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//! 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
//!
//! - Compile PRQL queries to SQL at run time.
//!
//! ```
//! # fn main() -> Result<(), prqlc::ErrorMessages> {
//! let sql = prqlc::compile(
//! "from albums | select {title, artist_id}",
//! &prqlc::Options::default().no_format()
//! )?;
//! assert_eq!(&sql[..35], "SELECT title, artist_id FROM albums");
//! # Ok(())
//! # }
//! ```
//!
//! - Compile PRQL queries to SQL at build time.
//!
//! For inline strings, use the `prql-compiler-macros` crate; for example:
//! ```ignore
//! let sql: &str = prql_to_sql!("from albums | select {title, artist_id}");
//! ```
//!
//! For compiling whole files (`.prql` to `.sql`), call `prqlc` from
//! `build.rs`. See [this example
//! project](https://github.com/PRQL/prql/tree/main/prqlc/prqlc/examples/compile-files).
//!
//! - Compile, format & debug PRQL from command line.
//!
//! ```sh
//! $ cargo install --locked prqlc
//! $ prqlc compile query.prql
//! ```
//!
//! ## Feature flags
//!
//! The following feature flags are available:
//!
//! * `cli`: enables the `prqlc` CLI binary. This is enabled by default. When
//! consuming this crate from another rust library, it can be disabled.
//! * `test-dbs`: enables the `prqlc` in-process test databases as part of the
//! crate's tests. This significantly increases compile times so is not
//! enabled by default.
//! * `test-dbs-external`: enables the `prqlc` external test databases,
//! requiring a docker container with the test databases to be running. Check
//! out the [integration tests](https://github.com/PRQL/prql/tree/main/prqlc/prqlc/tests/integration/dbs)
//! for more details.
//! * `serde_yaml`: Enables serialization and deserialization of ASTs to YAML.
//!
//! ## Large binary sizes
//!
//! For Linux users, the binary size contributed by this crate will probably be
//! quite large (>20MB) by default. That is because it includes a lot of
//! debuginfo symbols from our parser. They can be removed by adding the
//! following to `Cargo.toml`, reducing the contribution to around 7MB:
//! ```toml
//! [profile.release.package.prqlc]
//! strip = "debuginfo"
//! ```
#![forbid(unsafe_code)]
// 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)]
use std::{collections::HashMap, path::PathBuf, str::FromStr};
use anstream::adapter::strip_str;
pub use error_message::{ErrorMessage, ErrorMessages, SourceLocation};
pub use ir::Span;
use once_cell::sync::Lazy;
pub use prqlc_ast as ast;
use prqlc_parser::err::error::ErrorSource;
pub use prqlc_parser::err::error::{Error, Errors, MessageKind, Reason, WithErrorInfo};
use prqlc_parser::TokenVec;
use semver::Version;
use serde::{Deserialize, Serialize};
use strum::VariantNames;
mod codegen;
mod error_message;
pub mod ir;
pub mod parser;
pub mod semantic;
pub mod sql;
mod utils;
pub type Result<T, E = Error> = core::result::Result<T, E>;
pub static COMPILER_VERSION: Lazy<Version> =
Lazy::new(|| Version::parse(env!("CARGO_PKG_VERSION")).expect("Invalid prqlc 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 prqlc::{compile, Options, Target, sql::Dialect};
///
/// let prql = "from employees | select {name,age}";
/// let opts = Options::default().with_target(Target::Sql(Some(Dialect::SQLite))).with_signature_comment(false).with_format(false);
/// let sql = compile(&prql, &opts).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> {
let sources = SourceTree::from(prql);
Ok(&sources)
.and_then(parser::parse)
.and_then(|ast| {
semantic::resolve_and_lower(ast, &[], None)
.map_err(|e| e.with_source(ErrorSource::NameResolver).into())
})
.and_then(|rq| {
sql::compile(rq, options).map_err(|e| e.with_source(ErrorSource::SQL).into())
})
.map_err(|e| {
let error_messages = ErrorMessages::from(e).composed(&sources);
match options.display {
DisplayOptions::AnsiColor => error_messages,
DisplayOptions::Plain => ErrorMessages {
inner: error_messages
.inner
.into_iter()
.map(|e| ErrorMessage {
display: e.display.map(|s| strip_str(&s).to_string()),
..e
})
.collect(),
},
}
})
}
#[derive(Debug, Clone, Serialize, Deserialize)]
pub enum Target {
/// If `None` is used, dialect is extracted from `target` query header.
Sql(Option<sql::Dialect>),
}
impl Default for Target {
fn default() -> Self {
Self::Sql(None)
}
}
impl Target {
pub fn names() -> Vec<String> {
let mut names = vec!["sql.any".to_string()];
let dialects = sql::Dialect::VARIANTS;
names.extend(dialects.iter().map(|d| format!("sql.{d}")));
names
}
}
impl FromStr for Target {
type Err = Error;
fn from_str(s: &str) -> Result<Target, Self::Err> {
if let Some(dialect) = s.strip_prefix("sql.") {
if dialect == "any" {
return Ok(Target::Sql(None));
}
if let Ok(dialect) = sql::Dialect::from_str(dialect) {
return Ok(Target::Sql(Some(dialect)));
}
}
Err(Error::new(Reason::NotFound {
name: format!("{s:?}"),
namespace: "target".to_string(),
}))
}
}
/// 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,
/// Deprecated: use `display` instead.
pub color: bool,
/// Whether to use ANSI colors in error messages. This may be extended to
/// other formats in the future.
///
/// Note that we don't generally recommend threading a `color` option
/// through an entire application. Instead, in order of preferences:
/// - Use a library such as `anstream` to encapsulate presentation logic and
/// automatically disable colors when not connected to a TTY.
/// - Set an environment variable such as `CLI_COLOR=0` to disable any
/// colors coming back from this library.
/// - Strip colors from the output (possibly also with a library such as
/// `anstream`).
pub display: DisplayOptions,
}
impl Default for Options {
fn default() -> Self {
Self {
format: true,
target: Target::Sql(None),
signature_comment: true,
color: true,
display: DisplayOptions::AnsiColor,
}
}
}
impl Options {
pub fn with_format(mut self, format: bool) -> Self {
self.format = format;
self
}
pub fn no_format(self) -> Self {
self.with_format(false)
}
pub fn with_signature_comment(mut self, signature_comment: bool) -> Self {
self.signature_comment = signature_comment;
self
}
pub fn no_signature(self) -> Self {
self.with_signature_comment(false)
}
pub fn with_target(mut self, target: Target) -> Self {
self.target = target;
self
}
#[deprecated(note = "`color` is replaced by `display`; see `Options` docs for more details")]
pub fn with_color(mut self, color: bool) -> Self {
self.color = color;
self
}
pub fn with_display(mut self, display: DisplayOptions) -> Self {
self.display = display;
self
}
}
#[derive(Debug, Clone, Serialize, Deserialize, strum::EnumString)]
#[strum(serialize_all = "snake_case")]
#[non_exhaustive]
pub enum DisplayOptions {
/// Plain text
Plain,
/// With ANSI colors
AnsiColor,
}
#[doc = include_str!("../README.md")]
#[cfg(doctest)]
pub struct ReadmeDoctests;
/// Lex PRQL source into tokens.
pub fn prql_to_tokens(prql: &str) -> Result<TokenVec, ErrorMessages> {
prqlc_parser::lex_source(prql).map_err(|e| {
e.into_iter()
.map(|e| e.into())
.collect::<Vec<ErrorMessage>>()
.into()
})
}
/// Parse PRQL into a PL AST
// TODO: rename this to `prql_to_pl_simple`
pub fn prql_to_pl(prql: &str) -> Result<ast::ModuleDef, ErrorMessages> {
let source_tree = SourceTree::from(prql);
prql_to_pl_tree(&source_tree)
}
/// Parse PRQL into a PL AST
pub fn prql_to_pl_tree(prql: &SourceTree) -> Result<ast::ModuleDef, ErrorMessages> {
parser::parse(prql).map_err(|e| ErrorMessages::from(e).composed(prql))
}
/// Perform semantic analysis and convert PL to RQ.
// TODO: rename this to `pl_to_rq_simple`
pub fn pl_to_rq(pl: ast::ModuleDef) -> Result<ir::rq::RelationalQuery, ErrorMessages> {
semantic::resolve_and_lower(pl, &[], None)
.map_err(|e| e.with_source(ErrorSource::NameResolver).into())
}
/// Perform semantic analysis and convert PL to RQ.
pub fn pl_to_rq_tree(
pl: ast::ModuleDef,
main_path: &[String],
database_module_path: &[String],
) -> Result<ir::rq::RelationalQuery, ErrorMessages> {
semantic::resolve_and_lower(pl, main_path, Some(database_module_path))
.map_err(|e| e.with_source(ErrorSource::NameResolver).into())
}
/// Generate SQL from RQ.
pub fn rq_to_sql(rq: ir::rq::RelationalQuery, options: &Options) -> Result<String, ErrorMessages> {
sql::compile(rq, options).map_err(|e| e.with_source(ErrorSource::SQL).into())
}
/// Generate PRQL code from PL AST
pub fn pl_to_prql(pl: &ast::ModuleDef) -> Result<String, ErrorMessages> {
Ok(codegen::WriteSource::write(&pl.stmts, codegen::WriteOpt::default()).unwrap())
}
/// JSON serialization and deserialization functions
pub mod json {
use super::*;
/// JSON serialization
pub fn from_pl(pl: &ast::ModuleDef) -> Result<String, ErrorMessages> {
serde_json::to_string(pl).map_err(convert_json_err)
}
/// JSON deserialization
pub fn to_pl(json: &str) -> Result<ast::ModuleDef, ErrorMessages> {
serde_json::from_str(json).map_err(convert_json_err)
}
/// JSON serialization
pub fn from_rq(rq: &ir::rq::RelationalQuery) -> Result<String, ErrorMessages> {
serde_json::to_string(rq).map_err(convert_json_err)
}
/// JSON deserialization
pub fn to_rq(json: &str) -> Result<ir::rq::RelationalQuery, ErrorMessages> {
serde_json::from_str(json).map_err(convert_json_err)
}
fn convert_json_err(err: serde_json::Error) -> ErrorMessages {
ErrorMessages::from(Error::new_simple(err.to_string()))
}
}
/// All paths are relative to the project root.
// We use `SourceTree` to represent both a single file (including a "file" piped
// from stdin), and a collection of files. (Possibly this could be implemented
// as a Trait with a Struct for each type, which would use structure over values
// (i.e. `Option<PathBuf>` below signifies whether it's a project or not). But
// waiting until it's necessary before splitting it out.)
#[derive(Debug, Clone, Default, Serialize)]
pub struct SourceTree {
/// Path to the root of the source tree.
pub root: Option<PathBuf>,
/// Mapping from file paths into into their contents.
/// Paths are relative to the root.
pub sources: HashMap<PathBuf, String>,
/// Index of source ids to paths. Used to keep [error::Span] lean.
source_ids: HashMap<u16, PathBuf>,
}
impl SourceTree {
pub fn single(path: PathBuf, content: String) -> Self {
SourceTree {
sources: [(path.clone(), content)].into(),
source_ids: [(1, path)].into(),
root: None,
}
}
pub fn new<I>(iter: I, root: Option<PathBuf>) -> Self
where
I: IntoIterator<Item = (PathBuf, String)>,
{
let mut res = SourceTree {
sources: HashMap::new(),
source_ids: HashMap::new(),
root,
};
for (index, (path, content)) in iter.into_iter().enumerate() {
res.sources.insert(path.clone(), content);
res.source_ids.insert((index + 1) as u16, path);
}
res
}
pub fn insert(&mut self, path: PathBuf, content: String) {
let last_id = self.source_ids.keys().max().cloned().unwrap_or(0);
self.sources.insert(path.clone(), content);
self.source_ids.insert(last_id + 1, path);
}
pub fn get_path(&self, source_id: u16) -> Option<&PathBuf> {
self.source_ids.get(&source_id)
}
}
impl<S: ToString> From<S> for SourceTree {
fn from(source: S) -> Self {
SourceTree::single(PathBuf::from(""), source.to_string())
}
}
/// Debugging and unstable API functions
pub mod debug {
use super::*;
/// Create column-level lineage graph
pub fn pl_to_lineage(
pl: ast::ModuleDef,
) -> Result<semantic::reporting::FrameCollector, ErrorMessages> {
let ast = Some(pl.clone());
let root_module = semantic::resolve(pl, Default::default()).map_err(ErrorMessages::from)?;
let (main, _) = root_module.find_main_rel(&[]).unwrap();
let mut fc =
semantic::reporting::collect_frames(*main.clone().into_relation_var().unwrap());
fc.ast = ast;
Ok(fc)
}
pub mod json {
use super::*;
/// JSON serialization of FrameCollector lineage
pub fn from_lineage(
fc: &semantic::reporting::FrameCollector,
) -> Result<String, ErrorMessages> {
serde_json::to_string(fc).map_err(convert_json_err)
}
fn convert_json_err(err: serde_json::Error) -> ErrorMessages {
ErrorMessages::from(Error::new_simple(err.to_string()))
}
}
}
#[cfg(test)]
mod tests {
use std::str::FromStr;
use insta::assert_debug_snapshot;
use crate::ast::expr::Ident;
use crate::Target;
pub fn compile(prql: &str) -> Result<String, super::ErrorMessages> {
anstream::ColorChoice::Never.write_global();
super::compile(prql, &super::Options::default().no_signature())
}
#[test]
fn test_starts_with() {
// Over-testing, from co-pilot, can remove some of them.
let a = Ident::from_path(vec!["a", "b", "c"]);
let b = Ident::from_path(vec!["a", "b"]);
let c = Ident::from_path(vec!["a", "b", "c", "d"]);
let d = Ident::from_path(vec!["a", "b", "d"]);
let e = Ident::from_path(vec!["a", "c"]);
let f = Ident::from_path(vec!["b", "c"]);
assert!(a.starts_with(&b));
assert!(a.starts_with(&a));
assert!(!a.starts_with(&c));
assert!(!a.starts_with(&d));
assert!(!a.starts_with(&e));
assert!(!a.starts_with(&f));
}
#[test]
fn test_target_from_str() {
assert_debug_snapshot!(Target::from_str("sql.postgres"), @r###"
Ok(
Sql(
Some(
Postgres,
),
),
)
"###);
assert_debug_snapshot!(Target::from_str("sql.poostgres"), @r###"
Err(
Error {
kind: Error,
span: None,
reason: NotFound {
name: "\"sql.poostgres\"",
namespace: "target",
},
hints: [],
code: None,
},
)
"###);
assert_debug_snapshot!(Target::from_str("postgres"), @r###"
Err(
Error {
kind: Error,
span: None,
reason: NotFound {
name: "\"postgres\"",
namespace: "target",
},
hints: [],
code: None,
},
)
"###);
}
/// Confirm that all target names can be parsed.
#[test]
fn test_target_names() {
let _: Vec<_> = Target::names()
.into_iter()
.map(|name| Target::from_str(&name))
.collect();
}
}