4e69153e3e
git-subtree-dir: packages/graphql git-subtree-mainline:ac29392d7fgit-subtree-split:33e2f86ba7
75 lines
2.2 KiB
Dart
75 lines
2.2 KiB
Dart
import 'package:string_scanner/string_scanner.dart';
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import 'syntax_error.dart';
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import 'token.dart';
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import 'token_type.dart';
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final RegExp _comment = RegExp(r'#[^\n]*');
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final RegExp _whitespace = RegExp('[ \t\n\r]+');
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// final RegExp _boolean = RegExp(r'true|false');
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final RegExp _number = RegExp(r'-?[0-9]+(\.[0-9]+)?(E|e(\+|-)?[0-9]+)?');
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final RegExp _string = RegExp(
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r'"((\\(["\\/bfnrt]|(u[0-9a-fA-F][0-9a-fA-F][0-9a-fA-F][0-9a-fA-F])))|([^"\\]))*"');
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final RegExp _blockString = RegExp(r'"""(([^"])|(\\"""))*"""');
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final RegExp _name = RegExp(r'[_A-Za-z][_0-9A-Za-z]*');
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final Map<Pattern, TokenType> _patterns = {
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'@': TokenType.ARROBA,
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':': TokenType.COLON,
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',': TokenType.COMMA,
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r'$': TokenType.DOLLAR,
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'...': TokenType.ELLIPSIS,
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'=': TokenType.EQUALS,
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'!': TokenType.EXCLAMATION,
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'{': TokenType.LBRACE,
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'}': TokenType.RBRACE,
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'[': TokenType.LBRACKET,
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']': TokenType.RBRACKET,
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'(': TokenType.LPAREN,
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')': TokenType.RPAREN,
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// 'fragment': TokenType.FRAGMENT,
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// 'mutation': TokenType.MUTATION,
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// 'subscription': TokenType.SUBSCRIPTION,
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// 'on': TokenType.ON,
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// 'query': TokenType.QUERY,
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// 'null': TokenType.NULL,
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// _boolean: TokenType.BOOLEAN,
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_number: TokenType.NUMBER,
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_string: TokenType.STRING,
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_blockString: TokenType.BLOCK_STRING,
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_name: TokenType.NAME
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};
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List<Token> scan(String text, {sourceUrl}) {
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List<Token> out = [];
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var scanner = SpanScanner(text, sourceUrl: sourceUrl);
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while (!scanner.isDone) {
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List<Token> potential = [];
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if (scanner.scan(_comment) ||
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scanner.scan(_whitespace) ||
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scanner.scan(',') ||
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scanner.scan('\ufeff')) continue;
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for (var pattern in _patterns.keys) {
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if (scanner.matches(pattern)) {
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potential.add(
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Token(_patterns[pattern], scanner.lastMatch[0], scanner.lastSpan));
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}
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}
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if (potential.isEmpty) {
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var ch = String.fromCharCode(scanner.readChar());
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throw SyntaxError("Unexpected token '$ch'.", scanner.emptySpan);
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} else {
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// Choose longest token
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potential.sort((a, b) => b.text.length.compareTo(a.text.length));
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var chosen = potential.first;
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out.add(chosen);
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scanner.scan(chosen.text);
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}
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}
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return out;
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}
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