def _Atom(self, children):
# type: (List[PNode]) -> expr_t
"""Handles alternatives of 'atom' where there is more than one child."""
tok = children[0].tok
id_ = tok.id
n = len(children)
if id_ == Id.Op_LParen:
# atom: '(' [yield_expr|testlist_comp] ')' | ...
if n == 2: # () is a tuple
assert children[1].tok.id == Id.Op_RParen, children[1]
return expr.Tuple([], expr_context_e.Store)
return self._TestlistComp(children[1], id_)
if id_ == Id.Op_LBracket:
# atom: ... | '[' [testlist_comp] ']' | ...
if n == 2: # []
assert children[1].tok.id == Id.Op_RBracket, children[1]
return expr.List([],
expr_context_e.Store) # unused expr_context_e
return self._TestlistComp(children[1], id_)
if id_ == Id.Op_LBrace:
# atom: ... | '{' [Op_Newline] [dict] '}'
i = 1
if children[i].tok.id == Id.Op_Newline:
i += 1
return self._Dict(children[i])
if id_ == Id.Arith_Slash:
r = self._Regex(children[1])
flags = [] # type: List[Token]
# TODO: Parse translation preference.
trans_pref = None # type: Token
return expr.RegexLiteral(children[0].tok, r, flags, trans_pref)
if id_ == Id.Expr_Func:
# STUB. This should really be a Func, not Lambda.
return expr.Lambda([], expr.Implicit())
raise NotImplementedError(Id_str(id_))
def Expr(self, pnode):
# type: (PNode) -> expr_t
"""Transform expressions (as opposed to statements)."""
typ = pnode.typ
tok = pnode.tok
children = pnode.children
if ISNONTERMINAL(typ):
#
# Oil Entry Points / Additions
#
if typ == grammar_nt.oil_expr: # for if/while
# oil_expr: '(' testlist ')'
return self.Expr(children[1])
if typ == grammar_nt.command_expr:
# return_expr: testlist end_stmt
return self.Expr(children[0])
#
# Python-like Expressions / Operators
#
if typ == grammar_nt.atom:
if len(children) == 1:
return self.Expr(children[0])
return self._Atom(children)
if typ == grammar_nt.testlist:
# testlist: test (',' test)* [',']
return self._Tuple(children)
if typ == grammar_nt.test:
# test: or_test ['if' or_test 'else' test] | lambdef
if len(children) == 1:
return self.Expr(children[0])
# TODO: Handle lambdef
test = self.Expr(children[2])
body = self.Expr(children[0])
orelse = self.Expr(children[4])
return expr.IfExp(test, body, orelse)
if typ == grammar_nt.lambdef:
# lambdef: '|' [name_type_list] '|' test
n = len(children)
if n == 4:
params = self._NameTypeList(children[1])
else:
params = []
body = self.Expr(children[n-1])
return expr.Lambda(params, body)
#
# Operators with Precedence
#
if typ == grammar_nt.or_test:
# or_test: and_test ('or' and_test)*
return self._AssocBinary(children)
if typ == grammar_nt.and_test:
# and_test: not_test ('and' not_test)*
return self._AssocBinary(children)
if typ == grammar_nt.not_test:
# not_test: 'not' not_test | comparison
if len(children) == 1:
return self.Expr(children[0])
op_tok = children[0].tok # not
return expr.Unary(op_tok, self.Expr(children[1]))
elif typ == grammar_nt.comparison:
if len(children) == 1:
return self.Expr(children[0])
return self._CompareChain(children)
elif typ == grammar_nt.range_expr:
n = len(children)
if n == 1:
return self.Expr(children[0])
if n == 3:
return expr.Range(
self.Expr(children[0]),
self.Expr(children[2])
)
raise AssertionError(n)
elif typ == grammar_nt.expr:
# expr: xor_expr ('|' xor_expr)*
return self._AssocBinary(children)
if typ == grammar_nt.xor_expr:
# xor_expr: and_expr ('xor' and_expr)*
return self._AssocBinary(children)
if typ == grammar_nt.and_expr: # a & b
# and_expr: shift_expr ('&' shift_expr)*
return self._AssocBinary(children)
elif typ == grammar_nt.shift_expr:
# shift_expr: arith_expr (('<<'|'>>') arith_expr)*
return self._AssocBinary(children)
elif typ == grammar_nt.arith_expr:
# arith_expr: term (('+'|'-') term)*
return self._AssocBinary(children)
elif typ == grammar_nt.term:
# term: factor (('*'|'/'|'div'|'mod') factor)*
return self._AssocBinary(children)
elif typ == grammar_nt.factor:
# factor: ('+'|'-'|'~') factor | power
# the power would have already been reduced
if len(children) == 1:
return self.Expr(children[0])
assert len(children) == 2
op = children[0]
e = children[1]
assert isinstance(op.tok, Token)
return expr.Unary(op.tok, self.Expr(e))
elif typ == grammar_nt.power:
# power: atom trailer* ['^' factor]
node = self.Expr(children[0])
if len(children) == 1: # No trailers
return node
n = len(children)
i = 1
while i < n and ISNONTERMINAL(children[i].typ):
node = self._Trailer(node, children[i])
i += 1
if i != n: # ['^' factor]
op_tok = children[i].tok
assert op_tok.id == Id.Arith_Caret, op_tok
factor = self.Expr(children[i+1])
node = expr.Binary(op_tok, node, factor)
return node
elif typ == grammar_nt.array_literal:
left_tok = children[0].tok
items = [self._ArrayItem(p) for p in children[1:-1]]
return expr.ArrayLiteral(left_tok, items)
elif typ == grammar_nt.oil_expr_sub:
return self.Expr(children[0])
#
# Oil Lexer Modes
#
elif typ == grammar_nt.sh_array_literal:
return cast(sh_array_literal, children[1].tok)
elif typ == grammar_nt.sh_command_sub:
return cast(command_sub, children[1].tok)
elif typ == grammar_nt.braced_var_sub:
return cast(braced_var_sub, children[1].tok)
elif typ == grammar_nt.dq_string:
return cast(double_quoted, children[1].tok)
elif typ == grammar_nt.sq_string:
return cast(single_quoted, children[1].tok)
elif typ == grammar_nt.simple_var_sub:
return simple_var_sub(children[0].tok)
else:
nt_name = self.number2symbol[typ]
raise AssertionError(
"PNode type %d (%s) wasn't handled" % (typ, nt_name))
else: # Terminals should have a token
id_ = tok.id
if id_ == Id.Expr_Name:
return expr.Var(tok)
if id_ in (
Id.Expr_DecInt, Id.Expr_BinInt, Id.Expr_OctInt, Id.Expr_HexInt,
Id.Expr_Float):
return expr.Const(tok)
if id_ in (Id.Expr_Null, Id.Expr_True, Id.Expr_False):
return expr.Const(tok)
raise NotImplementedError(Id_str(id_))
