sql2expr.go

// Package sql2expr provides a SQL to expr-lang transpiler.
//
// sql2expr allows you to write SQL queries and transpile them to expr-lang expressions
// that can be used to filter and transform in-memory data structures and database results.
//
// Example usage:
//
//	expr, err := sql2expr.Transpile("SELECT * FROM items WHERE price > 100")
//	if err != nil {
//		log.Fatal(err)
//	}
//	// expr will be: "filter(items, {user.price > 100})"
//
//	// With custom data source:
//	expr, err := sql2expr.Transpile("SELECT id, name FROM users WHERE active = true")
//	if err != nil {
//		log.Fatal(err)
//	}
//	// expr will be: "map(filter(users, {user.active == true}), user)"
package sql2expr

import (
	"github.com/h22rana/sql2expr/transpiler"
)

// Transpile converts a SQL SELECT statement to an expr-lang expression.
// The data source variable name is automatically extracted from the FROM clause.
// If no FROM clause is present, a default name "data" is used.
//
// Supported SQL features:
//   - SELECT with field projections and aliasing
//   - WHERE clause with comparisons, AND, OR, NOT
//   - ORDER BY with ASC/DESC
//   - LIMIT and OFFSET
//   - Basic aggregation functions (COUNT, SUM, AVG)
//   - GROUP BY
//
// Example:
//
//	sql := "SELECT id, name FROM users WHERE age > 18 ORDER BY name LIMIT 10"
//	expr, err := sql2expr.Transpile(sql)
//	// Result: "sortBy(map(filter(users, {user.age > 18}), user), user.name)[:10]"
func Transpile(sql string) (string, error) {
	t := transpiler.New("data")
	return t.Transpile(sql)
}