Skip to content

README.md

Latest commit

 

History

History
98 lines (69 loc) · 2.4 KB

README.md

File metadata and controls

98 lines (69 loc) · 2.4 KB

cel-proto-parser

CEL (Common Expression Language) proto parser and deparser for TypeScript.

Overview

This package provides tools for working with CEL (Common Expression Language) Abstract Syntax Trees (ASTs):

  1. Proto Parser: Parse CEL protobuf definitions to generate TypeScript types
  2. Deparser: Convert CEL AST back to CEL expression strings
  3. AST Helpers: Factory functions for constructing CEL AST nodes

Installation

npm install cel-proto-parser

Usage

Deparser

Convert CEL AST to expression strings:

import { deparse, Expr } from 'cel-proto-parser';

// Simple expression: x > 5
const expr: Expr = {
  callExpr: {
    function: '_>_',
    args: [
      { identExpr: { name: 'x' } },
      { constExpr: { int64Value: 5 } }
    ]
  }
};

console.log(deparse(expr)); // Output: "x > 5"

Proto Parser

Generate TypeScript types from CEL proto files:

import { CelProtoParser } from 'cel-proto-parser';

const parser = new CelProtoParser('path/to/syntax.proto', {
  outDir: './generated',
  types: { enabled: true },
  enums: { enabled: true },
  utils: { astHelpers: { enabled: true } },
  deparser: { enabled: true }
});

parser.write();

CEL Expression Types

The deparser supports all CEL expression types:

  • Constants: null, true, false, integers, floats, strings, bytes
  • Identifiers: request, user, etc.
  • Field Access: request.auth.claims
  • Function Calls: size(list), str.startsWith("prefix")
  • Operators: +, -, *, /, %, ==, !=, <, <=, >, >=, &&, ||, !, - (unary)
  • Ternary: condition ? trueExpr : falseExpr
  • Index Access: list[0], map["key"]
  • Lists: [1, 2, 3]
  • Maps: {"key": value}
  • Message Construction: MyMessage{field: value}
  • Macros: has(), all(), exists(), etc.

API Reference

deparse(expr: Expr, options?: DeparserOptions): string

Converts a CEL AST expression to a string.

Options:

  • spaces: Whether to add spaces around operators (default: true)

CelProtoParser

Parses CEL proto files and generates TypeScript code.

Constructor options:

  • outDir: Output directory for generated files
  • types.enabled: Generate TypeScript interfaces
  • enums.enabled: Generate TypeScript enums
  • utils.astHelpers.enabled: Generate AST helper functions
  • deparser.enabled: Generate deparser module

License

MIT