Comparison of programming languages (syntax): Difference between revisions
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Language syntax comparison table |
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{| class="wikitable sortable" |
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! java !! visual basic !! c++ !!python !! php !! applescript !! bash !! windows powershell!! Header text !! Header text !! Header text !! Header text |
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|- |
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| if || Example || Example || Example || Example || Example || Example || Example || Example || Example || Example || Example |
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|- |
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| loop || Example || Example || Example || Example || Example || Example || Example || Example || Example || Example || Example |
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|- |
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| function || Example || Example || Example || Example || Example || Example || Example || Example || Example || Example || Example |
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|- |
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| string || Example || Example || Example || Example || Example || Example || Example || Example || Example || Example || Example |
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|- |
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| int || Example || Example || Example || Example || Example || Example || Example || Example || Example || Example || Example |
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|- |
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| comments || Example || Example || Example || Example || Example || Example || Example || Example || Example || Example || Example |
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|- |
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| Example || Example || Example || Example || Example || Example || Example || Example || Example || Example || Example || Example |
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| Example || Example || Example || Example || Example || Example || Example || Example || Example || Example || Example || Example |
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==See also== |
==See also== |
||
* [[Curly bracket programming languages]], a broad family of programming language syntaxes |
* [[Curly bracket programming languages]], a broad family of programming language syntaxes |
Revision as of 14:47, 12 April 2012
This article needs additional citations for verification. (October 2009) |
This is a comparison of programming language syntax.
Expressions
Programming language expressions can be broadly classified in three classes:
prefix notation
- Lisp (* (+ 2 3) (expt 4 5))
infix notation
suffix, postfix, or Reverse Polish notation
- Forth 2 3 + 4 5 ** *
Statements
Programming language statements typically have conventions for:
- statement separators;
- statement terminators; and
- line continuation
A statement separator is used to demarcate boundaries between two separate statements. A statement terminator is used to demarcate the end of an individual statement. Line continuation is a convention in languages where the newline character could potentially be misinterpreted as a statement terminator. In such languages, it allows a single statement to span more than just one line.
Language | Statement separator/terminator | Secondary separator[1] |
---|---|---|
ABAP | period separated | |
Ada | semicolon terminated | |
ALGOL | semicolon separated | |
ALGOL 68 | semicolon and comma separated[2] | |
AppleScript | newline terminated | |
AutoHotkey | newline terminated | |
BASIC | newline terminated | colon |
Boo | newline terminated | |
C | semicolon terminates statements | comma separates expressions |
C++ | semicolon terminates statements | comma separates expressions |
C# | semicolon terminated | |
COBOL | period separated | |
Cobra | newline terminated | |
D | semicolon terminated | |
Eiffel | newline terminated | semicolon |
Erlang | colon separated, period terminated | |
Falcon | newline separated | |
Fortran | newline terminated | semicolon |
Forth | ? | whitespace |
GFA BASIC | newline terminated | |
Go | semicolon separated (inserted by compiler) | |
Haskell (in do-notation) | semicolon separated | |
Haskell (in do-notation, when braces are omitted) | newline separated | |
Java | semicolon terminated | |
JavaScript | semicolon separated (but sometimes implicitly inserted on newlines) | |
Lua | whitespace separated (semicolon optional) | |
MATLAB | newline terminated | semicolon or comma[3] |
Object Pascal (Delphi) | semicolon separated | |
Objective-C | semicolon terminated | |
OCaml | semicolon separated | |
Pascal | semicolon separated | |
Perl | semicolon separated | |
PHP | semicolon terminated | |
Prolog | period terminated | |
Python | newline terminated | semicolon |
Ruby | newline terminated | semicolon |
Scala | newline terminated (semicolon optional) | semicolon |
Simula | semicolon separated | |
S-Lang | semicolon separated | |
Smalltalk | period separated | |
Standard ML | semicolon separated | |
Visual Basic | newline terminated | |
Visual Basic .NET | newline terminated | |
Windows PowerShell | newline terminated | semicolon separated |
Language | Statement separator/terminator | Secondary separator[1] |
Line continuation
Whitespace - Languages that do not need continuations
Ampersand as last character of line
Backslash as last character of line
Backtick as last character of line
Hyphen as last character of line
Left parenthesis as last character of line
- COMMAND.COM, cmd.exe: starting a parenthetical block can allow line continuation.[4]
Underscore as last character of line
Ellipsis (as three periods–not one special character)
- MATLAB: The ellipsis token need not be the last characters on the line, but any following it will be ignored.[5] (In essence, it begins a comment that extends through (i.e. including) the first subsequent newline character. Contrast this with an inline comment, which extends until the first subsequent newline.)
Some form of inline comment serves as line continuation
- Turbo Assembler:
\
- m4:
dnl
- TeX:
%
Character position
- Fortran 77: A non-comment line is a continuation of the previous non-comment line if any non-space character appears in column 6. Comment lines cannot be continued.
- Cobol: String constants may be continued by not ending the original string in a PICTURE clause with ', then inserting a - in column 7 (same position as the * for comment is used.)
- TUTOR: Lines starting with a tab (after any indentation required by the context) continue the previous command.
[End and Begin] using normal quotes
- C and C++ preprocessor: The string is ended normally and continues by starting with a quote on the next line.
Libraries
![]() | This section needs expansion. You can help by adding to it. (December 2009) |
To import a library is a way to read external, possibly compiled, routines, programs or packages. Imports can be classified by level (module, package, class, procedure,...) and by syntax (directive name, attributes,...)
File import
- ASP:
#include file="filename"
- AutoIt, C, C++:
#include "filename"
,#include <filename>
- Falcon:
load "filename"
- Lua:
require("filename")
- MATLAB:
addpath(directory)
[6] - Perl:
require "filename";
- PHP:
include filename
Package import
- Ada:
with package
- C, C++:
#include filename
- Cobra:
use Package.Name
- D:
import package.module;
,import altname = package.module;
- Falcon:
load module
,load module.submodule
- Go:
import altname "package/name"
- Haskell:
import Module
,import qualified Module as M
- Java, MATLAB:
import package.*
- Lua:
require("modname")
- Oberon:
IMPORT module
- Pascal:
uses unit
- Perl:
use Module;
- Python:
import module
,from module import *
- Scala:
import package._
,import package
Class import
- Falcon:
import class
- Java, MATLAB:
import package.class
- Python:
from module import class
- Scala:
import package.class
,import package.{ class1 => alternativeName, 'class2 }
,import
package._
Procedure/function import
- D:
import package.module : symbol;
,import package.module : altsymbolname = symbol;
- Haskell:
import Module (function)
- MATLAB:
import package.function
- Perl:
use Module ('symbol');
- Python:
from module import function
- Scala:
import package.class.function
,import package.class.{ function => alternativeName, otherFunction }
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
Required to access code
Blocks
![]() | This section needs expansion. You can help by adding to it. (November 2008) |
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 (aka Curly brackets) { }
:
- Curly bracket programming languages: C, C++, Objective-C, Go, Java, JavaScript, ECMAScript, C#, D, Perl, PHP (
for
&loop
loops, or pass a block as argument), Scala, S-Lang, Windows PowerShell, Haskell (in do-notation)
Parentheses
begin ... end:
do ... done:
- Visual Basic, Fortran, TUTOR (with mandatory indenting of block body), Visual Prolog
do ... end
X ... end (e.g. if ... end
):
- Bash (
for
&while
loops), 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 ...):
(progn ...):
(do ...):
Indentation
- Off-side rule languages: Cobra, Haskell (in do-notation when braces are omitted), occam, Python
Others
- Bash: if ~ fi, do ~ done, case ~ esac;
- ALGOL 68: begin ~ end, ( ~ ), if ~ fi, do ~ od
- Lua: repeat ~ until
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:
Symbol | Languages |
---|---|
C | Fortran 77 and earlier; the 'C' must be in column 1 of a line to indicate a comment. |
REM, ::, : | BASIC, COMMAND.COM, cmd.exe |
NB. | J; from the (historically) common abbreviation Nota bene, the Latin for "note well". |
⍝ | APL; the mnemonic is the glyph (jot overstruck with shoe-down) resembles a desk lamp, and hence "illuminates" the foregoing. |
# | bash, Cobra, Perl, Python, Ruby, Windows PowerShell, PHP, Maple, httpd.conf |
% | TeX, Prolog, MATLAB,[7] Erlang, S-Lang, Visual Prolog |
// | ActionScript, C (C99), C++, C#, D, Go, Java, JavaScript, Object Pascal (Delphi), Objective-C, PHP, Scala |
' | Visual Basic, VBScript, RealBasic |
! | Fortran, Basic Plus, Inform |
; | AutoHotkey, AutoIt, Lisp, Common Lisp, Clojure, Rebol, Scheme, many assemblers, Windows .ini and .reg files |
-- | Euphoria, Haskell, SQL, Ada, AppleScript, Eiffel, Lua, VHDL, SGML |
* | COBOL, PAW, many assemblers |
|| | Curl |
" | Vimscript |
\ | Forth |
:: | Batch file[8] |
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.
Examples:
Symbol | Languages |
---|---|
¢ ~ ¢, # ~ #, co ~ co, comment ~ comment | ALGOL 68 |
/* */ | ActionScript, AutoHotkey, C, C++, C#, D, Go, Java, JavaScript, Objective-C, PHP, PL/I, Scala (can be nested), SQL, Visual Prolog, CSS |
#cs #ce | AutoIt |
/+ +/ | D (can be nested) |
/# #/ | Cobra (can be nested) |
<# #> | Powershell |
=begin =cut | Perl |
=begin =end | Ruby |
#<tag> #</tag> | S-Lang |
{- -} | Haskell |
(* *) | Object Pascal (Delphi), ML, Mathematica, Pascal, Applescript, OCaml (can be nested), Standard ML (can be nested), Maple |
{ } | Object Pascal (Delphi), Pascal |
|# #| | Curl |
%{ %} | MATLAB[7] |
#| |# | Lisp |
--[[ ]] | Lua |
" " | Smalltalk |
(comment ...) | Clojure |
Unique variants
Fortran
- The indentation of 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 previous 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.
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-(double)quotes although sometimes used to comment-out lines of source, does not actually form a comment. The enclosed text becomes a string, usually a string statement. Python usually ignores a lone string as a statement (except when a string is the first statement in the body of a module, class or function; see docstring).
Ruby
- As with Python and Perl, Ruby has no specific block-comment syntax. However, like Perl, documentation blocks can be used as block comments as they are ignored by the interpreter.
S-Lang
- The region of lines enclosed by the #<tag> and #</tag> 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, #<latex> could indicate the start of a block of LaTeX formatted documentation.
Haskell
- Haskell's comments can be stacked as brackets:
{- some {-comments-} here -}
,
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, ETA) 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.
Language | In-line comment | Block comment | |
---|---|---|---|
Ada, Eiffel, Euphoria, Occam, SPARK, ANSI SQL, ToolBook OpenScript, and VHDL | -- InlineComment
|
||
ALGOL 60 | comment BlockComment;
| ||
ALGOL 68 | ¢ BlockComment ¢
| ||
AppleScript | -- InlineComment
|
(* BlockComment *)
| |
Assembly language (varies) | ; InlineComment one example (most assembly languages use line comments only)
|
||
AutoHotkey | ; InlineComment
|
/* BlockComment */
| |
AWK, Bash, Bourne shell, C shell, Maple, Python, R, Tcl, and Windows PowerShell | # InlineComment
|
<# BlockComment #>
|
|
BASIC (various dialects): | 'InlineComment (not all dialects)
|
||
C (K&R, ANSI/C89/C90), CHILL, CSS, PL/I, and REXX | /* BlockComment */
| ||
C (C99), C++, Go, and JavaScript | // InlineComment
|
/* BlockComment */
| |
C# | // InlineComment /// InlineComment (XML documentation comment)
|
/* BlockComment */ /** BlockComment */ (XML documentation comment)
| |
Cobol | InlineComment (when * is in column 7)
|
||
Curl | || InlineComment
|
|# BlockComment #|
| |
Cobra | # InlineComment
|
/# BlockComment #/ (nestable)
| |
D | // InlineComment /// Documentation InlineComment , (ddoc comments)
|
/* BlockComment */ /** Documentation BlockComment */ , (ddoc comments)
| |
DCL | $! InlineComment
|
||
ECMAScript (JavaScript, ActionScript, etc.) | // InlineComment
|
/* BlockComment */
| |
Forth | \ InlineComment
|
( BlockComment ) (single line only)
| |
FORTRAN 66/77 | C InlineComment (the letter 'C' in the first column makes the entire line a comment).
|
||
Fortran 90 | ! InlineComment (all characters on the line, from the exclamation mark onwards, are comments)
|
||
HTML (see SGML below) | |||
Java: | // InlineComment
|
/* BlockComment */
| |
Lisp and Scheme | ; InlineComment
|
#| BlockComment |#
| |
Lua | -- InlineComment
|
--[==[ BlockComment]==] (variable number of = signs)
| |
Maple | # InlineComment
|
(* BlockComment *)
| |
Mathematica | % (* BlockComment *)
| ||
Matlab | % InlineComment
|
%{ Note: Both percent–bracket symbols must be the only non-whitespace characters on their respective lines. | |
Object Pascal (Delphi) | // InlineComment
|
(* BlockComment *) { BlockComment }
| |
OCaml | (* BlockComment (* nestable *) *)
| ||
Pascal, Modula-2, Modula-3, Oberon, and ML: | (* BlockComment *) (OCaml comments are nestable)
| ||
Perl and Ruby | # InlineComment
|
=begin (POD documentation comment)
| |
PHP | # InlineComment // InlineComment
|
/* BlockComment */
| |
PILOT | R:InlineComment
|
||
PL/SQL and TSQL | -- InlineComment
|
/* BlockComment */
| |
REALbasic | ' InlineComment // InlineComment rem InlineComment
|
||
SAS | * BlockComment; /* BlockComment */
| ||
Seed7 | # InlineComment
|
(* BlockComment *)
| |
Simula | comment BlockComment; ! BlockComment;
| ||
SGML, including HTML | :A comment declaration starts with <! , followed by zero or more comments, followed by > . A comment starts and ends with -- , and does not contain any occurrence of -- . Valid examples are:
| ||
Smalltalk | "BlockComment"
| ||
Smarty | {* BlockComment *}
| ||
Standard ML | (* BlockComment *)
| ||
TeX, LaTeX, PostScript, Erlang, and S-Lang | % InlineComment
|
||
Texinfo | @c InlineComment
|
||
TUTOR | * InlineComment command $$ InlineComment
|
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Visual Basic | ' InlineComment Rem InlineComment
|
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Visual Basic .NET | ' InlineComment
|
||
Visual Prolog | % InlineComment
|
/* BlockComment */
| |
XML, including XHTML | <!--BlockComment--> (comment must not contain -- and must not start or end with single - )
|
Language syntax comparison table
java | visual basic | c++ | python | php | applescript | bash | windows powershell | Header text | Header text | Header text | Header text |
---|---|---|---|---|---|---|---|---|---|---|---|
if | Example | Example | Example | Example | Example | Example | Example | Example | Example | Example | Example |
loop | Example | Example | Example | Example | Example | Example | Example | Example | Example | Example | Example |
function | Example | Example | Example | Example | Example | Example | Example | Example | Example | Example | Example |
string | Example | Example | Example | Example | Example | Example | Example | Example | Example | Example | Example |
int | Example | Example | Example | Example | Example | Example | Example | Example | Example | Example | Example |
comments | Example | Example | Example | Example | Example | Example | Example | Example | Example | Example | Example |
Example | Example | Example | Example | Example | Example | Example | Example | Example | Example | Example | Example |
Example | Example | Example | Example | Example | Example | Example | Example | Example | Example | Example | Example |
See also
- Curly bracket programming languages, a broad family of programming language syntaxes
References
- ^ a b For multiple statements on one line
- ^ Three different kinds of clauses, each separates phrases and the units differently:
- serial-clause using go-on-token (viz. semicolon): begin a; b; c end - units are executed in order.
- collateral-clause using and-also-token (viz. “,”): begin a, b, c end - order of execution is to be optimised by the compiler.
- parallel-clause using and-also-token (viz. “,”): par begin a, b, c end - units must be run in parallel threads.
- ^ semicolon - result of receding statement hidden, comma - result displayed
- ^ http://ss64.com/nt/syntax-brackets.html
- ^ Mathworks.com
- ^ For an M-file (MATLAB source) to be accessible by name, its parent directory must be in the search path (or current directory).
- ^ a b Mathworks.com
- ^ SS64.com