Incremental parsing

[AnHeuermann]

Tree-sitter can use incremental parsing to speedup the re-parsing of files, see https://tree-sitter.github.io/tree-sitter/using-parsers#editing.

Currently modelica-language-server always parses the whole file on every change:

modelica-language-server/server/src/analyzer.ts

Line 73 in a52ced7

const tree = this.parser.parse(fileContent);

To incrementally parse a file the language server needs to track changes from the client. So all changed locations need to be added to the tree:

// first parsing
const sourceCode = 'let x = 1; console.log(x);';
const tree = parser.parse(sourceCode);

// Replace 'let' with 'const'
const newSourceCode = 'const x = 1; console.log(x);';

tree.edit({
  startIndex: 0,
  oldEndIndex: 3,
  newEndIndex: 5,
  startPosition: {row: 0, column: 0},
  oldEndPosition: {row: 0, column: 3},
  newEndPosition: {row: 0, column: 5},
});

const newTree = parser.parse(newSourceCode, tree);

(from https://github.com/tree-sitter/tree-sitter/blob/master/lib/binding_web/README.md#editing)