176 lines
6.8 KiB
Python
176 lines
6.8 KiB
Python
import ast
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from type_def import *
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from helper import *
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def parse_type(ctx: Context, ty):
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if ty is None:
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return None, set()
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elif isinstance(ty, ast.Name):
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# we should support string either, but no need for toy implementation
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if ty.id in ctx.types:
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return ctx.types[ty.id], set()
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elif ty.id in ctx.variables:
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return ctx.variables[ty.id], {ty.id}
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else:
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raise CustomError(f"Unbounded Type {ty.id}")
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elif isinstance(ty, ast.Subscript):
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if isinstance(ty.value, ast.Name):
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generic = ty.value.id
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else:
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raise CustomError(f"Unknown Generic Type {ty.value}")
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if not isinstance(ty.slice, ast.Name) and not isinstance(ty.slice, ast.Tuple) \
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and not isinstance(ty.slice, ast.Subscript):
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raise CustomError(f"Generic Type of the form {ty.slice} is not supported")
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if generic == 'tuple':
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if not isinstance(ty.slice, ast.Tuple):
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raise CustomError(f"Generic Type of the form {ty} is not supported")
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param = []
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var = set()
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for t in ty.slice.elts:
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p, v = parse_type(ctx, t)
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param.append(p)
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var |= v
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return TupleType(param), var
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elif generic == 'list':
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param, var = parse_type(ctx, ty.slice)
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return ListType(param), var
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elif generic == 'virtual':
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param, var = parse_type(ctx, ty.slice)
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if not isinstance(param, ClassType):
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raise CustomError(f"Parameter of virtual must be a class instead of {param}")
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return VirtualClassType(param), var
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else:
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raise CustomError(f"Unknown Generic Type {ty.value}")
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else:
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raise CustomError(f"Unrecognized Type {ty}")
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def parse_function(ctx: Context, base, fn: ast.FunctionDef):
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args = []
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var = set()
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for arg in fn.args.args:
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name = arg.arg
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ty, v = parse_type(ctx, arg.annotation)
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var |= v
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if name == 'self' and ty is None and base is not None:
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ty = SelfType()
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args.append(ty)
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if isinstance(fn.returns, ast.Name) and fn.returns.id == 'self'\
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and base is not None:
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result, v = SelfType(), set()
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else:
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result, v = parse_type(ctx, fn.returns)
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if len(v - var) > 0:
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raise CustomError(f"Unbounded variable in return type of {fn.name}")
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return args, result, var
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def parse_class(ctx, c: ast.ClassDef):
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node = ctx.types[c.name]
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functions = []
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for base in c.bases:
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if not isinstance(base, ast.Name):
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raise CustomError(f"Base class of the form {base} is not supported")
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name = base.id
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if name not in ctx.types:
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raise CustomError(f"Unbounded base class name {base}")
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if not isinstance(ctx.types[name], ClassType):
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raise CustomError(f"Base class must be a class instead of {base}")
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node.parents.append(ctx.types[name])
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for stmt in c.body:
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if isinstance(stmt, ast.AnnAssign):
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if not isinstance(stmt.target, ast.Name):
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raise CustomError(f"Assignment of the form {stmt.target} is not supported")
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field = stmt.target.id
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if field in node.fields:
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raise CustomError(f"Duplicated fields {field} in {c.name}")
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ty, var = parse_type(ctx, stmt.annotation)
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if len(var) > 0:
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raise CustomError(f"Type variable is not allowed in class fields")
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if ty == None:
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raise CustomError(f"{field} of {c.name} is not annotated")
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node.fields[field] = ty
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elif isinstance(stmt, ast.FunctionDef):
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name = stmt.name
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if name in node.methods:
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raise CustomError(f"Duplicated method {name} in {c.name}")
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args, result, var = parse_function(ctx, node, stmt)
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node.methods[name] = (args, result, var)
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functions.append((c.name, name, stmt))
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else:
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raise CustomError(f"{stmt} is not supported")
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return functions
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def parse_type_var(ctx: Context, node):
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if isinstance(node, ast.Assign):
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if not isinstance(node.value, ast.Call) or\
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not isinstance(node.value.func, ast.Name) or\
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node.value.func.id != 'TypeVar':
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return
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if not len(node.targets) == 1 or\
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not isinstance(node.targets[0], ast.Name):
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raise CustomError(
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'complicated variable assignment is not allowed',
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node)
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if len(node.value.args) == 0 or\
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not isinstance(node.value.args[0], ast.Constant) or\
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not isinstance(node.value.args[0].value, str):
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raise CustomError('call to TypeVar must at least have a name',
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node.value)
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name = node.targets[0].id
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if name in ctx.variables:
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raise CustomError('redefining type variable is not allowed', node)
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constraints = []
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for v in node.value.args[1:]:
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value, var = parse_type(ctx, v)
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if len(var) > 0:
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raise CustomError(
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'constraints cannot contain type variables',
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node)
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constraints.append(value)
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ctx.variables[name] = TypeVariable(node.value.args[0].value, constraints)
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def parse_top_level(ctx: Context, module: ast.Module):
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to_be_processed = []
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assignments = []
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# first pass, obtain all type names
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for element in module.body:
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if isinstance(element, ast.ClassDef):
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name = element.name
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if name in ctx.types or name in ctx.variables:
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raise CustomError(f"Duplicated class name: {name}")
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ctx.types[name] = ClassType(name)
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to_be_processed.append(element)
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elif isinstance(element, ast.FunctionDef):
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to_be_processed.append(element)
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elif isinstance(element, ast.Assign):
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assignments.append(element)
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# second pass, obtain all type variables
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for node in assignments:
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parse_type_var(ctx, node)
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# third pass, obtain all function types
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function_stmts = []
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for element in to_be_processed:
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if isinstance(element, ast.ClassDef):
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function_stmts += parse_class(ctx, element)
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elif isinstance(element, ast.FunctionDef):
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name = element.name
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if name in ctx.functions:
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raise CustomError(f"Duplicated function name {name}")
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if name in ctx.types:
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raise CustomError(f"Function name {name} clashed with type name")
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args, result, var = parse_function(ctx, None, element)
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ctx.functions[name] = (args, result, var)
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function_stmts.append((None, name, element))
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return ctx, function_stmts
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