nix: simplify the update script using nix flake eval

Signed-off-by: Avimitin <[email protected]>

nix/update_ts_parser.rb

@@ -5,28 +5,11 @@
 
 require 'json'
 
-pkg = `nix eval --impure --raw --expr \
-  "with import <nixpkgs> { overlays = [(import ./overlay.nix)]; }; nvim-treesitter-parsers"`
-puts "Updating dependencies for #{pkg}"
+srcs = `nix eval --json .#nvim-treesitter-parsers --apply \
+  "drv: map (p: { name = p.pname; url = p.src.url; hash = p.src.outputHash; }) drv.tsParsers"`
 
-drv_path = `nix-store --query --deriver "#{pkg}"`.strip
-puts "Derivation for #{pkg}: #{drv_path}"
-
-def filter_treesitter_drv(drv)
-  raw_output = `nix derivation show #{drv}^*`
-  JSON.parse(raw_output)[drv]['inputDrvs'].keys.select { |name| name.match(/tree-sitter-\w+-/) }
-end
-
-parser_inputs = filter_treesitter_drv(drv_path)
-src_inputs = parser_inputs.map { |drv| filter_treesitter_drv(drv) }.flatten
-
-srcs = src_inputs.map do |drv|
-  info = JSON.parse(`nix derivation show #{drv}^*`)[drv]['env']
-  { name: info['name'], url: info['urls'], hash: info['outputHash'] }
-end
-
-srcs.each do |info|
-  name, url, hash = info.values_at(:name, :url, :hash)
+JSON.parse(srcs).each do |info|
+  name, url, hash = info.values_at("name", "url", "hash")
   puts "Downloading #{name} source from #{url}"
   new_file = `nix-prefetch-url #{url} --print-path --type sha256 | tail -n1`.strip
   new_hash = `nix hash file --base16 --type sha256 --sri #{new_file}`.strip