Parser

MMO\client\scs · 1 symbol · generated 5 Oct 2026

class

Parser

Turns the tokens of a .scs source into an ast (StylesheetNode).

class MMO\client\scs\Parser

Namespace: MMO\client\scs

The parser reads two kinds of value: - **expressions** (`@let`, `@if`, `@for`, function arguments, `${...}`) where `+ - * /` are arithmetic; - **css values** (declarations, selectors, at-rule preludes) where they are plain css text, and only `$variables`, `${interpolations}` and known functions are evaluated -- this is exactly the distinction the language makes with `${...}` (`the` spec, 5.3).

$ast = (new Parser('@let $spacing = 16px', 'theme.scs'))->parse();

Index

	CSS_FUNCTIONS	css functions whose arguments must never be evaluated as arithmetic (`calc(100% - 20px)`)
	PRECEDENCE	operator precedence, highest binds tighter
	filename
	index
	source
	tokens
	accept($type, $text)
	at($type, $text)
	error($token, $message, $context)
	expect($type, $text)
	expectTerminator($node)	Consume the `;` that ends a statement, or say where it is missing.
	getFilename()
	getSource()
	location($token)
	needsTerminator($node)
	next()
	parse()
	parseArguments($raw, $selector)	Read the arguments of a call.
	parseArray()	`[4, 8, 16]`
	parseAtRule()
	parseBlock()	Parse a `{ ... }` block.
	parseComponent()
	parseConfig()
	parseCssTerm($selector)	Read one term of a css value: everything that is not scs is kept as written.
	parseDefinition($class)	`@style name($a, $b = default) { ...
	parseExpression($precedence)	Parse a full expression, where `+ - * /` are arithmetic (`PRECEDENCE`).
	parseFor()
	parseIdentPrimary()
	parseIdentTerm($selector)	An identifier in a css value is a call (`spacing(4)`, `lib::step(3)`, `php::round(1.2)`, `calc(...)`), a namespaced reference (`context::density`) or plain css text.
	parseIf()
	parseImport()
	parseInterpolated()	Parse the body of an interpolation: a single expression.
	parseInterpolation()
	parseLet()
	parseName()	Read a reference to a definition: `center`, or `lib::center` for one that belongs to another file.
	parseNamespace($token)	`@namespace ui` -- name the definitions of this file.
	parseOrder()
	parseParameters()
	parseParenthesis()	`(a + b)` or a map literal `(sm: 8px, md: 16px)`.
	parsePrimary()
	parseRawArgument($selector)	Read one argument of a css-only function (`calc`, `clamp`, ...): everything is kept verbatim but `$variables` and `${interpolations}`, which are still resolved.
	parseRawAtRule($token)	A css at-rule the language does not interpret: `@media`, `@keyframes`, `@font-face`, `@supports`...
	parseRuleOrDeclaration()	Decide between a nested rule and a declaration by looking ahead for the token that ends the statement: a `{` means everything read so far was a selector.
	parseScreen()
	parseStatement()
	parseStatements($inBlock)
	parseString()	Read a string token, keeping the `${...}` / `#{...}` it may contain interpolable.
	parseTheme()
	parseThemeEntries($prefix)	Read the `group { key: value }` body of a `@theme`, flattening it into dotted paths.
	parseThemeValue()	Read the value of a theme token.
	parseUnary()
	parseUse()
	parseValue()	Parse the whole source as a single value, for the evaluation api (`Compiler::evaluate`).
	parseValueList($css, $stop, $selector)	Read a css value, a selector or an `@let` value: a list of terms, up to the end of the statement.
	parseVariableRef()
	parseVariant()
	peek($offset)
	skipNewlines()	Skip end of lines, which are only statement separators.
	skipTerminators()	Skip what separates two statements: `;` and the newlines around it.
	startsThemeEntry($offset)
	__construct($source, $filename, $line, $col)

Constants2

CSS_FUNCTIONS

css functions whose arguments must never be evaluated as arithmetic (calc(100% - 20px))

const CSS_FUNCTIONS = […81 items]

PRECEDENCE

operator precedence, highest binds tighter

const PRECEDENCE = […15 items]

Properties4

filename

protected string $filename

Type: string

index

protected int $index = 0

Type: int

source

protected string $source

Type: string

tokens

protected array $tokens

Type: array

Methods55

accept($type, $text)

Parser.php:97

protected function accept(MMO\client\scs\TokenType $type, ?string $text = null): ?MMO\client\scs\Token

$type	TokenType
$text = null	null \| string
returns	null \| Token

at($type, $text)

Parser.php:93

protected function at(MMO\client\scs\TokenType $type, ?string $text = null): bool

$type	TokenType
$text = null	null \| string
returns	bool

error($token, $message, $context)

Parser.php:121

protected function error(MMO\client\scs\Token $token, string $message, array $context = []): MMO\client\exceptions\eSCS

$token	Token
$message	string
$context = []	array
returns	eSCS

expect($type, $text)

Parser.php:101

protected function expect(MMO\client\scs\TokenType $type, ?string $text = null): MMO\client\scs\Token

$type	TokenType
$text = null	null \| string
returns	Token

expectTerminator($node)

Parser.php:180

Consume the ; that ends a statement, or say where it is missing.

protected function expectTerminator(MMO\client\scs\nodes\Node $node): void

$node	Node	the statement it belongs to
returns	void
throws		when the statement is not terminated

getFilename()

Parser.php:67

function getFilename(): string

returns

string

getSource()

Parser.php:68

function getSource(): string

returns

string

location($token)

Parser.php:125

protected function location(MMO\client\scs\Token $token): MMO\client\scs\SourceLocation

$token	Token
returns	SourceLocation

needsTerminator($node)

Parser.php:162

protected function needsTerminator(MMO\client\scs\nodes\Node $node): bool

$node	Node	the statement that was just read
returns	bool	true when it must be followed by a `;` -- everything but a block

next()

Parser.php:87

protected function next(): MMO\client\scs\Token

returns

Token

parse()

Parser.php:74

function parse(): MMO\client\scs\nodes\StylesheetNode

returns	StylesheetNode	the parsed source
throws		on any syntax error, located on the offending token

parseArguments($raw, $selector)

Parser.php:699

Read the arguments of a call.

protected function parseArguments(bool $raw, bool $selector = false): array

$raw	bool	true to keep the arguments as css (only variables and interpolations are evaluated)
$selector = false	bool	true inside a selector, where a nested `name(...)` is itself a functional pseudo-class: `:not(:has(::slotted(*)))` is three selectors deep and still css
returns	array

parseArray()

Parser.php:962

[4, 8, 16]

protected function parseArray(): MMO\client\scs\nodes\Node

returns

Node

parseAtRule()

Parser.php:254

protected function parseAtRule(): MMO\client\scs\nodes\Node

returns

Node

parseBlock()

Parser.php:188

Parse a { ... } block.

protected function parseBlock(): array

returns

array

parseComponent()

Parser.php:444

protected function parseComponent(): MMO\client\scs\nodes\ComponentNode

returns

ComponentNode

parseConfig()

Parser.php:564

protected function parseConfig(): MMO\client\scs\nodes\ConfigNode

returns

ConfigNode

parseCssTerm($selector)

Parser.php:631

Read one term of a css value: everything that is not scs is kept as written.

protected function parseCssTerm(bool $selector = false): MMO\client\scs\nodes\Node

$selector = false	bool	true in a selector, a property name or an at-rule prelude, where a `name(...)` is a functional pseudo-class (`:not(.a, .b)`) rather than a function to evaluate
returns	Node

parseDefinition($class)

Parser.php:381

@style name($a, $b = default) { ... } / @fn name($a) { ... }

protected function parseDefinition(string $class): MMO\client\scs\nodes\Node

$class	string
returns	Node

parseExpression($precedence)

Parser.php:866

Parse a full expression, where + - * / are arithmetic (PRECEDENCE).

function parseExpression(int $precedence = 0): MMO\client\scs\nodes\Node

$precedence = 0	int	the minimum precedence to keep consuming operators at
returns	Node

parseFor()

Parser.php:512

protected function parseFor(): MMO\client\scs\nodes\ForNode

returns

ForNode

parseIdentPrimary()

Parser.php:921

protected function parseIdentPrimary(): MMO\client\scs\nodes\Node

returns

Node

parseIdentTerm($selector)

Parser.php:653

An identifier in a css value is a call (spacing(4), lib::step(3), php::round(1.2), calc(...)), a namespaced reference (context::density) or plain css text.

protected function parseIdentTerm(bool $selector = false): MMO\client\scs\nodes\Node

$selector = false	bool
returns	Node

parseIf()

Parser.php:490

protected function parseIf(): MMO\client\scs\nodes\IfNode

returns

IfNode

parseImport()

Parser.php:535

protected function parseImport(): MMO\client\scs\nodes\ImportNode|MMO\client\scs\nodes\AtRuleNode

returns

ImportNode | AtRuleNode

parseInterpolated()

Parser.php:814

Parse the body of an interpolation: a single expression.

function parseInterpolated(): MMO\client\scs\nodes\Node

returns

Node

parseInterpolation()

Parser.php:790

protected function parseInterpolation(): MMO\client\scs\nodes\Node

returns

Node

parseLet()

Parser.php:281

protected function parseLet(): MMO\client\scs\nodes\VariableNode

returns

VariableNode

parseName()

Parser.php:400

Read a reference to a definition: center, or lib::center for one that belongs to another file.

protected function parseName(): array

returns

array

?string, name: string}

parseNamespace($token)

Parser.php:415

@namespace ui -- name the definitions of this file.

protected function parseNamespace(MMO\client\scs\Token $token): MMO\client\scs\nodes\Node

`@namespace` is also a (rarely used) css at-rule: `@namespace svg url(...)` is left to css, only a lone identifier is read as the language instruction.

$token	Token
returns	Node

parseOrder()

Parser.php:486

protected function parseOrder(): MMO\client\scs\nodes\OrderNode

returns

OrderNode

parseParameters()

Parser.php:425

protected function parseParameters(): array

returns

array

[['name' => string, 'default' => ?Node], ...]

parseParenthesis()

Parser.php:932

(a + b) or a map literal (sm: 8px, md: 16px).

protected function parseParenthesis(): MMO\client\scs\nodes\Node

returns

Node

parsePrimary()

Parser.php:901

protected function parsePrimary(): MMO\client\scs\nodes\Node

returns

Node

parseRawArgument($selector)

Parser.php:723

Read one argument of a css-only function (calc, clamp, ...): everything is kept verbatim but $variables and ${interpolations}, which are still resolved.

protected function parseRawArgument(bool $selector = false): MMO\client\scs\nodes\ValueListNode

$selector = false	bool	true to keep reading the argument as a selector
returns	ValueListNode

parseRawAtRule($token)

Parser.php:580

A css at-rule the language does not interpret: @media, @keyframes, @font-face, @supports...

protected function parseRawAtRule(MMO\client\scs\Token $token): MMO\client\scs\nodes\AtRuleNode

$token	Token
returns	AtRuleNode

parseRuleOrDeclaration()

Parser.php:214

Decide between a nested rule and a declaration by looking ahead for the token that ends the statement: a { means everything read so far was a selector.

protected function parseRuleOrDeclaration(): MMO\client\scs\nodes\Node

returns

Node

parseScreen()

Parser.php:479

protected function parseScreen(): MMO\client\scs\nodes\ScreenNode

returns

ScreenNode

parseStatement()

Parser.php:196

protected function parseStatement(): MMO\client\scs\nodes\Node

returns

Node

parseStatements($inBlock)

Parser.php:137

protected function parseStatements(bool $inBlock): array

$inBlock	bool	true to stop on the closing `}` of the enclosing block
returns	array

parseString()

Parser.php:751

Read a string token, keeping the ${...} / #{...} it may contain interpolable.

protected function parseString(): MMO\client\scs\nodes\Node

returns Node a LiteralNode for a plain string, a StringNode otherwise

parseTheme()

Parser.php:287

protected function parseTheme(): MMO\client\scs\nodes\ThemeNode

returns

ThemeNode

parseThemeEntries($prefix)

Parser.php:305

Read the group { key: value } body of a @theme, flattening it into dotted paths.

protected function parseThemeEntries(string $prefix): array

$prefix	string
returns	array	dotted path => value node

parseThemeValue()

Parser.php:345

Read the value of a theme token.

protected function parseThemeValue(): MMO\client\scs\nodes\ValueListNode

Same as a css value, except that a top level comma ends the token when what follows it is another `key:` -- so both `sm: 8px, md: 16px` and `font: "Inter", sans-serif` mean what they look like.

returns

ValueListNode

parseUnary()

Parser.php:889

protected function parseUnary(): MMO\client\scs\nodes\Node

returns

Node

parseUse()

Parser.php:461

protected function parseUse(): MMO\client\scs\nodes\UseNode

returns

UseNode

parseValue()

Parser.php:803

Parse the whole source as a single value, for the evaluation api (Compiler::evaluate).

function parseValue(): MMO\client\scs\nodes\ValueListNode

returns

ValueListNode

parseValueList($css, $stop, $selector)

Parser.php:596

Read a css value, a selector or an @let value: a list of terms, up to the end of the statement.

protected function parseValueList(bool $css, array $stop = [], bool $selector = false): MMO\client\scs\nodes\ValueListNode

$css	bool	true for css context (`+ - * /` stay literal), false for an expression context
$stop = []	array	extra punctuation that ends the list (not consumed)
$selector = false	bool
returns	ValueListNode