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nac3-spec
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implemented basic statements

This commit is contained in:
pca006132 2020-12-22 15:14:34 +08:00 committed by pca006132
parent eb2ddfc617
commit 69cf20cb91
3 changed files with 118 additions and 22 deletions
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12
toy-impl/parse_expr.py
View File

@ -19,7 +19,7 @@ def parse_expr(ctx: Context,
if isinstance(body, ast.Constant):
return parse_constant(ctx, sym_table, body)
if isinstance(body, ast.UnaryOp):
return parse_unary_op(ctx, sym_table, body)
return parse_unary_ops(ctx, sym_table, body)
if isinstance(body, ast.BinOp):
return parse_bin_ops(ctx, sym_table, body)
if isinstance(body, ast.Name):
@ -131,7 +131,7 @@ def parse_bin_ops(ctx: Context,
def parse_unary_ops(ctx: Context,
sym_table: dict[str, Type],
node):
t = parse_expr(node.operand)
t = parse_expr(ctx, sym_table, node.operand)
if isinstance(node.op, ast.Not):
b = ctx.types['bool']
if t != b:
@ -206,7 +206,7 @@ def parse_if_expr(ctx: Context,
raise CustomError(f'divergent type for if expression: {ty1} != {ty2}')
return ty1
def parse_binding(name, ty):
def parse_simple_binding(name, ty):
if isinstance(name, ast.Name):
if name.id == '_':
return {}
@ -218,9 +218,9 @@ def parse_binding(name, ty):
raise CustomError(f'pattern matching length mismatch')
result = {}
for x, y in zip(name.elts, ty.params):
binding = parse_binding(x, y)
binding = parse_simple_binding(x, y)
expected = len(result) + len(binding)
result |= parse_binding(x, y)
result |= parse_simple_binding(x, y)
if len(result) != expected:
raise CustomError('variable name clash')
return result
@ -237,7 +237,7 @@ def parse_list_comprehension(ctx: Context,
ty = parse_expr(ctx, sym_table, node.generators[0].iter)
if not isinstance(ty, ListType):
raise CustomError(f'unable to iterate over {ty}')
sym_table2 = sym_table | parse_binding(node.generators[0].target, ty.params[0])
sym_table2 = sym_table | parse_simple_binding(node.generators[0].target, ty.params[0])
b = ctx.types['bool']
for c in node.generators[0].ifs:
if parse_expr(ctx, sym_table2, c) != b:

76
toy-impl/parse_stmt.py
View File

@ -3,19 +3,28 @@ import copy
from helper import *
from type_def import *
from inference import *
from parse_expr import parse_expr
from parse_expr import parse_expr, parse_simple_binding
def parse_stmts(ctx: Context,
sym_table: dict[str, Type],
used_sym_table: dict[str, Type],
return_ty: Type,
nodes):
sym_table2 = copy.copy(sym_table)
used_sym_table2 = copy.copy(used_sym_table)
for node in nodes:
if isinstance(node, ast.Assign):
a, b, returned = parse_assign(ctx, sym_table2, used_sym_table2, node)
a, b, returned = parse_assign(ctx, sym_table2, used_sym_table2, return_ty, node)
elif isinstance(node, ast.If):
a, b, returned = parse_if_stmt(ctx, sym_table2, used_sym_table2, node)
a, b, returned = parse_if_stmt(ctx, sym_table2, used_sym_table2, return_ty, node)
elif isinstance(node, ast.While):
a, b, returned = parse_while_stmt(ctx, sym_table2, used_sym_table2, return_ty, node)
elif isinstance(node, ast.For):
a, b, returned = parse_for_stmt(ctx, sym_table2, used_sym_table2, return_ty, node)
elif isinstance(node, ast.Return):
a, b, returned = parse_return_stmt(ctx, sym_table2, used_sym_table2, return_ty, node)
elif isinstance(node, ast.Break) or isinstance(node, ast.Continue):
continue
else:
raise CustomError(f'{node} is not supported yet')
sym_table2 |= a
@ -50,7 +59,7 @@ def get_target_type(ctx: Context,
else:
raise CustomError(f'assignment to {target} is not supported')
def parse_binding(ctx: Context,
def parse_stmt_binding(ctx: Context,
sym_table: dict[str, Type],
used_sym_table: dict[str, Type],
target,
@ -69,7 +78,7 @@ def parse_binding(ctx: Context,
raise CustomError(f'pattern matching length mismatch')
result = {}
for x, y in zip(target.elts, ty.params):
new = parse_binding(ctx, sym_table, used_sym_table, x, y)
new = parse_stmt_binding(ctx, sym_table, used_sym_table, x, y)
old_len = len(result)
result |= new
used_sym_table |= new
@ -85,6 +94,7 @@ def parse_binding(ctx: Context,
def parse_assign(ctx: Context,
sym_table: dict[str, Type],
used_sym_table: dict[str, Type],
return_ty: Type,
node):
# permitted assignment targets:
# variables, class fields, list elements
@ -93,19 +103,69 @@ def parse_assign(ctx: Context,
ty = parse_expr(ctx, sym_table, node.value)
results = {}
for target in node.targets:
results |= parse_binding(ctx, sym_table, used_sym_table, target, ty)
results |= parse_stmt_binding(ctx, sym_table, used_sym_table, target, ty)
return results, results, False
def parse_if_stmt(ctx: Context,
sym_table: dict[str, Type],
used_sym_table: dict[str, Type],
return_ty: Type,
node):
test = parse_expr(ctx, sym_table, node.test)
if test != ctx.types['bool']:
raise CustomError(f'condition must be bool instead of {test}')
a, b, r = parse_stmts(ctx, sym_table, used_sym_table, node.body)
a, b, r = parse_stmts(ctx, sym_table, used_sym_table, return_ty, node.body)
used_sym_table |= b
a1, b1, r1 = parse_stmts(ctx, sym_table, used_sym_table, node.orelse)
a1, b1, r1 = parse_stmts(ctx, sym_table, used_sym_table, return_ty, node.orelse)
defined = {k: a[k] for k in a if k in a1}
return defined, b | b1, r and r1
def parse_for_stmt(ctx: Context,
sym_table: dict[str, Type],
used_sym_table: dict[str, Type],
return_ty: Type,
node):
ty = parse_expr(ctx, sym_table, node.iter)
if not isinstance(ty, ListType):
raise CustomError('only iteration over list is supported')
binding = parse_simple_binding(node.target, ty.params[0])
for key, value in binding.items():
if key in used_sym_table:
if value != used_sym_table[key]:
raise CustomError('inconsistent type')
a, b, r = parse_stmts(ctx, sym_table | binding, used_sym_table | binding,
return_ty, node.body)
a1, b1, r1 = parse_stmts(ctx, sym_table, used_sym_table | b,
return_ty, node.orelse)
defined = {k: a[k] for k in a if k in a1}
return defined, b | b1, r and r1
def parse_while_stmt(ctx: Context,
sym_table: dict[str, Type],
used_sym_table: dict[str, Type],
return_ty: Type,
node):
ty = parse_expr(ctx, sym_table, node.test)
if ty != ctx.types['bool']:
raise CustomError('condition must be bool')
# more sophisticated return analysis is needed...
a, b, r = parse_stmts(ctx, sym_table, used_sym_table, return_ty, node.body)
a1, b1, r1 = parse_stmts(ctx, sym_table, used_sym_table | b,
return_ty, node.orelse)
defined = {k: a[k] for k in a if k in a1}
return defined, b | b1, r and r1
def parse_return_stmt(ctx: Context,
sym_table: dict[str, Type],
used_sym_table: dict[str, Type],
return_ty: Type,
node):
if return_ty is None:
if node.value is not None:
raise CustomError('no return value is allowed')
return {}, {}, True
ty = parse_expr(ctx, sym_table, node.value)
if ty != return_ty:
raise CustomError(f'expected returning {return_ty} but got {ty}')
return {}, {}, True

44
toy-impl/test_stmt.py
View File

@ -31,6 +31,7 @@ A = variables['A']
i32.methods['__init__'] = ([SelfType(), I], None, set())
i32.methods['__add__'] = ([SelfType(), i32], i32, set())
i32.methods['__sub__'] = ([SelfType(), i32], i32, set())
i32.methods['__neg__'] = ([SelfType()], i32, set())
i32.methods['__lt__'] = ([SelfType(), i32], b, set())
i32.methods['__gt__'] = ([SelfType(), i32], b, set())
i32.methods['__eq__'] = ([SelfType(), i32], b, set())
@ -41,6 +42,7 @@ i32.methods['__ge__'] = ([SelfType(), i32], b, set())
i64.methods['__init__'] = ([SelfType(), I], None, set())
i64.methods['__add__'] = ([SelfType(), i64], i64, set())
i64.methods['__sub__'] = ([SelfType(), i64], i64, set())
i64.methods['__neg__'] = ([SelfType()], i64, set())
i64.methods['__lt__'] = ([SelfType(), i64], b, set())
i64.methods['__gt__'] = ([SelfType(), i64], b, set())
i64.methods['__eq__'] = ([SelfType(), i64], b, set())
@ -51,14 +53,17 @@ i64.methods['__ge__'] = ([SelfType(), i64], b, set())
ctx = Context(variables, types)
def test_stmt(stmt, sym_table = {}):
print(f'Testing {stmt} w.r.t. {stringify_subst(sym_table)}')
def test_stmt(stmt, sym_table = {}, return_ty = None):
print(f'Testing:\n{stmt}\n\nw.r.t. {stringify_subst(sym_table)}')
try:
tree = ast.parse(stmt)
a, b, _ = parse_stmts(ctx, sym_table, sym_table, tree.body)
print(stringify_subst(a))
a, b, returned = parse_stmts(ctx, sym_table, sym_table, return_ty, tree.body)
print(f'defined variables: {stringify_subst(a)}')
print(f'returned: {returned}')
print('---')
except CustomError as err:
print(f'error: {err.msg}')
print('---')
test_stmt('a, b = 1, 2', {})
test_stmt('a, b = 1, [1, 2, 3]', {})
@ -95,4 +100,35 @@ c = a
b = [1, 2, 3]
""")
test_stmt("""
c = 0
for i in [1, 2, 3]:
c = c + i
""")
test_stmt("""
c = 0
for i in [1, 2, 3]:
c = c + i
if c > 0:
return c
else:
return -c
""", {}, i32)
test_stmt("""
c = 0
for i in [1, 2, 3]:
c = c + i
if c > 0:
return c
""", {}, i32)
test_stmt("""
c = i = 0
for i in [True, True, False]:
c = c + 1
if c > 0:
return c
""", {}, i32)