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# Copyright © 2009/2023 Andrey Vlasovskikh
#
# Permission is hereby granted, free of charge, to any person obtaining a copy of this
# software and associated documentation files (the "Software"), to deal in the Software
# without restriction, including without limitation the rights to use, copy, modify,
# merge, publish, distribute, sublicense, and/or sell copies of the Software, and to
# permit persons to whom the Software is furnished to do so, subject to the following
# conditions:
#
# The above copyright notice and this permission notice shall be included in all copies
# or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
# INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
# PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
# HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF
# CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE
# OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
"""A DOT language parser using funcparserlib.
The parser is based on [the DOT grammar][1]. It is pretty complete with a few
not supported things:
* String escapes
* Ports and compass points
* XML identifiers
At the moment, the parser builds only a parse tree, not an abstract syntax tree
(AST), or an API for dealing with DOT.
[1]: https://www.graphviz.org/doc/info/lang.html
"""
import os
import sys
from re import MULTILINE
from typing import Sequence, List, TypeVar, Callable, NamedTuple, Union, Optional
from funcparserlib.lexer import TokenSpec, make_tokenizer, Token, LexerError
from funcparserlib.parser import (
maybe,
many,
finished,
oneplus,
forward_decl,
NoParseError,
Parser,
tok,
)
from funcparserlib.util import pretty_tree
ENCODING = "UTF-8"
class Graph(NamedTuple):
strict: Optional[str]
type: Optional[str]
id: Optional[str]
stmts: List["Statement"]
class SubGraph(NamedTuple):
id: Optional[str]
stmts: List["Statement"]
class Attr(NamedTuple):
name: str
value: Optional[str]
class Node(NamedTuple):
id: str
attrs: List[Attr]
class Edge(NamedTuple):
nodes: List[Union[str, SubGraph]]
attrs: List[Attr]
class DefAttrs(NamedTuple):
object: str
attrs: List[Attr]
Statement = Union[DefAttrs, Edge, SubGraph, Node]
T = TypeVar("T")
def tokenize(s: str) -> Sequence[Token]:
specs = [
TokenSpec("Comment", r"/\*(.|[\r\n])*?\*/", MULTILINE),
TokenSpec("Comment", r"//.*"),
TokenSpec("NL", r"[\r\n]+"),
TokenSpec("Space", r"[ \t\r\n]+"),
TokenSpec("Name", r"[A-Za-z\200-\377_][A-Za-z\200-\377_0-9]*"),
TokenSpec("Op", r"[{};,=\[\]]|(->)|(--)"),
TokenSpec("Number", r"-?(\.[0-9]+)|([0-9]+(\.[0-9]*)?)"),
TokenSpec("String", r'"[^"]*"'), # '\"' escapes are ignored
]
useless = ["Comment", "NL", "Space"]
t = make_tokenizer(specs)
return [x for x in t(s) if x.type not in useless]
def parse(tokens: Sequence[Token]) -> Graph:
def un_arg(f: Callable[..., T]) -> Callable[[tuple], T]:
return lambda args: f(*args)
def flatten(xs: List[List[Attr]]) -> List[Attr]:
return sum(xs, [])
def n(s: str) -> Parser[Token, str]:
return tok("Name", s)
def op(s: str) -> Parser[Token, str]:
return tok("Op", s)
dot_id = (tok("Name") | tok("Number") | tok("String")).named("id")
def make_graph_attr(args: tuple) -> DefAttrs:
return DefAttrs("graph", [Attr(*args)])
def make_edge(
node: Union[str, SubGraph], xs: List[Union[str, SubGraph]], attrs: List[Attr]
) -> Edge:
return Edge([node] + xs, attrs)
node_id = dot_id # + maybe(port)
a_list = dot_id + maybe(-op("=") + dot_id) + -maybe(op(",")) >> un_arg(Attr)
attr_list = many(-op("[") + many(a_list) + -op("]")) >> flatten
attr_stmt = (n("graph") | n("node") | n("edge")) + attr_list >> un_arg(DefAttrs)
graph_attr = dot_id + -op("=") + dot_id >> make_graph_attr
node_stmt = node_id + attr_list >> un_arg(Node)
# We use a forward_decl because of circular definitions like
# (stmt_list -> stmt -> subgraph -> stmt_list)
subgraph: Parser[Token, SubGraph] = forward_decl()
edge_rhs = -(op("->") | op("--")) + (subgraph | node_id)
edge_stmt = (subgraph | node_id) + oneplus(edge_rhs) + attr_list >> un_arg(
make_edge
)
stmt = attr_stmt | edge_stmt | subgraph | graph_attr | node_stmt
stmt_list = many(stmt + -maybe(op(";")))
graph_body = -op("{") + stmt_list + -op("}")
subgraph.define(-n("subgraph") + maybe(dot_id) + graph_body >> un_arg(SubGraph))
graph_modifiers = maybe(n("strict")) + maybe(n("graph") | n("digraph"))
graph = graph_modifiers + maybe(dot_id) + graph_body >> un_arg(Graph)
dotfile = graph + -finished
return dotfile.parse(tokens)
def pretty_parse_tree(obj: object) -> str:
class NamedValues(NamedTuple):
name: str
values: Sequence[object]
def kids(x: object) -> Sequence[object]:
if isinstance(x, (Graph, SubGraph)):
return [NamedValues("stmts", x.stmts)]
elif isinstance(x, (Node, DefAttrs)):
return [NamedValues("attrs", x.attrs)]
elif isinstance(x, Edge):
return [NamedValues("nodes", x.nodes), NamedValues("attrs", x.attrs)]
elif isinstance(x, NamedValues):
return x.values
else:
return []
def show(x: object) -> str:
if isinstance(x, NamedValues):
return x.name
elif isinstance(x, Graph):
return "Graph [id=%s, strict=%r, type=%s]" % (
x.id,
x.strict is not None,
x.type,
)
elif isinstance(x, SubGraph):
return "SubGraph [id=%s]" % (x.id,)
elif isinstance(x, Edge):
return "Edge"
elif isinstance(x, Attr):
return "Attr [name=%s, value=%s]" % (x.name, x.value)
elif isinstance(x, DefAttrs):
return "DefAttrs [object=%s]" % (x.object,)
elif isinstance(x, Node):
return "Node [id=%s]" % (x.id,)
else:
return str(x)
return pretty_tree(obj, kids, show)
def main() -> None:
# import logging
# logging.basicConfig(level=logging.DEBUG)
# import funcparserlib
# funcparserlib.parser.debug = True
try:
stdin = os.fdopen(sys.stdin.fileno(), "rb")
text = stdin.read().decode(ENCODING)
tree = parse(tokenize(text))
# print(pformat(tree))
print(pretty_parse_tree(tree).encode(ENCODING))
except (NoParseError, LexerError) as e:
msg = ("syntax error: %s" % e).encode(ENCODING)
print(msg, file=sys.stderr)
sys.exit(1)
if __name__ == "__main__":
main()
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