We need to implement a lexer and parser for our Raccoon language. The lexer should be able to tokenize the input source code into a stream of tokens, while the parser should be able to parse the tokens into an abstract syntax tree (AST). These components are essential for implementing the rest of the compiler.

The lexer and parser should be implemented according to the language specification, which can be found in the docs/specs.md file. The lexer should be able to handle all of the language's keywords, operators, and symbols, as well as any user-defined identifiers or literals. The parser should be able to generate a valid AST from the token stream, with appropriate error handling for syntax errors.

This issue involves writing a significant amount of code, so we should break it down into smaller subtasks and create separate issues for each subtask. We should also provide documentation and tests for the lexer and parser, to ensure that they work correctly and efficiently.

Tasks:

• Define the grammar of the language #3
• Implement the lexer to tokenize the input source code
• Implement the parser to generate an AST from the token stream
• Implement error handling for syntax errors in the lexer and parser
• Write unit tests for the lexer and parser
• Write documentation for the lexer and parser, including usage instructions and examples