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// @flow
import SourceLocation from "./SourceLocation";
/**
* Interface required to break circular dependency between Token, Lexer, and
* ParseError.
*/
export interface LexerInterface {input: string, tokenRegex: RegExp}
/**
* The resulting token returned from `lex`.
*
* It consists of the token text plus some position information.
* The position information is essentially a range in an input string,
* but instead of referencing the bare input string, we refer to the lexer.
* That way it is possible to attach extra metadata to the input string,
* like for example a file name or similar.
*
* The position information is optional, so it is OK to construct synthetic
* tokens if appropriate. Not providing available position information may
* lead to degraded error reporting, though.
*/
export class Token {
text: string;
loc: ?SourceLocation;
noexpand: ?boolean; // don't expand the token
treatAsRelax: ?boolean; // used in \noexpand
constructor(
text: string, // the text of this token
loc: ?SourceLocation,
) {
this.text = text;
this.loc = loc;
}
/**
* Given a pair of tokens (this and endToken), compute a `Token` encompassing
* the whole input range enclosed by these two.
*/
range(
endToken: Token, // last token of the range, inclusive
text: string, // the text of the newly constructed token
): Token {
return new Token(text, SourceLocation.range(this, endToken));
}
}
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