GenericWordState

A WordState returns a word from a scanner.

Implements: IWordState

Description

The GenericWordState class allows you to create a WordState that returns a word from a scanner.

Important points

  • Like other states, a tokenizer transfers the job of reading to this state, depending on an initial character.
  • This state determines which characters may appear as a second or later character in a word. These are typically different sets of characters; in particular, it is typical for digits to appear as parts of a word, but not as the initial character of a word.
  • By default, the following characters may appear in a word (The method setWordChars() allows customizing this):
From     To
 'a',    'z'
 'A',    'Z'
 '0',    '9'

As well as: minus sign, underscore, and apostrophe.

Constructors

Constructs a word state with a default idea of what characters are admissible inside a word (as described in the class comment).

GenericWordState()

Instance methods

clearWordChars

Clears definitions of word chars.

@override

void clearWordChars()

nextToken

Ignores a word (such as blanks and tabs), and returns the tokenizer’s next token.

@override

Token? nextToken(IScanner scanner, ITokenizer? tokenizer)

  • scanner: IScanner - textual string to be tokenized.
  • tokenizer: ITokenizer - tokenizer class that controls the process.
  • returns: Token - next token from the top of the stream.

setWordChars

Establishes characters in the given range as valid characters for part of a word after the first character.

Note that the tokenizer must determine which characters are valid as the beginning character of a word.

@override

void setWordChars(int fromSymbol, int toSymbol, bool enable)

  • fromSymbol: int - first character index of the interval.
  • toSymbol: int - last character index of the interval.
  • enable: bool - true if this state should ignore characters in the given range.