def expr_call(self, method, args, fallible):
# NOTE: Currently "AstBuilder" functions are made fallible using the
# fallible_methods taken from some Rust code which extract this
# information to produce a JSON file.
if self.method_trait == "AstBuilder":
fallible = None
return grammar.CallMethod(method, args or (),
types.Type(self.method_trait), fallible
is not None)
def finish_grammar(nt_defs,
goals,
variable_terminals,
synthetic_terminals,
single_grammar=True,
extensions=[]):
nt_grammars = {}
for nt_name, eq, _ in nt_defs:
if nt_name in nt_grammars:
raise ValueError(
"duplicate definitions for nonterminal {!r}".format(nt_name))
nt_grammars[nt_name] = eq
# Figure out which grammar we were trying to get (":" for syntactic,
# "::" for lexical) based on the goal symbols.
goals = list(goals)
if len(goals) == 0:
raise ValueError("no goal nonterminals specified")
if single_grammar:
selected_grammars = set(nt_grammars[goal] for goal in goals)
assert len(selected_grammars) != 0
if len(selected_grammars) > 1:
raise ValueError(
"all goal nonterminals must be part of the same grammar; "
"got {!r} (matching these grammars: {!r})".format(
set(goals), set(selected_grammars)))
[selected_grammar] = selected_grammars
terminal_set = set()
def hack_production(p):
for i, e in enumerate(p.body):
if isinstance(e, str) and e[:1] == "`":
if len(e) < 3 or e[-1:] != "`":
raise ValueError(
"Unrecognized grammar symbol: {!r} (in {!r})".format(
e, p))
p[i] = token = e[1:-1]
terminal_set.add(token)
nonterminals = {}
for nt_name, eq, rhs_list_or_lambda in nt_defs:
if single_grammar and eq != selected_grammar:
continue
if isinstance(rhs_list_or_lambda, grammar.NtDef):
nonterminals[nt_name] = rhs_list_or_lambda
else:
rhs_list = rhs_list_or_lambda
for p in rhs_list:
if not isinstance(p, grammar.Production):
raise ValueError(
"invalid grammar: ifdef in non-function-call context")
hack_production(p)
if nt_name in nonterminals:
raise ValueError("unsupported: multiple definitions for nt " +
nt_name)
nonterminals[nt_name] = rhs_list
for t in terminal_set:
if t in nonterminals:
raise ValueError(
"grammar contains both a terminal `{}` and nonterminal {}".
format(t, t))
# Add execution modes to generate the various functions needed to handle
# syntax parsing and full parsing execution modes.
exec_modes = collections.defaultdict(OrderedSet)
noop_parser = types.Type("ParserTrait",
(types.Lifetime("alloc"), types.UnitType))
token_parser = types.Type("ParserTrait",
(types.Lifetime("alloc"),
types.Type("StackValue",
(types.Lifetime("alloc"), ))))
ast_builder = types.Type("AstBuilderDelegate", (types.Lifetime("alloc"), ))
# Full parsing takes token as input and build an AST.
exec_modes["full_actions"].extend([token_parser, ast_builder])
# Syntax parsing takes token as input but skip building the AST.
# TODO: The syntax parser is commented out for now, as we need something to
# be produced when we cannot call the AstBuilder for producing the values.
# No-op parsing is used for the simulator, which is so far used for
# querying whether we can end the incremental input and lookup if a state
# can accept some kind of tokens.
exec_modes["noop_actions"].add(noop_parser)
# Extensions are using an equivalent of Rust types to define the kind of
# parsers to be used, this map is used to convert these type names to the
# various execution modes.
full_parser = types.Type("FullParser")
syntax_parser = types.Type("SyntaxParser")
noop_parser = types.Type("NoopParser")
type_to_modes = {
noop_parser: ["noop_actions", "full_actions"],
syntax_parser: ["full_actions"],
full_parser: ["full_actions"],
}
result = grammar.Grammar(nonterminals,
goal_nts=goals,
variable_terminals=variable_terminals,
synthetic_terminals=synthetic_terminals,
exec_modes=exec_modes,
type_to_modes=type_to_modes)
result.patch(extensions)
return result
def parameterized_type(self, name, args):
return types.Type(name, args)
def simple_type(self, name):
return types.Type(name)
