classLookaheadFilter

packages/sql-parser/src/PostgreSql/Lexer/LookaheadFilter.php:21

final class LookaheadFilter

Restricted visibility: declared "@visibility root". Code outside that scope must not name this declaration.

The token substitutions PostgreSQL makes between its scanner and its parser.

A few keywords mean something else when a particular keyword follows: NOT before LIKE is the NOT of the predicate, WITH before TIME belongs to a type name. The parser's own lexer wrapper looks one token ahead and renames them, and it also finishes Unicode literals, which may carry their escape character in a following UESCAPE clause.

Constants§

public const SUBSTITUTIONS = ['FORMAT' => ['FORMAT_LA', ['JSON']], 'NOT' => ['NOT_LA', ['BETWEEN', 'IN_P', '…

source §

Renamed terminal by the terminal that precedes a listed one.

Methods§

public function apply(list<Lexeme> $lexemes, string $source): list<Lexeme>

source §

Applies the substitutions to a lexeme sequence.

Parameters

`$lexemes`	`list<Lexeme>`	Lexemes as scanned
`$source`	`string`	The SQL text

Returns

list<Lexeme> Lexemes as the parser receives them

Throws

LexicalException When a `UESCAPE` clause is malformed

Test cases 2

Called from 1

method-call SqlParser\PostgreSql\Lexer\PostgreSqlLexer::scan() packages/sql-parser/src/PostgreSql/Lexer/PostgreSqlLexer.php:62

Calls 5

function-call count line 47
class-const LookaheadFilter::SUBSTITUTIONS() line 50
function-call in_array line 51
new Lexeme line 52
method-call LookaheadFilter::unicode() line 54

public function unicode(
    Lexeme $lexeme,
    list<Lexeme> $lexemes,
    int &$index,
    string $source,
): Lexeme

source §

Finishes a Unicode literal, taking in its UESCAPE clause when one follows.

Parameters

`$lexeme`	`Lexeme`	The Unicode identifier or string
`$lexemes`	`list<Lexeme>`	Every lexeme, to look ahead in
`$index`	`int`	Position of the literal, advanced past the clause
`$source`	`string`	The SQL text