You cannot select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
43 lines
1.4 KiB
JavaScript
43 lines
1.4 KiB
JavaScript
// @flow
|
|
import type {LexerInterface} from "./Token";
|
|
|
|
/**
|
|
* Lexing or parsing positional information for error reporting.
|
|
* This object is immutable.
|
|
*/
|
|
export default class SourceLocation {
|
|
// The + prefix indicates that these fields aren't writeable
|
|
+lexer: LexerInterface; // Lexer holding the input string.
|
|
+start: number; // Start offset, zero-based inclusive.
|
|
+end: number; // End offset, zero-based exclusive.
|
|
|
|
constructor(lexer: LexerInterface, start: number, end: number) {
|
|
this.lexer = lexer;
|
|
this.start = start;
|
|
this.end = end;
|
|
}
|
|
|
|
/**
|
|
* Merges two `SourceLocation`s from location providers, given they are
|
|
* provided in order of appearance.
|
|
* - Returns the first one's location if only the first is provided.
|
|
* - Returns a merged range of the first and the last if both are provided
|
|
* and their lexers match.
|
|
* - Otherwise, returns null.
|
|
*/
|
|
static range(
|
|
first?: {loc: ?SourceLocation},
|
|
second?: {loc: ?SourceLocation},
|
|
): ?SourceLocation {
|
|
if (!second) {
|
|
return first && first.loc;
|
|
} else if (!first || !first.loc || !second.loc ||
|
|
first.loc.lexer !== second.loc.lexer) {
|
|
return null;
|
|
} else {
|
|
return new SourceLocation(
|
|
first.loc.lexer, first.loc.start, second.loc.end);
|
|
}
|
|
}
|
|
}
|