Class LookaheadIterator

constructor

• new LookaheadIterator(language: Language, state: number): LookaheadIterator

  Create a new lookahead iterator for this language and parse state.

  This returns null if the state is invalid for this language.

  Iterating LookaheadIterator will yield valid symbols in the given parse state. Newly created lookahead iterators will have currentType populated with the ERROR symbol.

  Lookahead iterators can be useful to generate suggestions and improve syntax error diagnostics. To get symbols valid in an ERROR node, use the lookahead iterator on its first leaf node state. For MISSING nodes, a lookahead iterator created on the previous non-extra leaf node may be appropriate.

  Parameters

  • language: Language

    The language to use for the lookahead iterator

  • state: number

    The parse state to use for the lookahead iterator

  Returns LookaheadIterator

ReadonlycurrentType

ReadonlycurrentTypeId

[iterator]

• "[iterator]"(): Iterator<string>

  Get an iterator for the lookahead iterator.

  This allows the lookahead iterator to be used in a for-of loop, iterating over the valid symbols in the current parse state.

  Returns Iterator<string>

  An iterator over the symbol names

reset

• reset(language: Language, stateId: number): boolean

  Reset the lookahead iterator.

  This returns true if the language was set successfully and false otherwise.

  Parameters

  • language: Language

    The language to use for the lookahead iterator

  • stateId: number

    The parse state to use for the lookahead iterator

  Returns boolean

resetState

• resetState(stateId: number): boolean

  Reset the lookahead iterator to another state.

  This returns true if the iterator was reset to the given state and false otherwise.

  Parameters

  • stateId: number

    The parse state to reset the lookahead iterator to

  Returns boolean