def alternatives(self, ast):
options = [o for o in ast.options if o is not None]
if len(options) == 1:
return options[0]
else:
options = [model.Option(o) for o in options]
return model.Choice(options)
class TOKEN_TREE:
tokens: list
RULE = grammars.Rule(
ast=None,
name="TOKEN_TREE",
exp=grammars.Choice([
grammars.RuleRef("LITERAL"),
grammars.RuleRef("IDENT"),
grammars.RuleRef("LIFETIME"),
grammars.RuleRef("PUNCT"),
grammars.Sequence(
AST(sequence=[
grammars.Token("("),
grammars.Closure(grammars.RuleRef("TOKEN_TREE")),
grammars.Token(")"),
])),
grammars.Sequence(
AST(sequence=[
grammars.Token("{"),
grammars.Closure(grammars.RuleRef("TOKEN_TREE")),
grammars.Token("}"),
])),
grammars.Sequence(
AST(sequence=[
grammars.Token("["),
grammars.Closure(grammars.RuleRef("TOKEN_TREE")),
grammars.Token("]"),
])),
]),
params=None,
kwparams=None,
)
@classmethod
def from_ast(cls, ast) -> TOKEN_TREE:
return cls(ast)
def choice(self, ast, *args):
if len(ast) == 1:
return ast[0]
return grammars.Choice(ast)
def node_to_tatsu(node: gll_grammar.RuleNode):
match node:
case gll_grammar.Empty():
return tatsu_grammars.EmptyClosure()
case gll_grammar.LabeledNode(name, item):
return tatsu_grammars.Named(AST(name=name, exp=node_to_tatsu(item)))
case gll_grammar.StringLiteral(s):
return tatsu_grammars.Token(ast=s)
case gll_grammar.CharacterRange(_, _):
raise NotImplementedError("character ranges")
case gll_grammar.SymbolName(name):
return tatsu_grammars.RuleRef(ast=name)
case gll_grammar.Concatenation(items):
return tatsu_grammars.Sequence(
ast=AST(sequence=list(map(node_to_tatsu, items)))
)
case gll_grammar.Alternation(items):
return tatsu_grammars.Choice(ast=list(map(node_to_tatsu, items)))
case gll_grammar.Option(item):
return tatsu_grammars.Optional(exp=node_to_tatsu(item))
case gll_grammar.Repeated(False, item, separator=None, allow_trailing=False):
return tatsu_grammars.Closure(exp=node_to_tatsu(item))
case gll_grammar.Repeated(True, item, separator=None, allow_trailing=False):
return tatsu_grammars.PositiveClosure(exp=node_to_tatsu(item))
case gll_grammar.Repeated(False, item, separator, allow_trailing=False):
return tatsu_grammars.Join(
ast=AST(exp=node_to_tatsu(item), sep=tatsu_grammars.Token(ast=separator))
)
case gll_grammar.Repeated(True, item, separator, allow_trailing=False):
return tatsu_grammars.PositiveJoin(
ast=AST(exp=node_to_tatsu(item), sep=tatsu_grammars.Token(ast=separator))
)
case gll_grammar.Repeated(False, item, separator, allow_trailing=True):
item = node_to_tatsu(item)
separator = tatsu_grammars.Token(ast=separator)
return tatsu_grammars.Sequence(
ast=AST(
sequence=[
tatsu_grammars.Closure(
exp=tatsu_grammars.Sequence(
ast=AST(
sequence=[
item,
separator,
]
)
),
),
tatsu_grammars.Optional(exp=item),
]
)
)
case gll_grammar.Repeated(True, item, separator, allow_trailing=True):
item = node_to_tatsu(item)
separator = tatsu_grammars.Token(ast=separator)
return tatsu_grammars.Sequence(
ast=AST(
sequence=[
item,
tatsu_grammars.Closure(
exp=tatsu_grammars.Sequence(
ast=AST(
sequence=[
separator,
item,
]
)
),
),
tatsu_grammars.Optional(exp=separator),
]
)
)
case _:
# should be unreachable
assert False, repr(node)