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The IF-THEN-ELSE is the basis of the McCarthy formalism: its usage replaces both primitive recursion and the mu-operator. The earliest Fortran compilers supported the computed GOTO statement for multi-way branching. Early ALGOL compilers supported a SWITCH data type which contains a list of "designational expressions". A GOTO statement could ...
Pro*C (also known as Pro*C/C++) is an embedded SQL programming language used by Oracle Database DBMSes. Pro*C uses either C or C++ as its host language. During compilation , the embedded SQL statements are interpreted by a precompiler and replaced by C or C++ function calls to their respective SQL library.
Recursion that contains only a single self-reference is known as single recursion, while recursion that contains multiple self-references is known as multiple recursion. Standard examples of single recursion include list traversal, such as in a linear search, or computing the factorial function, while standard examples of multiple recursion ...
In standard SQL:1999 hierarchical queries are implemented by way of recursive common table expressions (CTEs). Unlike Oracle's earlier connect-by clause, recursive CTEs were designed with fixpoint semantics from the beginning. [1] Recursive CTEs from the standard were relatively close to the existing implementation in IBM DB2 version 2. [1]
In compiler theory, common subexpression elimination (CSE) is a compiler optimization that searches for instances of identical expressions (i.e., they all evaluate to the same value), and analyzes whether it is worthwhile replacing them with a single variable holding the computed value.
Mutual recursion is very common in functional programming, and is often used for programs written in LISP, Scheme, ML, and similar programming languages. For example, Abelson and Sussman describe how a meta-circular evaluator can be used to implement LISP with an eval-apply cycle. [7] In languages such as Prolog, mutual recursion is almost ...
The predecessor program changes the variable x 2, which might be in use elsewhere. To expand the statement x 0 := x 1 ∸ 1, one could initialize the variables x n, x n+1 and x n+2 (for a big enough n) to 0, x 1 and 0 respectively, run the code on these variables and copy the result (x n) to x 0. A compiler can do this.
If the target of a tail is the same subroutine, the subroutine is said to be tail recursive, which is a special case of direct recursion. Tail recursion (or tail-end recursion) is particularly useful, and is often easy to optimize in implementations. Tail calls can be implemented without adding a new stack frame to the call stack.