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|
"""Parser for bytecodes.inst."""
from dataclasses import dataclass, field
from typing import NamedTuple, Callable, TypeVar
import lexer as lx
from plexer import PLexer
P = TypeVar("P", bound="Parser")
N = TypeVar("N", bound="Node")
def contextual(func: Callable[[P], N|None]) -> Callable[[P], N|None]:
# Decorator to wrap grammar methods.
# Resets position if `func` returns None.
def contextual_wrapper(self: P) -> N|None:
begin = self.getpos()
res = func(self)
if res is None:
self.setpos(begin)
return
end = self.getpos()
res.context = Context(begin, end, self)
return res
return contextual_wrapper
class Context(NamedTuple):
begin: int
end: int
owner: PLexer
def __repr__(self):
return f"<{self.begin}-{self.end}>"
@dataclass
class Node:
context: Context|None = field(init=False, default=None)
@property
def text(self) -> str:
return self.to_text()
def to_text(self, dedent: int = 0) -> str:
context = self.context
if not context:
return ""
tokens = context.owner.tokens
begin = context.begin
end = context.end
return lx.to_text(tokens[begin:end], dedent)
@dataclass
class Block(Node):
tokens: list[lx.Token]
@dataclass
class InstDef(Node):
name: str
inputs: list[str] | None
outputs: list[str] | None
block: Block | None
@dataclass
class Super(Node):
name: str
ops: list[str]
@dataclass
class Family(Node):
name: str
members: list[str]
class Parser(PLexer):
@contextual
def inst_def(self) -> InstDef | None:
if header := self.inst_header():
if block := self.block():
header.block = block
return header
raise self.make_syntax_error("Expected block")
return None
@contextual
def inst_header(self):
# inst(NAME) | inst(NAME, (inputs -- outputs))
# TODO: Error out when there is something unexpected.
# TODO: Make INST a keyword in the lexer.
if (tkn := self.expect(lx.IDENTIFIER)) and tkn.text == "inst":
if (self.expect(lx.LPAREN)
and (tkn := self.expect(lx.IDENTIFIER))):
name = tkn.text
if self.expect(lx.COMMA):
inp, outp = self.stack_effect()
if (self.expect(lx.RPAREN)
and self.peek().kind == lx.LBRACE):
return InstDef(name, inp, outp, [])
elif self.expect(lx.RPAREN):
return InstDef(name, None, None, [])
return None
def stack_effect(self):
# '(' [inputs] '--' [outputs] ')'
if self.expect(lx.LPAREN):
inp = self.inputs() or []
if self.expect(lx.MINUSMINUS):
outp = self.outputs() or []
if self.expect(lx.RPAREN):
return inp, outp
raise self.make_syntax_error("Expected stack effect")
def inputs(self):
# input (, input)*
here = self.getpos()
if inp := self.input():
near = self.getpos()
if self.expect(lx.COMMA):
if rest := self.inputs():
return [inp] + rest
self.setpos(near)
return [inp]
self.setpos(here)
return None
def input(self):
# IDENTIFIER
if (tkn := self.expect(lx.IDENTIFIER)):
if self.expect(lx.LBRACKET):
if arg := self.expect(lx.IDENTIFIER):
if self.expect(lx.RBRACKET):
return f"{tkn.text}[{arg.text}]"
if self.expect(lx.TIMES):
if num := self.expect(lx.NUMBER):
if self.expect(lx.RBRACKET):
return f"{tkn.text}[{arg.text}*{num.text}]"
raise self.make_syntax_error("Expected argument in brackets", tkn)
return tkn.text
if self.expect(lx.CONDOP):
while self.expect(lx.CONDOP):
pass
return "??"
return None
def outputs(self):
# output (, output)*
here = self.getpos()
if outp := self.output():
near = self.getpos()
if self.expect(lx.COMMA):
if rest := self.outputs():
return [outp] + rest
self.setpos(near)
return [outp]
self.setpos(here)
return None
def output(self):
return self.input() # TODO: They're not quite the same.
@contextual
def super_def(self) -> Super | None:
if (tkn := self.expect(lx.IDENTIFIER)) and tkn.text == "super":
if self.expect(lx.LPAREN):
if (tkn := self.expect(lx.IDENTIFIER)):
if self.expect(lx.RPAREN):
if self.expect(lx.EQUALS):
if ops := self.ops():
res = Super(tkn.text, ops)
return res
def ops(self) -> list[str] | None:
here = self.getpos()
if tkn := self.expect(lx.IDENTIFIER):
ops = [tkn.text]
while self.expect(lx.PLUS):
if tkn := self.require(lx.IDENTIFIER):
ops.append(tkn.text)
self.require(lx.SEMI)
return ops
@contextual
def family_def(self) -> Family | None:
if (tkn := self.expect(lx.IDENTIFIER)) and tkn.text == "family":
if self.expect(lx.LPAREN):
if (tkn := self.expect(lx.IDENTIFIER)):
if self.expect(lx.RPAREN):
if self.expect(lx.EQUALS):
if members := self.members():
if self.expect(lx.SEMI):
return Family(tkn.text, members)
return None
def members(self):
here = self.getpos()
if tkn := self.expect(lx.IDENTIFIER):
near = self.getpos()
if self.expect(lx.COMMA):
if rest := self.members():
return [tkn.text] + rest
self.setpos(near)
return [tkn.text]
self.setpos(here)
return None
@contextual
def block(self) -> Block:
tokens = self.c_blob()
return Block(tokens)
def c_blob(self):
tokens = []
level = 0
while tkn := self.next(raw=True):
if tkn.kind in (lx.LBRACE, lx.LPAREN, lx.LBRACKET):
level += 1
elif tkn.kind in (lx.RBRACE, lx.RPAREN, lx.RBRACKET):
level -= 1
if level <= 0:
break
tokens.append(tkn)
return tokens
if __name__ == "__main__":
import sys
if sys.argv[1:]:
filename = sys.argv[1]
if filename == "-c" and sys.argv[2:]:
src = sys.argv[2]
filename = None
else:
with open(filename) as f:
src = f.read()
srclines = src.splitlines()
begin = srclines.index("// BEGIN BYTECODES //")
end = srclines.index("// END BYTECODES //")
src = "\n".join(srclines[begin+1 : end])
else:
filename = None
src = "if (x) { x.foo; // comment\n}"
parser = Parser(src, filename)
x = parser.inst_def()
print(x)
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