rawsql-ts
Version:
[beta]High-performance SQL parser and AST analyzer written in TypeScript. Provides fast parsing and advanced transformation capabilities.
77 lines • 3.45 kB
JavaScript
;
Object.defineProperty(exports, "__esModule", { value: true });
exports.OrderByClauseParser = void 0;
const Clause_1 = require("../models/Clause");
const Lexeme_1 = require("../models/Lexeme");
const SqlTokenizer_1 = require("./SqlTokenizer");
const ValueParser_1 = require("./ValueParser");
class OrderByClauseParser {
// Parse SQL string to AST (was: parse)
static parse(query) {
const tokenizer = new SqlTokenizer_1.SqlTokenizer(query); // Initialize tokenizer
const lexemes = tokenizer.readLexmes(); // Get tokens
// Parse
const result = this.parseFromLexeme(lexemes, 0);
// Error if there are remaining tokens
if (result.newIndex < lexemes.length) {
throw new Error(`Syntax error: Unexpected token "${lexemes[result.newIndex].value}" at position ${result.newIndex}. The ORDER BY clause is complete but there are additional tokens.`);
}
return result.value;
}
// Parse from lexeme array (was: parse)
static parseFromLexeme(lexemes, index) {
let idx = index;
if (lexemes[idx].value !== 'order by') {
throw new Error(`Syntax error at position ${idx}: Expected 'ORDER BY' keyword but found "${lexemes[idx].value}". ORDER BY clauses must start with the ORDER BY keywords.`);
}
idx++;
const items = [];
const item = this.parseItem(lexemes, idx);
items.push(item.value);
idx = item.newIndex;
while (idx < lexemes.length && (lexemes[idx].type & Lexeme_1.TokenType.Comma)) {
idx++;
const item = this.parseItem(lexemes, idx);
items.push(item.value);
idx = item.newIndex;
}
if (items.length === 0) {
throw new Error(`Syntax error at position ${index}: No ordering expressions found. The ORDER BY clause requires at least one expression to order by.`);
}
else {
const clause = new Clause_1.OrderByClause(items);
return { value: clause, newIndex: idx };
}
}
static parseItem(lexemes, index) {
let idx = index;
const parsedValue = ValueParser_1.ValueParser.parseFromLexeme(lexemes, idx);
const value = parsedValue.value;
idx = parsedValue.newIndex;
if (idx >= lexemes.length) {
return { value: value, newIndex: idx };
}
// asc, desc
const sortDirection = idx >= lexemes.length
? null
: lexemes[idx].value === 'asc'
? (idx++, Clause_1.SortDirection.Ascending)
: lexemes[idx].value === 'desc'
? (idx++, Clause_1.SortDirection.Descending)
: null;
// nulls first, nulls last
const nullsSortDirection = idx >= lexemes.length
? null
: lexemes[idx].value === 'nulls first'
? (idx++, Clause_1.NullsSortDirection.First)
: lexemes[idx].value === 'nulls last'
? (idx++, Clause_1.NullsSortDirection.Last)
: null;
if (sortDirection === null && nullsSortDirection === null) {
return { value: value, newIndex: idx };
}
return { value: new Clause_1.OrderByItem(value, sortDirection, nullsSortDirection), newIndex: idx };
}
}
exports.OrderByClauseParser = OrderByClauseParser;
//# sourceMappingURL=OrderByClauseParser.js.map