All Questions
575
questions
2
votes
1
answer
94
views
Is there a way to define expressiveness that includes a notion of computational complexity?
There is a nice answer here providing an exposition of Felleisen's definition of expressiveness. But there is a missing piece for me.
It feels like adding tail calls to a language that lacks any ...
- 597
7
votes
6
answers
3k
views
Why do relational comparison operators never short-circuit?
I just thought about the possibility for the less-than and-greater than operators to short-circuit. That is, they can skip evaluating their second operand if the value of the second operand logically ...
- 6,382
1
vote
6
answers
525
views
Why tag function definition with def, fn, fun, func or function etc?
What makes it hard for compilers/interpreters that we need to tag the function definition with keyword fn/fun/func/function?
I can understand that types for numbers: int, int32, float32, float64... ...
- 143
5
votes
2
answers
2k
views
Creating a new language with Rust without Garbage Collection?
I am new to language development. I am aware of Rust's ownership model that builds programs in a way that does not need garbage collection.
So if I am to build a new programming language using safe ...
- 153
6
votes
1
answer
445
views
What, if any, runtime cost is incurred by using 64-bit ints on 32-bit platforms in LLVM?
I'm writing a language frontend for LLVM, and I noticed that the IR docs say that integers of (almost)any width can be used without limit. I presume this to mean that LLVM or its backends convert ...
- 2,047
2
votes
1
answer
373
views
Is it correct that Python does not encourage us to read objects's content? [closed]
After playing around Python a little bit, I feel like Python does not encourage us to read objects's content. Take JavaScript for example: just a simple act of calling an object will list all the ...
- 147
16
votes
6
answers
3k
views
Possible to mix garbage collection and manual memory management?
Do you think it is possible to have a language that uses garbage collection (GC) by default, but allows you take more control with manual memory management like C++ or Rust, in areas of the software ...
- 923
2
votes
1
answer
203
views
Are enum members literals or constants in an IR?
While implementing enums in Tyr, I just realized that enum constants are the only form of literal-like entity that is not represented like a literal in the intermediate representation.
The enum ...
- 1,248
7
votes
2
answers
496
views
Why do many languages use square brackets for array indexing?
A lot of languages use square brackets for array indexing, and round brackets (also known as parentheses) for function calls. For example, in C:
...
- 808
3
votes
1
answer
561
views
Why is the ECMAScript specification formatted the way it is? [closed]
The ECMAScript specification and its drafts are very accessible, but they're formatted a bit oddly -- case in point, the current version of the ToBigInt abstract operation uses three fonts:
The base (...
- 8,089
42
votes
5
answers
11k
views
Why do programming languages use the asterisk * for multiplication?
Having had very little math(s) education I'm trying to bring myself up to speed for university, which currently involves teaching myself the times tables, where X ...
- 91
10
votes
0
answers
226
views
What styles of interpreter are not well-supported by RPython?
The RPython toolchain translates interpreters to JIT compilers. The interpreter may be written in any style; the corresponding JIT compiler is defined by annotations on the main loops of the ...
- 385
5
votes
1
answer
207
views
What is the difference between having an auto type and having dynamic typing?
In C++, you can define variables with auto instead of giving it a default type such as int. Like this (where ...
- 881
5
votes
2
answers
149
views
How to ensure coherent choices of representatives in an e-graph?
E-graphs are a neat intermediate representation for program transformations and optimisations, which group program terms into equivalence classes (e-classes). An optimising compiler can then select ...
- 14.6k
8
votes
4
answers
835
views
Data structures for scopes and variable shadowing
Let's say I have some code in my target language like:
...
- 923
12
votes
3
answers
2k
views
Is type checking usually preceded by a pass that looks at just names and declarations?
Let's say I've parsed a file of code into an AST, and now I want to walk the AST and type check it. My AST nodes have a signature like this (C++)
...
- 923
2
votes
1
answer
199
views
Can a language like Mojo include multiple dispatch like in Julia? [closed]
Julia supports multiple dispatch of functions when appropriate type annotations are provided. Is Julia's strong type system necessary to support that, or could a new language like Mojo include ...
- 137
6
votes
0
answers
112
views
Extending Hindley Milner with (mutual) recursion
What's a good approach for extending Hindley Milner with mutual recursion without de-sugaring to let+fix+records?
My thinking is (assuming no polymorphic recursion)
Collect mutually recursive lets ...
- 161
8
votes
1
answer
253
views
What are the tradeoffs between using sea of nodes, CFG of basic blocks, and egraphs for compiler optimizations?
I've heard of "sea of nodes" intermediate representations mostly in the context of just-in-time compilation (JVM, V8, Graal) whereas intermediate representations such as LLVM IR are used in ...
- 91
3
votes
2
answers
227
views
Why does the C library include fgetpos()/fsetpos() if the same functionality can be achieved with ftell()/fseek()?
C includes 2 methods for saving the position of a stream and setting it later. Using fseek() and ftell():
...
- 6,382
14
votes
5
answers
1k
views
What are some techniques for faster, fine-grained incremental compilation and static analysis?
An incremental compiler is one which only needs to recompile the parts of a program which changed since the last output, as opposed to a batch compiler which must re-compile everything. Incremental ...
- 2,025
18
votes
10
answers
4k
views
Why would accessing uninitialized memory necessarily be undefined behavior?
In C, accessing any indeterminate/uninitialized memory is undefined behavior, period. Even in the case that the type in question is guaranteed to have no trap representations, such as ...
- 6,382
6
votes
1
answer
563
views
What is a CAS language?
Is it by any chance just this (otherwise Google was no help)? I've seen throwaway remarks on this site by SK_Logic and Jorg-W-Mittag that use this term but I'm not entirely convinced and cannot find ...
- 63
9
votes
1
answer
233
views
How to efficiently generate stack traces
Errors are a lot easier to troubleshoot if the language reports precise source locations. In case of runtime errors, the stack trace is probably important, showing each function in the call stack and ...
- 1,391
14
votes
2
answers
2k
views
How do languages support executing untrusted user code at runtime?
Many dynamic languages such as Javascript, PHP and Python have a built-in eval function for executing code from a string. It's well known that such functions are ...
- 14.6k
8
votes
1
answer
336
views
Creating an interface for stringifying objects that allows loop detection
Suppose a language has a rust-style trait system but is garbage collected and most types are reference types by default.
I could create a trait like this:
...
- 6,424
15
votes
4
answers
4k
views
Why does Rust choose not to provide `for` comprehensions?
Okay, so this might be a silly question. I'm a big fan of functional programming paradigms in higher-level scripting languages, so I'm probably using Rust wrong. However, I'm new to Rust and I'm ...
6
votes
1
answer
182
views
How do you implement a structural subtyping checker?
In a structurally-typed language, one type is a subtype of another iff it has all of the fields/methods of the other with compatible types, meaning that field or return types are subtypes, parameter ...
- 9,210
10
votes
2
answers
454
views
Can you represent a language with a group with a small/simple generator set?
I'm wondering whether its possible to construct a group where the elements are all possible valid programs, with a small or simple generator set. That way you could have a series of operations you can ...
- 103
4
votes
2
answers
417
views
Were there attempts to support triggering accessors on modifying subelements of properties?
Some languages offer the feature of properties, different from normal member variables, that trigger some code when you read from or write to the property. The triggered code are called accessors. The ...
- 1,812
5
votes
0
answers
119
views
What are some design errors that lead to hard-to-debug code? [closed]
There are some design features in programming languages that make code written in the language difficult to debug (e.g. C's default fallthrough behavior).
So it would be helpful to make a list of ...
- 159
11
votes
1
answer
307
views
Typeclasses, traits, interfaces, protocols: is there any consistent terminology?
Many languages have some form of expressing "user-defined duck typing": defining a type by its behavior, rather than anything about the structure or data of an instance of the type itself. ...
- 157
27
votes
6
answers
11k
views
Why do programming languages use delimiters (quotes) for strings?
Almost every programming language requires strings (or char* or equivelent) to be marked with quotes. Few languages allow other delimiters, many languages allow ...
- 381
27
votes
1
answer
4k
views
Why did JavaScript choose to include a void operator?
In JavaScript, there is an operator void that, given an expression, evaluates it but then ignores the result and evaluates to ...
- 6,424
34
votes
6
answers
4k
views
How to ensure that an optimising compiler will terminate?
An optimising compiler typically applies some set of rewrites to some intermediate representation of the program, replacing terms with other terms which are supposed to be equivalent but more ...
- 14.6k
7
votes
3
answers
299
views
How to incorporate sum types into SQL?
The blog post states that a major drawback of SQL is its lack of sum type support.
Assuming we could redesign SQL today (without necessarily having to worry about compatibility) what are some specific ...
- 103
29
votes
2
answers
8k
views
How expressive of a type system is too expressive, for the average programmer?
The advantages of an expressive type system cannot be denied. The usual definition applies - how much valid behaviour a chosen system allows, while also preventing invalid behaviour.
In terms of "...
- 1,115
2
votes
1
answer
181
views
7
votes
1
answer
1k
views
Why can you implement a Monoid type in Java or C#, but not Monad or Functor?
Haskell and some other functional languages have Monad and Monoid types (and Semigroup, Functor, Applicative, and many others), and lists, trees, Maybe, and other types subtype all or some of these. ...
- 9,210
4
votes
1
answer
201
views
Can analysis of periodic loop behaviour be generalised to unstructured control flow?
The basic form of a loop is as follows:
loopvars := init
body:
loopvars := f(loopvars)
done := term(loopvars)
br done, end, body
end:
Suppose we've recognised ...
- 597
3
votes
1
answer
169
views
How can I design a Functor trait to handle trait?
In programming languages like Rust, variables of different types that implement the same trait can have different sizes, i.e., the number of bytes used in the memory representation of the type. For ...
- 103
2
votes
0
answers
70
views
Is it more readable to declare the return type of a function on the left side of it's name? [duplicate]
A lot of C-like programming languages (Java, C#, ...) use the following syntax for defining functions:
returnType functionName(parameters...) {
}
Is there a ...
- 121
7
votes
1
answer
177
views
Techniques for resilient parsing in the face of mismatched brackets?
Suppose you want to build an IDE-grade parser for a language with highly uniform and nestable syntax (e.g. Lisp). Without a lot of "special" constructs like top-level functions, you can't ...
- 111
14
votes
3
answers
460
views
Why does C# have events as a language construct, rather than in the standard library?
In C#, events and event listeners have direct support within the language, with event being a keyword, and event declarations being a special kind of member ...
- 14.6k
5
votes
4
answers
389
views
How do interpreters avoid stack buffer overflow-related undefined behavior and exploits?
Most interpreters (including those for bytecode-based languages like Java) are assumed to be exempt of UB at the low-level. For instance, I would never expect NodeJS or the Hotspot JVM to allow ...
- 203
9
votes
5
answers
992
views
How to make logical operators that return operands consistent in a statically typed language?
In C++, 3 || 4 returns true. But in Python, 3 or 4 returns 3 instead. That's a logical operator that returns its operand. I don'...
- 1,812
6
votes
5
answers
315
views
Declaring infix operators like Haskell's in other languages?
Haskell has support for declaring custom infix operators, including their precedence and associativity. In addition, any identifier can be used as binary infix operator by placing it between ...
- 251
1
vote
1
answer
163
views
Scalability of a language [closed]
When building a language, one of the things to consider is scalability, the ability of a programming language to efficiently manage large or small amounts of code. How should one factor this when ...
- 135
22
votes
6
answers
2k
views
Language features for making code easier to unit test
What can programming languages do to make unit testing easier?
For the purposes of this question, I'm especially interested in unit testing procedural code with lots of heavy side effects.
Let me ...
- 321
9
votes
8
answers
3k
views
Invalid signed integer in C and similar languages
In C a signed integer is just a binary number and all binary numbers are valid integers. There is no NaN value.
C uses 2s complement for signed integers meaning ...
- 191