simplepy #

An interpreter for a subset of the Python language, written purely in Dart. It is intended for adding scripting capabilities to Dart projects and for educational purposes.

Features #

• Available python features:

  • Variable types: int, float, bool, str, list, dict, set, tuple, NoneType
    (some dict methods with limitations)
  • f-strings: {value:[[fill]align][sign][0][width][.precision][dfs]} ; #, and types b/o/x/e/g/% are not yet supported.
  • arithmetic operators: + - * / // ** % and bitwise operators
  • assignments: = += -= *= /= **= //= %=
  • comparisons: == > >= < <= !=
  • boolean operators: and, or, not
  • if, else, elif (newline after colon is required, in loops and function definitions as well)
  • for loops, while loops
  • functions (default arguments, *args, **kwargs are partially implemented), lambda functions
  • some built-in functions: print(), range(), len(), str(), repr(), int(), float(), bool(), type(), list(), dict(), set(), tuple(), abs(), round(), min(), max(), sum()
  • classes (no class attributes, no multiple inheritance)

  Some more features might be added soon, but this will never become a full python interpreter.

• Missing python features:

  • int limited to dart int: ±1<<63 native ; ±1<<53 in web
  • list.sort() not yet implemented
  • dict.key(), dict.values(), dict.items() return list copies, not dynamic views as in Python
  • str.startswith(), str.endswith(): 1st argument can only be a single string for comparison, no tuple with alternatives
  • set operators | & - ^ <= >=
  • import
  • list comprehensions
  • list or string slices
  • file I/O
  • exceptions
  • decorators
  • async functions, generators
  • input() and some other built-in functions
  • complex numbers
  • anything else not mentioned as available

Usage #

import 'package:simplepy/simplepy.dart';

void main() {
  String py = "print(3**4)";
  final tokens = Lexer(py).scanTokens();
  final stmts = Parser(tokens).parse();
  Interpreter().interpret(stmts);
}

Additional information #

Please report any errors (except for missing features, that are not mentioned as available) at the issue tracker.