def _EvalLhsAndLookupArith(self, node):
# type: (arith_expr_t) -> Tuple[int, lvalue_t]
""" For x = y and x += y and ++x """
lval = self.EvalArithLhs(node, runtime.NO_SPID)
val = OldValue(lval, self.mem, self.exec_opts)
# BASH_LINENO, arr (array name with shopt -s compat_array), etc.
if val.tag_() in (value_e.MaybeStrArray, value_e.AssocArray
) and lval.tag_() == lvalue_e.Named:
named_lval = cast(lvalue__Named, lval)
if word_eval.CheckCompatArray(named_lval.name, self.exec_opts):
if val.tag_() == value_e.MaybeStrArray:
lval = lvalue.Indexed(named_lval.name, 0)
elif val.tag_() == value_e.AssocArray:
lval = lvalue.Keyed(named_lval.name, '0')
val = word_eval.ResolveCompatArray(val)
# This error message could be better, but we already have one
#if val.tag_() == value_e.MaybeStrArray:
# e_die("Can't use assignment like ++ or += on arrays")
span_id = location.SpanForArithExpr(node)
i = self._ValToIntOrError(val, span_id=span_id)
return i, lval
def EvalToInt(self, node):
# type: (arith_expr_t) -> int
"""Used externally by ${a[i+1]} and ${a:start:len}.
Also used internally.
"""
val = self.Eval(node)
# TODO: Can we avoid the runtime cost of adding location info?
span_id = location.SpanForArithExpr(node)
i = self._ValToIntOrError(val, span_id=span_id)
return i
def EvalToInt(self, node):
# type: (arith_expr_t) -> int
"""Used externally by ${a[i+1]} and ${a:start:len}.
Also used internally.
"""
val = self.Eval(node)
# BASH_LINENO, arr (array name with shopt -s compat_array), etc.
if val.tag_() in (value_e.MaybeStrArray, value_e.AssocArray) and node.tag_() == arith_expr_e.VarRef:
tok = cast(Token, node)
if word_eval.CheckCompatArray(tok.val, self.exec_opts):
val = word_eval.ResolveCompatArray(val)
# TODO: Can we avoid the runtime cost of adding location info?
span_id = location.SpanForArithExpr(node)
i = self._ValToIntOrError(val, span_id=span_id)
return i
def Eval(self, node):
# type: (arith_expr_t) -> value_t
"""
Args:
node: arith_expr_t
Returns:
None for Undef (e.g. empty cell) TODO: Don't return 0!
int for Str
List[int] for MaybeStrArray
Dict[str, str] for AssocArray (TODO: Should we support this?)
NOTE: (( A['x'] = 'x' )) and (( x = A['x'] )) are syntactically valid in
bash, but don't do what you'd think. 'x' sometimes a variable name and
sometimes a key.
"""
# OSH semantics: Variable NAMES cannot be formed dynamically; but INTEGERS
# can. ${foo:-3}4 is OK. $? will be a compound word too, so we don't have
# to handle that as a special case.
UP_node = node
with tagswitch(node) as case:
if case(arith_expr_e.VarRef): # $(( x )) (can be array)
node = cast(arith_expr__VarRef, UP_node)
tok = node.token
return _LookupVar(tok.val, self.mem, self.exec_opts)
elif case(
arith_expr_e.ArithWord): # $(( $x )) $(( ${x}${y} )), etc.
node = cast(arith_expr__ArithWord, UP_node)
return self.word_ev.EvalWordToString(node.w)
elif case(arith_expr_e.UnaryAssign): # a++
node = cast(arith_expr__UnaryAssign, UP_node)
op_id = node.op_id
old_int, lval = self._EvalLhsAndLookupArith(node.child)
if op_id == Id.Node_PostDPlus: # post-increment
new_int = old_int + 1
ret = old_int
elif op_id == Id.Node_PostDMinus: # post-decrement
new_int = old_int - 1
ret = old_int
elif op_id == Id.Arith_DPlus: # pre-increment
new_int = old_int + 1
ret = new_int
elif op_id == Id.Arith_DMinus: # pre-decrement
new_int = old_int - 1
ret = new_int
else:
raise AssertionError(op_id)
#log('old %d new %d ret %d', old_int, new_int, ret)
self._Store(lval, new_int)
return value.Int(ret)
elif case(arith_expr_e.BinaryAssign): # a=1, a+=5, a[1]+=5
node = cast(arith_expr__BinaryAssign, UP_node)
op_id = node.op_id
if op_id == Id.Arith_Equal:
lval = _EvalLhsArith(node.left, self.mem, self)
# Disallowing (( a = myarray ))
# It has to be an integer
rhs_int = self.EvalToInt(node.right)
self._Store(lval, rhs_int)
return value.Int(rhs_int)
old_int, lval = self._EvalLhsAndLookupArith(node.left)
rhs = self.EvalToInt(node.right)
if op_id == Id.Arith_PlusEqual:
new_int = old_int + rhs
elif op_id == Id.Arith_MinusEqual:
new_int = old_int - rhs
elif op_id == Id.Arith_StarEqual:
new_int = old_int * rhs
elif op_id == Id.Arith_SlashEqual:
if rhs == 0:
e_die('Divide by zero') # TODO: location
new_int = old_int / rhs
elif op_id == Id.Arith_PercentEqual:
if rhs == 0:
e_die('Divide by zero') # TODO: location
new_int = old_int % rhs
elif op_id == Id.Arith_DGreatEqual:
new_int = old_int >> rhs
elif op_id == Id.Arith_DLessEqual:
new_int = old_int << rhs
elif op_id == Id.Arith_AmpEqual:
new_int = old_int & rhs
elif op_id == Id.Arith_PipeEqual:
new_int = old_int | rhs
elif op_id == Id.Arith_CaretEqual:
new_int = old_int ^ rhs
else:
raise AssertionError(op_id) # shouldn't get here
self._Store(lval, new_int)
return value.Int(new_int)
elif case(arith_expr_e.Unary):
node = cast(arith_expr__Unary, UP_node)
op_id = node.op_id
i = self.EvalToInt(node.child)
if op_id == Id.Node_UnaryPlus:
ret = i
elif op_id == Id.Node_UnaryMinus:
ret = -i
elif op_id == Id.Arith_Bang: # logical negation
ret = 1 if i == 0 else 0
elif op_id == Id.Arith_Tilde: # bitwise complement
ret = ~i
else:
raise AssertionError(op_id) # shouldn't get here
return value.Int(ret)
elif case(arith_expr_e.Binary):
node = cast(arith_expr__Binary, UP_node)
op_id = node.op_id
# Short-circuit evaluation for || and &&.
if op_id == Id.Arith_DPipe:
lhs = self.EvalToInt(node.left)
if lhs == 0:
rhs = self.EvalToInt(node.right)
ret = int(rhs != 0)
else:
ret = 1 # true
return value.Int(ret)
if op_id == Id.Arith_DAmp:
lhs = self.EvalToInt(node.left)
if lhs == 0:
ret = 0 # false
else:
rhs = self.EvalToInt(node.right)
ret = int(rhs != 0)
return value.Int(ret)
if op_id == Id.Arith_LBracket:
# NOTE: Similar to bracket_op_e.ArrayIndex in osh/word_eval.py
left = self.Eval(node.left)
UP_left = left
with tagswitch(left) as case:
if case(value_e.MaybeStrArray):
left = cast(value__MaybeStrArray, UP_left)
rhs_int = self.EvalToInt(node.right)
try:
# could be None because representation is sparse
s = left.strs[rhs_int]
except IndexError:
s = None
elif case(value_e.AssocArray):
left = cast(value__AssocArray, UP_left)
key = self.EvalWordToString(node.right)
s = left.d.get(key)
else:
# TODO: Add error context
e_die(
'Expected array or assoc in index expression, got %s',
ui.ValType(left))
if s is None:
val = value.Undef() # type: value_t
else:
val = value.Str(s)
return val
if op_id == Id.Arith_Comma:
self.Eval(node.left) # throw away result
return self.Eval(node.right)
# Rest are integers
lhs = self.EvalToInt(node.left)
rhs = self.EvalToInt(node.right)
if op_id == Id.Arith_Plus:
ret = lhs + rhs
elif op_id == Id.Arith_Minus:
ret = lhs - rhs
elif op_id == Id.Arith_Star:
ret = lhs * rhs
elif op_id == Id.Arith_Slash:
if rhs == 0:
# TODO: Could also blame /
e_die('Divide by zero',
span_id=location.SpanForArithExpr(node.right))
ret = lhs / rhs
elif op_id == Id.Arith_Percent:
if rhs == 0:
# TODO: Could also blame /
e_die('Divide by zero',
span_id=location.SpanForArithExpr(node.right))
ret = lhs % rhs
elif op_id == Id.Arith_DStar:
# OVM is stripped of certain functions that are somehow necessary for
# exponentiation.
# Python/ovm_stub_pystrtod.c:21: PyOS_double_to_string: Assertion `0'
# failed.
if rhs < 0:
e_die("Exponent can't be less than zero"
) # TODO: error location
ret = 1
for i in xrange(rhs):
ret *= lhs
elif op_id == Id.Arith_DEqual:
ret = int(lhs == rhs)
elif op_id == Id.Arith_NEqual:
ret = int(lhs != rhs)
elif op_id == Id.Arith_Great:
ret = int(lhs > rhs)
elif op_id == Id.Arith_GreatEqual:
ret = int(lhs >= rhs)
elif op_id == Id.Arith_Less:
ret = int(lhs < rhs)
elif op_id == Id.Arith_LessEqual:
ret = int(lhs <= rhs)
elif op_id == Id.Arith_Pipe:
ret = lhs | rhs
elif op_id == Id.Arith_Amp:
ret = lhs & rhs
elif op_id == Id.Arith_Caret:
ret = lhs ^ rhs
# Note: how to define shift of negative numbers?
elif op_id == Id.Arith_DLess:
ret = lhs << rhs
elif op_id == Id.Arith_DGreat:
ret = lhs >> rhs
else:
raise AssertionError(op_id)
return value.Int(ret)
elif case(arith_expr_e.TernaryOp):
node = cast(arith_expr__TernaryOp, UP_node)
cond = self.EvalToInt(node.cond)
if cond: # nonzero
return self.Eval(node.true_expr)
else:
return self.Eval(node.false_expr)
else:
raise AssertionError(node.tag_())