The Parle\Lexer class

(PECL parle >= 0.5.1)

Introduction

Single state lexer class. Lexemes can be defined on the fly. If the particular lexer instance is meant to be used with Parle\Parser, the token IDs need to be taken from there. Otherwise, arbitrary token IDs can be supplied. This lexer can give a certain performance advantage over Parle\RLexer, if no multiple states are required. Note, that Parle\RParser is not compatible with this lexer.

Class synopsis

class Parle\Lexer {

/* Constants */

const int ICASE = 1;

const int DOT_NOT_LF = 2;

const int DOT_NOT_CRLF = 4;

const int SKIP_WS = 8;

const int MATCH_ZERO_LEN = 16;

/* Properties */

public bool $bol = false;

public int $flags = 0;

public int $state = 0;

public int $marker = 0;

public int $cursor = 0;

/* Methods */

public advance(): void

public build(): void

public callout(int $id, callable $callback): void

public consume(string $data): void

public dump(): void

public getToken(): Parle\Token

public insertMacro(string $name, string $regex): void

public push(string $regex, int $id): void

public reset(int $pos): void

}

Predefined Constants

Parle\Lexer::ICASE
Parle\Lexer::DOT_NOT_LF
Parle\Lexer::DOT_NOT_CRLF
Parle\Lexer::SKIP_WS
Parle\Lexer::MATCH_ZERO_LEN

Properties

bol: Start of input flag.
flags: Lexer flags.
state: Current lexer state, readonly.
marker: Position of the latest token match, readonly.
cursor: Current input offset, readonly.

Parle\Lexer::advance — Process next lexer rule
Parle\Lexer::build — Finalize the lexer rule set
Parle\Lexer::callout — Define token callback
Parle\Lexer::consume — Pass the data for processing
Parle\Lexer::dump — Dump the state machine
Parle\Lexer::getToken — Retrieve the current token
Parle\Lexer::insertMacro — Insert regex macro
Parle\Lexer::push — Add a lexer rule
Parle\Lexer::reset — Reset lexer

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