How to implement dynamic scoping?
Dynamic scoping is useful for forms of dependency injection, error handling and alternatives to thread local storage.
Some examples of dynamic scoping include React's useContext and Java's proposed scoped values.
The C2 wiki mentions deep binding and shallow bind...
Statically-typed languages specify the types of variables and functions and reject programs they know won't work before they run. Dynamically-typed languages don't include these annotations or checks, and let any program run as far as it can. I see languages that are "gradually typed" now, which ...
I just saw this question.
It's actually quite a good question in terms of relating to on-topic questions (being about implementation of error messages) and it has 2 answers, both of which are good-quality. It even goes so far as to point out differences between the question and a related question...
sincos() is just a way to compute sin() and cos() at once, possibly at improved performance compared to separate calls to sin() and cos(). However, many languages, notably C, lack this feature in the standard library. I do not see how this could be hard to implement, as the compiler could just em...
Different programming languages handle multiple return values differently, used in functions such as divmod.
For example, in Python or Haskell, you would just return a tuple. In Go or Lua, you would return multiple values - not a specific type.
What are the different ways of handling multiple ret...
I am not sure why the red circle is appearing. The queue is ostensibly cleared but I have Approve Tag Wiki Edits. At first I thought the ghost items triggering the circle were tag wiki edits I could not yet approve, but I just approved 3 now and now the queue is showing as cleared. I also have no...
Many questions ask for 'What are some examples of ...?' (Including the pros-cons questions). But I would expect 'What are some examples of <thing>' with no elaboration to be closed as lacking details but others are well received.
What should be the quality standards and guidelines for asking such...
Who handles flags during the private beta? I know the site's moderators typically handles them, but we don't (to my knowledge) have any yet.
I don't know the standard words for these, but:
complex enum is like enum { E1(t1: T1, t2: T2, ...), E2(...), ... }
simple enum is like enum { E1(T1), E2(T2), ... }
The difference is the simple one always contain a tag and a type, the complex one contains a tag and multiple name-type pairs.
In ...
Background
Trilangle is an interpreted 2-D esolang that I made in February and March of this year. At some point, I had the idea to implement an AOT compiler for the language, and what resulted was a "disassembler" feature to convert it to an assembly-like syntax.
For example, when passing the c...
Some programming languages allow you to create generators - lazily evaluated iterable objects that use a function to determine what the next item should be.
For example, python allows:
def f():
x = 0
yield x
x += 1
To generate an infinite list of numbers.
What other syntax options ex...
For languages that allow generators (iterables where elements are determined by a function), what are the pros and cons of having a unique type for generators?
For example, languages like python have a special type for generators, meaning there's no immediate shared superclass for lists and gener...
I ask motivated in particular by this question, but also by the general pattern seen so far.
That question was originally titled Should generators be their own type?, but was now renamed to What are the pros and cons of having a unique type for generators?, in line with a number of others on the ...
I was looking forward to the PLDI StackExchange site, but am dismayed to seee that it has fallen victim to Wadler's law:
In any language design, the total time spent discussing
a feature in this list is proportional to two raised to
the power of its position.
0. Semantics
...
I recognize that not everyone designing a new language is doing it to compete with other languages in the same problem/application-domain and achieve (and retain over time) similar adoption levels and. But for those who are, what overarching, high-level design strategies matter?
Some additional q...
From Wikipedia:
In computing, fixed-point is a method of representing fractional
(non-integer) numbers by storing a fixed number of digits of their
fractional part. ... More generally, the term may refer to representing fractional
values as integer multiples of some fixed small unit, e.g. a
frac...
Algebraic data types include two concepts with names that feel like they imply something clever, but that I can't for the life of me understand:
Sum type: This refers to tagged unions, like Rust's enums
Product type: This refers to collection types like tuples and structs
Why are these referred...
Right now, the question "What is implied by the names 'sum type' and 'product type'?" is closed for being off-topic, but the help center doesn't specify what is on-topic for PLDI.
The question is not directly about how to design or implement a programming language, but it's about terminology comm...
Many languages that use async nowadays are implemented via stackless coroutines. That is, in a language like Python or Javascript, when you await an expression, that await returns to the caller, returning the minimal amount of information needed to resume the function later. The caller can, in tu...
The Rust programming language has an infinite loop construct, which looks like this:
loop {
<some code>
}
It's the only language I can think of that has dedicated syntax for this; in most other languages some variation of while true is used instead. Why does Rust have it?
Most languages have a way of writing doc comments. Doc comments above a function, class, or struct provide a strucutred way to describe every part of the function, like this:
/** Compute the sum of two numbers
* @param A the first operand
* @param B the second operand
* @returns the sum of ...
I'm working on a REPL for a language that has a null type, and I'm not sure how to represent it in the output. The behavior of existing REPLs seems to be either to represent it by its name (null) or not to show it at all. For example, Python doesn't show any output when a None-returning expressio...
I am considering asking a question along the lines of 'How could I best describe a void or never type in a formal language specification?'
However I thought that may be more of an English question than a technical question.
Should questions about writing a language specification (a document that ...
Using unconditional jump instruction such as goto in C programming language is generally considered as a bad programming practise. It can be argued that the same can be quite useful in certain scenario.
However, there can be possible scenarios where using it can come in handy. What are the potent...
I've been seeing questions and their answers like
Should a REPL show null values as null?
Enforcing doc comments in the compiler, good idea or no? - There is an objective criteria hiding in a complaint, and that complaint itself is really hiding a goal-oriented question that I think is worth its...
Some languages support binding a function call to an attribute.
Python, for example, supports this via property
class Foo:
_values = [1, 2, 3]
@property
def last_value(self):
return self._values[-1]
@last_value.setter
def last_value(self, new_value):
self._va...
