Crate wdl

Workflow Description Language (WDL) document parsing and linting.

There are three top-level modules to this crate:

• grammar - used to parse WDL source into a Concrete Syntax Tree (CST).
• ast - used to parse a WDL document into an Abstract Syntax Tree (AST).
• lint - provides additional lint rules that can be used in a validation pass over a document.

The above are re-exports of the individual wdl-grammar, wdl-ast, and wdl-lint crates, respectively.

The CST is based on the rowan crate and represents an immutable red-green tree. Mutations to the tree require creating a new tree where unaffected nodes are shared between the old and new trees; the cost of editing a node of the tree depends solely on the depth of the node, as it must update the parent chain to produce a new tree root.

Note that in this implementation, the AST is a facade over the CST; each AST representation internally holds a CST node or token. As a result, the AST is very cheaply constructed and may be cheaply cloned at any level.

Examples

An example of parsing WDL source into a CST and printing the tree:

use wdl::grammar::SyntaxTree;

let (tree, diagnostics) = SyntaxTree::parse("version 1.1");
assert!(diagnostics.is_empty());
println!("{tree:#?}");

An example of parsing a WDL document into an AST and validating it:

use wdl::ast::Document;
use wdl::ast::Validator;

let (document, diagnostics) = Document::parse(source);
if !diagnostics.is_empty() {
    // Handle the failure to parse
}

let mut validator = Validator::default();
if let Err(diagnostics) = validator.validate(&document) {
    // Handle the failure to validate
}

An example of parsing a WDL document and linting it:

use wdl::ast::Document;
use wdl::ast::Validator;
use wdl::lint::LintVisitor;

let (document, diagnostics) = Document::parse(source);
if !diagnostics.is_empty() {
    // Handle the failure to parse
}

let mut validator = Validator::default();
validator.add_visitor(LintVisitor::default());
if let Err(diagnostics) = validator.validate(&document) {
    // Handle the failure to validate
}

Modules

• analysis
  Analysis of Workflow Description Language (WDL) documents.
• ast
  An abstract syntax tree for Workflow Description Language (WDL) documents.
• grammar
  Lexing and parsing for Workflow Description Language (WDL) documents.
• lint
  Lint rules for Workflow Description Language (WDL) documents.
• lsp
  A Language Server Protocol implementation for analyzing WDL documents.