1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244
//! Compiler for PRQL language.
//! Targets SQL and exposes PL and RQ abstract syntax trees.
//!
//! You probably want to start with [compile] wrapper function.
//!
//! For more granular access, refer to this diagram:
//! ```ascii
//! PRQL
//!
//! (parse) │ ▲
//! prql_to_pl │ │ pl_to_prql
//! │ │
//! ▼ │ json::from_pl
//! ────────►
//! PL AST PL JSON
//! ◄────────
//! │ json::to_pl
//! │
//! (resolve) │
//! pl_to_rq │
//! │
//! │
//! ▼ json::from_rq
//! ────────►
//! RQ AST RQ JSON
//! ◄────────
//! │ json::to_rq
//! │
//! rq_to_sql │
//! ▼
//!
//! SQL
//! ```
//!
//! ## Common use-cases
//!
//! I want to ...
//! - ... compile PRQL queries at run time, because I cannot commit them into
//! the source tree.
//!
//! ```
//! # fn main() -> Result<(), prql_compiler::ErrorMessages> {
//! let sql = prql_compiler::compile(
//! "from albums | select [title, artist_id]",
//! prql_compiler::Options::default().no_format()
//! )?;
//! assert_eq!(&sql[..35], "SELECT title, artist_id FROM albums");
//! # Ok(())
//! # }
//! ```
//!
//! - ... compile PRQL queries to SQL at build time.
//!
//! Use `prql-compiler-macros` crate (unreleased), which can be used like
//! this:
//! ```ignore
//! let sql: &str = prql_to_sql!("from albums | select [title, artist_id]");
//! ```
//!
//! - ... compile .prql files to .sql files at build time.
//!
//! Call this crate from `build.rs`. See
//! [this example project](https://github.com/PRQL/prql/tree/main/prql-compiler/examples/compile-files).
//!
//! - ... compile, format & debug PRQL from command line.
//!
//! ```sh
//! $ cargo install prqlc
//! $ prqlc compile query.prql
//! ```
//!
// Our error type is 128 bytes, because it contains 5 strings & an Enum, which
// is exactly the default warning level. Given we're not that performance
// sensitive, it's fine to ignore this at the moment (and not worth having a
// clippy config file for a single setting). We can consider adjusting it as a
// yak-shaving exercise in the future.
#![allow(clippy::result_large_err)]
pub mod ast;
mod error;
mod parser;
pub mod semantic;
pub mod sql;
#[cfg(test)]
mod test;
mod utils;
pub use error::{downcast, ErrorMessage, ErrorMessages, SourceLocation, Span};
pub use utils::IntoOnly;
use once_cell::sync::Lazy;
use semver::Version;
use serde::{Deserialize, Serialize};
pub static PRQL_VERSION: Lazy<Version> =
Lazy::new(|| Version::parse(env!("CARGO_PKG_VERSION")).expect("Invalid PRQL version number"));
/// Compile a PRQL string into a SQL string.
///
/// This is a wrapper for:
/// - [prql_to_pl] — Build PL AST from a PRQL string
/// - [pl_to_rq] — Finds variable references, validates functions calls, determines frames and converts PL to RQ.
/// - [rq_to_sql] — Convert RQ AST into an SQL string.
/// # Example
/// Use the prql compiler to convert a PRQL string to SQLite dialect
///
/// ```
/// use prql_compiler::{compile, Options, Target, sql::Dialect};
///
/// let prql = "from employees | select [name,age] ";
/// let opt = Options {
/// format: false,
/// target: Target::Sql(Some(Dialect::SQLite)),
/// signature_comment: false
/// };
/// let sql = compile(&prql, opt).unwrap();
/// println!("PRQL: {}\nSQLite: {}", prql, &sql);
/// assert_eq!("SELECT name, age FROM employees", sql)
///
/// ```
/// See [`sql::Options`](sql/struct.Options.html) and [`sql::Dialect`](sql/enum.Dialect.html) for options and supported SQL dialects.
pub fn compile(prql: &str, options: Options) -> Result<String, ErrorMessages> {
parser::parse(prql)
.and_then(semantic::resolve)
.and_then(|rq| sql::compile(rq, options))
.map_err(error::downcast)
.map_err(|e| e.composed("", prql, false))
}
#[derive(Debug, Clone, Serialize, Deserialize)]
pub enum Target {
/// If `None` is used, dialect is extracted from `target` query header.
Sql(Option<sql::Dialect>),
}
impl Target {
pub fn names() -> Vec<String> {
sql::Dialect::names()
.into_iter()
.map(|d| format!("sql.{d}"))
.collect()
}
}
/// Compilation options for SQL backend of the compiler.
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct Options {
/// Pass generated SQL string trough a formatter that splits it
/// into multiple lines and prettifies indentation and spacing.
///
/// Defaults to true.
pub format: bool,
/// Target and dialect to compile to.
pub target: Target,
/// Emits the compiler signature as a comment after generated SQL
///
/// Defaults to true.
pub signature_comment: bool,
}
impl Default for Options {
fn default() -> Self {
Self {
format: true,
target: Target::Sql(None),
signature_comment: true,
}
}
}
impl Options {
pub fn no_format(mut self) -> Self {
self.format = false;
self
}
pub fn no_signature(mut self) -> Self {
self.signature_comment = false;
self
}
pub fn with_target(mut self, target: Target) -> Self {
self.target = target;
self
}
pub fn some(self) -> Option<Self> {
Some(self)
}
}
#[doc = include_str!("../README.md")]
#[cfg(doctest)]
pub struct ReadmeDoctests;
/// Parse PRQL into a PL AST
pub fn prql_to_pl(prql: &str) -> Result<Vec<ast::pl::Stmt>, ErrorMessages> {
parser::parse(prql)
.map_err(error::downcast)
.map_err(|e| e.composed("", prql, false))
}
/// Perform semantic analysis and convert PL to RQ.
pub fn pl_to_rq(pl: Vec<ast::pl::Stmt>) -> Result<ast::rq::Query, ErrorMessages> {
semantic::resolve(pl).map_err(error::downcast)
}
/// Generate SQL from RQ.
pub fn rq_to_sql(rq: ast::rq::Query, options: Options) -> Result<String, ErrorMessages> {
sql::compile(rq, options).map_err(error::downcast)
}
/// Generate PRQL code from PL AST
pub fn pl_to_prql(pl: Vec<ast::pl::Stmt>) -> Result<String, ErrorMessages> {
Ok(format!("{}", ast::pl::Statements(pl)))
}
/// JSON serialization and deserialization functions
pub mod json {
use super::*;
/// JSON serialization
pub fn from_pl(pl: Vec<ast::pl::Stmt>) -> Result<String, ErrorMessages> {
serde_json::to_string(&pl).map_err(|e| error::downcast(anyhow::anyhow!(e)))
}
/// JSON deserialization
pub fn to_pl(json: &str) -> Result<Vec<ast::pl::Stmt>, ErrorMessages> {
serde_json::from_str(json).map_err(|e| error::downcast(anyhow::anyhow!(e)))
}
/// JSON serialization
pub fn from_rq(rq: ast::rq::Query) -> Result<String, ErrorMessages> {
serde_json::to_string(&rq).map_err(|e| error::downcast(anyhow::anyhow!(e)))
}
/// JSON deserialization
pub fn to_rq(json: &str) -> Result<ast::rq::Query, ErrorMessages> {
serde_json::from_str(json).map_err(|e| error::downcast(anyhow::anyhow!(e)))
}
}