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Prototype of imperative (Starlark-based) syntax traversal#72
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Prototype of imperative (Starlark-based) syntax traversal#72
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The first part of our stack graph loader creates a stack graph node for each graph DSL node. You use attributes to specify the kind of stack graph node (defaulting to “internal”), along with any other necessary properties of the node.
If you set the `source_node` attribute for a graph DSL node, whose value must be a syntax node reference, then we will calculate the location of that syntax node in the source file and fill in the stack graph node's “source info” accordingly.
- Add `StackGraphLanguage` constructor that accepts a parse `tree_sitter_graph::ast::File` instead of a source. - Add parameter to pass `Functions` to the `StackGraphLanguage`. - Rename `load_` to `build_` where TSG is executed. - Add parameter to pass global `Variables` to `build_` method.
- Implement loading tree-sitter language and tree-sitter-graph file - Parse test files and run the given TSG file against them Co-authored-by: Douglas Creager <dcreager@dcreager.net>
Error context was lost for some errors, resulting in unhelpful error messages. This uses the same mechanism for wrapping errors everywhere, and ensures context is preserved up to the top level.
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This is an extremely rough proof of concept that I threw together last night of an alternative notation to TSG for expressing the syntax tree traversal. The StackGraph node and edge creation primitives are not yet implemented.
See https://github.com/github/stack-graphs/blob/adonovan/starlark-visitor/demo/demo.go for the driver program. It's in Go and uses the Go bindings for tree-sitter to parse the input file, and it uses Starlark (a simple embeddable Python dialect) to express the tree traversal.
See https://github.com/github/stack-graphs/blob/adonovan/starlark-visitor/demo/demo.star for the Starlark program. Observe that it allows, in few lines of familiar imperative code, fine control over the traversal ordering, and that it closely resembles the concepts and terminology of the Tree Sitter grammar.
This gist shows the output of the tool when run on its own Go source: https://gist.github.com/adonovan/4b477ceaa2d5016a826213697d639953