Extensions for swc used in dprint-plugin-typescript and Deno.
- Adds a
SourcePosandSourceRangetype to compensate for swc havingBytePos(0)as a magical value. - Adds many helper methods.
With the view cargo feature enabled:
- Creates a wrapper AST around swc's AST that stores the node parents.
- This is similar to a "red tree", but it creates it for every node. It's very fast to create these.
- Most of this code is code generated.
- Adds a
Nodeenum type to allow referencing any kind of node.
All (SourceRanged trait):
.start(&self) -> SourcePos.end(&self) -> SourcePos.text_fast(&self, root_node: &dyn SourceTextInfoProvider) -> &'a str-- Doesn't require going up the tree to the root node.start_line_fast(&self, root_node: &dyn SourceTextInfoProvider) -> usize.end_line_fast(&self, root_node: &dyn SourceTextInfoProvider) -> usize.start_column_fast(&self, root_node: &dyn SourceTextInfoProvider) -> usize.end_column_fast(&self, root_node: &dyn SourceTextInfoProvider) -> usize.width_fast(&self, root_node: &dyn SourceTextInfoProvider) -> usize.tokens_fast(&self, root_node: &dyn RootNode) -> &'a [TokenAndSpan].leading_comments_fast(&self, root_node: &dyn RootNode) -> CommentsIterator<'a>.trailing_comments_fast(&self, root_node: &dyn RootNode) -> CommentsIterator<'a>.previous_token_fast(&self, root_node: &dyn RootNode) -> Option<&TokenAndSpan>.next_token_fast(&self, root_node: &dyn RootNode) -> Option<&TokenAndSpan>.previous_tokens_fast(&self, root_node: &dyn RootNode) -> &'a [TokenAndSpan].next_tokens_fast(&self, root_node: &dyn RootNode) -> &'a [TokenAndSpan]
Node/Enum Node/Nodes (view cargo feature only):
.module(&self) -> &'a Module- Gets the root node if the view was created from aModule. Otherwise panics..script(&self) -> &'a Script- Gets the root node if the view was created from aScript. Otherwise panics..program(&self) -> Program<'a>- Gets the root node whether it be aModuleor aScript..parent(&self) -> Option<Node<'a>>.children(&self) -> Vec<Node<'a>>.child_index(&self) -> usize.ancestors(&self) -> AncestorsIterator<'a>.previous_sibling(&self) -> Option<Node<'a>>.next_sibling(&self) -> Option<Node<'a>>.previous_siblings(&self) -> Vec<Node<'a>>.next_siblings(&self) -> Vec<Node<'a>>.text(&self) -> &str- Slightly slower than.text_fast(module)because it requires going up the tree to get the root node.start_line(&self) -> usize.end_line(&self) -> usize.start_column(&self) -> usize.end_column(&self) -> usize.width(&self) -> usize.tokens(&self) -> &[TokenAndSpan]- All the descendant tokens within the span of the node..children_with_tokens(&self) -> Vec<NodeOrToken<'a>>- Gets the children with the tokens found between the children.children_with_tokens_fast(&self, root_node: &dyn RootNode) -> Vec<NodeOrToken<'a>>.leading_comments(&self) -> CommentsIterator<'a>.trailing_comments(&self) -> CommentsIterator<'a>.kind(&self) -> NodeKind- Gets the "node kind" enum variant associated with the node (ex.NodeKind::ClassDecl)..previous_token(&self) -> Option<&TokenAndSpan>.next_token(&self) -> Option<&TokenAndSpan>.previous_tokens(&self) -> &'a [TokenAndSpan].next_tokens(&self) -> &'a [TokenAndSpan]
Node/Enum Node (view cargo feature only):
.to::<NodeType>(&self) -> Option<&NodeType>.expect::<NodeType>(&self) -> &NodeType.is::<NodeType>(&self) -> bool
TokenAndSpan:
.token_index(&self, root_node: &dyn RootNode) -> usize- Gets the token index of the specified module.
Root Node (Program/Module/Script):
token_at_index(&self, index: &usize) - Option<&TokenAndSpan>
with_ast_view- Creates a view from an swcProgram(eitherModuleorScript)with_ast_view_for_module- Creates a view from an swcModulewith_ast_view_for_script- Creates a view from an swcScript
- Right now this only works if analyzing one file at a time. It would be good to improve the API to accept a large collection of source files (should be easy).
- Unit tests
Given the following parsed input code:
class MyClass { prop: string; myMethod() {}}Code can be written like so:
// setup swc (parse an AST and optionally get the comments and tokens)
let text_info = SourceTextInfo::new(...);
let program: swc_ecmascript::ast::Program = ...;
let comments: swc_common::comments::SingleThreadedComments = ...;
let tokens: Vec<TokenAndSpan> = ...;
// setup for creating a view
let program_info = ProgramInfo {
program: &program,
text_info: Some(&text_info),
// optionally provide the comments for comment related methods
comments: Some(&comments)
// optionally provide the tokens for token related methods
tokens: Some(&tokens),
};
// now create and use the view
dprint_swc_ecma_ast_view::with_ast_view(program_info, |program| {
let class = program.children()[0].expect::<ClassDecl>().class;
println!("{:?}", class.text());
for child in class.children() {
println!("---------");
println!("Child: {:?}", child.text());
println!("Parent: {:?}", child.parent().unwrap().text());
if let Some(prev_sibling) = child.prev_sibling() {
println!("Previous sibling: {:?}", prev_sibling.text());
}
if let Some(next_sibling) = child.next_sibling() {
println!("Next sibling: {:?}", next_sibling.text());
}
}
});Outputs:
"class MyClass { prop: string; myMethod() {}}"
---------
Child: "prop: string;"
Parent: "class MyClass { prop: string; myMethod() {}}"
Next sibling: "myMethod() {}"
---------
Child: "myMethod() {}"
Parent: "class MyClass { prop: string; myMethod() {}}"
Previous sibling: "prop: string;"
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