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94-635: Using eval with data from an untrusted source may introduce security vulnerabilities. For instance, assuming that the get_data() function gets data from the Internet, this Python code is insecure: An attacker could supply the program with the string "session.update(authenticated=True)" as data, which would update the session dictionary to set an authenticated key to be True. To remedy this, all data which will be used with eval must be escaped, or it must be run without access to potentially harmful functions. In interpreted languages , eval

188-636: A just-in-time (JIT) compiler. Because of the significant changes, the reworked Zend Engine was called Zend Engine 3 , succeeding Zend Engine 2 used in PHP ;5. Because of the major internal changes in phpng, it must receive a new major version number of PHP, rather than a minor PHP 5 release, according to PHP's release process. Major versions of PHP are allowed to break backward-compatibility of code and therefore PHP 7 presented an opportunity for other improvements beyond phpng that require backward-compatibility breaks. In particular, it involved

282-505: A . However, maintaining the validity of this equation means that while the result of a%b is, as expected, in the half-open interval [0, b ), where b is a positive integer, it has to lie in the interval ( b , 0] when b is negative. Python provides a round function for rounding a float to the nearest integer. For tie-breaking , Python 3 uses round to even : round(1.5) and round(2.5) both produce 2 . Versions before 3 used round-away-from-zero : round(0.5)

376-419: A certain type. Python does not support tail call optimization or first-class continuations , and, according to Van Rossum, it never will. However, better support for coroutine -like functionality is provided by extending Python's generators . Before 2.5, generators were lazy iterators ; data was passed unidirectionally out of the generator. From Python 2.5 on, it is possible to pass data back into

470-648: A combination of reference counting and a cycle-detecting garbage collector for memory management . It uses dynamic name resolution ( late binding ), which binds method and variable names during program execution. Its design offers some support for functional programming in the Lisp tradition. It has filter , map and reduce functions; list comprehensions , dictionaries , sets, and generator expressions. The standard library has two modules ( itertools and functools ) that implement functional tools borrowed from Haskell and Standard ML . Its core philosophy

564-420: A decrease in indentation signifies the end of the current block. Thus, the program's visual structure accurately represents its semantic structure. This feature is sometimes termed the off-side rule . Some other languages use indentation this way; but in most, indentation has no semantic meaning. The recommended indent size is four spaces. Python's statements include: The assignment statement ( = ) binds

658-510: A generator function; and from version 3.3, it can be passed through multiple stack levels. Python's expressions include: In Python, a distinction between expressions and statements is rigidly enforced, in contrast to languages such as Common Lisp , Scheme , or Ruby . This leads to duplicating some functionality. For example: Statements cannot be a part of an expression—so list and other comprehensions or lambda expressions , all being expressions, cannot contain statements. A particular case

752-469: A half), followed by 3 years of security support (for same total support as before). Security updates were expedited in 2021 (and again twice in 2022, and more fixed in 2023 and in September 2024 for Python 3.12.6 down to 3.8.20), since all Python versions were insecure (including 2.7 ) because of security issues leading to possible remote code execution and web-cache poisoning . Python 3.10 added

846-445: A matrix‑multiplication operator @ . These operators work like in traditional math; with the same precedence rules , the operators infix ( + and - can also be unary to represent positive and negative numbers respectively). The division between integers produces floating-point results. The behavior of division has changed significantly over time: In Python terms, / is true division (or simply division ), and //

940-422: A minor release should occur which may include new features. Every minor release should at least be supported for two years with security and bug fixes, followed by at least one year of only security fixes, for a total of a three-year release process for every minor release. No new features, unless small and self-contained, are to be introduced into a minor release during the three-year release process. The mascot of

1034-402: A name as a reference to a separate, dynamically allocated object . Variables may subsequently be rebound at any time to any object. In Python, a variable name is a generic reference holder without a fixed data type ; however, it always refers to some object with a type. This is called dynamic typing —in contrast to statically-typed languages, where each variable may contain only a value of

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1128-460: A new static return type, and a new mixed type. "Attributes", often referred to as "annotations" in other programming languages, were added in PHP 8, which allow metadata to be added to classes. throw was changed from being a statement to being an expression. This allows exceptions to be thrown in places that were not previously possible. PHP 8 includes changes to allow alternate, more concise, or more consistent syntaxes in

1222-461: A new and improved interactive interpreter ( REPL ), featuring multi-line editing and color support; an incremental garbage collector (producing shorter pauses for collection in programs with a lot of objects, and addition to the improved speed in 3.11 and 3.12), and an experimental just-in-time (JIT) compiler (such features, can/needs to be enabled specifically for the increase in speed), and an experimental free-threaded build mode, which disables

1316-419: A number of scenarios. For example, the nullsafe operator is similar to the null coalescing operator ?? , but used when calling methods. The following code snippet will not throw an error if getBirthday() returns null: Constructor property promotion has been added as " syntactic sugar ," allowing class properties to be set automatically when parameters are passed into a class constructor . This reduces

1410-460: A programming language [...] I just kept adding the next logical step on the way." A development team began to form and, after months of work and beta testing, officially released PHP/FI 2 in November 1997. The fact that PHP was not originally designed, but instead was developed organically has led to inconsistent naming of functions and inconsistent ordering of their parameters. In some cases,

1504-411: A standard format for distributing Python Binaries. Python 3.15 will "Make UTF-8 mode default", the mode exists in all current Python versions, but currently needs to be opted into. UTF-8 is already used, by default, on Windows (and elsewhere), for most things, but e.g. to open files it's not and enabling also makes code fully cross-platform, i.e. use UTF-8 for everything on all platforms. Python

1598-653: A string literal, with no certainty as to which one a programmer should use. Alex Martelli , a Fellow at the Python Software Foundation and Python book author, wrote: "To describe something as 'clever' is not considered a compliment in the Python culture." Python's developers usually strive to avoid premature optimization and reject patches to non-critical parts of the CPython reference implementation that would offer marginal increases in speed at

1692-525: A title the Python community bestowed upon him to reflect his long-term commitment as the project's chief decision-maker (he has since come out of retirement and is self-titled "BDFL-emeritus"). In January 2019, active Python core developers elected a five-member Steering Council to lead the project. Python 2.0 was released on 16 October 2000, with many major new features such as list comprehensions , cycle-detecting garbage collection, reference counting , and Unicode support. Python 2.7's end-of-life

1786-458: A value: In Lua 5.1, loadstring compiles Lua code into an anonymous function. Example as an expression evaluator: Example to do the evaluation in two steps: Lua 5.2 deprecates loadstring in favor of the existing load function, which has been augmented to accept strings. In addition, it allows providing the function's environment directly, as environments are now upvalues . PostScript 's exec operator takes an operand — if it

1880-417: A variety of operating systems and platforms . The PHP language has evolved without a written formal specification or standard, with the original implementation acting as the de facto standard that other implementations aimed to follow. W3Techs reports that as of 27 October 2024 (about two years since PHP 7 was discontinued and 11 months after the PHP 8.3 release), PHP 7

1974-585: Is 1.0 , round(-0.5) is −1.0 . Python allows Boolean expressions with multiple equality relations in a manner that is consistent with general use in mathematics. For example, the expression a < b < c tests whether a is less than b and b is less than c . C-derived languages interpret this expression differently: in C, the expression would first evaluate a < b , resulting in 0 or 1, and that result would then be compared with c . Python uses arbitrary-precision arithmetic for all integer operations. The Decimal type/class in

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2068-526: Is dynamically typed and garbage-collected . It supports multiple programming paradigms , including structured (particularly procedural ), object-oriented and functional programming . It is often described as a "batteries included" language due to its comprehensive standard library . Guido van Rossum began working on Python in the late 1980s as a successor to the ABC programming language and first released it in 1991 as Python 0.9.0. Python 2.0

2162-403: Is floor division. / before version 3.0 is classic division . Rounding towards negative infinity, though different from most languages, adds consistency. For instance, it means that the equation ( a + b ) // b == a // b + 1 is always true. It also means that the equation b * ( a // b ) + a % b == a is valid for both positive and negative values of

2256-522: Is a multi-paradigm programming language . Object-oriented programming and structured programming are fully supported, and many of their features support functional programming and aspect-oriented programming (including metaprogramming and metaobjects ). Many other paradigms are supported via extensions, including design by contract and logic programming . Python is known as a glue language , able to work very well with many other languages with ease of access. Python uses dynamic typing and

2350-476: Is a class called RBScript which can execute REALbasic code at runtime. RBScript is very sandboxed—only the most core language features are there, and you have to allow it access to things you want it to have. You can optionally assign an object to the context property. This allows for the code in RBScript to call functions and use properties of the context object. However, it is still limited to only understanding

2444-572: Is a major version and has breaking changes from previous versions. New features and notable changes include: Just-in-time compilation is supported in PHP 8. PHP 8's JIT compiler can provide substantial performance improvements for some use cases, while (then PHP) developer Nikita Popov stated that the performance improvements for most websites will be less substantial than the upgrade from PHP 5 to PHP 7. Substantial improvements are expected more for mathematical-type operations than for common web-development use cases. Additionally,

2538-478: Is a simple literal it pushes it back on the stack. If one takes a string containing a PostScript expression however, one can convert the string to an executable which then can be executed by the interpreter, for example: converts the PostScript expression which pops the string "Hello World" off the stack and displays it on the screen, to have an executable type, then is executed. PostScript's run operator

2632-413: Is a statically compiled language and therefore does not include an " eval " statement in the traditional sense, but does include the related " mixin " statement. The difference is that, where " eval " interprets a string as code at runtime, with a " mixin " the string is statically compiled like ordinary code and must be known at compile time. For example: The above example will compile to exactly

2726-402: Is almost always implemented with the same interpreter as normal code. In compiled languages , the same compiler used to compile programs may be embedded in programs using the eval function; separate interpreters are sometimes used, though this results in code duplication . In JavaScript , eval is something of a hybrid between an expression evaluator and a statement executor. It returns

2820-537: Is an example of how PHP variables are declared and initialized. Unlike function and class names, variable names are case-sensitive. Both double-quoted ("") and heredoc strings provide the ability to interpolate a variable's value into the string. PHP treats newlines as whitespace in the manner of a free-form language , and statements are terminated by a semicolon. PHP has three types of comment syntax : /* */ marks block and inline comments; // or # are used for one-line comments. The echo statement

2914-497: Is compiled, and possibly semantics are slightly changed. Python's developers aim for it to be fun to use. This is reflected in its name—a tribute to the British comedy group Monty Python —and in occasionally playful approaches to tutorials and reference materials, such as the use of the terms "spam" and "eggs" (a reference to a Monty Python sketch ) in examples, instead of the often-used "foo" and "bar" . A common neologism in

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3008-407: Is interpreted at compile-time instead of run-time, so it is not the meaning of eval used in this article. In PHP , eval executes code in a string almost exactly as if it had been put in the file instead of the call to eval() . The only exception is that errors are reported as coming from a call to eval() , and return statements become the result of the function. Unlike some languages,

3102-532: Is meant to be an easily readable language. Its formatting is visually uncluttered and often uses English keywords where other languages use punctuation. Unlike many other languages, it does not use curly brackets to delimit blocks, and semicolons after statements are allowed but rarely used. It has fewer syntactic exceptions and special cases than C or Pascal . Python uses whitespace indentation, rather than curly brackets or keywords, to delimit blocks . An increase in indentation comes after certain statements;

3196-707: Is no recommendation against the echo short tag <?= . Prior to PHP 5.4.0, this short syntax for echo only works with the short_open_tag configuration setting enabled, while for PHP 5.4.0 and later it is always available. The purpose of all these delimiters is to separate PHP code from non-PHP content, such as JavaScript code or HTML markup. So the shortest "Hello, World!" program written in PHP is: The first form of delimiters, <?php and ?> , in XHTML and other XML documents, creates correctly formed XML processing instructions. This means that

3290-411: Is not of a suitable type. Despite being dynamically typed , Python is strongly typed , forbidding operations that are not well-defined (for example, adding a number to a string) rather than silently attempting to make sense of them. Python allows programmers to define their own types using classes , most often used for object-oriented programming . New instances of classes are constructed by calling

3384-425: Is not processed by PHP, although the non-PHP text is still subject to control structures described in PHP code. The most common delimiters are <?php to open and ?> to close PHP sections. The shortened form <? also exists. This short delimiter makes script files less portable since support for them can be disabled in the local PHP configuration and it is therefore discouraged. Conversely, there

3478-511: Is now no longer under development and nor are any security updates planned to be released. On 1 July 2004, PHP 5 was released, powered by the new Zend Engine II. PHP 5 included new features such as improved support for object-oriented programming , the PHP Data Objects (PDO) extension (which defines a lightweight and consistent interface for accessing databases), and numerous performance enhancements. In 2008, PHP 5 became

3572-417: Is one of several facilities PHP provides to output text. In terms of keywords and language syntax, PHP is similar to C-style syntax. if conditions, for and while loops and function returns are similar in syntax to languages such as C, C++, C#, Java and Perl. PHP is loosely typed . It stores integers in a platform-dependent range, either as a 32, 64 or 128-bit signed integer equivalent to

3666-402: Is similar in functionality but instead the interpreter interprets PostScript expressions in a file, itself. In Python , the eval function in its simplest form evaluates a single expression. eval example (interactive shell): The eval function takes two optional arguments, global and locals , which allow the programmer to set up a restricted environment for the evaluation of

3760-610: Is slow, inconsistent and buggy [and it has] has many corner cases and oddities. Code that works around those may need to be changed. Code that uses locals() for simple templating, or print debugging, will continue to work correctly." Some (more) standard library modules and many deprecated classes, functions and methods, will be removed in Python 3.15 or 3.16. Python 3.14 is now in alpha 2; regarding possible change to annotations: "In Python 3.14, from __future__ import annotations will continue to work as it did before, converting annotations into strings." PEP 711 proposes PyBI:

3854-663: Is still used by 50.0% of PHP websites, which is outdated and known to be insecure. In addition the even more outdated (discontinued for 5+ years) and insecure PHP 5 is used by 13.2% and the no longer supported PHP 8.0 is also very popular. Meaning the vast majority do not use the supported versions. PHP development began in 1993 when Rasmus Lerdorf wrote several Common Gateway Interface (CGI) programs in C , which he used to maintain his personal homepage . He extended them to work with web forms and to communicate with databases , and called this implementation "Personal Home Page/Forms Interpreter" or PHP/FI. An example of

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3948-549: Is summarized in the Zen of Python (PEP 20), which includes aphorisms such as: However, Python features regularly violate these principles and have received criticism for adding unnecessary language bloat. Responses to these criticisms are that the Zen of Python is a guideline rather than a rule. The addition of some new features had been so controversial that Guido van Rossum resigned as Benevolent Dictator for Life following vitriol over

4042-460: Is that an assignment statement such as a = 1 cannot form part of the conditional expression of a conditional statement. Methods on objects are functions attached to the object's class; the syntax instance . method ( argument ) is, for normal methods and functions, syntactic sugar for Class . method ( instance , argument ) . Python methods have an explicit self parameter to access instance data , in contrast to

4136-399: Is the latest stable release, and it and, for few more months, 3.12 are the only releases with active support including for bugfixes (as opposed to just for security) and Python 3.9, is the oldest supported version of Python (albeit in the 'security support' phase), due to Python 3.8 reaching end-of-life . Starting with 3.13, it and later versions have 2 years of full support (up from one and

4230-548: The decimal module provides decimal floating-point numbers to a pre-defined arbitrary precision and several rounding modes. The Fraction class in the fractions module provides arbitrary precision for rational numbers . Due to Python's extensive mathematics library, and the third-party library NumPy that further extends the native capabilities, it is frequently used as a scientific scripting language to aid in problems such as numerical data processing and manipulation. "Hello, World!" program : Program to calculate

4324-443: The random extension, which provides a pseudorandom number generator with an object-oriented API , Sensitive Parameter value redaction, and a ton of other features. PHP 8.3 was released on November 23, 2023. This release introduced readonly array properties, allowing arrays to be declared as immutable after initialization. It also added support for class aliases for built-in PHP classes, new methods for random float generation in

4418-570: The | union type operator and the match and case keywords (for structural pattern matching statements). 3.11 expanded exception handling functionality. Python 3.12 added the new keyword type . Notable changes in 3.11 from 3.10 include increased program execution speed and improved error reporting. Python 3.11 claims to be between 10 and 60% faster than Python 3.10, and Python 3.12 adds another 5% on top of that. It also has improved error messages (again improved in 3.14), and many other changes. Python 3.13 introduces more syntax for types,

4512-520: The C-language long type . Unsigned integers are converted to signed values in certain situations, which is different behaviour to many other programming languages. Integer variables can be assigned using decimal (positive and negative), octal , hexadecimal , and binary notations. Floating-point numbers are also stored in a platform-specific range. They can be specified using floating-point notation, or two forms of scientific notation . PHP has

4606-630: The Netherlands as a successor to the ABC programming language, which was inspired by SETL , capable of exception handling and interfacing with the Amoeba operating system. Its implementation began in December ;1989. Van Rossum shouldered sole responsibility for the project, as the lead developer, until 12 July 2018, when he announced his "permanent vacation" from his responsibilities as Python's " benevolent dictator for life " (BDFL),

4700-460: The factorial of a positive integer: PHP PHP is a general-purpose scripting language geared towards web development . It was originally created by Danish-Canadian programmer Rasmus Lerdorf in 1993 and released in 1995. The PHP reference implementation is now produced by the PHP Group. PHP was originally an abbreviation of Personal Home Page , but it now stands for

4794-491: The global interpreter lock (GIL), allowing threads to run more concurrently, that latter feature enabled with python3.13t or python3.13t.exe . Python 3.13 introduces some change in behavior, i.e. new "well-defined semantics", fixing bugs (plus many removals of deprecated classes, functions and methods, and removed some of the C ;API and outdated modules): "The [old] implementation of locals() and frame.f_locals

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4888-563: The recursive acronym PHP: Hypertext Preprocessor . PHP code is usually processed on a web server by a PHP interpreter implemented as a module , a daemon or a Common Gateway Interface (CGI) executable. On a web server, the result of the interpreted and executed PHP code—which may be any type of data, such as generated HTML or binary image data—would form the whole or part of an HTTP response. Various web template systems , web content management systems , and web frameworks exist that can be employed to orchestrate or facilitate

4982-678: The recursive acronym PHP: Hypertext Preprocessor . Afterwards, public testing of PHP 3 began, and the official launch came in June 1998. Suraski and Gutmans then started a new rewrite of PHP's core, producing the Zend Engine in 1999. They also founded Zend Technologies in Ramat Gan , Israel . On 22 May 2000, PHP 4, powered by the Zend Engine 1.0, was released. By August 2008, this branch had reached version 4.4.9. PHP 4

5076-598: The Flash 8 documentation, its usage is limited to expressions which represent "the name of a variable, property, object, or movie clip to retrieve. This parameter can be either a String or a direct reference to the object instance." ActionScript 3 does not support eval. The ActionScript 3 Eval Library and the D.eval API were development projects to create equivalents to eval in ActionScript 3. Both have ended, as Adobe Flash Player has reached its end-of-life . Lisp

5170-482: The JIT compiler provides the future potential to move some code from C to PHP, due to the performance improvements for some use cases. PHP 8 introduced the match expression. The match expression is conceptually similar to a switch statement and is more compact for some use cases. Because match is an expression, its result can be assigned to a variable or returned from a function. PHP 8 introduced union types,

5264-447: The PHP project is the elePHPant , a blue elephant with the PHP logo on its side, designed by Vincent Pontier in 1998. "The (PHP) letters were forming the shape of an elephant if viewed in a sideways angle." The elePHPant is sometimes differently coloured when in plush toy form. Many variations of this mascot have been made over the years. Only the elePHPants based on the original design by Vincent Pontier are considered official by

5358-518: The PHP source code or by using pre-built binaries. For PHP versions 5.3 and 5.4, the only available Microsoft Windows binary distributions were 32-bit IA-32 builds, requiring Windows 32-bit compatibility mode while using Internet Information Services (IIS) on a 64-bit Windows platform. PHP version 5.5 made the 64-bit x86-64 builds available for Microsoft Windows. Official security support for PHP 5.6 ended on 31 December 2018. PHP received mixed reviews due to lacking native Unicode support at

5452-475: The PHP 6 Unicode experiments had never been released, several articles and book titles referenced the PHP 6 names, which might have caused confusion if a new release were to reuse the name. After a vote, the name PHP 7 was chosen. The foundation of PHP 7 is a PHP branch that was originally dubbed PHP next generation ( phpng ). It was authored by Dmitry Stogov, Xinchen Hui and Nikita Popov, and aimed to optimize PHP performance by refactoring

5546-403: The Python community is pythonic , which has a wide range of meanings related to program style. "Pythonic" code may use Python idioms well, be natural or show fluency in the language, or conform with Python's minimalist philosophy and emphasis on readability. Code that is difficult to understand or reads like a rough transcription from another programming language is called unpythonic . Python

5640-595: The Random extension, and enhanced PHP INI settings with fallback value support. Additionally, the new stream_context_set_options function provides improved API for stream manipulation, among other updates and deprecations. PHP 8.4 was released on November 21, 2024. Beginning on 28 June 2011, the PHP Development Team implemented a timeline for the release of new versions of PHP. Under this system, at least one release should occur every month. Once per year,

5734-411: The Zend Engine while retaining near-complete language compatibility. By 14 July 2014, WordPress -based benchmarks, which served as the main benchmark suite for the phpng project, showed an almost 100% increase in performance. Changes from phpng make it easier to improve performance in future versions, as more compact data structures and other changes are seen as better suited for a successful migration to

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5828-420: The ability to embed HTML . By this point, the syntax had changed to resemble that of Perl , but was simpler, more limited, and less consistent. Early PHP was never intended to be a new programming language ; rather, it grew organically, with Lerdorf noting in retrospect: "I don't know how to stop it [...] there was never any intent to write a programming language [...] I have absolutely no idea how to write

5922-497: The addition of the assignment expression operator in Python 3.8. Nevertheless, rather than building all of its functionality into its core, Python was designed to be highly extensible via modules. This compact modularity has made it particularly popular as a means of adding programmable interfaces to existing applications. Van Rossum's vision of a small core language with a large standard library and easily extensible interpreter stemmed from his frustrations with ABC , which espoused

6016-472: The amount of boilerplate code that must be written. Other minor changes include support for use of ::class on objects, which serves as an alternative for the use of get_class() ; non-capturing catches in try-catch blocks; variable syntax tweaks to resolve inconsistencies; support for named arguments; and support for trailing commas in parameter lists, which adds consistency with support for trailing commas in other contexts, such as in arrays. PHP 8.1

6110-490: The argument to eval must be a string of one or more complete statements, not just expressions; however, one can get the "expression" form of eval by putting the expression in a return statement, which causes eval to return the result of that expression. Unlike some languages, PHP's eval is a "language construct" rather than a function, and so cannot be used in some contexts where functions can be, like higher-order functions. Example using echo: Example returning

6204-481: The basis of the first Lisp interpreter. Later versions of the Lisp eval function have also been implemented as compilers. The eval function in Lisp expects a form to be evaluated as it's argument. The resulting value of the given form will be the returned value of the call to eval . This is an example Lisp code: Lisp is well known to be very flexible and so is the eval function. For example, to evaluate

6298-475: The class (for example, SpamClass () or EggsClass () ), and the classes are instances of the metaclass type (itself an instance of itself), allowing metaprogramming and reflection . Before version 3.0, Python had two kinds of classes (both using the same syntax): old-style and new-style ; current Python versions only support the semantics of the new style. Python supports optional type annotations . These annotations are not enforced by

6392-556: The community. These are collectable and some of them are extremely rare. The following "Hello, World!" program is written in PHP code embedded in an HTML document: However, as no requirement exists for PHP code to be embedded in HTML, the simplest version of Hello, World! may be written like this, with the closing tag ?> omitted as preferred in files containing pure PHP code. The PHP interpreter only executes PHP code within its delimiters . Anything outside of its delimiters

6486-428: The content of a string, the string would first have to be converted into a Lisp form using the read-from-string function and then the resulting form would have to be passed to eval : One major point of confusion is the question, in which context the symbols in the form will be evaluated. In the above example, form1 contains the symbol + . Evaluation of this symbol must yield the function for addition to make

6580-479: The core language level. In 2005, a project headed by Andrei Zmievski was initiated to bring native Unicode support throughout PHP, by embedding the International Components for Unicode (ICU) library, and representing text strings as UTF-16 internally. Since this would cause major changes both to the internals of the language and to user code, it was planned to release this as version 6.0 of

6674-399: The cost of clarity. Execution speed can be improved by moving speed-critical functions to extension modules written in languages such as C, or by using a just-in-time compiler like PyPy . It is also possible to cross-compile to other languages , but it either doesn't provide the full speed-up that might be expected, since Python is a very dynamic language , or a restricted subset of Python

6768-480: The early PHP syntax : PHP/FI could be used to build simple, dynamic web applications . To accelerate bug reporting and improve the code, Lerdorf initially announced the release of PHP/FI as "Personal Home Page Tools (PHP Tools) version 1.0" on the Usenet discussion group comp.infosystems.www.authoring.cgi on 8 June 1995. This release included basic functionality such as Perl-like variables , form handling, and

6862-456: The example work as intended. Thus some dialects of Lisp allow an additional parameter for eval to specify the context of evaluation (similar to the optional arguments to Python's eval function - see below). An example in the Scheme dialect of Lisp (RRS and later): In Perl , the eval function is something of a hybrid between an expression evaluator and a statement executor. It returns

6956-469: The expression. The exec statement (or the exec function in Python 3.x) executes statements: exec example (interactive shell): The most general form for evaluating statements/expressions is using code objects. Those can be created by invoking the compile() function and by telling it what kind of input it has to compile: an " exec " statement, an " eval " statement or a " single " statement: compile example (interactive shell): D

7050-431: The following changes: PHP 7 also included new language features. Most notably, it introduced return type declarations for functions which complement the existing parameter type declarations, and support for the scalar types (integer, float, string, and boolean) in parameter and return type declarations. PHP 8 was released on 26 November 2020, and is currently the second-most used PHP major version. PHP 8

7144-408: The function names were chosen to match the lower-level libraries which PHP was "wrapping", while in some very early versions of PHP the length of the function names was used internally as a hash function , so names were chosen to improve the distribution of hash values . Zeev Suraski and Andi Gutmans rewrote the parser in 1997 and formed the base of PHP 3, changing the language's name to

7238-489: The generation of that response. Additionally, PHP can be used for many programming tasks outside the web context, such as standalone graphical applications and drone control. PHP code can also be directly executed from the command line . The standard PHP interpreter, powered by the Zend Engine , is free software released under the PHP License . PHP has been widely ported and can be deployed on most web servers on

7332-609: The implicit self (or this ) in some other object-oriented programming languages (e.g., C++ , Java , Objective-C , Ruby ). Python also provides methods, often called dunder methods (due to their names beginning and ending with double-underscores), to allow user-defined classes to modify how they are handled by native operations including length, comparison, in arithmetic operations and type conversion. Python uses duck typing and has typed objects but untyped variable names. Type constraints are not checked at compile time ; rather, operations on an object may fail, signifying that it

7426-432: The language, along with other major features then in development. However, a shortage of developers who understood the necessary changes, and performance problems arising from conversion to and from UTF-16, which is rarely used in a web context, led to delays in the project. As a result, a PHP 5.3 release was created in 2009, with many non-Unicode features back-ported from PHP 6, notably namespaces. In March 2010,

7520-507: The language, but may be used by external tools such as mypy to catch errors. Mypy also supports a Python compiler called mypyc, which leverages type annotations for optimization. 1.33333 Python has the usual symbols for arithmetic operators ( + , - , * , / ), the floor division operator // and the modulo operation % (where the remainder can be negative, e.g. 4 % -3 == -2 ). It also has ** for exponentiation , e.g. 5**3 == 125 and 9**0.5 == 3.0 , and

7614-477: The most basic types, so if you have a function that returns a Dictionary or MySpiffyObject, RBScript will be unable to use it. You can also communicate with your RBScript through the Print and Input events. Python (programming language) Python is a high-level , general-purpose programming language . Its design philosophy emphasizes code readability with the use of significant indentation . Python

7708-572: The only stable version under development. Late static binding had been missing from previous versions of PHP, and was added in version 5.3. Many high-profile open-source projects ceased to support PHP 4 in new code from February 5, 2008, because of the GoPHP5 initiative, provided by a consortium of PHP developers promoting the transition from PHP 4 to PHP 5. Over time, PHP interpreters became available on most existing 32-bit and 64-bit operating systems, either by building them from

7802-458: The opposite approach. Python claims to strive for a simpler, less-cluttered syntax and grammar while giving developers a choice in their coding methodology. In contrast to Perl 's " there is more than one way to do it " motto, Python embraces a "there should be one—and preferably only one—obvious way to do it." philosophy. In practice, however, Python provides many ways to achieve the same task. There are, for example, at least three ways to format

7896-408: The plus meaning (at least some) " backported security updates". Python 3.0 was released on 3 December 2008, with some new semantics and changed syntax. At least every Python release since (now unsupported) 3.5 has added some syntax to the language, and a few later releases have dropped outdated modules, or changed semantics, at least in a minor way. Since 7 October 2024 , Python 3.13

7990-473: The project in its current form was officially abandoned, and a PHP 5.4 release was prepared to contain most remaining non-Unicode features from PHP 6, such as traits and closure re-binding. Initial hopes were that a new plan would be formed for Unicode integration, but by 2014 none had been adopted. During 2014 and 2015, a new major PHP version was developed, PHP 7. The numbering of this version involved some debate among internal developers. While

8084-489: The result of the last expression evaluated (all statements are expressions in Perl programming), and allows the final semicolon to be left off. Example as an expression evaluator: Example as a statement executor: Perl also has eval blocks , which serves as its exception handling mechanism (see Exception handling syntax#Perl ). This differs from the above use of eval with strings in that code inside eval blocks

8178-434: The result of the last expression evaluated. Example as an expression evaluator: Example as a statement executor: One use of JavaScript's eval is to parse JSON text, perhaps as part of an Ajax framework. However, modern browsers provide JSON.parse as a more secure alternative for this task. In ActionScript (Flash's programming language), eval cannot be used to evaluate arbitrary expressions. According to

8272-497: The resulting mixture of PHP code and other markups in the server-side file is itself well-formed XML. Variables are prefixed with a dollar symbol , and a type does not need to be specified in advance. PHP 5 introduced type declarations that allow functions to force their parameters to be objects of a specific class, arrays, interfaces or callback functions . However, before PHP 7, type declarations could not be used with scalar types such as integers or strings. Below

8366-442: The same assembly language instructions as if " num++; " had been written directly instead of mixed in. The argument to mixin doesn't need to be a string literal, but arbitrary expressions resulting in a string value, including function calls, that can be evaluated at compile time. ColdFusion 's evaluate function lets you evaluate a string expression at runtime. It is particularly useful when you need to programmatically choose

8460-591: The variable you want to read from. The Ruby programming language interpreter offers an eval function similar to Python or Perl, and also allows a scope , or binding , to be specified. Aside from specifying a function's binding, eval may also be used to evaluate an expression within a specific class definition binding or object instance binding, allowing classes to be extended with new methods specified in strings. Most standard implementations of Forth have two variants of eval : EVALUATE and INTERPRET . Win32FORTH code example: In REALbasic , there

8554-414: Was initially set for 2015, then postponed to 2020 out of concern that a large body of existing code could not easily be forward-ported to Python 3. No further security patches or other improvements will be released for it. While Python 2.7 and older versions are officially unsupported, a different unofficial Python implementation, PyPy , continues to support Python 2, i.e. "2.7.18+" (plus 3.10), with

8648-477: Was released in 2000. Python 3.0, released in 2008, was a major revision not completely backward-compatible with earlier versions. Python 2.7.18, released in 2020, was the last release of Python 2. Python consistently ranks as one of the most popular programming languages, and has gained widespread use in the machine learning community. Python was conceived in the late 1980s by Guido van Rossum at Centrum Wiskunde & Informatica (CWI) in

8742-502: Was released on November 25, 2021. It added support for enumerations (also called "enums"), declaring properties as readonly (which prevents modification of the property after initialization), and array unpacking with string keys. The new never type can be used to indicate that a function does not return. PHP 8.2 was released on December 8, 2022. New in this release are readonly classes (whose instance properties are implicitly readonly), disjunctive normal form (DNF) types, and

8836-428: Was the original language to make use of an eval function in 1958. In fact, definition of the eval function led to the first implementation of the language interpreter. Before the eval function was defined, Lisp functions were manually compiled to assembly language statements. However, once the eval function had been manually compiled it was then used as part of a simple read-eval-print loop which formed

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