A program transformation is any operation that takes a
computer program
A computer program is a sequence or set of instructions in a programming language for a computer to execute. Computer programs are one component of software, which also includes documentation and other intangible components.
A computer program ...
and generates another program. In many cases the transformed program is required to be
semantically equivalent to the original, relative to a particular
formal semantics and in fewer cases the transformations result in programs that semantically differ from the original in predictable ways.
While the transformations can be performed manually, it is often more practical to use a
program transformation system that applies specifications of the required transformations. Program transformations may be specified as automated procedures that modify compiler data structures (e.g.
abstract syntax trees) representing the program text, or may be specified more conveniently using patterns or templates representing parameterized source code fragments.
A practical requirement for
source code
In computing, source code, or simply code, is any collection of code, with or without comments, written using a human-readable programming language, usually as plain text. The source code of a program is specially designed to facilitate the wo ...
transformation systems is that they be able to effectively process programs written in a
programming language
A programming language is a system of notation for writing computer programs. Most programming languages are text-based formal languages, but they may also be graphical. They are a kind of computer language.
The description of a programming ...
. This usually requires integration of a full front-end for the programming language of interest, including source code
parsing
Parsing, syntax analysis, or syntactic analysis is the process of analyzing a string of symbols, either in natural language, computer languages or data structures, conforming to the rules of a formal grammar. The term ''parsing'' comes from Lati ...
, building internal program representations of code structures, the meaning of program symbols, useful
static analyses, and regeneration of valid source code from transformed program representations. The problem of building and integrating adequate front ends for conventional languages (
Java
Java (; id, Jawa, ; jv, ꦗꦮ; su, ) is one of the Greater Sunda Islands in Indonesia. It is bordered by the Indian Ocean to the south and the Java Sea to the north. With a population of 151.6 million people, Java is the world's List ...
,
C++,
PHP
PHP is a general-purpose scripting language geared toward 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 ...
etc.) may be of equal difficulty as building the program transformation system itself because of the complexity of such languages. To be widely useful, a transformation system must be able to handle many target programming languages, and must provide some means of specifying such front ends.
A generalisation of semantic equivalence is the notion of
program refinement
Refinement is a generic term of computer science that encompasses various approaches for producing correct computer programs and simplifying existing programs to enable their formal verification.
Program refinement
In formal methods, program re ...
: one program is a refinement of another if it terminates on all the initial states for which the original program terminates, and for each such state it is guaranteed to terminate in a possible final state for the original program. In other words, a refinement of a program is ''more defined'' and ''more deterministic'' than the original program. If two programs are refinements of each other, then the programs are equivalent.
See also
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List of program transformation systems
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Metaprogramming
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Program synthesis
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Source-to-source compiler
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Source code generation
In computer science, the term automatic programming identifies a type of computer programming in which some mechanism generates a computer program to allow human programmers to write the code at a higher abstraction level.
There has been little ...
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Transformation language
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Transformational grammar
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Dynamic recompilation
In computer science, dynamic recompilation is a feature of some emulators and virtual machines, where the system may recompile some part of a program during execution. By compiling during execution, the system can tailor the generated code to r ...
References
External links
The Program transformation WikiPapers on program transformation theory and practiceTransformation Technology Bibliography*
DMS Software Reengineering Toolkit: A Program Transformation System for DSLs and modern (C++, Java, ...) and legacy (COBOL, RPG) computer languages
Spoon A library to analyze, transform, rewrite, and transpile Java source code. It parses source files to build a well-designed AST with powerful analysis and transformation API.
JavaParser The JavaParser library provides you with an Abstract Syntax Tree of your Java code. The AST structure then allows you to work with your Java code in an easy programmatic way..
Metaprogramming
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