Interface BaseParser

Base interface for all parsers. Mainly used by the parser-builder-base.ts to perform work on different kinds of parsers. The main use cases are:

AST parser: Based on a string, create an AST for the current grammar
Completion parser: Based on a partial string, identify the current position of the input within the grammar

interface BaseParser {
    get unorderedGroups(): Map<string, boolean[]>;
    action($type: string, action: GrammarAST.Action): void;
    alternatives(idx: number, choices: IOrAlt<any>[]): void;
    atLeastOne(idx: number, callback: DSLMethodOpts<unknown>): void;
    construct(): unknown;
    consume(idx: number, tokenType: TokenType, feature: GrammarAST.AbstractElement): void;
    getRule(name: string): undefined | RuleResult;
    getRuleStack(): number[];
    isRecording(): boolean;
    many(idx: number, callback: DSLMethodOpts<unknown>): void;
    optional(idx: number, callback: DSLMethodOpts<unknown>): void;
    rule(rule: GrammarAST.ParserRule, impl: RuleImpl): RuleResult;
    subrule(idx: number, rule: RuleResult, feature: GrammarAST.AbstractElement, args: Args): void;
}

Implemented by

AbstractLangiumParser

Index

Accessors

unorderedGroups

Methods

action alternatives atLeastOne construct consume getRule getRuleStack isRecording many optional rule subrule

Accessors

unorderedGroups

get unorderedGroups(): Map<string, boolean[]>
Current state of the unordered groups

Returns Map<string, boolean[]>
- Defined in packages/langium/src/parser/langium-parser.ts:115

Methods

action

action($type, action): void
Executes a grammar action that modifies the currently active AST node
Parameters
- $type: string
- action: GrammarAST.Action
Returns void
- Defined in packages/langium/src/parser/langium-parser.ts:101

alternatives

alternatives(idx, choices): void
Performs alternatives parsing (the | operation in EBNF/Langium)
Parameters
- idx: number
- choices: IOrAlt<any>[]
Returns void
- Defined in packages/langium/src/parser/langium-parser.ts:74

atLeastOne

atLeastOne(idx, callback): void
Parses the callback 1 or more times (the + operation in EBNF/Langium)
Parameters
- idx: number
- callback: DSLMethodOpts<unknown>
Returns void
- Defined in packages/langium/src/parser/langium-parser.ts:86

construct

construct(): unknown
Finishes construction of the current AST node. Only used by the AST parser.

Returns unknown
- Defined in packages/langium/src/parser/langium-parser.ts:105

consume

consume(idx, tokenType, feature): void
Consumes a specific token type from the token input stream. Requires a unique index within the rule for a specific token type.
Parameters
- idx: number
- tokenType: TokenType
- feature: GrammarAST.AbstractElement
Returns void
- Defined in packages/langium/src/parser/langium-parser.ts:91

getRule

getRule(name): undefined | RuleResult
Returns the executable rule function for the specified rule name
Parameters
- name: string
Returns undefined | RuleResult
- Defined in packages/langium/src/parser/langium-parser.ts:70

getRuleStack

getRuleStack(): number[]
The rule stack indicates the indices of rules that are currently invoked, in order of their invocation.

Returns number[]
- Defined in packages/langium/src/parser/langium-parser.ts:120

isRecording

isRecording(): boolean
Whether the parser is currently actually in use or in "recording mode". Recording mode is activated once when the parser is analyzing itself. During this phase, no input exists and therefore no AST should be constructed

Returns boolean
- Defined in packages/langium/src/parser/langium-parser.ts:111

many

many(idx, callback): void
Parses the callback 0 or more times (the * operation in EBNF/Langium)
Parameters
- idx: number
- callback: DSLMethodOpts<unknown>
Returns void
- Defined in packages/langium/src/parser/langium-parser.ts:82

optional

optional(idx, callback): void
Parses the callback as optional (the ? operation in EBNF/Langium)
Parameters
- idx: number
- callback: DSLMethodOpts<unknown>
Returns void
- Defined in packages/langium/src/parser/langium-parser.ts:78

rule

rule(rule, impl): RuleResult
Adds a new parser rule to the parser
Parameters
- rule: GrammarAST.ParserRule
- impl: RuleImpl
Returns RuleResult
- Defined in packages/langium/src/parser/langium-parser.ts:66

subrule

subrule(idx, rule, feature, args): void
Invokes the executable function for a given parser rule. Requires a unique index within the rule for a specific sub rule. Arguments can be supplied to the rule invocation for semantic predicates
Parameters
- idx: number
- rule: RuleResult
- feature: GrammarAST.AbstractElement
- args: Args
Returns void
- Defined in packages/langium/src/parser/langium-parser.ts:97

Interface BaseParser

Implemented by

Index

Accessors

Methods

Accessors

unorderedGroups

Returns Map<string, boolean[]>

Methods

action

Parameters

Returns void

alternatives

Parameters

Returns void

atLeastOne

Parameters

Returns void

construct

Returns unknown

consume

Parameters

Returns void

getRule

Parameters

Returns undefined | RuleResult

getRuleStack

Returns number[]

isRecording

Returns boolean

many

Parameters

Returns void

optional

Parameters

Returns void

rule

Parameters

Returns RuleResult

subrule

Parameters

Returns void

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