convert0(Convert.java:392)
at org.jooq.tools.Convert.convert(Convert.java:384)
at org.jooq.tools.Convert.convert(Convert.java:458)
at org.jooq.impl.AbstractDataType.convert(AbstractDataType.java:534)
at org.jooq.impl.DefaultDataType.convert(DefaultDataType.java:86)
at org.jooq.impl.DSL.val(DSL.java:24409)
at org.jooq.impl.DSL.val(DSL.java:24377)
at org.jooq.impl.Tools.field(Tools.java:1794)
at org.jooq.impl.Tools.fields(Tools.java:1865)
at org.jooq.impl.BatchSingle.executePrepared(BatchSingle.java:226)
at org.jooq.impl.BatchSingle.execute(BatchSingle.java:170)
According docs it should work ? Atleast it works without explicit casting when using jdbc. Is there anyway to get it work to sent bind variables only once instead of many times like in first example?
I think you're calling the wrong BatchBindStep.bind(Object...) method, or at least not in the way you're expecting. There's currently no overload accepting a collection of type List<Object[]>. So, what you should do instead is create an Object[][] type for your bind variable sets:
Object[][] arguments = balances
.stream()
.map(balance -> new Object[] {
balance.getAmount(),
balance.Id
}).toArray();
I'm having trouble understanding how to set with $priority in angularfire. I am trying to add a username with the key as username.
For example if I try:
var object = {user : "name",
$priority : "this"};
var ref = new Firebase(FIREBASE_URL + 'users');
var newBar = $firebase(ref);
newBar.$set(username, object);
The firebase set fails because of the invalid character "$" in priority.
I understand that instead I could try :
var object = {user : "name",
$priority : "this"};
var ref = new Firebase(FIREBASE_URL + 'users');
var newBar = $firebase(ref).$asArray();
newBar.$add(object);
This succeeds in adding the object to the array, but doesn't give me the opportunity to set the key to username as I require.
I can't think of any other way to achieve this currently. Is there any way to use set that allows me to set $priority? Or any alternative method to achieve the same?
Thanks
$priority is a property that exists on synchronized objects and records inside a synchronized array. As you've noted, it's not an allowed key in firebase data, so using it with $firebase::$set doesn't make sense here (since $set takes a valid json object which is stored directly into Firebase). Reading the API specifications can be a big help here.
There is also no need to create a synchronized binding for this use case. Just use the existing Firebase reference:
var ref = new Firebase(URL);
ref.child(username).set(object, function(error){ /* ... */ });
If there is some use case for working within a synchronized binding, then just use the Firebase meta property .priority:
var object = {user: "name", ".priority": "this"};
var ref = new Firebase(URL);
var sync = $firebase(ref);
sync.$set(object).then(/* ... */);
In case anyone else is looking at this, I have now taken the approach of using set first and then setting priority thereafter like this:
var object = {user : "name",
$priority : "this"};
var username = "user1";
var ref = new Firebase(FIREBASE_URL + 'users');
var newBar = $firebase(ref);
newBar.$set(username, object).then(function(){
var ref2 = new Firebase(FIREBASE_URL + 'users/' + username);
var newBar2 = $firebase(ref2).$asObject();
newBar2.$loaded().then(function(){
newBar2.$priority = authUser.uid;
newBar2.$save();
});
});
I want to convert my class to a Map so I'm using Serialization package. From the example it looks simple:
var address = new Address();
address.street = 'N 34th';
address.city = 'Seattle';
var serialization = new Serialization()
..addRuleFor(Address);
Map output = serialization.write(address);
I expect to see an output like {'street' : 'N 34th', 'city' : 'Seattle'} but instead it just output something I-don't-know-what-that-is
{"roots":[{"__Ref":true,"rule":3,"object":0}],"data":[[],[],[],[["Seattle","N 34th"]]],"rules":"{\"roots\":[{\"__Ref\":true,\"rule\":1,\"object\":0}],\"data\":[[],[[{\"__Ref\":true,\"rule\":4,\"object\":0},{\"__Ref\":true,\"rule\":3,\"object\":0},{\"__Ref\":true,\"rule\":5,\"object\":0},{\"__Ref\":true,\"rule\":6,\"object\":0}]],[[],[],[\"city\",\"street\"]],[[]],[[]],[[]],[[{\"__Ref\":true,\"rule\":2,\"object\":0},{\"__Ref\":true,\"rule\":2,\"object\":1},\"\",{\"__Ref\":true,\"rule\":2,\"object\":2},{\"__Ref\":true,\"rule\":7,\"object\":0}]],[\"Address\"]],\"rules\":null}"}
Serialization is not supposed to create human-readable output. Maybe JSON output is more what you look for:
import dart:convert;
{
var address = new Address();
..address.street = 'N 34th';
..address.city = 'Seattle';
var encoded = JSON.encode(address, mirrorJson);
}
Map mirrorJson(o) {
Map map = new Map();
InstanceMirror im = reflect(o);
ClassMirror cm = im.type;
var decls = cm.declarations.values.where((dm) => dm is VariableMirror);
decls.forEach((dm) {
var key = MirrorSystem.getName(dm.simpleName);
var val = im.getField(dm.simpleName).reflectee;
map[key] = val;
});
return map;
}
The new Address() creates a full prototype object which is what you are seeing. That being said, they could have done something to avoid part of those, but if you want to restore the object just the way it is, that's necessary.
To see the full content of an object you use the for() instruction in this way:
for(obj in idx) alert(obj[idx]);
You'll see that you get loads of data this way. Without the new Address() it would probably not be that bad.
Serialization won't help you here...
You might give a try to JsonObject library, and maybe go through this in depth explanation how to do what you are trying to do using mirrors.
Suppose I have a module models.js:
exports.User = mongoose.model('User', UserSchema);
exports.Question = mongoose.model('Question', QuestionSchema);
exports.Answer = mongoose.model('Answer', AnswerSchema);
exports.Comment = mongoose.model('Comment', CommentSchema);
Now I want to use it in another file:
var models = require('./models');
var User = models.User;
var Question = models.Question;
var Answer = models.Answer;
var Comment = models.Comment
// then use them
var user = new User();
It is boring that I have to declare all the models I defined in models.js.
Is there any way to simplify it, that I don't need to declare the models again:
var models = require('./models');
// !!! do some magic
var user = new User();
Curious why don't you want to simply do with no magic needed - what is issue with simple ..
var models = require('./models');
var user = new models.User();
I am dynamically creating a Lambda expression (based on user input but at the moment using dummy values for a proof-of-concept) for a type which I will only know at runtime. I therefore need to pass the T portion of the Func<T,TResult> as a dynamic type, since I won't know the type until runtime (TResult will always be a bool).
It seems that I cannot pass in a Type variable or use typeof with generics. Basically I'm trying to do something like this:
// (f => f.Baz == 1)
Type theType = Type.GetType("Foo");
ParameterExpression pe = Expression.Parameter(theType, "f");
Expression left = Expression.Property(pe, theType.GetProperty("Baz"));
Expression right = Expression.Constant(1);
Expression expr = Expression.Equal(left, right);
// This works fine but uses a hard-coded type, which I won't know until runtime:
// var lambda = Expression.Lambda<Func<Foo,bool>>(expr, new ParameterExpression[] { pe }).Compile();
var lambda = Expression.Lambda<Func<theType, bool>>(expr, new ParameterExpression[] { pe }).Compile();
However, I cannot use the variable theType as the T portion of the Func. How can I fix this?
No you can't.
For example, in C#, you can't:
Type t = typeof(int);
List<t> list = new List<t>();
or
object list = new List<t>();
Unless you use reflection, but then you have to put the list in an object, and you can use it only through reflection.
So if you want you can save your Func<> in an object (or a dynamic) but nothing more.
What you COULD do is always return Func<object, bool> and cast the object to the desidered type IN the lambda function (so use a Expression.Convert(pe, theType));
Or you could use the dynamic:
// lambda == Func<Foo, bool>
dynamic lamdba = Expression.Lambda(expr, new ParameterExpression[] { pe }).Compile();
bool res = lambda(myvalue);
or
// lambda == Func<Foo, bool>
Delegate lamdba = Expression.Lambda(expr, new ParameterExpression[] { pe }).Compile();
bool res = (bool)lambda2.DynamicInvoke(t);
To be taken "not as real" some benchmarks (in StopWatch.Ticks, look at them only for proportions) (Release Mode + Start Without Debugging + some useless cycles so that they are "hot"):
236384685 dynamic
56773593 Func<object, bool> + cast
10556024247 DynamicInvoke
as a note, Func<Foo, bool> has the same speed, so there isn't any speed lost in the extra cast.
You can see the code here http://ideone.com/qhnVP3