classLemonGrammarReader

packages/sql-parser/src/Compiler/LemonGrammarReader.php:47

final class LemonGrammarReader

Public API: explicitly declared with @visibility public.

Turns a Lemon grammar file into the grammar the automaton is built from.

The file is read with lemon-parser after its %ifdef regions are settled with the names given; this class keeps what the automaton needs. %token names terminals, %left, %right and %nonassoc rank them, %token_class declarations and A|B positions become token classes, %fallback, %wildcard and %start_symbol are recorded for the parser, a [PREC] mark names a rule's precedence, and any upper-case name on a right-hand side is a terminal.

Reading a small grammardoctest

$grammar = (new \SqlParser\Compiler\LemonGrammarReader())->read("%left PLUS.\nexpr ::= expr PLUS|MINUS expr.\nexpr ::= NUM.\n");
    [count($grammar->rules), $grammar->symbols->name($grammar->startSymbol())] // => [3, "expr"]

Settling a conditional regiondoctest

$source = "%ifndef OMIT\ncmd ::= EXTRA.\n%endif\ncmd ::= SELECT.\n";
    [count((new \SqlParser\Compiler\LemonGrammarReader())->read($source)->rules), count((new \SqlParser\Compiler\LemonGrammarReader())->read($source, ['OMIT'])->rules)] // => [3, 2]

Methods§

public function __construct(private Parser $parser = new \LemonParser\Parser())

source §

Parameters

$parser Parser Reads Lemon grammar files

Calls 1

new Parser line 52

public function read(string $source, list<string> $defines = []): Grammar

source §

Reads a grammar file.

Parameters

`$source`	`string`	The text of the `.y` file
`$defines`	`list<string>`	Names defined for `%ifdef`, as Lemon's `-D` option defines them

Returns

Grammar The grammar with Lemon's precedence policy

Throws

SyntaxException When the file is not a grammar Lemon accepts

GrammarException When the grammar is inconsistent

UnknownSymbolException When a declaration names an unknown symbol

Test cases 3

Calls 7

method-call Parser::parse() line 70
new GrammarBuilder line 71
method-call GrammarBuilder::policy() line 72
class-const PrecedencePolicy::FirstRankedTerminal() line 72
method-call LemonGrammarReader::rule() line 75
method-call LemonGrammarReader::declaration() line 77
method-call GrammarBuilder::build() line 81

public function declaration(Declaration $declaration, GrammarBuilder $builder): void

source §

Records what a declaration says about terminals, precedence, token classes, fallbacks, the wildcard or the start symbol.

Parameters

`$declaration`	`Declaration`	The declaration
`$builder`	`GrammarBuilder`	Collects the grammar

Test cases 1

LemonGrammarReaderTest::testDeclaration calls

Called from 1

method-call SqlParser\Compiler\LemonGrammarReader::read() packages/sql-parser/src/Compiler/LemonGrammarReader.php:77

Calls 11

method-call GrammarBuilder::precedence() line 93
method-call LemonGrammarReader::names() line 93
method-call LemonGrammarReader::associativity() line 93
method-call GrammarBuilder::terminal() line 96
method-call Declaration::fallback() line 98
method-call GrammarBuilder::fallback() line 99
method-call Declaration::tokens() line 99
method-call GrammarBuilder::wildcard() line 101
method-call GrammarBuilder::tokenClass() line 103
class-const DirectiveKeyword::StartSymbol() line 104
method-call GrammarBuilder::start() line 105

public function associativity(Associativity $associativity): Associativity

source §

Maps Lemon's associativity onto the grammar's.

Parameters

$associativity Associativity As declared

Returns

Associativity As the automaton resolves conflicts

Test cases 1

LemonGrammarReaderTest::testAssociativity calls

Called from 1

method-call SqlParser\Compiler\LemonGrammarReader::declaration() packages/sql-parser/src/Compiler/LemonGrammarReader.php:93

Calls 6

class-const Associativity::Left() line 119
class-const Associativity::Left() line 119
class-const Associativity::Right() line 120
class-const Associativity::Right() line 120
class-const Associativity::NonAssoc() line 121
class-const Associativity::NonAssoc() line 121

public function rule(Rule $rule, GrammarBuilder $builder): void

source §

Adds a rule, turning a position shared by several terminals into a token class.

Parameters

`$rule`	`Rule`	The rule
`$builder`	`GrammarBuilder`	Collects the grammar

Test cases 1

LemonGrammarReaderTest::testRule calls

Called from 1

method-call SqlParser\Compiler\LemonGrammarReader::read() packages/sql-parser/src/Compiler/LemonGrammarReader.php:75

Calls 6

method-call LemonGrammarReader::names() line 135
function-call implode line 136
method-call GrammarBuilder::isTerminal() line 137
method-call GrammarBuilder::tokenClass() line 138
method-call GrammarBuilder::terminal() line 140
method-call GrammarBuilder::rule() line 144

public function names(list<Symbol> $symbols): list<string>

source §

Lists the names of symbols.

Parameters

$symbols list<Symbol> The symbols

Returns

list<string> Their names in order

Test cases 1

LemonGrammarReaderTest::testNames calls

Called from 4

Calls 1

function-call array_map line 156

Private surface 1§

Implementation details, listed for orientation only.

private Parser $parser = new \LemonParser\Parser()

Test cases 7§

Test cases that cover or call this symbol, from the coverage report and from the analyzed test sources.

Dedicated tests 7