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TreeSitter C# bindings - new languages

· 3 min read

I updated my TreeSitter.Bindings packages to support additional languages. I wanted to check how solid the bindings were and if I could implement a more complex sample with the respect to the json one I started with.

The tree-sitter documentation provides a multilanguage sample which involves three languages:

  • embedded template
  • ruby
  • html

Luckily for me, my poor understanding of c/c++ build stack and lack of skills regarding scripting didn't stop me.

I was able to update TreeSitter.Bindings with the bindings for the new libraries, update the runtime packages to include the compiled libraries of the new languages (using version 0.20.8-extra.1).

The sample project in the repo now provides both samples:

  • json
  • multilanguage

I suggest to run it in the provided Dev Container. If not possible install libcxx in your linux distribution.

Here is a sample code

using ClangSharp.Interop;
using TreeSitter.Bindings;
using static TreeSitter.Bindings.EmbdeddedTemplate.TSBindingsEmbdeddedTemplate;
using static TreeSitter.Bindings.Html.TSBindingsHtml;
using static TreeSitter.Bindings.Ruby.TSBindingsRuby;
using static TreeSitter.Bindings.TSBindings;

Console.WriteLine("-- Multi language sample --");

void MultiLanguageDocumentSample()
var parser = parser_new();
parser_set_language(parser, tree_sitter_embedded_template());

MarshaledString sourceCode =
new MarshaledString(
"<ul>\n <% people.each do |person| %>\n <li><%= %></li>\n <% end %>\n</ul>");
TSTree* tree = parser_parse_string(
(uint) sourceCode.Length

TSNode erbRootNode = tree_root_node(tree);
var childCount = node_child_count(erbRootNode);
TSRange[] htmlRanges = new TSRange[childCount];
TSRange[] rubyRanges = new TSRange[childCount];
uint htmlRangesCount = 0;
uint rubyRangesCount = 0;

for (uint i = 0; i < childCount; i++)
TSNode node = node_child(erbRootNode, i);

if (new string(node_type(node)) == "content")
var htmlRange = new TSRange()
start_point = node_start_point(node),
end_point = node_end_point(node),
start_byte = node_start_byte(node),
end_byte = node_end_byte(node)

htmlRanges[htmlRangesCount++] = htmlRange;
TSNode codeNode = node_named_child(node, 0);
var rubyRange = new TSRange()
start_point = node_start_point(codeNode),
end_point = node_end_point(codeNode),
start_byte = node_start_byte(codeNode),
end_byte = node_end_byte(codeNode)
rubyRanges[rubyRangesCount++] = rubyRange;

fixed (TSRange* ph = &htmlRanges[0])
fixed (TSRange* pr = &rubyRanges[0])
parser_set_language(parser, tree_sitter_html());
parser_set_included_ranges(parser, ph, htmlRangesCount);
TSTree* htmlTree = parser_parse_string(parser, null, sourceCode, (uint) sourceCode.Length);
TSNode htmlRootNode = tree_root_node(htmlTree);

parser_set_language(parser, tree_sitter_ruby());
parser_set_included_ranges(parser, pr, rubyRangesCount);
TSTree* rubyTree = parser_parse_string(parser, null, sourceCode, (uint) sourceCode.Length);
TSNode rubyRootNode = tree_root_node(rubyTree);

string erbSexp = new string(node_string(erbRootNode));
string htmlSexp = new string(node_string(htmlRootNode));
string rubySexp = new string(node_string(rubyRootNode));


The result is

-- Multi language sample --
(template (content) (directive (code)) (content) (output_directive (code)) (content) (directive (code)) (content))
(fragment (element (start_tag (tag_name)) (element (start_tag (tag_name)) (end_tag (tag_name))) (end_tag (tag_name))))
(program (call receiver: (identifier) method: (identifier) block: (do_block parameters: (block_parameters (identifier)) body: (body_statement (call receiver: (identifier) method: (identifier))))))