type inference

In computer science, a datatype (often simply a type) is a name or label for a set of values and some operations which one can perform on that set of values. Programming languages implicitly or explicitly support one or more datatypes; these types may act as a statically or dynamically checked constraint, ensuring valid programs for a given language. Datatype - Basis. Assigning datatypes ("typing") has the basic purpose of giving some semantic meaning to otherwise meaningless collections of bits. Typ ...

Including:

• Datatype - Basis
• Datatype - Type checking
• Datatype - Static and dynamic typing
• Datatype - Static and dynamic type checking in practice
• Datatype - Strong and weak typing
• Datatype - Polymorphism and types
• Datatype - Explicit or implicit declaration and inference
• Datatype - Collections of types
• Datatype - Specialized types
• Datatype - Compatibility equivalence and substitutability

Read more here: » Datatype: Encyclopedia - Datatype

Probably the most important feature of Nemerle is the ability to mix object oriented and functional programming styles. The top-level program structure is object oriented, while in the body of methods one can (but is not forced to) use functional style. This is very handy in some programming problems. The feature set here include functional values, variants and pattern matching. Another very important feature is taking a high-level approach in all aspects of the language - trying to lift as much of the burden from the programmer as possible. Features like ...

See also:

Nemerle, Nemerle - Features, Nemerle - Examples, Nemerle - Hello World!, Nemerle - Examples of macros, Nemerle - Nemerle with ASP.NET, Nemerle - PInvoke

Read more here: » Nemerle: Encyclopedia II - Nemerle - Features

Snippets of OCaml code are most easily studied by entering them into the "top-level". This is an interactive OCaml session that prints the inferred types of resulting or defined expressions. The OCaml top-level is started by simply executing the "ocaml" program: $ ocaml Objective Caml version 3.09.0 # Code can then be entered at the "#" prompt. For example, to calculate 1+2*3: # 1 + 2 * 3;; - : int = 7 OCaml infers the type of the expression to be "int" (a machine-precision integer) and gives the result "7". OCaml - Hello World. See also:

OCaml, OCaml - Philosophy, OCaml - Features, OCaml - Applications, OCaml - Computer science, OCaml - Natural science, OCaml - Education, OCaml - Code examples, OCaml - Hello World, OCaml - Birthday paradox, OCaml - Factorial function recursion and purely functional programming, OCaml - Arbitrary-precision factorial function libraries, OCaml - Numerical derivative higher-order functions, OCaml - Discrete Wavelet Transform pattern matching, OCaml - Triangle graphics, OCaml - Programs written in OCaml, OCaml - Derived languages, OCaml - MetaOCaml, OCaml - Other derived languages

Read more here: » OCaml: Encyclopedia II - OCaml - Code examples

In type theory, a recursive type has the general form μα.T where the type variable α may appear in the type T and stands for the entire type itself. For example, the natural number (see Peano arithmetic) may be defined by the Haskell datatype: data Nat = Zero | Succ Nat And in type theory we would say list = μα.1 + α. Where the two arms of the sum type represent the Zero and Succ data constructors, with Zero taking no arguments (thus represented by the unit type), and Succ taking another Nat (thus another element of < ...

See also:

Recursive type, Recursive type - Theory, Recursive type - Isorecursive types, Recursive type - Equirecursive types

Read more here: » Recursive type: Encyclopedia II - Recursive type - Theory

The Boolean type is defined as: , where α is a type variable. This produces the following two definitions for the boolean values TRUE and FALSE: TRUE := Λα.λxαλyα.x FALSE := Λα.λxαλyα.y Then, with these two λ-terms, we can define some logic operators: AND := λxB ...

See also:

System F, System F - Logic and predicates, System F - System F Structures, System F - Use in programming languages

Read more here: » System F: Encyclopedia II - System F - Logic and predicates

Snippets of SML code are most easily studied by entering them into a "top-level". This is an interactive session that prints the inferred types of resulting or defined expressions. Many SML implementations provide an interactive top-level, including SML/NJ: $ sml Standard ML of New Jersey v110.52 [built: Fri Jan 21 16:42:10 2005] - Code can then be entered at the "-" prompt. For example, to calculate 1+2*3: - 1 + 2 * 3; val it = 7 : int The top-level infers the type of the expression to be "int" and gives the result "7". Standard ML - Hello world. ...

See also:

Standard ML, Standard ML - Language, Standard ML - Code examples, Standard ML - Hello world, Standard ML - Arbitrary-precision factorial function libraries, Standard ML - Numerical derivative higher-order functions, Standard ML - Discrete Wavelet Transform pattern matching, Standard ML - Implementations

Read more here: » Standard ML: Encyclopedia II - Standard ML - Code examples

The process of verifying and enforcing the constraints of types - type checking - may occur either at compile-time (a static check) or run-time (a dynamic check). Static type-checking becomes a primary task of the semantic analysis carried out by a compiler. If a language enforces type rules strongly (that is, generally allowing only those automatic type conversions which do not lose information), one can refer to the process as strongly typed, if not, as weakly typed. Da ...

See also:

Datatype, Datatype - Basis, Datatype - Type checking, Datatype - Static and dynamic typing, Datatype - Static and dynamic type checking in practice, Datatype - Strong and weak typing, Datatype - Polymorphism and types, Datatype - Explicit or implicit declaration and inference, Datatype - Collections of types, Datatype - Specialized types, Datatype - Compatibility equivalence and substitutability, Datatype - Nominative vs structural typing

Read more here: » Datatype: Encyclopedia II - Datatype - Type checking

In CLOS and C++ and some other languages, very flexible static binding capabilities, called "generic" or template or operator overloading facilities, provided the same advantages but not typically as late as run time. A distinction was made between this static polymorphism and the runtime use of facilities for dynamic types, though most theorists considered it undesirable to have any such distinction. In response: Some Smalltalk architects sought to achieve true polymorphism with the Smalltalk protocol proposal fo ...

See also:

Duck typing, Duck typing - Versus generics and structural subtyping, Duck typing - Duck Typing in Python, Duck typing - Duck Typing in Java, Duck typing - Duck Typing in Ruby, Duck typing - Duck Typing in ColdFusion

Read more here: » Duck typing: Encyclopedia II - Duck typing - Versus generics and structural subtyping

Boo programming language - Hello world program. print "Hello, world!" Boo programming language - Fibonacci series generator function. def fib(): a, b = 0L, 1L while true: yield b a, b = b, a + b Boo programming language - Basic Windows Form example demonstrating classes closures and events. import System.Windows.Forms import System.Drawing class MyForm(Form): def constructor(): b = Button(Te ...

See also:

Boo programming language, Boo programming language - Code samples, Boo programming language - Hello world program, Boo programming language - Fibonacci series generator function, Boo programming language - Basic Windows Form example demonstrating classes closures and events, Boo programming language - Asynchronous design pattern with a closure, Boo programming language - Currying

Read more here: » Boo programming language: Encyclopedia II - Boo programming language - Code samples

The process of verifying and enforcing the constraints of types - type checking - may occur either at compile-time (a static check) or run-time (a dynamic check). Static type-checking becomes a primary task of the semantic analysis carried out by a compiler. If a language enforces type rules strongly (that is, generally allowing only those automatic type conversions which do not lose information), one can refer to the process as strongly typed, if not, as weakly typed. Da ...

See also:

Datatype, Datatype - Basis, Datatype - Type checking, Datatype - Static and dynamic typing, Datatype - Static and dynamic type checking in practice, Datatype - Strong and weak typing, Datatype - Polymorphism and types, Datatype - Explicit or implicit declaration and inference, Datatype - Collections of types, Datatype - Specialized types, Datatype - Compatibility equivalence and substitutability

Read more here: » Datatype: Encyclopedia II - Datatype - Type checking

OCaml - MetaOCaml. MetaOCaml [3] is a multi-stage programming extension of Ocaml enabling incremental compiling of new machine code during runtime. Under certain circumstances, significant speedups are possible using multi-stage programming, because more detailed information about the data to process is available at runtime than at the regular compile time, so the incremental compiler can optimize ...

See also:

OCaml, OCaml - Philosophy, OCaml - Features, OCaml - Applications, OCaml - Computer science, OCaml - Natural science, OCaml - Education, OCaml - Code examples, OCaml - Hello World, OCaml - Birthday paradox, OCaml - Factorial function recursion and purely functional programming, OCaml - Arbitrary-precision factorial function libraries, OCaml - Numerical derivative higher-order functions, OCaml - Discrete Wavelet Transform pattern matching, OCaml - Triangle graphics, OCaml - Programs written in OCaml, OCaml - Derived languages, OCaml - MetaOCaml, OCaml - Other derived languages

Read more here: » OCaml: Encyclopedia II - OCaml - Derived languages

The question of compatibility and equivalence becomes a complicated and controversial topic and relates to the problem of substitutability; in other words: given type A and type B, are they equal types or compatible? Can one use the value with type B in the place of the value with type A? If type A is compatible with type B, A is a subtype of B (but not always vice versa) - according to the Liskov substitution principle. Type conversion may ...

See also:

Datatype, Datatype - Basis, Datatype - Type checking, Datatype - Static and dynamic typing, Datatype - Static and dynamic type checking in practice, Datatype - Strong and weak typing, Datatype - Polymorphism and types, Datatype - Explicit or implicit declaration and inference, Datatype - Collections of types, Datatype - Specialized types, Datatype - Compatibility equivalence and substitutability

Read more here: » Datatype: Encyclopedia II - Datatype - Compatibility equivalence and substitutability

Many static type systems, such as C's and Java's, require type declarations: the programmer must explicitly associate each variable with a particular type. Others, such as Haskell's, perform type inference: the compiler draws conclusions about the types of variables based on how programmers use those variables. For example, given a function f(x,y) which adds x and y together, the compiler can infer that x and y must be numbers -- since addition is only defined for numbers. Therefore, any call to f elsewhere in the program that specifies a non-nu ...

See also:

Datatype, Datatype - Basis, Datatype - Type checking, Datatype - Static and dynamic typing, Datatype - Static and dynamic type checking in practice, Datatype - Strong and weak typing, Datatype - Polymorphism and types, Datatype - Explicit or implicit declaration and inference, Datatype - Collections of types, Datatype - Specialized types, Datatype - Compatibility equivalence and substitutability

Read more here: » Datatype: Encyclopedia II - Datatype - Explicit or implicit declaration and inference

Main article: strongly-typed programming language For a fuller discussion of the different meanings of the phrase strongly typed, see strongly-typed programming language. One definition of strongly typed involves not allowing an operation to succeed on arguments which have the wrong type. A C cast gone wrong exemplifies the absence of strong typing; if a programmer casts a value in C, not only must the compiler allow the code, but the runtime should allow it as well. This allows compact and fas ...

See also:

Datatype, Datatype - Basis, Datatype - Type checking, Datatype - Static and dynamic typing, Datatype - Static and dynamic type checking in practice, Datatype - Strong and weak typing, Datatype - Polymorphism and types, Datatype - Explicit or implicit declaration and inference, Datatype - Collections of types, Datatype - Specialized types, Datatype - Compatibility equivalence and substitutability

Read more here: » Datatype: Encyclopedia II - Datatype - Strong and weak typing

System F allows recursive constructions to be embedded in a natural manner, related to that in Martin-Löf's type theory. Suppose you want to create an abstract structure (call it S). The first thing you'll need are constructors. These will be functions whose type will be . Recursivity is manifested when S itself appears within one of the types Ki. If you have m of these constructors, you can define the type of See also:

System F, System F - Logic and predicates, System F - System F Structures, System F - Use in programming languages

Read more here: » System F: Encyclopedia II - System F - System F Structures

Some SML implementations include: MLton is a whole-program optimizing compiler that produces very fast code compared to other ML implementations. [1] Standard ML of New Jersey (abbreviated SML/NJ) is a full compiler, with associated libraries, tools, an interactive shell, and documentation. [2] Moscow ML is a light-weight implementation, based on the CAML Light runtime engine. It implements the full SML language, including SML Modules, and much of the SML Basis Library. [3] Poly/ML is a full implementa ...

See also:

Standard ML, Standard ML - Language, Standard ML - Code examples, Standard ML - Hello world, Standard ML - Arbitrary-precision factorial function libraries, Standard ML - Numerical derivative higher-order functions, Standard ML - Discrete Wavelet Transform pattern matching, Standard ML - Implementations

Read more here: » Standard ML: Encyclopedia II - Standard ML - Implementations

OCaml is a general-purpose programming language, but some of its more popular applications include: OCaml - Computer science. Theorem proving (e.g. Coq, HOL Light, MetaPRL) Computer program analysis (CIL, C Code Analyzer, Astrée) Compiler writing (OCaml compiler, Felix, MTASC) OCaml - Natural science. OCaml is also widely used in physics, chemistry, biology and, more recently, bioinformatics: Analysis Visualisation See also:

OCaml, OCaml - Philosophy, OCaml - Features, OCaml - Applications, OCaml - Computer science, OCaml - Natural science, OCaml - Education, OCaml - Code examples, OCaml - Hello World, OCaml - Birthday paradox, OCaml - Factorial function recursion and purely functional programming, OCaml - Arbitrary-precision factorial function libraries, OCaml - Numerical derivative higher-order functions, OCaml - Discrete Wavelet Transform pattern matching, OCaml - Triangle graphics, OCaml - Programs written in OCaml, OCaml - Derived languages, OCaml - MetaOCaml, OCaml - Other derived languages

Read more here: » OCaml: Encyclopedia II - OCaml - Applications

Standard ML is a mostly functional programming language. Programs written in Standard ML mostly consist of expressions whose values are to be calculated. Like all functional programming languages, a key feature of Standard ML is the function which is used for abstraction. For instance, the factorial function can be expressed as: fun factorial x = if x = 0 thenSee also:

Standard ML, Standard ML - Language, Standard ML - Code examples, Standard ML - Hello world, Standard ML - Arbitrary-precision factorial function libraries, Standard ML - Numerical derivative higher-order functions, Standard ML - Discrete Wavelet Transform pattern matching, Standard ML - Implementations

Read more here: » Standard ML: Encyclopedia II - Standard ML - Language

ML-derived languages are most well known for their static type systems and type-inferring compilers. OCaml unifies functional, imperative, and object-oriented programming under an ML-like type system. OCaml's static type system eliminates a large class of programmer errors that may cause problems at runtime. However, it also forces the programmer to conform to the constraints of the type system, which can require careful thought and close attention. The type-inferring compiler greatly reduces the need for manual type annotation (for e ...

See also:

OCaml, OCaml - Philosophy, OCaml - Features, OCaml - Applications, OCaml - Computer science, OCaml - Natural science, OCaml - Education, OCaml - Code examples, OCaml - Hello World, OCaml - Birthday paradox, OCaml - Factorial function recursion and purely functional programming, OCaml - Arbitrary-precision factorial function libraries, OCaml - Numerical derivative higher-order functions, OCaml - Discrete Wavelet Transform pattern matching, OCaml - Triangle graphics, OCaml - Programs written in OCaml, OCaml - Derived languages, OCaml - MetaOCaml, OCaml - Other derived languages

Read more here: » OCaml: Encyclopedia II - OCaml - Philosophy

The question of compatibility and equivalence becomes a complicated and controversial topic and relates to the problem of substitutability; in other words: given type A and type B, are they equal types or compatible? Can one use the value with type B in the place of the value with type A? If type A is compatible with type B, A is a subtype of B (but not always vice versa) - according to the Liskov substitution principle. Type conversion may ...

See also:

Datatype, Datatype - Basis, Datatype - Type checking, Datatype - Static and dynamic typing, Datatype - Static and dynamic type checking in practice, Datatype - Strong and weak typing, Datatype - Polymorphism and types, Datatype - Explicit or implicit declaration and inference, Datatype - Collections of types, Datatype - Specialized types, Datatype - Compatibility equivalence and substitutability, Datatype - Nominative vs structural typing

Read more here: » Datatype: Encyclopedia II - Datatype - Compatibility equivalence and substitutability