Questions involving the design and structure of programming languages.

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114
votes
26answers
24k views

Are null references really a bad thing?

I've heard it said that the inclusion of null references in programming languages is the "billion dollar mistake". But why? Sure, they can cause NullReferenceExceptions, but so what? Any element of ...
64
votes
11answers
8k views

Did the developers of Java consciously abandon RAII?

As a long-time C# programmer, I have recently come to learn more about the advantages of Resource Acquisition Is Initialization (RAII). In particular, I have discovered that the C# idiom: using (var ...
74
votes
12answers
9k views

I've been told that Exceptions should only be used in exceptional cases. How do I know if my case is exceptional?

My specific case here is that the user can pass in a string into the application, the application parses it and assigns it to structured objects. Sometimes the user may type in something invalid. ...
20
votes
5answers
4k views

When does it make sense to compile my own language to C code first?

When designing an own programming language, when does it make sense to write a converter that takes the source code and converts it to C or C++ code so that I can use an existing compiler like gcc to ...
17
votes
9answers
3k views

Why are self-hosting compilers considered a rite of passage for new languages?

I've heard in a number of places now that people expect languages to use, or at least have, a self-hosting compiler in order to deserve respect. I'm curious as to why this is. A compiler seems like a ...
69
votes
11answers
26k views

Why is String immutable in Java?

I couldn't understand the reason of it. I always use String class like other developers, but when I modify the value of it, new instance of String created. What might be the reason of immutability ...
84
votes
14answers
46k views

Why is 0 false?

This question may sound dumb, but why does 0 evaluates to false and any other [integer] value to true is most of programming languages? String comparison Since the question seems a little bit too ...
20
votes
16answers
12k views

What can be done to programming languages to avoid floating point pitfalls?

The misunderstanding of floating point arithmetic and its short-comings is a major cause of surprise and confusion in programming (consider the number of questions on Stack Overflow pertaining to "...
28
votes
7answers
5k views

Why are so many languages passed by value?

Even languages where you have explicit pointer manipulation like C it's always passed by value (you can pass them by reference but that's not the default behavior). What is the benefit of this, why ...
11
votes
2answers
540 views

How easy should a language development framework be to use?

This is part of a series of questions which focuses on a project called the Abstraction Project, which aims to abstract the concepts used in language design in the form of a framework. Another ...
6
votes
3answers
777 views

Is structural typing in a hierarchical model necessary?

This is part of a series of questions which focuses on a project called the Abstraction Project, which aims to abstract the concepts used in language design in the form of a framework. Another ...
5
votes
3answers
1k views

Is it easier to write robust code in compiled, strictly-typed languages? [closed]

I'd like to read the opinion of experts on whether compiled, strictly-typed languages help programmers write robust code easier, having their backs, checking for type mismatches, and in general, ...
1
vote
5answers
406 views

Why does Kotlin require type after variable, rather than before?

C, C++, C#, Java, as well as many other statically typed languages have the type before variable like (int a =5, auto c = 4, etc.). Non-statically typed languages (such as Javascript, basic) use var (...
46
votes
2answers
3k views

Why do bitwise operators have lower priority than comparisons?

Could someone explain the rationale, why in a bunch of most popular languages (see note below) comparison operators (==, !=, <, >, <=, >=) have higher priority than bitwise operators (&, |, ^...
35
votes
8answers
4k views

Disadvantages of scoped-based memory management

I really like scope-based memory management (SBMM), or RAII, as it is more commonly (confusingly?) referred to by the C++ community. As far as I know, except for C++ (and C), there's no other ...
28
votes
15answers
2k views

I'm writing about language syntax. Is there a language out there in which parameters are placed inside method name?

in JavaScript: function getTopCustomersOfTheYear(howManyCustomers, whichYear) { // Some code here. } getTopCustomersOfTheYear(50, 2010); in C#: public List<Customer> ...
9
votes
4answers
2k views

Building a DSL: Scripted atop a general-purpose language or stand-alone?

I'm debating designing a domain specific language to simplify a given, obscure programming model. Part of the debate is whether to build it (as a script) atop an existing language/runtime (e.g. Java) ...
3
votes
3answers
4k views

What are the advantages of pass by value?

I always thought pass by value is a legacy from the early languages, because the designers had never seen anything else. But after seeing the brand new languages like Go adapting the same principle ...
14
votes
2answers
3k views

Why does a Java source file bear the name of the public class it contains?

I am a newbie learning Java. In Java every source file must contain a public class and that source file should have the same name as that public class. Moreover, no source file can contain two public ...
27
votes
6answers
4k views

Why do programming languages allow shadowing/hiding of variables and functions?

Many of the most popular programming languges (such as C++, Java, Python etc.) have the concept of hiding / shadowing of variables or functions. When I've encountered hiding or shadowing they have ...
8
votes
4answers
692 views

Could a programming language work as well without statements?

As programming in JavaScript, I've noticed everything that can be done with statements and blocks can be done with expressions alone. Can a programming language work fine with only expressions? And, ...
16
votes
2answers
2k views

In hindsight, is basing XAML on XML a mistake or a good approach?

XAML is essentially a subset of XML. One of the main benefits of basing XAML on XML is said to be that it can be parsed with existing tools. And it can, to a large degree, although the (syntactically ...
12
votes
2answers
4k views

How does C++ handle multiple inheritance with a shared common ancestor?

I'm not a C++ guy, but I'm forced to think about this. Why is multiple inheritance possible in C++, but not in C#? (I know of the diamond problem, but that's not what I'm asking here). How does C++ ...
6
votes
3answers
1k views

Why is scanf called scanf? (Same for printf.)

I am just curious why in the C programming language the function to read formatted input was called "scanf" as opposed to "readf". I assume it is derived from an earlier language, so in that case why ...
3
votes
5answers
737 views

Should sanity be a property of a programmer or a program? [closed]

I design and implement languages, that can range from object notations to markup languages. In many cases I have considered restrictions in favor of sanity (common knowledge), like in the case of ...
61
votes
10answers
41k views

If null is bad, why do modern languages implement it? [closed]

I'm sure designers of languages like Java or C# knew issues related to existence of null references (see Are null references really a bad thing?). Also implementing an option type isn't really much ...
64
votes
8answers
14k views

How were some language communities (eg, Ruby and Python) able to prevent fragmentation while others (eg, Lisp or ML) were not?

The term "Lisp" (or "Lisp-like") is an umbrella for lots of different languages, such as Common Lisp, Scheme, and Arc. There is similar fragmentation in other language communities, like in ML. ...
35
votes
2answers
12k views

What are 4th & 5th programming language generations? Are there more of them? [closed]

As it is often classified at school/college level, popular programming languages (C#, Java, C++) are all 3rd generation languages (with higher level of abstraction from the machine's physical parts). ...
22
votes
9answers
4k views

Are there any programming languages that follow a minimalist development approach?

I find it that when languages are considered the same as commercial software, there is always a constant need to add new features to justify new releases. Can there be or are there languages where ...
15
votes
6answers
2k views

Are there any ultra high level languages out there? [closed]

Historically a HLL is something like C, Fortran or Pascal and a VHLL is something like Ruby or Python. I am familiar with the terms 4GL, 5GL, DSL and LOP, and those who aren't should read Wikipedia ...
28
votes
4answers
4k views

Why is .compareTo() in an interface while .equals() is in a class in Java?

I want to know why the .compareTo() is in the Comparable interface while a method like .equals is in the Object class. To me, it seems arbitrary why a method like .compareTo() is not in the Object ...
28
votes
4answers
2k views

How do programming languages define functions?

How do programming languages define and save functions/methods? I am creating an interpreted programming language in Ruby, and I am trying to figure out how to implement function declaration. My ...
14
votes
4answers
2k views

Is garbage collection needed for implementing safe closures?

I recently attended an online course on programming languages in which, among other concepts, closures were presented. I write down two examples inspired by this course to give some context before ...
37
votes
4answers
4k views

Why are structs and classes separate concepts in C#?

While programming in C#, I stumbled upon a strange language design decision that I just can't understand. So, C# (and the CLR) has two aggregate data types: struct (value-type, stored on the stack, ...
29
votes
5answers
6k views

Why do all <algorithm> functions take only ranges, not containers?

There are many useful functions in <algorithm>, but all of them operate on "sequences" - pairs of iterators. E.g., if I have a container and like to run std::accumulate on it, I need to write: ...
21
votes
3answers
2k views

Why is the rec keyword needed in F#?

In F# it is necessary to use the rec keyword. In Haskell there is no need to explicitly tell if a given function is recursive or not. Given the role of recursion in functional programming, the F# ...
8
votes
7answers
2k views

Please explain the benefit(s) of using an XML-based syntax (e.g. XAML) instead of normal source code (e.g. WinForms)? [closed]

First off, please note that this question is not about WPF vs. WinForms. What are the highest-ranking benefits that led Microsoft to invent XAML in favour of the “old” approach of generating ...
5
votes
5answers
3k views

Scalability and Programming languages

What makes a language scalable ? I believe scalability is more about system design. It sounds really odd to me, to say that one language is more scalable than the another.
9
votes
3answers
1k views

Is duplicate syntax for defining named functions a bad language design decision?

I am modelling a programming language for fun, and the syntax is heavily influenced by Scala - specifically function definitions. I have encountered a design problem because my language does not ...
3
votes
4answers
2k views

Why many programming languages have only 2 data-structures: arrays and hashes?

Many programming languages have only those 2 structures, and even some languages that have more structures still only provide special syntax for those 2; usually, [] and {}. Why is this? Is there ...
2
votes
2answers
230 views

Why not expose activation records as data types? [closed]

Scoped languages tend to store the local variables of a given scope or function together in a data structure known as an activation record. Stack frames are examples of instances of activation records....
9
votes
3answers
516 views

What rationale is used when programming language designers decide what sign the result of modulo operation takes?

Going through Modulo operation (the avenue I entered while exploring the difference between rem and mod) I came across: In mathematics the result of the modulo operation is the remainder of the ...
5
votes
6answers
3k views

C++: calling non-member functions with the same syntax of member ones

One thing I'd like to do in C++ is to call non-member functions with the same syntax you call member functions: class A { }; void f( A & this ) { /* ... */ } // ... A a; a.f(); // this is the ...
4
votes
6answers
553 views

Do you have to have boxing of primitives in OO language?

Is boxing of primitives required in OO languages to keep them consistent with the rest of the object system (generics etc.)? Or is it avoidable - is it possible to avoid any additional performance ...
4
votes
3answers
719 views

Why do you need “self.” in Python to refer to instance variables?

I have been programming into a number of languages like Java, Ruby, Haskell and Python. I have to switch between many languages per day due to different projects I work on. Now, the issue is I often ...
4
votes
1answer
2k views

Reasoning behind the syntax of octal notation in Java?

Java has the following syntax for different bases: int x1 = 0b0101; //binary int x2 = 06; //octal int x3 = 0xff; //hexadecimal Is there any reasoning on why it is 0 instead of something like ...
3
votes
1answer
393 views

Question about Java nested classes design decision

I was shocked today to discover that this code compiles cleanly in Java: public class A { public static class B { private static void x() {} } private static class C { private /* So, ...
1
vote
2answers
5k views

Why doesn't Ruby have implicit conversion of Fixnum into String?

Ruby normally makes things easy. However, it doesn't allow implicitely converting a number to a string: 2.0.0p247 :010 > "a"+1 TypeError: no implicit conversion of Fixnum into String Why is this ...
38
votes
22answers
3k views

Has whitespace in identifiers ever been idiomatic? [closed]

C# style suggests using CamelCase in identifiers to delimit words. Lisp tradition suggests using-dashes-instead. Has there ever existed a programming language where using spaces in identifiers was ...
8
votes
1answer
2k views

What's the problem with Scala's XML literals?

In this post, Martin (the language's head honcho) writes: [XML literals] Seemed a great idea at the time, now it sticks out like a sore thumb. I believe with the new string interpolation ...