Questions tagged [syntax]

Syntax refers to the set of rules that define how to write a correctly structured program in a language. It explicitly does not deal with the program's meaning or interpretation.

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14
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5answers
682 views

Is there a programming language where every string is a valid program?

Does there exist a Turing complete programming language such that for a fixed alphabet (say, ASCII), every possible permutation of those characters is a semantically valid program capable of being ...
6
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5answers
4k views

Which programming languages don't use operator precedence besides Lisp-like languages? [closed]

And what do you think about operator precedence? Would be harder programming in a language where the operations are executed in sequential order? Ex.: 2 + 3 * 4 == 20 2 + (3 * 4) == 14 OK, the Lisp ...
13
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3answers
703 views

Why does Forth's flexibility make a grammar inappropriate for it?

I've recently undertaken the task of writing a stack-based programming language. Before I started designing my language however, I thought it'd be a good idea to read and experiment with existing ...
6
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9answers
2k views

Would a “downcast if block” be a reasonable language feature?

Consider the following "if cast": class A { public void f1() { ... } } class B : A { public void f2() { ... } } A a = foo(); // might return A or B if ( a is B ) { // Inside block,...
42
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5answers
16k 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 ...
31
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14answers
12k views

Why don't programming languages automatically manage the synchronous/asynchronous problem?

I have not found many resources about this: I was wondering if it's possible/a good idea to be able to write asynchronous code in a synchronous way. For example, here is some JavaScript code which ...
5
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5answers
288 views

Reasons to use (and not to use) a repeated delimiter to escape that delimiter?

For the designer of a language syntax, what are some reasons to choose a repeated delimiter to escape that delimiter, instead of having a separate escape character to escape that delimiter. A common ...
0
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2answers
52 views

Does Get in Repo Imply GetById?

REST APIs in virtually all languages use methods named Get to get GetById(int id). Is it ok to use this convention for repositories? Let's say I have a Professions repository for the sake of example. ...
-2
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1answer
144 views

Is there a common agreed upon token symbol used in computer science or common across languages?

I have seen tokens like this: var message = "Hello, {Name}"; and like this: var message = "Hello, ${name}"; and like this: var message = "Hello, @NAME"; and a few ...
0
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2answers
2k views

Nested functions; allow or not? [closed]

Having programmed a whole lot in python, using nested functions is a good way to not clutter the namespace with small helper functions that are only used once. Now I'm programming in go, and upon ...
219
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21answers
174k views

Are `break` and `continue` bad programming practices?

My boss keeps mentioning nonchalantly that bad programmers use break and continue in loops. I use them all the time because they make sense; let me show you the inspiration: function verify(object) {...
4
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2answers
8k views

How to generate C++ code? (probably WITH (not FROM) Python) [closed]

For a scientific simulation I need to write some computations in C++. Since this became extremely tedious, I built myself a small code generator: In a scripting language (Python) you put together a ...
26
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4answers
14k views

Is colon in python blocks technically necesary?

This is really just a theoretical question by a python newbie who wants to understand more. I keep forgetting the colon after the block initial statements in python. Those are what I mean: for <...
42
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10answers
6k views

Why do most mainstream languages not support “x < y < z” syntax for 3-way Boolean comparisons?

If I want to compare two numbers (or other well-ordered entities), I would do so with x < y. If I want to compare three of them, the high-school algebra student will suggest trying x < y < z....
25
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6answers
3k views

Explaining new or uncommon syntax in comments [duplicate]

As per the title, should I be explaining syntax that I use in my code when I have a reasonable expectation that a developer looking at my code in the future will not be familiar with it? Short caveats ...
0
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3answers
324 views

Does compiler AST include functions and classes?

In most of the examples for Abstract Syntax Trees (AST), I see no function or classes. I am wondering, if the functions and classes are represented in the AST? If no, where should the functions, ...
145
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15answers
29k views

Why did memory-managed languages like Java, Javascript, and C# retain the `new` keyword?

The new keyword in languages like Java, Javascript, and C# creates a new instance of a class. This syntax seems to have been inherited from C++, where new is used specifically to allocate a new ...
0
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2answers
203 views

What Does “The Program Must Process Each Character Before Reading the Next One” Mean?

From the book Think Like a Programmer (emphasis mine) The Luhn formula is a widely used system for validating identification numbers. Using the original number, double the value of every other ...
0
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2answers
431 views

Logically, is there a reason why ++i++ can not be a valid expression?

I had to increment my integer twice in a loop, so I thought I would try and be clever: for (int i = 0; !sl.isEmpty(); ++i++) { ... } ++i++ however is not an assignable expression, at least in GCC. ...
0
votes
4answers
185 views

Language design : use equals symbol = both for affectation and comparison, like in MySQL

I'm currently designing a database query language and I came to wonder what should be the best syntax for the comparison operator. Most modern languages use ==, but amongst the database languages ...
9
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1answer
417 views

Which was the first language to allow underscore in numeric literals?

Java 7+ allows to use underscores in numeric literals,which do not affect the value of the literal, yet are useful for grouping. Examples from the Java 7 documentation, entitled "Underscores in ...
1
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1answer
62 views

Lexicon for syntax patterns? [closed]

I am having trouble finding a lexicon which provides terminology for the explicit patterns that are employed when parsing syntax. I am trying to write about the niggling differences between the 10+ ...
1
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1answer
134 views

What is the BNF (or BNF-like) syntax for a specific number of repetitions?

I would like to write something like <byte> ::= <bit>*8 to mean that a <byte> is a sequence of exactly 8 <bit>'s. Is there a way to do this in BNF[1][2] or a widely used ...
26
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9answers
11k views

What is the benefit of having the assignment operator return a value?

I'm developing a language which I intend to replace both Javascript and PHP. (I can't see any problem with this. It's not like either of these languages have a large install base.) One of the things ...
23
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6answers
15k views

Is there a language that transpiles to C, with better syntax? [closed]

CoffeeScript is a language that transpiles to JavaScript, with a clean syntax, inspired by Ruby. Is there a similar language that transpiles to C, allowing for more readable code without compromising ...
70
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4answers
12k views

Why does the type go after the variable name in modern programming languages?

Why is it that in nearly all modern programming languages (Go, Rust, Kotlin, Swift, Scala, Nim, even Python last version) types always come after the variable name in the variable declaration, and not ...
2
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4answers
1k views

When to (enforce) linting in a software project

I'm heading a new team of developers working on a software project that makes use of continuous integration (circleci) w/ a pretty fleshed out suite of busterjs unit/integration/acceptance tests. Our ...
-3
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3answers
3k views

What is the difference between extending a class and instantiating an object of that class? [closed]

I frequently see people extending a class like this for example: public class Bananas extends Fruits { public void eatFruit(){ } } rather than public class Bananas { Fruits ...
2
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3answers
368 views

Is a literal out of range a syntax error or a semantic error?

I am reading more about the differences between syntax and semantics, but I am still wondering about this one. Let's assume that we have a language that only allows integers to be in the range of 0-...
54
votes
4answers
59k views

Why do C# developers newline opening brackets? [closed]

I've spent most of the last several years working mainly with C# and SQL. Every programmer I've worked with over that time was in the habit of placing the opening brace of a function or control flow ...
3
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7answers
1k views

Why don't languages use the words “and” and “or” instead of “&&” and “||”?

When I was a beginner it took a while to learn the language syntax and the idea that languages couldn't improve after they were invented. But now we're seeing new language features added every year ...
8
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1answer
1k views

quantitatively comparing AST shapes

How could one compare the shape of abstract syntax trees of similar source code programs (C, C++, Go, or anything compiled with GCC...)? I guess that plagiarism detection on source code would use ...
1
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1answer
148 views

Question about Backus-NaurForm (BNF)

To write the grammar for Whole Numbers (0,1,2...) in BNF, we may write: Number ::⇒ Digit MoreDigits MoreDigits ::⇒ MoreDigits ::⇒ Number Digit ::⇒ 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 For a ...
68
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5answers
38k views

What's the difference between implementing an Interface explicitly or implicitly?

In Visual Studio I can right-click on an interface and choose to Implement Interface, or Implement Interface Explicitly. public class Test : ITest { public string Id // Generated by Implement ...
66
votes
3answers
26k views

Is there a performance benefit to using the method reference syntax instead of lambda syntax in Java 8?

Do method references skip the overhead of the lambda wrapper? Might they in the future? According to the Java Tutorial on Method References: Sometimes... a lambda expression does nothing but call an ...
-2
votes
1answer
155 views

Are there languages/syntaxes for representing graphs? [closed]

S-expressions are a well-known way of describing trees in high-level code. Is there something similar for describing graphs? The two closest things I've found are DOT and Ko. Both aren't quite what ...
1
vote
2answers
291 views

How to parse DSL file to HTML?

There's DSL format for creating and distributing dictionaries. Every dictionary article in such formats looks like this: algorithm [m0][b]al·go·rithm[/b] {{id=000001018}} [c rosybrown]\[[/c][c ...
3
votes
2answers
113 views

What is the term for the side on which a variable type is written in a given language?

In the case that a type is specified, it could be on the left (before) or the right (after) of the variable name. For example, C, C# and Java have the type specified before the variable: int num = 5;...
77
votes
8answers
57k views

A practical use of “yield” keyword in C# [closed]

After almost 4 years of experience, I haven't seen a code where yield keyword is used. Can somebody show me a practical usage (along explanation) of this keyword, and if so, aren't there other ways ...
0
votes
1answer
119 views

Why are new modern languages shifting to a variableName: VariableType syntax approach? [duplicate]

Modern languages like Rust, Kotlin, and TypeScript, define their syntax to declare variables as: myVariableName: VariableType As opposed to the C-like approach not so old languages like JavaScript, ...
1
vote
0answers
233 views

What obstacles should I expect in building universal Abstract Syntax Tree's manipulation tool?

I am trying to build code generation and transformation tool and hence I need software for Abstract Syntax Tree manipulation for at least three languages (Coq, Haskell, Java). So far I have managed to ...
134
votes
14answers
20k views

Why are statements in many programming languages terminated by semicolons?

Is there a reason that a semi-colon was chosen as a line terminator instead of a different symbol? I want to know the history behind this decision, and hope the answers will lead to insights that may ...
9
votes
5answers
68k views

Checking “instanceof” rather than value using a switch statement

Is there some syntax (other than a series of if statements) that allows for the use of a switch statement in Java to check if an object is an instanceof a class? I.e., something like this: switch (...
91
votes
13answers
121k views

What's the difference between syntax and semantics?

I've always thought that referring to the syntax of a language was the same as referring to the semantics of a language. But I've been informed that apparently that's not the case. What's the ...
11
votes
2answers
2k views

How did the custom of using square brackets for array elements develop?

Many programming language use the syntax a[i] to refer to the i'th element of an array, sequence, or vector a - specifically, C and Pascal (from the late 1960s and early 1970s) do this. On the other ...
11
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2answers
2k views

Is i,j = 1 really misleading? [closed]

There is a common argument about multiple variable initialisation in a one liner, that is : Consider for example int i, j = 1; which might lead some people to mistakingly believe both variables ...
16
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6answers
6k views

One-liners vs. readability: when to stop reducing code? [closed]

Context I recently got interested into producing better formatted code. And by better I mean "following rules endorsed by enough people to consider it a good practice" (since there will never be one ...
3
votes
2answers
15k views

foreach over multiple lists at once

Are there any languages that support foreach over multiple lists at once? Something like this: foreach (string a in names, string b in places, string c in colors) { // do stuff with a, b, c }...
8
votes
1answer
578 views

What makes some things easier to parse than others?

I was just reading the Wikipedia page for WebAssembly and it says: “WebAssembly is… designed to be faster to parse than JavaScript” , which got me thinking, what makes a certain language or data ...
20
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9answers
6k views

Why do most programming languages not nest block comments?

A few do, but not any of the popular ones as far as I know. Is there something bad about nesting comments? I plan to have block comments nest in the (small) language I'm working on, but I would like ...