All Questions
656
questions
1
vote
1
answer
83
views
What are the potential consequences of allowing decimal-point-less number literals to be interpreted as floats?
In some languages, a number literal's type can be inferred from nearby expressions. For example, 1u64 + 2 might give a u64 value ...
- 4,088
-1
votes
0
answers
33
views
Should addition assignment `a += b` be equivalent to addition then assignment `a = a + b` [closed]
I am looking for the pros and cons of a += b being an exact synonymous, or not, of a = a + b. The question also holds regarding <...
- 244
4
votes
1
answer
126
views
Should bitwise operations have dedicated operators? [closed]
Many programming languages have built-in support for bitwise operations, often using C's syntax:
~ = NOT
& = AND
...
- 1,534
0
votes
1
answer
97
views
How to minimize total size of static data?
I am implementing a WASM backend and I hope to optimize the size.
I have collected a series of static data. After erasing the type, it can be simply
considered as ...
- 2,552
2
votes
1
answer
112
views
Possible ways to determine reach of implicit lambda expressions
When defining an inline function, even the shortest way to do so usually requires naming its argument (unless you're going for the point-free style and you have an expression that returns a function).
...
- 557
5
votes
5
answers
860
views
Correctness of mixed signed/unsigned arithmetic
I'm implementing signed and unsigned integers in my language. They are represented in C as signed long and unsigned long ...
- 147
10
votes
1
answer
236
views
How to tolerate syntax errors in a typed language?
In my tokenizers and parsers, once I find a syntax error (like an unexpected token) I usually throw a fatal exception that finishes parsing of the input source.
The downside of how I usually do it is ...
- 769
-1
votes
0
answers
49
views
How to be (more) critical during Code Reviews of team members? [closed]
I'm a Software Engineer who sometimes need to review the code of my fellow team members. I often look at the source code and think; this looks fine. I'm having a hard time to think critical about it. ...
- 1
4
votes
5
answers
252
views
How can memory addresses be compile-time constants?
In C the memory address of a statically allocated object or a function is considered compile-time constant. For example this is valid code:
...
- 7,285
10
votes
4
answers
253
views
Are there languages that implement a more granular precondition system than just safe/unsafe
In a language like C, many functions and operators have some preconditions to work. Violating a precondition is undefined behavior. For example, when indexing an array the index must be less than the ...
- 6,746
9
votes
1
answer
159
views
What was the rationale for making realloc(ptr, 0) have UB in C23
This is the first breaking change that C made, which was making realloc(ptr, 0) have UB instead of being roughly equivalent to ...
- 513
11
votes
9
answers
6k
views
Can sine converge to zero at infinity?
In common languages, sine produces an error, NaN, or exception when evaluated at infinity. For example, in Python:
...
- 670
5
votes
4
answers
289
views
What goes wrong when division-by-zero is defined as multiplication-by-infinity?
Sometimes, we want to implement floating-point operations on systems which use IEEE 754 representations of values, but don't necessarily support IEEE 754 semantics. For example, we may be using the <...
- 670
1
vote
1
answer
121
views
Implementing automatic derivation without macros?
In Rust:
#[derive(Display)]
struct Foo<T>(T);
If T conforms to the Display trait, ...
- 121
2
votes
1
answer
158
views
How to assign unique names to variables within a function?
I want to promote all variables within the function to the top level of the function, make it more cache-friendly and reduce size bloat caused by alignment fill.
In other words, it will roughly ...
- 2,552
22
votes
3
answers
5k
views
Why are volatile objects so difficult to work with in C++?
C++ does not generate default copy/move constructors or assignment operators for any volatile struct or ...
- 8,563
-2
votes
0
answers
58
views
How to Integrate Python with HTML? [closed]
I am a learner and am learning python currently. To know what all I have to learn I wanted to create a chatbot with algorithm that uses python. But I want that I have a input page to take commands ...
2
votes
1
answer
151
views
What if all static methods in Java or C# could be extension methods just by default?
C# 3.0 introduced extension methods to "enhance" behavior of existing types without interface bloating to avoid modifying/breaking existing interfaces. This was the first time I learned of ...
0
votes
0
answers
69
views
What is best practice for a programming language which allows more than one syntax for class method invocations? [closed]
Consider the following code written in a syntax consistent with the programming language known as "python":
...
- 283
9
votes
3
answers
1k
views
What is a "primary expression"?
I've found that many grammars have a production called PrimaryExpression or something along those lines. ECMAScript has ...
- 557
-2
votes
1
answer
135
views
Low effort, high impact optimizations? [closed]
The Pareto principle tells us that 20% of our efforts will bring us 80% of the results. The same should be true of optimizations.
Are there optimization techniques out there that:
Are simple and easy ...
- 147
-1
votes
2
answers
162
views
Why hasn't html a simple way of showing html tags as they are? [closed]
html comments meant to be read by the person reading the source are like <!-- Write your comments here -->
But sometimes we want to depict a html as it is, ...
- 107
0
votes
0
answers
188
views
Pros and cons of treating endless loops as "anything can happen" UB, versus allowing limited reordering
Many programming languages, including C89, specify that the behavior of a program in terms of sequentially executed steps, whose behavior is in turn defined in terms of the program's state when the ...
- 1,562
11
votes
1
answer
195
views
What exactly is Pratt parsing used for and how does it work?
I've come across the term “Pratt parsing”. The only thing I know is that it's an algorithm (or a pattern, a technique) used to parse expressions.
How does it work? I'd like to see the intuition behind ...
- 557
26
votes
2
answers
3k
views
Studies on learnability of braces vs. indentation for code blocks for beginners?
The discussion whether using indentation for code blocks is better or worse than using braces is an old one, but I don't want to rehash that discussion here (for reference, there was a fairly recent ...
- 363
9
votes
0
answers
110
views
How to detect changes to definitions and their impacts?
I'm implementing the Language Server Protocol (LSP) for my language, and I'm having huge problems tracking updated definitions.
1. How to determine which files have been changed?
lsp can only monitor ...
- 2,552
4
votes
0
answers
120
views
Determining the most optimized date type for the platform with type inference
For my programming language, I have built an engine that goes after the parser and before the compiler. This engine analyzes, validates, and simplifies the AST.
During the analasys, it determines as ...
- 171
5
votes
1
answer
185
views
Optimization algorithm using conditional invariants
I am looking for an optimization algorithm that would make use of invariants in regions of code. For example
if (n == 0) f(n);
should be changed to
...
- 628
4
votes
2
answers
142
views
Supporting reasonably efficient high-level indexing for strings
I'm designing a language that I intend to be implemented on the .NET platform. To my understanding, the native string representation uses UTF-16, by storing an array of ...
- 1,155
2
votes
1
answer
994
views
Why do we put imports at the top of files? [closed]
Most of the popular programming languages I know of either require or strongly encourage import statements to be at the top of the file, before any of the ...
- 2,857
6
votes
1
answer
136
views
What's the benefit of using different tokens for accessing nested namespaces/modules versus properties?
In JavaScript, accessing items from a module is done using ., e.g. moduleBar.moduleFoo.functionFoo, which looks exactly the same ...
- 557
32
votes
2
answers
17k
views
Why do common Rust packages depend on C code?
Chapter 1 of "The Rust Programming Language" (Klabnik and Nichols) says:
[S]ome common Rust packages depend on C code and will need a C compiler.
Why do Rust packages have any dependency ...
- 455
1
vote
3
answers
274
views
Is there any way a Java-like language could implement immutable primitive arrays without incurring performance penalties?
I asked: What prevents Java from having immutable primitive arrays? a while back and got an answer: Because immutable primitive arrays would typically require checking some immutable flag every time a ...
- 7,285
6
votes
3
answers
3k
views
How to implement + in a language where functions accept only one argument? [closed]
While reading about currying, I found the argument that it is beneficial in languages, which have only functions accepting only one argument.
I am wondering how to implement a 2-ary function like the ...
- 356
1
vote
1
answer
111
views
Expressing runtime constraints with trait-bounds
I've recently listened to Corecursive episode with John A De Goes and there's one thing that really got me thinking: the idea of type class laws pertaining to performance guarantees. The example ...
- 143
9
votes
1
answer
229
views
What is the difference between GAT and HKT?
I implemented a basic generics-free, parameterless trait (type class) system. And I want to parameterize my trait system. The alternative paths I know of are Generic Associated Types (GAT) and Higher-...
- 2,552
9
votes
3
answers
1k
views
Do parsers typically need access to all tokens?
Do parsers typically operate on the entire array/list of tokens available in memory, or are the tokens often streamed one by one as they are recognized? What influences the decision?
- 557
5
votes
3
answers
272
views
Reading Floating Point, perhaps without libc/msvcrt
Given a new language, how best should we convert decimal to binary floating point? And please don't just say "use strtod(3)": The venerable C function supports a baroque variety of weird ...
- 153
20
votes
10
answers
4k
views
What are the drawbacks of allowing implicit boolean/integer conversions?
Some languages (C, C++, JavaScript, Python) allow one to use integers as booleans and vice versa:
int x;
if (x) // Equivalent to: x != 0
y();
Or:
...
- 7,285
29
votes
5
answers
5k
views
Are there Haskell-like languages where equations allow for arbitrary left-hand sides?
In Haskell, you can define algorithms by equations that pattern-match on left-hand side constructors. For example:
...
- 391
13
votes
1
answer
635
views
Is there a difference between Rust's `macro_rules!` and Scheme's `syntax-rules`?
This is an example for the use of Rust's macro_rules!:
...
- 356
20
votes
6
answers
7k
views
Why do some languages have both immutable "variables" and constants?
Some programming languages (Rust is one I can think of off the top of my head) provides mechanisms to have immutable variables but they also have constants. Isn't an immutable variable just a constant?...
- 311
2
votes
1
answer
179
views
Generic method: type inference
I am developing a verifier for the ActionScript 3 language and I have gone through implementing one before for my personal language.
I had a type inference limitation with the following construct:
<...
- 769
0
votes
2
answers
104
views
Challanges to integrate sum types into json/protobuffer/toml/yaml? [closed]
What challenges might arise when integrating sum types into data exchange or configuration file formats such as json, protobuf, toml or yaml?
- 121
9
votes
1
answer
323
views
Why does ATTAPL's linear product introduction rule not delete the objects from the context?
In Chapter 1 of Advanced Topics in Types and Programming Languages, the following rule is presented for the introduction of a product in a linear/unrestricted type system:
($\circ$ is context ...
- 1,582
29
votes
11
answers
18k
views
Why do so many programming languages not have a "built-in" way to do simple math functions?
Note 1: My question is not about the factorial function. It's about "simple math functions" that high-school level pocket calculators can do, but most programming languages cannot do without ...
- 805
5
votes
2
answers
616
views
How does the map function work in stack-based languages?
In many languages, the map function takes a function and a list, and applies the function to each element of the list, returning a new list of the results. Some ...
- 670
9
votes
1
answer
627
views
How does Rust parse ambiguous macros?
Rust's macros require them to be delimited by either parentheses, braces, or brackets, such as println!(arg) or foo! { bar, baz }...
- 2,594
14
votes
1
answer
2k
views
What language was the first to treat null checks as smart casts to non-nullable types?
As far as I know, for many decades, in mainstream programming languages, there were only two options to handle null-like optionality:
Pointer or reference types are always nullable (the famous "...
- 1,526
2
votes
3
answers
226
views
How do different template languages handle parsing?
In template languages, most of the content is written out as-is, with only certain special markers for expression evaluation or flow control. In my attempts to develop a language of this style, I've ...
- 1,722