library-ts/browser/text/lexer/LexerSequence.ts

import { LexerEvent } from "./LexerEvent";
import { BooleanExpression } from "../../expressions/BooleanExpression";
import { LexerQuery } from "./LexerQuery";

export class LexerSequence
{
  sequence:BooleanExpression<LexerEvent>[] = [];
  ignore:BooleanExpression<LexerEvent> = null;


  get( query:LexerQuery, tokenOffset:number, sequenceOffset:number ):number[]
  {
    let sequenceIndices:number[] = [];
    
    for ( let s of this.sequence ){ sequenceIndices.push( -1 ); }
    
    if ( ! this.sequence[ sequenceOffset ].evaluate( query.tokens[ tokenOffset ] ) )
    {
      //console.log( "Offset is not matching" );
      return null;
    }

    sequenceIndices[ sequenceOffset ] = tokenOffset;

    let previousSearchIndex = tokenOffset;

    for ( let i = sequenceOffset - 1; i >= 0; i-- )
    {
      let matcher = this.sequence[ i ];
      let index = query.searchIndex( previousSearchIndex, false, matcher, this.ignore, 2 );      

      if ( index === -1 )
      {
        let startTokenIndex = Math.max( 0, previousSearchIndex - 5 );
        let previousTokens = query.tokens.slice( startTokenIndex, previousSearchIndex );
        let infos = previousTokens.map(
          ( le )=>
          {
            let ignoreResult = this.ignore.evaluate( le );
            let matchResult  = matcher.evaluate( le );
            return `'${le.match}' ${query.index(le)} ${le.type} ignore:${ignoreResult} match:${matchResult}`;
          }
        );

        //console.log( `Sequence not matching at #${i}(${previousSearchIndex})`, matcher, "\n", `[${infos}]` );
        return null;
      }

      sequenceIndices[ i ] = index;
      previousSearchIndex = index;
      let token = query.tokens[ index ];

    }

    let nextSearchIndex = tokenOffset;

    for ( let i = sequenceOffset + 1; i < this.sequence.length; i++ )
    {
      let matcher = this.sequence[ i ];
      let index = query.searchIndex( nextSearchIndex, true, matcher, this.ignore, 2 );      

      if ( index === -1 )
      {
        let endTokenIndex = Math.min( query.tokens.length, nextSearchIndex + 5 );
        let nextTokens = query.tokens.slice( nextSearchIndex, endTokenIndex );

        let infos = nextTokens.map(
          ( le )=>
          {
            let ignoreResult = this.ignore.evaluate( le );
            let matchResult  = matcher.evaluate( le );
            return `'${le.match}' ${query.index(le)} ${le.type} ignore:${ignoreResult} match:${matchResult}`;
          }
        );
  
        //console.log( `Sequence not at #${i}(${nextSearchIndex})`, matcher, "\n", `[${infos}]` );
        return null;
      }

      sequenceIndices[ i ] = index;
      nextSearchIndex = index;
      let token = query.tokens[ index ];

    }

    return sequenceIndices;
  }
}