Crate prql_compiler

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:

           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.

  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");

• Compile PRQL queries to SQL at build time.

  For inline strings, use the prql-compiler-macros crate; for example:

  let sql: &str = prql_to_sql!("from albums | select {title, artist_id}");

  For compiling whole files (.prql to .sql), call prql-compiler from build.rs. See this example project.

• Compile, format & debug PRQL from command line.

  $ cargo install --locked prqlc
  $ prqlc compile query.prql
  

Feature flags

The following feature flags are available:

• serde_yaml: adapts the Serialize implementation for prqlc_ast::expr::ExprKind::Literal to serde_yaml, which doesn’t support the serialization of nested enums

Modules

• ir
  Intermediate Representations of Abstract Syntax Tree
• json
  JSON serialization and deserialization functions
• semantic
  Semantic resolver (name resolution, type checking and lowering to RQ)
• sql
  Backend for translating RQ into SQL

Structs

• Error
• ErrorMessage
• ErrorMessages
• Errors
• Options
  Compilation options for SQL backend of the compiler.
• SourceLocation
  Location within the source file. Tuples contain:
• SourceTree
  All paths are relative to the project root.
• Span

Enums

• MessageKind
  Compile message kind. Currently only Error is implemented.
• Reason
• Target

Statics

• COMPILER_VERSION

Traits

• WithErrorInfo

Functions

• compile
  Compile a PRQL string into a SQL string.
• downcast
• pl_to_prql
  Generate PRQL code from PL AST
• pl_to_rq
  Perform semantic analysis and convert PL to RQ.
• pl_to_rq_tree
  Perform semantic analysis and convert PL to RQ.
• prql_to_pl
  Parse PRQL into a PL AST
• prql_to_pl_tree
  Parse PRQL into a PL AST
• rq_to_sql
  Generate SQL from RQ.