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289 lines
11 KiB
Python
289 lines
11 KiB
Python
"""
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Programming Language for 6502/6510 microprocessors
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This is the expression parser/evaluator.
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Written by Irmen de Jong (irmen@razorvine.net)
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License: GNU GPL 3.0, see LICENSE
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"""
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import ast
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from typing import Union, Optional, List, Tuple, Any
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from .symbols import FLOAT_MAX_POSITIVE, FLOAT_MAX_NEGATIVE, SourceRef, SymbolTable, SymbolError, PrimitiveType
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class ParseError(Exception):
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def __init__(self, message: str, sourcetext: str, sourceref: SourceRef) -> None:
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self.sourceref = sourceref
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self.msg = message
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self.sourcetext = sourcetext
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def __str__(self):
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return "{} {:s}".format(self.sourceref, self.msg)
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class SourceLine:
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def __init__(self, text: str, sourceref: SourceRef) -> None:
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self.sourceref = sourceref
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self.text = text.strip()
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def to_error(self, message: str) -> ParseError:
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return ParseError(message, self.text, self.sourceref)
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def preprocess(self) -> str:
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# transforms the source text into valid Python syntax by bending some things, so ast can parse it.
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# $d020 -> 0xd020
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# %101001 -> 0xb101001
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# #something -> __ptr@something (matmult operator)
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text = ""
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quotes_stack = ""
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characters = enumerate(self.text + " ")
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for i, c in characters:
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if c in ("'", '"'):
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if quotes_stack and quotes_stack[-1] == c:
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quotes_stack = quotes_stack[:-1]
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else:
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quotes_stack += c
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text += c
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continue
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if not quotes_stack:
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if c == '%' and self.text[i + 1] in "01":
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text += "0b"
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continue
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if c == '$' and self.text[i + 1] in "0123456789abcdefABCDEF":
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text += "0x"
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continue
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if c == '#':
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if i > 0:
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text += " "
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text += "__ptr@"
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continue
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text += c
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return text
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def parse_arguments(text: str, sourceref: SourceRef) -> List[Tuple[str, PrimitiveType]]:
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src = SourceLine(text, sourceref)
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text = src.preprocess()
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try:
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nodes = ast.parse("__func({:s})".format(text), sourceref.file, "eval")
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except SyntaxError as x:
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raise src.to_error(str(x))
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args = [] # type: List[Tuple[str, Any]]
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if isinstance(nodes, ast.Expression):
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for arg in nodes.body.args:
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reprvalue = astnode_to_repr(arg)
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args.append((None, reprvalue))
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for kwarg in nodes.body.keywords:
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reprvalue = astnode_to_repr(kwarg.value)
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args.append((kwarg.arg, reprvalue))
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return args
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else:
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raise TypeError("ast.Expression expected")
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def parse_expr_as_comparison(text: str, sourceref: SourceRef) -> Tuple[str, str, str]:
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src = SourceLine(text, sourceref)
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text = src.preprocess()
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try:
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node = ast.parse(text, sourceref.file, mode="eval")
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except SyntaxError as x:
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raise src.to_error(str(x))
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if not isinstance(node, ast.Expression):
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raise TypeError("ast.Expression expected")
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if isinstance(node.body, ast.Compare):
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if len(node.body.ops) != 1:
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raise src.to_error("only one comparison operator at a time is supported")
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operator = {
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"Eq": "==",
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"NotEq": "!=",
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"Lt": "<",
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"LtE": "<=",
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"Gt": ">",
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"GtE": ">=",
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"Is": None,
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"IsNot": None,
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"In": None,
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"NotIn": None
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}[node.body.ops[0].__class__.__name__]
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if not operator:
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raise src.to_error("unsupported comparison operator")
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left = text[node.body.left.col_offset:node.body.comparators[0].col_offset].rstrip()[:-len(operator)]
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right = text[node.body.comparators[0].col_offset:]
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return left.strip(), operator, right.strip()
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left = astnode_to_repr(node.body)
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return left, "", ""
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def parse_expr_as_int(text: str, context: Optional[SymbolTable], ppcontext: Optional[SymbolTable], sourceref: SourceRef, *,
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minimum: int=0, maximum: int=0xffff) -> int:
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result = parse_expr_as_primitive(text, context, ppcontext, sourceref, minimum=minimum, maximum=maximum)
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if isinstance(result, int):
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return result
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src = SourceLine(text, sourceref)
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raise src.to_error("int expected, not " + type(result).__name__)
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def parse_expr_as_number(text: str, context: Optional[SymbolTable], ppcontext: Optional[SymbolTable], sourceref: SourceRef, *,
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minimum: float=FLOAT_MAX_NEGATIVE, maximum: float=FLOAT_MAX_POSITIVE) -> Union[int, float]:
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result = parse_expr_as_primitive(text, context, ppcontext, sourceref, minimum=minimum, maximum=maximum)
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if isinstance(result, (int, float)):
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return result
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src = SourceLine(text, sourceref)
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raise src.to_error("int or float expected, not " + type(result).__name__)
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def parse_expr_as_string(text: str, context: Optional[SymbolTable], ppcontext: Optional[SymbolTable], sourceref: SourceRef) -> str:
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result = parse_expr_as_primitive(text, context, ppcontext, sourceref)
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if isinstance(result, str):
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return result
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src = SourceLine(text, sourceref)
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raise src.to_error("string expected, not " + type(result).__name__)
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def parse_expr_as_primitive(text: str, context: Optional[SymbolTable], ppcontext: Optional[SymbolTable], sourceref: SourceRef, *,
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minimum: float = FLOAT_MAX_NEGATIVE, maximum: float = FLOAT_MAX_POSITIVE) -> PrimitiveType:
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src = SourceLine(text, sourceref)
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text = src.preprocess()
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try:
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node = ast.parse(text, sourceref.file, mode="eval")
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except SyntaxError as x:
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raise src.to_error(str(x))
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if isinstance(node, ast.Expression):
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result = ExpressionTransformer(src, context, ppcontext).evaluate(node)
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else:
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raise TypeError("ast.Expression expected")
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if isinstance(result, bool):
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return int(result)
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if isinstance(result, (int, float)):
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if minimum <= result <= maximum:
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return result
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raise src.to_error("number too large")
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if isinstance(result, str):
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return result
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raise src.to_error("int or float or string expected, not " + type(result).__name__)
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class EvaluatingTransformer(ast.NodeTransformer):
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def __init__(self, src: SourceLine, context: SymbolTable, ppcontext: SymbolTable) -> None:
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super().__init__()
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self.src = src
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self.context = context
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self.ppcontext = ppcontext
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def error(self, message: str, column: int=0) -> ParseError:
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if column:
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ref = self.src.sourceref.copy()
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ref.column = column
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else:
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ref = self.src.sourceref
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return ParseError(message, self.src.text, ref)
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def evaluate(self, node: ast.Expression) -> PrimitiveType:
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node = self.visit(node)
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code = compile(node, self.src.sourceref.file, mode="eval")
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if self.context:
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globals = None
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locals = self.context.as_eval_dict(self.ppcontext)
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else:
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globals = {"__builtins__": {}}
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locals = None
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try:
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result = eval(code, globals, locals) # XXX unsafe...
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except Exception as x:
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raise self.src.to_error(str(x)) from x
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else:
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if type(result) is bool:
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return int(result)
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return result
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class ExpressionTransformer(EvaluatingTransformer):
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def _dotted_name_from_attr(self, node: ast.Attribute) -> str:
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if isinstance(node.value, ast.Name):
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return node.value.id + '.' + node.attr
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if isinstance(node.value, ast.Attribute):
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return self._dotted_name_from_attr(node.value) + '.' + node.attr
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raise self.error("dotted name error")
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def visit_Name(self, node: ast.Name):
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# convert true/false names to True/False constants
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if node.id == "true":
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return ast.copy_location(ast.NameConstant(True), node)
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if node.id == "false":
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return ast.copy_location(ast.NameConstant(False), node)
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return node
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def visit_UnaryOp(self, node):
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if isinstance(node.operand, ast.Num):
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if isinstance(node.op, ast.USub):
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node = self.generic_visit(node)
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return ast.copy_location(ast.Num(-node.operand.n), node)
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if isinstance(node.op, ast.UAdd):
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node = self.generic_visit(node)
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return ast.copy_location(ast.Num(node.operand.n), node)
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if isinstance(node.op, ast.Invert):
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if isinstance(node.operand, ast.Num):
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node = self.generic_visit(node)
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return ast.copy_location(ast.Num(~node.operand.n), node)
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else:
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raise self.error("can only bitwise invert a number")
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raise self.error("expected unary + or - or ~")
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elif isinstance(node.operand, ast.UnaryOp):
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# nested unary ops, for instance: "~-2" = invert(minus(2))
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node = self.generic_visit(node)
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return self.visit_UnaryOp(node)
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else:
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print(node.operand)
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raise self.error("expected constant numeric operand for unary operator")
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def visit_BinOp(self, node):
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node = self.generic_visit(node)
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if isinstance(node.op, ast.MatMult):
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if isinstance(node.left, ast.Name) and node.left.id == "__ptr":
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if isinstance(node.right, ast.Attribute):
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symbolname = self._dotted_name_from_attr(node.right)
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elif isinstance(node.right, ast.Name):
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symbolname = node.right.id
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else:
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raise self.error("can only take address of a named variable")
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try:
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address = self.context.get_address(symbolname)
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except SymbolError as x:
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raise self.error(str(x))
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else:
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return ast.copy_location(ast.Num(address), node)
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else:
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raise self.error("invalid MatMult/Pointer node in AST")
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return node
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def astnode_to_repr(node: ast.AST) -> str:
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if isinstance(node, ast.Name):
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return node.id
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if isinstance(node, ast.Num):
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return repr(node.n)
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if isinstance(node, ast.Str):
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return repr(node.s)
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if isinstance(node, ast.BinOp):
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if node.left.id == "__ptr" and isinstance(node.op, ast.MatMult): # type: ignore
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return '#' + astnode_to_repr(node.right)
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else:
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print("error", ast.dump(node))
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raise TypeError("invalid arg ast node type", node)
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if isinstance(node, ast.Attribute):
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return astnode_to_repr(node.value) + "." + node.attr
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if isinstance(node, ast.UnaryOp):
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if isinstance(node.op, ast.USub):
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return "-" + astnode_to_repr(node.operand)
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if isinstance(node.op, ast.UAdd):
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return "+" + astnode_to_repr(node.operand)
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if isinstance(node.op, ast.Invert):
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return "~" + astnode_to_repr(node.operand)
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if isinstance(node.op, ast.Not):
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return "not " + astnode_to_repr(node.operand)
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if isinstance(node, ast.List):
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# indirect values get turned into a list...
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return "[" + ",".join(astnode_to_repr(elt) for elt in node.elts) + "]"
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raise TypeError("invalid arg ast node type", node)
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