monty 0.0.21

A sandboxed, snapshotable Python interpreter written in Rust.
Documentation 
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# === Basic break ===
result = []
for x in [1, 2, 3, 4, 5]:
    if x == 3:
        break
    result.append(x)
assert result == [1, 2]

# === Break skips else ===
flag = 0
for x in [1, 2, 3]:
    if x == 2:
        break
else:
    flag = 1
assert flag == 0

# === No break runs else ===
flag = 0
for x in [1, 2, 3]:
    pass
else:
    flag = 1
assert flag == 1

# === Basic continue ===
result = []
for x in [1, 2, 3, 4, 5]:
    if x % 2 == 0:
        continue
    result.append(x)
assert result == [1, 3, 5]

# === Continue with else ===
flag = 0
for x in [1, 2, 3]:
    if x == 2:
        continue
else:
    flag = 1
assert flag == 1

# === Nested loops - break inner ===
result = []
for i in [1, 2, 3]:
    for j in ['a', 'b', 'c']:
        if j == 'b':
            break
        result.append((i, j))
assert result == [(1, 'a'), (2, 'a'), (3, 'a')]

# === Nested loops - continue inner ===
result = []
for i in [1, 2]:
    for j in ['a', 'b', 'c']:
        if j == 'b':
            continue
        result.append((i, j))
assert result == [(1, 'a'), (1, 'c'), (2, 'a'), (2, 'c')]

# === Break in nested with else on inner ===
result = []
for i in [1, 2]:
    for j in [10, 20, 30]:
        if j == 20:
            break
        result.append(j)
    else:
        result.append('inner-else')
assert result == [10, 10]

# === No break in inner runs inner else ===
result = []
for i in [1, 2]:
    for j in [10, 20]:
        result.append(j)
    else:
        result.append('inner-else')
assert result == [10, 20, 'inner-else', 10, 20, 'inner-else']

# === Continue does not affect else ===
result = []
for x in [1, 2, 3]:
    if x == 2:
        continue
    result.append(x)
else:
    result.append('else')
assert result == [1, 3, 'else']

# === Empty loop with else ===
flag = 0
for x in []:
    flag = 1
else:
    flag = 2
assert flag == 2

# === Break on first iteration ===
result = []
for x in [1, 2, 3]:
    result.append('before')
    break
    result.append('after')  # unreachable
assert result == ['before']


# === Double break (unreachable second break) ===
def double_break(value):
    for i in range(0, 1):
        break
        break
    return value


assert double_break('hello') == 'hello'
assert double_break(42) == 42


# === Two breaks in different branches (both reachable) ===
def two_breaks(items):
    result = []
    for x in items:
        if x < 0:
            result.append('negative')
            break
        if x > 100:
            result.append('too big')
            break
        result.append(x)
    return result


assert two_breaks([1, 2, 3]) == [1, 2, 3]
assert two_breaks([1, -1, 3]) == [1, 'negative']
assert two_breaks([1, 200, 3]) == [1, 'too big']
assert two_breaks([-5]) == ['negative']
assert two_breaks([999]) == ['too big']


# === Double continue (unreachable second continue) ===
def double_continue(items):
    out = []
    for x in items:
        out.append(x)
        continue
        continue
    return out


assert double_continue([1, 2, 3]) == [1, 2, 3]
assert double_continue([]) == []

# === Continue on every iteration ===
result = []
for x in [1, 2, 3]:
    result.append(x)
    continue
    result.append('after')  # unreachable
assert result == [1, 2, 3]

# === StopIteration raised in a for body propagates, it does not end the loop ===
log = []
try:
    for x in [1, 2, 3]:
        log.append(x)
        raise StopIteration
except StopIteration:
    log.append('propagated')
assert log == [1, 'propagated']

# === StopIteration raised in a while body propagates too ===
log = []
try:
    while True:
        raise StopIteration
except StopIteration:
    log.append('propagated')
assert log == ['propagated']