greybel-core

A lexer and parser that extends miniscript-core with Greybel-specific language features. Greybel is a superset of MiniScript that adds a preprocessor, file management directives, bitwise operators, and other utilities. It produces a full AST and is designed to be extended further by greyscript-core.

Features on top of miniscript-core

Preprocessor conditionals

Conditional compilation via environment variables:

#if DEBUG
print("debug mode")
#else
print("release mode")
#endif

File directives

| Directive | Description | |---|---| | #include "file.src" | Include and inline a file | | #include type "file.src" | Type-only include (definitions only, no runtime code) | | #import Name from "file.src" | Import a file and bind it to a variable | | #inject "file.src" | Raw code injection |

Comment-style aliases //include and //import are also supported.

Built-in macros

| Macro | Description | |---|---| | #line | Expands to the current source line number | | #filename | Expands to the current source filename | | #envar NAME | Expands to an environment variable value |

Debugger statement

debugger

Emits a debugger breakpoint AST node.

Bitwise operators

| Operator | Description | |---|---| | & | Bitwise AND | | \| | Bitwise OR | | << | Left shift | | >> | Right shift | | >>> | Unsigned right shift |

Install

npm install greybel-core

Usage

import { Parser } from 'greybel-core';

const parser = new Parser('#include "utils.src"\nprint("hello")', {
  filename: 'main.src'
});
const chunk = parser.parseChunk();

console.log(chunk.imports);   // []
console.log(chunk.includes);  // [ASTFeatureIncludeExpression]
console.log(chunk.toString());

Preprocessor conditionals

import { Parser } from 'greybel-core';

const code = `
#if DEBUG
print("debug")
#else
print("release")
#endif
`;

const parser = new Parser(code, {
  environmentVariables: new Map([['DEBUG', '1']])
});
const chunk = parser.parseChunk();
// Only the truthy branch is included in the AST

Unsafe mode

import { UnsafeParser, UnsafeLexer } from 'greybel-core';

const code = 'print("hello"\nprint("world")';
const lexer = new UnsafeLexer(code);
const parser = new UnsafeParser(code, { lexer });

parser.parseChunk();

console.log(parser.errors); // recoverable errors
console.log(lexer.errors);  // lexer-level errors

Extending

greybel-core follows the same extension patterns as miniscript-core. The keyword handler builder is available via greybelKeywordHandlerBuilder() and can be extended with additional entries. The operator builders (greybelInfixOpBuilder, greybelAtomOpBuilder) work the same way.

GreybelParserState extends ParserState with imports, includes, and injects arrays. Subclasses that add their own state fields should override snapshot(), restore(), merge(), createEmpty(), and clone().

Testing

npm test