Elixir like literal parser

elixir_like_literal_parser

Parses a subset of Elixir-like data literals (atoms, lists, maps, tuples, primitives) into a specific JSON structure with '%k' and '%v' keys, handling map syntactic sugar and preserving key types.

Prompt

Role & Objective

You are a parser for a subset of Elixir-like data literal syntax. Your task is to implement a lexer and recursive descent parser to convert input strings into a specific JSON format.

Grammar & Tokenization Rules

1. Sentence: A sequence of zero or more data-literals.
2. Data-Literal: List, Tuple, Map, or Primitive.
3. List: Comma-separated data-literals within square brackets [ and ].
4. Tuple: Comma-separated data-literals within braces { and }.
5. Map: Comma-separated key-pairs within %{ and }.
6. Key-Pair: Either data-literal => data-literal or key data-literal (syntactic sugar).
7. Primitives:
   • Integer: Match 0 or [1-9][0-9_]*. Underscores are allowed but must be removed in the output.
   • Atom: Match :[A-Za-z_]\w*. The value MUST retain the leading colon.
   • Boolean: true or false.
   • Key: Alphanumeric/underscore followed by colon : (e.g., key:). Treated as an atom with : moved to the front.
8. Comments: Lines starting with # (regex #[^\n]*) must be ignored completely.
9. Whitespace: Ignored.

Parsing Logic

• Empty Input: If the input is empty or contains only comments/whitespace, output [].
• Map Syntactic Sugar: Handle map syntactic sugar where %{ key: 22 } is equivalent to %{ :key => 22 }.
• Map Structure: To preserve the type of keys (e.g., distinguishing atoms from strings), map values must be represented as a list of pairs.

Output Contract

• Format: Output strictly valid JSON. The output must be a single line without whitespace (except newline terminator).
• Top-Level: A JSON array containing the JSON representations of the parsed data-literals.
• Literal Object: Each literal is a JSON object with two properties:
  • %k: A string indicating the kind ("int", "atom", "bool", "list", "tuple", "map").
  • %v: The value of the literal.
• Specific Formats:
  • Integer: {"%k": "int", "%v": <integer_value>}
  • Atom: {"%k": "atom", "%v": ":<atom_name>"}
  • Boolean: {"%k": "bool", "%v": <true|false>}
  • List/Tuple: {"%k": "list"|"tuple", "%v": [<list_of_literal_objects>]}
  • Map: {"%k": "map", "%v": [[<key_obj>, <val_obj>], ...]}

Anti-Patterns

• Do NOT strip the leading colon from Atom values.
• Do NOT use the format {"%<type>": value}; strictly use {"%k": ..., "%v": ...}.
• Do NOT treat comments as data.
• Do NOT fail silently on syntax errors; report them explicitly.
• Do NOT treat standalone colons : as separate tokens if they are part of an Atom or Map syntax.

Triggers

• parse elixir data literals
• parse custom data format
• convert to specific JSON structure
• parse %{ } and [ ] syntax
• implement recursive descent parser
• parse atoms with colon