Search results
Results From The WOW.Com Content Network
Keywords are predefined reserved words with special syntactic meaning. [2] The language has two types of keyword — contextual and reserved. The reserved keywords such as false or byte may only be used as keywords. The contextual keywords such as where or from are only treated as keywords in certain situations. [3]
A classic example is "New York-based", which a naive tokenizer may break at the space even though the better break is (arguably) at the hyphen. Tokenization is particularly difficult for languages written in scriptio continua , which exhibit no word boundaries, such as Ancient Greek , Chinese , [ 4 ] or Thai .
As such, hash tables usually perform in O(1) time, and usually outperform alternative implementations. Hash tables must be able to handle collisions: the mapping by the hash function of two different keys to the same bucket of the array. The two most widespread approaches to this problem are separate chaining and open addressing.
The parsing stage itself can be divided into two parts: the parse tree, or "concrete syntax tree", which is determined by the grammar, but is generally far too detailed for practical use, and the abstract syntax tree (AST), which simplifies this into a usable form. The AST and contextual analysis steps can be considered a form of semantic ...
The two characters commonly used for this purpose are the hyphen ("-") and the underscore ("_"); e.g., the two-word name "two words" would be represented as "two-words" or "two_words". The hyphen is used by nearly all programmers writing COBOL (1959), Forth (1970), and Lisp (1958); it is also common in Unix for commands and packages, and is ...
Apart from assignments and subroutine calls, most languages start each statement with a special word (e.g. goto, if, while, etc.) as shown in the above examples. Various methods have been used to describe the form of statements in different languages; the more formal methods tend to be more precise:
Some lemmatisation algorithms are stochastic in that, given a word which may belong to multiple parts of speech, a probability is assigned to each possible part. This may take into account the surrounding words, called the context, or not. Context-free grammars do not take into account any additional information.
Here is the beginning of Dr. Seuss's Green Eggs and Ham, with character numbers at the beginning of lines for convenience.Green Eggs and Ham is a good example to illustrate LZSS compression because the book itself only contains 50 unique words, despite having a word count of 170. [2]