gramforge

1.0.9 verified Sat May 09 auth: no python

gramforge is a Python library for efficient multi-language generation from context-free or context-sensitive grammars (CFG/CSG). It supports generating strings and structures from grammar definitions, suitable for tasks like fuzzing, test generation, and language prototyping. Current version is 1.0.9, with a stable release cadence.

pip install gramforge

Common errors

error ModuleNotFoundError: No module named 'gramforge' ↓

cause Package not installed or installed in wrong environment.

fix

Run 'pip install gramforge' in the correct Python environment.

error AttributeError: module 'gramforge' has no attribute 'Grammar' ↓

cause Wrong import path; user tried to import 'gramforge' then access Grammar.

fix

Use 'from gramforge import Grammar' instead of 'import gramforge'.

error gramforge.grammar.ParseError: Expected '=' ↓

cause Grammar rule syntax error, e.g., missing '=' or incorrect formatting.

fix

Check grammar rules: each production should be like 'NonTerminal = ...'.

Warnings

gotcha Grammar syntax is custom and not compatible with common grammar formats (e.g., ANTLR, EBNF). Double-check the format for rules and terminals. ↓

fix Refer to the official documentation for grammar syntax (e.g., S = 'hello' Name).

gotcha The generator is not deterministic unless explicitly seeded. Repeated calls to generate() may yield different outputs. ↓

fix Use gen = Generator(grammar, seed=42) for reproducible output.

gotcha Grammar.from_string() may raise ParseError for malformed rules. Always catch exceptions when processing dynamic grammars. ↓

fix Wrap in try-except: try: grammar = Grammar.from_string(rule) except Exception as e: print(e).

Imports

Grammar
wrong
```
import Grammar
```
correct
```
from gramforge import Grammar
```
Grammar is not a top-level module; import from gramforge

Generator

wrong

from gramforge.generator import Generator

correct

from gramforge import Generator

Generator is directly accessible from the main package

Quickstart

Defines a grammar and generates a string from it.

from gramforge import Grammar, Generator

# Define a simple grammar
grammar = Grammar.from_string('''
S = 'Hello ' Name
Name = 'world' | 'Alice' | 'Bob'
''')

# Create a generator
gen = Generator(grammar)

# Generate a string
result = gen.generate()
print(result)  # e.g., 'Hello world'