def _worth_extracting(element: pyparsing.ParserElement) -> bool:
"""
Returns true if this element is worth having its own sub-diagram. Simply, if any of its children
themselves have children, then its complex enough to extract
"""
children = element.recurse()
return any(child.recurse() for child in children)
def _to_diagram_element(
element: pyparsing.ParserElement,
parent: typing.Optional[EditablePartial],
lookup: ConverterState = None,
vertical: int = None,
index: int = 0,
name_hint: str = None,
show_results_names: bool = False,
show_groups: bool = False,
) -> typing.Optional[EditablePartial]:
"""
Recursively converts a PyParsing Element to a railroad Element
:param lookup: The shared converter state that keeps track of useful things
:param index: The index of this element within the parent
:param parent: The parent of this element in the output tree
:param vertical: Controls at what point we make a list of elements vertical. If this is an integer (the default),
it sets the threshold of the number of items before we go vertical. If True, always go vertical, if False, never
do so
:param name_hint: If provided, this will override the generated name
:param show_results_names: bool flag indicating whether to add annotations for results names
:returns: The converted version of the input element, but as a Partial that hasn't yet been constructed
:param show_groups: bool flag indicating whether to show groups using bounding box
"""
exprs = element.recurse()
name = name_hint or element.customName or element.__class__.__name__
# Python's id() is used to provide a unique identifier for elements
el_id = id(element)
element_results_name = element.resultsName
# Here we basically bypass processing certain wrapper elements if they contribute nothing to the diagram
if not element.customName:
if isinstance(
element,
(
# pyparsing.TokenConverter,
# pyparsing.Forward,
pyparsing.Located, ),
):
# However, if this element has a useful custom name, and its child does not, we can pass it on to the child
if exprs:
if not exprs[0].customName:
propagated_name = name
else:
propagated_name = None
return _to_diagram_element(
element.expr,
parent=parent,
lookup=lookup,
vertical=vertical,
index=index,
name_hint=propagated_name,
show_results_names=show_results_names,
show_groups=show_groups,
)
# If the element isn't worth extracting, we always treat it as the first time we say it
if _worth_extracting(element):
if el_id in lookup:
# If we've seen this element exactly once before, we are only just now finding out that it's a duplicate,
# so we have to extract it into a new diagram.
looked_up = lookup[el_id]
looked_up.mark_for_extraction(el_id, lookup, name=name_hint)
ret = EditablePartial.from_call(railroad.NonTerminal,
text=looked_up.name)
return ret
elif el_id in lookup.diagrams:
# If we have seen the element at least twice before, and have already extracted it into a subdiagram, we
# just put in a marker element that refers to the sub-diagram
ret = EditablePartial.from_call(
railroad.NonTerminal,
text=lookup.diagrams[el_id].kwargs["name"])
return ret
# Recursively convert child elements
# Here we find the most relevant Railroad element for matching pyparsing Element
# We use ``items=[]`` here to hold the place for where the child elements will go once created
if isinstance(element, pyparsing.And):
# detect And's created with ``expr*N`` notation - for these use a OneOrMore with a repeat
# (all will have the same name, and resultsName)
if not exprs:
return None
if len(set((e.name, e.resultsName) for e in exprs)) == 1:
ret = EditablePartial.from_call(railroad.OneOrMore,
item="",
repeat=str(len(exprs)))
elif _should_vertical(vertical, exprs):
ret = EditablePartial.from_call(railroad.Stack, items=[])
else:
ret = EditablePartial.from_call(railroad.Sequence, items=[])
elif isinstance(element, (pyparsing.Or, pyparsing.MatchFirst)):
if not exprs:
return None
if _should_vertical(vertical, exprs):
ret = EditablePartial.from_call(railroad.Choice, 0, items=[])
else:
ret = EditablePartial.from_call(railroad.HorizontalChoice,
items=[])
elif isinstance(element, pyparsing.Each):
if not exprs:
return None
ret = EditablePartial.from_call(EachItem, items=[])
elif isinstance(element, pyparsing.NotAny):
ret = EditablePartial.from_call(AnnotatedItem, label="NOT", item="")
elif isinstance(element, pyparsing.FollowedBy):
ret = EditablePartial.from_call(AnnotatedItem,
label="LOOKAHEAD",
item="")
elif isinstance(element, pyparsing.PrecededBy):
ret = EditablePartial.from_call(AnnotatedItem,
label="LOOKBEHIND",
item="")
elif isinstance(element, pyparsing.Group):
if show_groups:
ret = EditablePartial.from_call(AnnotatedItem, label="", item="")
else:
ret = EditablePartial.from_call(railroad.Group, label="", item="")
elif isinstance(element, pyparsing.TokenConverter):
ret = EditablePartial.from_call(AnnotatedItem,
label=type(element).__name__.lower(),
item="")
elif isinstance(element, pyparsing.Opt):
ret = EditablePartial.from_call(railroad.Optional, item="")
elif isinstance(element, pyparsing.OneOrMore):
ret = EditablePartial.from_call(railroad.OneOrMore, item="")
elif isinstance(element, pyparsing.ZeroOrMore):
ret = EditablePartial.from_call(railroad.ZeroOrMore, item="")
elif isinstance(element, pyparsing.Group):
ret = EditablePartial.from_call(railroad.Group,
item=None,
label=element_results_name)
elif isinstance(element, pyparsing.Empty) and not element.customName:
# Skip unnamed "Empty" elements
ret = None
elif len(exprs) > 1:
ret = EditablePartial.from_call(railroad.Sequence, items=[])
elif len(exprs) > 0 and not element_results_name:
ret = EditablePartial.from_call(railroad.Group, item="", label=name)
else:
terminal = EditablePartial.from_call(railroad.Terminal,
element.defaultName)
ret = terminal
if ret is None:
return
# Indicate this element's position in the tree so we can extract it if necessary
lookup[el_id] = ElementState(
element=element,
converted=ret,
parent=parent,
parent_index=index,
number=lookup.generate_index(),
)
if element.customName:
lookup[el_id].mark_for_extraction(el_id, lookup, element.customName)
i = 0
for expr in exprs:
# Add a placeholder index in case we have to extract the child before we even add it to the parent
if "items" in ret.kwargs:
ret.kwargs["items"].insert(i, None)
item = _to_diagram_element(
expr,
parent=ret,
lookup=lookup,
vertical=vertical,
index=i,
show_results_names=show_results_names,
show_groups=show_groups,
)
# Some elements don't need to be shown in the diagram
if item is not None:
if "item" in ret.kwargs:
ret.kwargs["item"] = item
elif "items" in ret.kwargs:
# If we've already extracted the child, don't touch this index, since it's occupied by a nonterminal
ret.kwargs["items"][i] = item
i += 1
elif "items" in ret.kwargs:
# If we're supposed to skip this element, remove it from the parent
del ret.kwargs["items"][i]
# If all this items children are none, skip this item
if ret and (("items" in ret.kwargs and len(ret.kwargs["items"]) == 0) or
("item" in ret.kwargs and ret.kwargs["item"] is None)):
ret = EditablePartial.from_call(railroad.Terminal, name)
# Mark this element as "complete", ie it has all of its children
if el_id in lookup:
lookup[el_id].complete = True
if el_id in lookup and lookup[el_id].extract and lookup[el_id].complete:
lookup.extract_into_diagram(el_id)
if ret is not None:
ret = EditablePartial.from_call(
railroad.NonTerminal,
text=lookup.diagrams[el_id].kwargs["name"])
return ret
def _to_diagram_element(
element: pyparsing.ParserElement,
parent: Optional[EditablePartial],
lookup: ConverterState = None,
vertical: Union[int, bool] = 3,
index: int = 0,
name_hint: str = None,
) -> Optional[EditablePartial]:
"""
Recursively converts a PyParsing Element to a railroad Element
:param lookup: The shared converter state that keeps track of useful things
:param index: The index of this element within the parent
:param parent: The parent of this element in the output tree
:param vertical: Controls at what point we make a list of elements vertical. If this is an integer (the default),
it sets the threshold of the number of items before we go vertical. If True, always go vertical, if False, never
do so
:param name_hint: If provided, this will override the generated name
:returns: The converted version of the input element, but as a Partial that hasn't yet been constructed
"""
exprs = element.recurse()
name = name_hint or element.customName or element.__class__.__name__
# Python's id() is used to provide a unique identifier for elements
el_id = id(element)
# Here we basically bypass processing certain wrapper elements if they contribute nothing to the diagram
if isinstance(
element,
(pyparsing.Group, pyparsing.Forward)) and (not element.customName
or not exprs[0].customName):
# However, if this element has a useful custom name, we can pass it on to the child
if not exprs[0].customName:
propagated_name = name
else:
propagated_name = None
return _to_diagram_element(
element.expr,
parent=parent,
lookup=lookup,
vertical=vertical,
index=index,
name_hint=propagated_name,
)
# If the element isn't worth extracting, we always treat it as the first time we say it
if _worth_extracting(element):
if el_id in lookup.first:
# If we've seen this element exactly once before, we are only just now finding out that it's a duplicate,
# so we have to extract it into a new diagram.
looked_up = lookup.first[el_id]
looked_up.mark_for_extraction(el_id, lookup, name=name_hint)
return EditablePartial.from_call(railroad.NonTerminal,
text=looked_up.name)
elif el_id in lookup.diagrams:
# If we have seen the element at least twice before, and have already extracted it into a subdiagram, we
# just put in a marker element that refers to the sub-diagram
return EditablePartial.from_call(
railroad.NonTerminal,
text=lookup.diagrams[el_id].kwargs["name"])
# Recursively convert child elements
# Here we find the most relevant Railroad element for matching pyparsing Element
# We use ``items=[]`` here to hold the place for where the child elements will go once created
if isinstance(element, pyparsing.And):
if _should_vertical(vertical, len(exprs)):
ret = EditablePartial.from_call(railroad.Stack, items=[])
else:
ret = EditablePartial.from_call(railroad.Sequence, items=[])
elif isinstance(element, (pyparsing.Or, pyparsing.MatchFirst)):
if _should_vertical(vertical, len(exprs)):
ret = EditablePartial.from_call(railroad.Choice, 0, items=[])
else:
ret = EditablePartial.from_call(railroad.HorizontalChoice,
items=[])
elif isinstance(element, pyparsing.Optional):
ret = EditablePartial.from_call(railroad.Optional, item="")
elif isinstance(element, pyparsing.OneOrMore):
ret = EditablePartial.from_call(railroad.OneOrMore, item="")
elif isinstance(element, pyparsing.ZeroOrMore):
ret = EditablePartial.from_call(railroad.ZeroOrMore, item="")
elif isinstance(element, pyparsing.Group):
ret = EditablePartial.from_call(railroad.Group, item=None, label=name)
elif isinstance(element, pyparsing.Empty) and not element.customName:
# Skip unnamed "Empty" elements
ret = None
elif len(exprs) > 1:
ret = EditablePartial.from_call(railroad.Sequence, items=[])
elif len(exprs) > 0:
ret = EditablePartial.from_call(railroad.Group, item="", label=name)
else:
# If the terminal has a custom name, we annotate the terminal with it, but still show the defaultName, because
# it describes the pattern that it matches, which is useful to have present in the diagram
terminal = EditablePartial.from_call(railroad.Terminal,
element.defaultName)
if element.customName is not None:
ret = EditablePartial.from_call(railroad.Group,
item=terminal,
label=element.customName)
else:
ret = terminal
# Indicate this element's position in the tree so we can extract it if necessary
lookup.first[el_id] = ElementState(
element=element,
converted=ret,
parent=parent,
index=index,
number=lookup.generate_index(),
)
i = 0
for expr in exprs:
# Add a placeholder index in case we have to extract the child before we even add it to the parent
if "items" in ret.kwargs:
ret.kwargs["items"].insert(i, None)
item = _to_diagram_element(expr,
parent=ret,
lookup=lookup,
vertical=vertical,
index=i)
# Some elements don't need to be shown in the diagram
if item is not None:
if "item" in ret.kwargs:
ret.kwargs["item"] = item
elif "items" in ret.kwargs:
# If we've already extracted the child, don't touch this index, since it's occupied by a nonterminal
if ret.kwargs["items"][i] is None:
ret.kwargs["items"][i] = item
i += 1
elif "items" in ret.kwargs:
# If we're supposed to skip this element, remove it from the parent
del ret.kwargs["items"][i]
# If all this items children are none, skip this item
if ret and (("items" in ret.kwargs and len(ret.kwargs["items"]) == 0) or
("item" in ret.kwargs and ret.kwargs["item"] is None)):
return EditablePartial.from_call(railroad.Terminal, name)
# Mark this element as "complete", ie it has all of its children
if el_id in lookup.first:
lookup.first[el_id].complete = True
if (el_id in lookup.first and lookup.first[el_id].extract
and lookup.first[el_id].complete):
lookup.extract_into_diagram(el_id)
return EditablePartial.from_call(
railroad.NonTerminal, text=lookup.diagrams[el_id].kwargs["name"])
else:
return ret
