Crate wdl_ast

An abstract syntax tree for Workflow Description Language (WDL) documents.

The AST implementation is effectively a facade over the concrete syntax tree (CST) implemented by SyntaxTree from wdl-grammar.

An AST is cheap to construct and may be cheaply cloned at any level.

However, an AST (and the underlying CST) are immutable; updating the tree requires replacing a node in the tree to produce a new tree. The unaffected nodes of the replacement are reused from the old tree to the new tree.

Examples

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
}

Modules

• support
• v1
  AST representation for a 1.x WDL document.
• version
  Representation for version definitions.

Structs

• AstChildren
• Comment
  Represents a comment token in the AST.
• Diagnostic
  Represents a diagnostic to display to the user.
• Diagnostics
  Represents a collection of validation diagnostics.
• Document
  Represents a single WDL document.
• Ident
  Represents an identifier token.
• Label
  Represents a label that annotates the source code.
• Span
  Represents a span of source.
• SyntaxTree
  Represents an untyped concrete syntax tree.
• TokenStrHash
  Helper for hashing any AST token on string representation alone.
• Validator
  Implements an AST validator.
• Version
  Represents a version in the AST.
• VersionStatement
  Represents a version statement in a WDL AST.
• Whitespace
  Represents a whitespace token in the AST.
• WorkflowDescriptionLanguage
  Represents the Workflow Definition Language (WDL).

Enums

• Ast
  Represents the AST of a Document.
• Direction
• Severity
  Represents the severity of a diagnostic.
• SupportedVersion
  Represents a supported WDL version.
• SyntaxKind
  Represents the kind of syntax element (node or token) in a WDL concrete syntax tree (CST).
• VisitReason
  Represents the reason an AST node has been visited.

Constants

• EXCEPT_COMMENT_PREFIX
  The prefix of except comments.

Traits

• AstNode
  The main trait to go from untyped SyntaxNode to a typed AST. The conversion itself has zero runtime cost: AST and syntax nodes have exactly the same representation: a pointer to the tree root and a pointer to the node itself.
• AstNodeExt
  An extension trait for AST nodes.
• AstToken
  The trait implemented on AST tokens to go from untyped SyntaxToken to a typed representation.
• ToSpan
  A trait implemented on types that convert to spans.
• Visitor
  A trait used to implement an AST visitor.

Type Aliases

• SyntaxElement
  Represents an element (node or token) in the concrete syntax tree.
• SyntaxNode
  Represents a node in the concrete syntax tree.
• SyntaxToken
  Represents a token in the concrete syntax tree.