In his PhD thesis Aho created indexed grammars and the nested stack automaton as vehicles for extending the power of context-free languages but retaining many of their decidability and closure properties.

A basic routine is to start with a ball secretly concealed, the cups being nested in a stack.

The trampoline is a small piece of code which is constructed on the fly on the stack when the address of a nested function is taken.

* Display register or data structure, for locating the stack frames of nested functions in computer programming

Each nested call creates a new stack frame in memory, which persists until that call completes.

Manx shearwaters nested on Lianamul stack until the late 18th century, when they were driven away by puffins, and tysties have also been recorded there.

A stack trace allows to track the sequence of nested functions called up to the point where the stack trace is generated.

Such activations of subroutines may be nested to any level ( recursive as a special case ), hence the stack structure.

Programming languages that support nested subroutines also have a field in the call frame that points to the stack frame of the latest activation of the procedure that most closely encapsulates the callee, i. e. the immediate scope of the callee.

Some historical computers, such as the Burroughs large systems, had special " display registers " to support nested functions while compilers for most modern machines ( such as the ubiquitous x86 ) simply reserve a few words on the stack for the pointers, as needed.

To reach the switching yard, visitors had to walk the spiraling passageway through the miniature landscape that expanded the basement to enormous size — a landscape filled with railroad stations ; houses ; bridges ; factories ; a cliff-side gravel road that ran under a concrete arch supporting a steel railroad bridge in front of a hydroelectric dam with a generating plant beside it topped with twin round chimneys and, above and behind it on a plateau, a solitary white two-story wood frame house ; railroad crossings ; shacks ; coal companies ; a three-story brick ' Central Light And Power Company ' with a brick smoke stack that dwarfed it, cars loaded with coal from the ' Ynysybwl Coal Company ' waiting out front, and high-tension power lines running up the mountainside behind ; small town streets lined with banks and stores ; and even a careful and detailed reconstruction of the diner in Edward Hopper's famous painting Nighthawks, complete with customers, nested up against a two-story beige brick building that had beside it an equally tall red brick building, upon the wall of which was mounted a billboard for an ' East End Hardware ' store with their slogan ' Nuts To You!

Pascal, like many programming languages of today ( but unlike most languages in the C family ), allows nested procedure definitions to any level of depth, and also allows most kinds of definitions and declarations inside procedures and functions.

By default, PmWiki allows exactly one hierarchical level of the pages (" WikiGroup / WikiPage "), but through recipes, it is possible to have a flat structure ( no wiki groups ), multiple nested groups, or sub-pages.

Some notable differences between D and C in the area of imperative programming include D's loop construct, which allows looping over a collection, and nested functions, which are functions that are declared inside of another and may access the enclosing function's local variables.

For the purposes of the List example, these two formulations are not significantly different ; but the second form allows one to express so-called nested data types, i. e., those where the recursive type differs parametrically from the original.

The trampoline sets up the static link pointer, which allows the nested function to access local variables of the enclosing functions.

The language allows for the definition of nested records with alphanumeric, integer, and fractional fields of arbitrary size and precision, as well as fields that automatically format any value assigned to them ( e. g., insertion of currency signs, decimal points, and digit group separators ).

The Oberon programming language ( a descendant of Pascal ) allows functions both as parameters and return values but the assigned function may not be a nested function.

This allows digital CNN processors to included nested processor units, non-linearities, etc.

This nested function < code > increment < code > has access to, which from its point of view is a non-local variable.

* The B6500 had a Display to allow nested subroutines to access variables in outer blocks.

; Enclosing subroutine context: Some programming languages ( e. g., Pascal and Ada ) support nested subroutines, allowing an inner routine to access the context of its outer enclosing routine, i. e., the parameters and local variables within the scope of the outer routine.

Some architectures, compilers, or optimization cases store one link for each enclosing level ( not just the immediately enclosing ), so that deeply nested routines that access shallow data do not have to traverse several links ; this strategy is often called a display.

The set of query plans examined is formed by examining the possible access paths ( e. g. index scan, sequential scan ) and join algorithms ( e. g. sort-merge join, hash join, nested loop join ).

Traditionally, the Start menu provided a customizable nested list of programs for the user to launch, as well as a list of most recently opened documents, a way to find files and get help, and access to the system settings.

The following identity (" Hadamard Lemma ") involving nested commutators, underlying the Campbell – Baker – Hausdorff expansion of log ( expA expB ), is also useful:

However, the SGML concept of generalized markup is based on elements ( nested annotated ranges with attributes ) rather than merely print effects, with also the separation of structure and processing ; HTML has been progressively moved in this direction with CSS.

Instructions directly supporting nested ALGOL-family languages such as Pascal and PL / M were also added.

The SPITBOL implementation also introduced a number of features which, while not using traditional structured programming keywords, nevertheless can be used to provide many of the equivalent capabilities normally thought of as " structured programming ", most notably nested if / then / else type constructs.

If there is uncertainty about the diagnosis, a test of saliva or blood may be carried out ; a newer diagnostic confirmation, using real-time nested polymerase chain reaction ( PCR ) technology, has also been developed.

Gascony is also famed for its douceur de vivre (" sweetness of life "): its food ( it is home to foie gras and Armagnac brandy ), its medieval towns and villages locally called bastides nested amidst green rolling hills, its sunny weather, the beauty of its landscape, with the occasional distant views of the Pyrenees mountain range, all contribute to the popularity of Gascony as a tourist destination.

2008 ), and phylogenetic constraints, whereby related taxa are nested based on their common evolutionary history, are also evident ( Cattin et al.

This could be confusing to programmers accustomed to unique addressing schemes, but it can also be used to advantage, for example when addressing multiple nested data structures.

Often nested models are run forced by the global models for boundary conditions, to achieve higher local resolution: for example, the Met Office runs a mesoscale model with an resolution covering the UK, and various agencies in the U. S. also run nested models such as the NGM and NAM models.

Coaxial downdraft gasification stove An alternative stove based on the downdraft principle and typically built with nested cylinders also provides high efficiency.

In Lisp, however, the cons cell is not used only to build linked lists but also to build pair and nested pair structures, i. e. the of a cons cell need not be a list.

Howard Odum also extended the nature of the scale of ecosystems from that of a single pond upwards, showing that a " nested hierarchy ", " heterarchy " or " holarchy " existed in which systems could be considered as elements of larger systems ( leaf to tree to glade to forest to bioregion to biotic realm or biomes ).

The modern formulation of Warshall's algorithm as three nested for-loops was first described by Peter Ingerman, also in 1962.

PFA is also closely related to the nested Winograd FFT algorithm, where the latter performs the decomposed N < sub > 1 </ sub > by N < sub > 2 </ sub > transform via more sophisticated two-dimensional convolution techniques.

It adds to the functionality of C ++ by also implementing design by contract, unit testing, true modules, garbage collection, first class arrays, associative arrays, dynamic arrays, array slicing, nested functions, inner classes, closures, anonymous functions, compile time function execution, lazy evaluation and has a reengineered template syntax.

A relational-database implementation of an hierarchical model was first discussed in published form in 1992 ( see also nested set model ).

Thomas thus proposes a typology for the case study wherein purposes are first identified ( evaluative or exploratory ), then approaches are delineated ( theory-testing, theory-building or illustrative ), then processes are decided upon, with a principal choice being between whether the study is to be single or multiple, and choices also about whether the study is to be retrospective, snapshot or diachronic, and whether it is nested, parallel or sequential.

If the coefficients of the quartic equation are real then the nested depressed cubic equation ( 5 ) also has real coefficients, thus it has at least one real root.

This is a common programming problem with languages such as C, where the assignment operator also returns the value assigned, and can be validly nested inside expressions ( in the same way that a function returns a value ).

The condition is trivially satisfied if the intersection over the entire collection is nonempty ( in particular, if the collection itself is empty ), and it is also trivially satisfied if the collection is nested, meaning that the collection is totally ordered by inclusion ( equivalently, for any finite subcollection, a particular element of the subcollection is contained in all the other elements of the subcollection ), e. g. the nested sequence of intervals

Tern nesting sites can also be affected by the tides ; if a tern colony has nested to close to the high tide mark a spring tide would flood the nesting site and kill the chicks and make unhatched eggs infertile.