comparison of programming languages syntax

AutoHotkey, AutoIt, C, C++
#import "filename", Objective-C
#import Objective-C
Import["filename"] Mathematica, Wolfram Language
include 'filename' Fortran
include "filename";PHP
include [filename] program, Pick Basic
#include [filename] program Pick Basic
include!("filename");Rust
load "filename"Ruby
load %filename Red
require('filename') Lua
require "filename"; Perl, PHP
require "filename" Ruby
source(""filename"") R
@import("filename");Zig
Package import
#include filename C, C++
#[path = "filename"] mod altname;, Rust
@import module; Objective-C
< :-use_module(module). Prolog:
from module import * Python
extern crate libname;, Rust
extern crate libname as altname; Rust
mod modname;, Rust
library("package") R:
IMPORT module Oberon
import altname "package/name" Go:
import package.module;, D
import altname = package.module; D
import Module, Haskell
import qualified Module as M Haskell
import package.* Java, MATLAB, Kotlin
import "modname"; JavaScript:
import altname from "modname";, JavaScript:
import package Scala
import package._, Scala
import module Swift
import module V (Vlang)
import module, Python
require('modname') Lua:
require "gem", Ruby
use module, Fortran 90+
use module, only : identifier Fortran 90+
use Module;, Perl
use Module qw(import options);Perl
use Package.Name Cobra
uses unit Pascal
with package Ada
@import("pkgname");Zig
Class import
from module import Class Python
import package.class Java, MATLAB, kotlin
import class from "modname";, JavaScript
import {class} from "modname";, JavaScript
import {class as altname} from "modname";JavaScript
import package.class, Scala
import package.{ class1 => alternativeName, class2 }, Scala
import package._Scala
use Namespace\ClassName;, PHP
use Namespace\ClassName as AliasName; PHP
Procedure/function import
from module import function Python:
import package.module : symbol;, D:
import package.module : altsymbolname = symbol; D:
import Module (function) Haskell:
import function from "modname";, JavaScript:
import {function} from "modname";, JavaScript:
import {function as altname} from "modname";JavaScript:
import package.function MATLAB:
import package.class.function, Scala:
import package.class.{ function => alternativeName, otherFunction }Scala:
use Module ('symbol');Perl:
use function Namespace\function_name;, PHP:
use Namespace\function_name as function_alias_name; PHP:
use module::submodule::symbol;, Rust:
use module::submodule::{symbol1, symbol2};, Rust:
use module::submodule::symbol as altname; Rust:
Constant import
use const Namespace\CONST_NAME; PHP
The above statements can also be classified by whether they are a syntactic convenience (allowing things to be referred to by a shorter name, but they can still be referred to by some fully qualified name without import), or whether they are actually required to access the code (without which it is impossible to access the code, even with fully qualified names).

Syntactic convenience
import package.* Java
import package.class Java
open module OCaml
Required to access code
import altname "package/name" Go
import altname from "modname";JavaScript
import modulePython

Blocks

A block is a notation for a group of two or more statements, expressions or other units of code that are related in such a way as to comprise a whole.

Braces (a.k.a. curly brackets) { ... }

Curly bracket programming languages: C, C++, Objective-C, Go, Java, JavaScript/ECMAScript, V (Vlang), C#, D, Perl, PHP (for & loop loops, or pass a block as argument), R, Rust, Scala, S-Lang, Swift, PowerShell, Haskell (in do-notation), AutoHotkey, Zig
Parentheses ( ... )
Batchfile, F# (lightweight syntax), OCaml, Prolog, Standard ML
Square brackets [ ... ]
Rebol, Red, Self, Smalltalk (blocks are first class objects. a.k.a. closures)
begin ... end

Ada, ALGOL, F# (verbose syntax), Pascal, Ruby (for, do/while & do/until loops), OCaml, SCL, Simula, Erlang.
do ... end

PL/I, REXX
do ... done

Bash (for & while loops), F# (verbose syntax) Visual Basic, Fortran, TUTOR (with mandatory indenting of block body), Visual Prolog
do ... end
Lua, Ruby (pass blocks as arguments, for loop), Seed7 (encloses loop bodies between do and end)
X ... end (e.g. if ... end):
Ruby (if, while, until, def, class, module statements), OCaml (for & while loops), MATLAB (if & switch conditionals, for & while loops, try clause, package, classdef, properties, methods, events, & function blocks), Lua (then / else & function)
(begin ...)

Scheme
(progn ...)

Lisp
(do ...)

Clojure
Indentation
Off-side rule languages: Boo, Cobra, CoffeeScript, F#, Haskell (in do-notation when braces are omitted), LiveScript, occam, Python, Nemerle (Optional; the user may use white-space sensitive syntax instead of the curly-brace syntax if they so desire), Nim, Scala (Optional, as in Nemerle)
Free-form languages: most descendants from ALGOL (including C, Pascal, and Perl); Lisp languages
Others
Ada, Visual Basic, Seed7: if ... end if
APL: :If ... :EndIf or :If ... :End
Bash, sh, and ksh: if ... fi, do ... done, case ... esac;
ALGOL 68: begin ... end, ( ... ), if ... fi, do ... od
Lua, Pascal, Modula-2, Seed7: repeat ... until
COBOL: IF ... END-IF, PERFORM ... END-PERFORM, etc. for statements; ... . for sentences.
Visual Basic .Net: If ... End If, For ... Next, Do ... Loop
Small Basic: If ... EndIf, For ... EndFor, While ... EndWhile

Comments

Comments can be classified by:

style (inline/block)
parse rules (ignored/interpolated/stored in memory)
recursivity (nestable/non-nestable)
uses (docstrings/throwaway comments/other)

= Inline comments

=
Inline comments are generally those that use a newline character to indicate the end of a comment, and an arbitrary delimiter or sequence of tokens to indicate the beginning of a comment.
Examples:

= Block comments

=
Block comments are generally those that use a delimiter to indicate the beginning of a comment, and another delimiter to indicate the end of a comment. In this context, whitespace and newline characters are not counted as delimiters. In the examples, the symbol ~ represents the comment; and, the symbols surrounding it are understood by the interpreters/compilers as the delimiters.
Examples:

= Unique variants

=
Fortran
Indenting lines in Fortran 66/77 is significant. The actual statement is in columns 7 through 72 of a line. Any non-space character in column 6 indicates that this line is a continuation of the prior line. A 'C' in column 1 indicates that this entire line is a comment. Columns 1 though 5 may contain a number which serves as a label. Columns 73 though 80 are ignored and may be used for comments; in the days of punched cards, these columns often contained a sequence number so that the deck of cards could be sorted into the correct order if someone accidentally dropped the cards. Fortran 90 removed the need for the indentation rule and added inline comments, using the ! character as the comment delimiter.
COBOL
In fixed format code, line indentation is significant. Columns 1–6 and columns from 73 onwards are ignored. If a * or / is in column 7, then that line is a comment. Until COBOL 2002, if a D or d was in column 7, it would define a "debugging line" which would be ignored unless the compiler was instructed to compile it.
Cobra
Cobra supports block comments with "/# ... #/" which is like the "/* ... */" often found in C-based languages, but with two differences. The # character is reused from the single-line comment form "# ...", and the block comments can be nested which is convenient for commenting out large blocks of code.
Curl
Curl supports block comments with user-defined tags as in |foo# ... #foo|.
Lua
Like raw strings, there can be any number of equals signs between the square brackets, provided both the opening and closing tags have a matching number of equals signs; this allows nesting as long as nested block comments/raw strings use a different number of equals signs than their enclosing comment: --[[comment --[=[ nested comment ]=] ]]. Lua discards the first newline (if present) that directly follows the opening tag.
Perl
Block comments in Perl are considered part of the documentation, and are given the name Plain Old Documentation (POD). Technically, Perl does not have a convention for including block comments in source code, but POD is routinely used as a workaround.
PHP

PHP supports standard C/C++ style comments, but supports Perl style as well.
Python
The use of the triple-quotes to comment-out lines of source, does not actually form a comment. The enclosed text becomes a string literal, which Python usually ignores (except when it is the first statement in the body of a module, class or function; see docstring).
Elixir
The above trick used in Python also works in Elixir, but the compiler will throw a warning if it spots this. To suppress the warning, one would need to prepend the sigil ~S (which prevents string interpolation) to the triple-quoted string, leading to the final construct ~S""" ... """. In addition, Elixir supports a limited form of block comments as an official language feature, but as in Perl, this construct is entirely intended to write documentation. Unlike in Perl, it cannot be used as a workaround, being limited to certain parts of the code and throwing errors or even suppressing functions if used elsewhere.
Raku
Raku uses #`(...) to denote block comments. Raku actually allows the use of any "right" and "left" paired brackets after #` (i.e. #`(...), #`[...], #`{...}, #`<...>, and even the more complicated #`{{...}} are all valid block comments). Brackets are also allowed to be nested inside comments (i.e. #`{ a { b } c } goes to the last closing brace).
Ruby
Block comment in Ruby opens at =begin line and closes at =end line.
S-Lang
The region of lines enclosed by the # and # delimiters are ignored by the interpreter. The tag name can be any sequence of alphanumeric characters that may be used to indicate how the enclosed block is to be deciphered. For example, # could indicate the start of a block of LaTeX formatted documentation.
Scheme and Racket
The next complete syntactic component (s-expression) can be commented out with #; .
ABAP
ABAP supports two different kinds of comments. If the first character of a line, including indentation, is an asterisk (*) the whole line is considered as a comment, while a single double quote (") begins an in-line comment which acts until the end of the line. ABAP comments are not possible between the statements EXEC SQL and ENDEXEC because Native SQL has other usages for these characters. In the most SQL dialects the double dash (--) can be used instead.

Esoteric languages
Many esoteric programming languages follow the convention that any text not executed by the instruction pointer (e.g., Befunge) or otherwise assigned a meaning (e.g., Brainfuck), is considered a "comment".

= Comment comparison

=
There is a wide variety of syntax styles for declaring comments in source code.
BlockComment in italics is used here to indicate block comment style.
InlineComment in italics is used here to indicate inline comment style.

M3GAN (2022)

Expressions

Statements

= Line continuation

Libraries

Blocks

Comments

= Inline comments

= Block comments

= Unique variants

= Comment comparison

See also

References

Notes

Kata Kunci Pencarian:

Expressions

Statements

= Line continuation

Libraries

Blocks

Comments

= Inline comments

= Block comments

= Unique variants

= Comment comparison

See also

References

Notes

Kata Kunci Pencarian:

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