rawsql-ts
Version:
[beta]High-performance SQL parser and AST analyzer written in TypeScript. Provides fast parsing and advanced transformation capabilities.
114 lines • 4.92 kB
JavaScript
;
Object.defineProperty(exports, "__esModule", { value: true });
exports.SelectItemParser = exports.SelectClauseParser = void 0;
const Clause_1 = require("../models/Clause");
const Lexeme_1 = require("../models/Lexeme");
const ValueComponent_1 = require("../models/ValueComponent");
const SqlTokenizer_1 = require("./SqlTokenizer");
const ValueParser_1 = require("./ValueParser");
class SelectClauseParser {
// 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 SELECT clause is complete but there are additional tokens.`);
}
return result.value;
}
// Parse from lexeme array (was: parse)
static parseFromLexeme(lexemes, index) {
let idx = index;
let distinct = null;
if (lexemes[idx].value !== 'select') {
throw new Error(`Syntax error at position ${idx}: Expected 'SELECT' keyword but found "${lexemes[idx].value}". SELECT clauses must start with the SELECT keyword.`);
}
idx++;
if (idx < lexemes.length && lexemes[idx].value === 'distinct') {
idx++;
distinct = new Clause_1.Distinct();
}
else if (idx < lexemes.length && lexemes[idx].value === 'distinct on') {
idx++;
const argument = ValueParser_1.ValueParser.parseArgument(Lexeme_1.TokenType.OpenParen, Lexeme_1.TokenType.CloseParen, lexemes, idx);
distinct = new Clause_1.DistinctOn(argument.value);
idx = argument.newIndex;
}
const items = [];
const item = SelectItemParser.parseItem(lexemes, idx);
items.push(item.value);
idx = item.newIndex;
while (idx < lexemes.length && (lexemes[idx].type & Lexeme_1.TokenType.Comma)) {
idx++;
const item = SelectItemParser.parseItem(lexemes, idx);
items.push(item.value);
idx = item.newIndex;
}
if (items.length === 0) {
throw new Error(`Syntax error at position ${index}: No select items found. The SELECT clause requires at least one expression to select.`);
}
else {
const clause = new Clause_1.SelectClause(items, distinct);
return { value: clause, newIndex: idx };
}
}
}
exports.SelectClauseParser = SelectClauseParser;
// Extracted SelectItemParser for parsing individual select items
class SelectItemParser {
/**
* Parses a single select item from a SQL string.
* @param query The SQL string representing a select item (e.g. 'id as user_id').
* @returns The parsed SelectItem instance.
*/
static parse(query) {
const tokenizer = new SqlTokenizer_1.SqlTokenizer(query);
const lexemes = tokenizer.readLexmes();
const result = this.parseItem(lexemes, 0);
if (result.newIndex < lexemes.length) {
throw new Error(`Syntax error: Unexpected token "${lexemes[result.newIndex].value}" at position ${result.newIndex}. The select item is complete but there are additional tokens.`);
}
return result.value;
}
/**
* Parses a single select item from lexemes.
* @param lexemes The array of lexemes.
* @param index The starting index.
* @returns An object containing the SelectItem and the new index.
*/
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 && lexemes[idx].value === 'as') {
// Skip 'AS' keyword
idx++;
}
if (idx < lexemes.length && (lexemes[idx].type & Lexeme_1.TokenType.Identifier)) {
const alias = lexemes[idx].value;
idx++;
return {
value: new Clause_1.SelectItem(value, alias),
newIndex: idx,
};
}
else if (value instanceof ValueComponent_1.ColumnReference && value.column.name !== "*") {
// nameless select item
return {
value: new Clause_1.SelectItem(value, value.column.name),
newIndex: idx,
};
}
// nameless select item
return {
value: new Clause_1.SelectItem(value),
newIndex: idx,
};
}
}
exports.SelectItemParser = SelectItemParser;
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