---
id: "0941f48c-e025-448e-b4bb-b95b517fabd2"
name: "elixir_like_literal_parser"
description: "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."
version: "0.1.2"
tags:
  - "parser"
  - "elixir"
  - "json"
  - "lexer"
  - "custom-format"
  - "tokenizer"
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"
---

# 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