Questions tagged [language-specifications]
126 questions
9
votes
3 answers
runtime type vs compile-time type method invocation
The C# 4.0 specs read:
When a virtual method is invoked, the runtime type of the instance for
which that invocation takes place determines the actual method
implementation to invoke. In a nonvirtual method invocation, the
compile-time type…
P.Brian.Mackey
- 43,228
- 68
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- 348
8
votes
2 answers
Is the lambda->expression tree transformation process specified anywhere?
There are two important steps to compiling a LINQ query in C#. The first is transforming LINQ query syntax into a chain of method calls, as described in section 7.16 of the C# language specification. This transformation process is specified in…
Mason Wheeler
- 82,511
- 50
- 270
- 477
7
votes
7 answers
Questions about Structs
MSDN says that a class that would be 16 bytes or less would be better handled as a struct [citation].
Why is that?
Does that mean that if a struct is over 16 bytes it's less efficient than a class or is it the same?
How do you determine if your…
Malfist
- 31,179
- 61
- 182
- 269
7
votes
3 answers
Why is this C++ explicit template specialization code illegal?
(Note: I know how it is illegal, I'm looking for the reason that the language make it so.)
template void Foo(); // Note: no generic version, here or anywhere.
int main(){
Foo();
return 0;
}
template<> void…
BCS
- 75,627
- 68
- 187
- 294
7
votes
1 answer
What is a "Maximal Sub-expression" in Scala 2.8 specification §6.26.5 Eta Expansion?
In Scala 2.8 language specification, §6.26.5 Eta Expansion, it states that we need a maximal sub-expression, however, no definition of this can be found. Can someone clarify this?
Felix
- 8,385
- 10
- 40
- 59
6
votes
0 answers
Can't add a new keyword to Python
I tried to add a new keyword (a new flow statement) to Python, by following this blog post and this PEP. I'm pretty sure I've added what I needed to add to the right places, according to the PEP that I've mentioned. These are the files that I've…
SwedishOwlSerpent
- 356
- 1
- 7
6
votes
1 answer
Why Class.forName("BumpTest"), not BumpTest.class?
In JLS Sec 8.4.3.6, synchronized methods, it says:
class BumpTest {
// ...
static synchronized void classBump() {
classCount++;
}
}
has exactly the same effect as:
class BumpTest {
// ...
static void classBump() {
…
Andy Turner
- 137,514
- 11
- 162
- 243
6
votes
1 answer
Java 8 Type Inference - How reduction is done for generic constructors?
I was reading the java 8 language specification type inference. It says that
List ls = new ArrayList<>()
would be first reduced
ArrayList<α> -> List
and then to
α <= String
and at the end to
α = String
I'm having a hard time…
psaw.mora
- 868
- 1
- 7
- 18
6
votes
2 answers
Is the F# language reference documentation available in an offline format (PDF, CHM)?
I've found several posts on hubFS of people asking if there is, or will be, offline documentation for F#. These posts haven't been answered. So I want to give it a shot and ask the same question here on SO.
Where I've looked for offline…
stakx - no longer contributing
- 83,039
- 20
- 168
- 268
6
votes
3 answers
C# 'dynamic' keyword... is it really a RESERVED keyword or just a identifier that means something special when used as type?
I have a C# 4.0 parser. It accepts 'dynamic' as a keyword as a type. My parser trips over
statements found in working C# 3.0 programs of the form of:
dynamic = ;
So, it dynamic really a keyword? Or can it still be used as an arbitrary…
Ira Baxter
- 93,541
- 22
- 172
- 341
6
votes
2 answers
Syntax (probably BNF) spec of VBA ?
I have to maintain a portion of Access 2003 VBA code, which is not my primary programming language, and while I'm pretty solid on doing regular stuff, I would still like to have a pure spec of the language syntax.. It just saves a lot of time…
Jörg Haubrichs
- 2,215
- 3
- 24
- 26
5
votes
2 answers
What does "execution trace" mean in Java Memory Model
The part of the language specification dedicated to the Java Memory Model (JMM) (link) mentions "execution trace" a lot.
For example right from the start:
A memory model describes, given a program and an execution trace of that program, whether the…
sanyok
- 51
- 2
5
votes
2 answers
Assignability question in golang specification
While reading go specification "Assignability" section, I tried to execute a couple of examples to get a better understanding of the topic, and now I can't get what am I doing wrong in my code.
According to the specification,
One of the cases when a…
Nick B
- 141
- 1
- 7
5
votes
1 answer
Why doesn't an array access expression of a null array reference throw a NullPointerException?
Consider the following code:
int[] r = null;
r[0] = 1 % 0;
I would have expected this to throw a NullPointerException: according to JLS Sec 15.7.1:
The left-hand operand of a binary operator appears to be fully evaluated before any part of the…
Andy Turner
- 137,514
- 11
- 162
- 243
5
votes
1 answer
Binary compatibility of changing a class with static methods to interface in Java
I've faced the following weird case of an incompleteness of the Java/JVM specification. Suppose we have the classes (we will use Java 1.8 and HotSpot):
public class Class {
public static void foo() {
System.out.println("hi");
}
}
public…
Sergei Patrikeev
- 105
- 5