An environment with some Scheme standard procedures.
()
| 75 | # end::ENV_CLASS[] |
| 76 | |
| 77 | def standard_env() -> Environment: |
| 78 | "An environment with some Scheme standard procedures." |
| 79 | env = Environment() |
| 80 | env.update(vars(math)) # sin, cos, sqrt, pi, ... |
| 81 | env.update({ |
| 82 | '+': op.add, |
| 83 | '-': op.sub, |
| 84 | '*': op.mul, |
| 85 | '/': op.truediv, |
| 86 | 'quotient': op.floordiv, |
| 87 | '>': op.gt, |
| 88 | '<': op.lt, |
| 89 | '>=': op.ge, |
| 90 | '<=': op.le, |
| 91 | '=': op.eq, |
| 92 | 'abs': abs, |
| 93 | 'append': lambda *args: list(chain(*args)), |
| 94 | 'apply': lambda proc, args: proc(*args), |
| 95 | 'begin': lambda *x: x[-1], |
| 96 | 'car': lambda x: x[0], |
| 97 | 'cdr': lambda x: x[1:], |
| 98 | 'cons': lambda x, y: [x] + y, |
| 99 | 'display': lambda x: print(lispstr(x)), |
| 100 | 'eq?': op.is_, |
| 101 | 'equal?': op.eq, |
| 102 | 'filter': lambda *args: list(filter(*args)), |
| 103 | 'length': len, |
| 104 | 'list': lambda *x: list(x), |
| 105 | 'list?': lambda x: isinstance(x, list), |
| 106 | 'map': lambda *args: list(map(*args)), |
| 107 | 'max': max, |
| 108 | 'min': min, |
| 109 | 'not': op.not_, |
| 110 | 'null?': lambda x: x == [], |
| 111 | 'number?': lambda x: isinstance(x, (int, float)), |
| 112 | 'procedure?': callable, |
| 113 | 'round': round, |
| 114 | 'symbol?': lambda x: isinstance(x, Symbol), |
| 115 | }) |
| 116 | return env |
| 117 | |
| 118 | |
| 119 | ################ Interaction: A REPL |