def OldValue(lval, mem, exec_opts):
# type: (lvalue_t, Mem, optview.Exec) -> value_t
"""
Used by s+='x' and (( i += 1 ))
TODO: We need a stricter and less ambiguous version for Oil.
Problem:
- why does lvalue have Indexed and Keyed, while sh_lhs_expr only has
IndexedName?
- should I have lvalue.Named and lvalue.Indexed only?
- and Indexed uses the index_t type?
- well that might be Str or Int
"""
assert isinstance(lval, lvalue_t), lval
# TODO: refactor lvalue_t to make this simpler
UP_lval = lval
with tagswitch(lval) as case:
if case(lvalue_e.Named): # (( i++ ))
lval = cast(lvalue__Named, UP_lval)
var_name = lval.name
elif case(lvalue_e.Indexed): # (( a[i]++ ))
lval = cast(lvalue__Indexed, UP_lval)
var_name = lval.name
elif case(lvalue_e.Keyed): # (( A['K']++ )) ? I think this works
lval = cast(lvalue__Keyed, UP_lval)
var_name = lval.name
else:
raise AssertionError()
val = _LookupVar(var_name, mem, exec_opts)
UP_val = val
with tagswitch(lval) as case:
if case(lvalue_e.Named):
return val
elif case(lvalue_e.Indexed):
lval = cast(lvalue__Indexed, UP_lval)
array_val = None # type: value__MaybeStrArray
with tagswitch(val) as case2:
if case2(value_e.Undef):
array_val = value.MaybeStrArray([])
elif case2(value_e.MaybeStrArray):
tmp = cast(value__MaybeStrArray, UP_val)
# mycpp rewrite: add tmp. cast() creates a new var in inner scope
array_val = tmp
else:
e_die("Can't use [] on value of type %s", ui.ValType(val))
s = word_eval.GetArrayItem(array_val.strs, lval.index)
if s is None:
val = value.Str('') # NOTE: Other logic is value.Undef()? 0?
else:
assert isinstance(s, str), s
val = value.Str(s)
elif case(lvalue_e.Keyed):
lval = cast(lvalue__Keyed, UP_lval)
assoc_val = None # type: value__AssocArray
with tagswitch(val) as case2:
if case2(value_e.Undef):
# This never happens, because undef[x]+= is assumed to
raise AssertionError()
elif case2(value_e.AssocArray):
tmp2 = cast(value__AssocArray, UP_val)
# mycpp rewrite: add tmp. cast() creates a new var in inner scope
assoc_val = tmp2
else:
e_die("Can't use [] on value of type %s", ui.ValType(val))
s = assoc_val.d.get(lval.key)
if s is None:
val = value.Str('')
else:
val = value.Str(s)
else:
raise AssertionError()
return val
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)
tok = cast(Token, UP_node)
return _LookupVar(tok.val, self.mem, self.exec_opts)
elif case(arith_expr_e.Word): # $(( $x )) $(( ${x}${y} )), etc.
w = cast(compound_word, UP_node)
return self.word_ev.EvalWordToString(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:
# Don't really need a span ID here, because tdop.CheckLhsExpr should
# have done all the validation.
lval = self.EvalArithLhs(node.left, runtime.NO_SPID)
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):
array_val = cast(value__MaybeStrArray, UP_left)
index = self.EvalToInt(node.right)
s = word_eval.GetArrayItem(array_val.strs, index)
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.EvalToInt(node.left) # throw away result
ret = self.EvalToInt(node.right)
return value.Int(ret)
# 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_())