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Otbs Contact the OTBS Bexleyheath depot VideoOtbs Forums New posts Search forums. Retrieved Freefram January For consistency, the indentation depth has been kept constant at 4 spaces, regardless of the preferred indentation depth of each style. Khan, E.
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Whitesmiths, along with Allman , have been the most common bracing styles with equal popularity according to the Jargon File.
This style puts the brace associated with a control statement on the next line, indented. Statements within the braces are indented to the same level as the braces.
The advantages of this style are similar to those of the Allman style. Blocks are clearly set apart from control statements.
The alignment of the braces with the block emphasizes that the full block is conceptually, and programmatically, one compound statement.
Indenting the braces emphasizes that they are subordinate to the control statement. The ending brace no longer lines up with the statement, but instead with the opening brace.
Like the Allman and Whitesmiths styles, GNU style puts braces on a line by themselves, indented by two spaces, except when opening a function definition, where they are not indented.
Popularised by Richard Stallman , the layout may be influenced by his background of writing Lisp code. This style combines the advantages of Allman and Whitesmiths , thereby removing the possible Whitesmiths disadvantage of braces not standing out from the block.
One disadvantage is that the ending brace no longer lines up with the statement it conceptually belongs to. In both cases, automatic reformatting destroys the original spacing, but automatic line indenting will work properly.
Steve McConnell , in his book Code Complete , advises against using this style: he marks a code sample which uses it with a "Coding Horror" icon, symbolizing especially dangerous code, and states that it impedes readability.
Horstmann adapts Allman by placing the first statement of a block on the same line as the opening brace.
However, the edition now uses Allman style throughout. This is the style used most commonly in the language Pico by its designers.
Pico lacks return statements, and uses semicolons as statement separators instead of terminators.
It yields this syntax: . In the book Programmers at Work ,  C. Wayne Ratliff discussed using the style below.
The style begins much like 1TBS but then the closing brace lines up with the indentation of the nested block. He indicated that it was originally documented in material from Digital Research Inc.
This style has sometimes been termed banner style,  possibly for the resemblance to a banner hanging from a pole. Kernighan and Plauger use this style in the Ratfor code in Software Tools.
A programmer may even go as far as to insert closing braces in the last line of a block. This style makes indentation the only way to distinguish blocks of code, but has the advantage of containing no uninformative lines.
This could easily be called the Lisp style because this style is very common in Lisp code or the Python style Python has no braces, but the layout is very similar, as shown in the code blocks below.
In Python, layout is a part of the language, called the off-side rule. Haskell layout can make the placement of braces optional, although braces and semicolons are allowed in the language.
In Haskell, layout can replace braces. Usually the braces and semicolons are omitted for procedural do sections and the program text in general, but the style is commonly used for lists, records and other syntactic elements made up of some pair of parentheses or braces, which are separated with commas or semicolons.
In some situations, there is a risk of losing track of block boundaries. This is often seen in large sections of code containing many compound statements nested to many levels of indentations.
By the time the programmer scrolls to the bottom of a huge set of nested statements, they may have lost track of which control statements go where.
However, overly-long code could have other causes, such as being too complex , and a programmer facing this problem might instead consider whether code refactoring would help in the longer term.
To avoid losing track of control statements such as for , a large indentation can be used, such as an 8-unit-wide hard tab, along with breaking up large functions into smaller and more readable functions.
The cursor then jumps to the opposing brace. Since the text cursor's next key viz. Another solution is implemented in a folding editor , which can hide or reveal blocks of code via their indentation level or compound-statement structure.
Many editors will also highlight matching brackets or braces when the cursor is positioned next to one. A statement mistakenly inserted between the control statement and the opening brace of the loop block turns the body of the loop into a single trip.
From Wikipedia, the free encyclopedia. Redirected from Indent style. Main article: GNU coding standards. Retrieved 6 June Retrieved 9 July Communications of the ACM.
Retrieved 3 August Retrieved 18 August Checking C programs with Lint. California: O'Reilly and Assosciates. At the initial addition of TBSCl, there is only a minor amount of monoanion in solution with the rest being in suspension.
This small portion reacts and shifts the equilibrium of the monoanion to draw more into solution, thereby allowing for high yields of the mono-TBS compound to be obtained.
Superior results in some cases may be obtained with butyllithium : . Selective deprotection of silyl groups is possible in many instances. For example, in the synthesis of taxol : .
Silyl ethers are mainly differentiated on the basis of sterics or electronics. In general, acidic deprotections deprotect less hindered silyl groups faster, with the steric bulk on silicon being more significant than the steric bulk on oxygen.
Fluoride-based deprotections deprotect electron-poor silyl groups faster than electron-rich silyl groups.
There is some evidence that some silyl deprotections proceed via hypervalent silicon species. The selective deprotection of silyl ethers has been extensively reviewed.
A selective deprotection will likely be successful if there is a substantial difference in sterics e. Unfortunately, some optimization is inevitably required and it is often necessary to run deprotections partway and recycle material.
From Wikipedia, the free encyclopedia. Protective Groups In Organic Synthesis. Tetrahedron Lett. Gong, Q. Sin, Synthesis , , 51 , Sodium tetrachloroaurate III dihydrate as catalyst enables a simple and mild removal of tert -butyl dimethyl silyl TBS protecting groups.
A selective deprotection of aliphatic TBS ethers is possible in the presence of aromatic TBS ethers, aliphatic triisopropylsilyl ethers, aliphatic tert -butyl diphenyl silyl ethers, or sterically hindered aliphatic TBS ethers.
Additionally, TBS ethers can also be transformed into benzyl ethers in one pot. Zhang, X. Kang, L. Long, L. Zhu, Y.
Chai, Synthesis , , 47 , This method is high yielding, fast, clean, safe, and cost-effective. Gopinath, B. Patel, Org. The silyl ethers of phenols were deprotected at longer reaction times.
Sabitha, M. Syamala, J. Yadav, Org. This mild and convenient method tolerates various other protecting groups and does not lead to acylated or chlorinated byproducts.
Khan, E. Mondal, Synlett , , Catalytic quantities of fluoride at neutral pH in mixed organic-aqueous solutions that contain buffer cleaved various silicon-oxygen bonds.
These conditions show tolerance for acid- and base-sensitive groups. A modified procedure using catalytic fluoride in anhydrous dimethyl sulfoxide-methanol generates primarily volatile silicon byproducts.
DiLauro, W. Seo, S. Phillips, J. Various tert -butyldimethylsilyl ethers are easily removed in excellent yields by treatment with a catalytic amount of N -iodosuccinimide in methanol.
Karimi, A. Zamani, D. Zarayee, Tetrahedron Lett. The supported catalyst and the solvent can be readily recovered and recycled.
Kumar, S. Baskaran, J. A chemoselective, efficient and operationally simple desilylation of O-tert -butyldimethylsilyl ethers was achieved using chlorotrimethylsilane and potassium fluoride dihydrate in acetonitrile.
Peng, W. Li, Synlett , , A microwave-assisted, chemoselective and efficient method for the cleavage of silyl ethers is catalyzed by Selectfluor.
In addition, the transetherification and etherification of benzylic hydroxy groups in alcoholic solvents is observed. Shah, S. Singh, P.Silylenolether können analog durch Reaktion von Silylchlorid mit der Carbonylfunktion von Aldehyden und Ketonen in Devisen Broker Vergleich einer Aminbase erhalten werden. Um dies in unerwünschten Fällen zu verhindern, wurde die Schutzgruppentechnik in der organischen Chemie eingeführt. Namensräume Artikel Diskussion.