def EvalExpr(self, node):
# type: (expr_t) -> Any
"""
This is a naive PyObject evaluator! It uses the type dispatch of the host
Python interpreter.
Returns:
A Python object of ANY type. Should be wrapped in value.Obj() for
storing in Mem.
"""
if 0:
print('EvalExpr()')
node.PrettyPrint()
print('')
if node.tag == expr_e.Const:
id_ = node.c.id
if id_ == Id.Expr_DecInt:
return int(node.c.val)
elif id_ == Id.Expr_BinInt:
return int(node.c.val, 2)
elif id_ == Id.Expr_OctInt:
return int(node.c.val, 8)
elif id_ == Id.Expr_HexInt:
return int(node.c.val, 16)
elif id_ == Id.Expr_Float:
return float(node.c.val)
elif id_ == Id.Expr_Null:
return None
elif id_ == Id.Expr_True:
return True
elif id_ == Id.Expr_False:
return False
elif id_ == Id.Expr_Name:
# for {name: 'bob'}
# Maybe also :Symbol?
return node.c.val
# NOTE: We could allow Ellipsis for a[:, ...] here, but we're not using
# it yet.
raise AssertionError(id_)
if node.tag == expr_e.Var:
return self.LookupVar(node.name.val)
if node.tag == expr_e.CommandSub:
return self.ex.RunCommandSub(node.command_list)
if node.tag == expr_e.ShArrayLiteral:
words = braces.BraceExpandWords(node.words)
strs = self.word_ev.EvalWordSequence(words)
#log('ARRAY LITERAL EVALUATED TO -> %s', strs)
return objects.StrArray(strs)
if node.tag == expr_e.DoubleQuoted:
# In an ideal world, I would *statically* disallow:
# - "$@" and "${array[@]}"
# - backticks like `echo hi`
# - $(( 1+2 )) and $[] -- although useful for refactoring
# - not sure: ${x%%} -- could disallow this
# - these enters the ArgDQ state: "${a:-foo bar}" ?
# But that would complicate the parser/evaluator. So just rely on
# strict_array to disallow the bad parts.
return self.word_ev.EvalDoubleQuotedToString(node)
if node.tag == expr_e.SingleQuoted:
return word_eval.EvalSingleQuoted(node)
if node.tag == expr_e.BracedVarSub:
return self.word_ev.EvalBracedVarSubToString(node)
if node.tag == expr_e.SimpleVarSub:
return self.word_ev.EvalSimpleVarSubToString(node.token)
if node.tag == expr_e.Unary:
child = self.EvalExpr(node.child)
if node.op.id == Id.Arith_Minus:
return -child
if node.op.id == Id.Arith_Tilde:
return ~child
if node.op.id == Id.Expr_Not:
return not child
raise NotImplementedError(node.op.id)
if node.tag == expr_e.Binary:
left = self.EvalExpr(node.left)
right = self.EvalExpr(node.right)
if node.op.id == Id.Arith_Plus:
return left + right
if node.op.id == Id.Arith_Minus:
return left - right
if node.op.id == Id.Arith_Star:
return left * right
if node.op.id == Id.Arith_Slash:
# NOTE: from __future__ import division changes 5/2!
# But just make it explicit.
return float(left) / right # floating point division
if node.op.id == Id.Expr_Div:
return left // right # integer divison
if node.op.id == Id.Expr_Mod:
return left % right
if node.op.id == Id.Arith_Caret: # Exponentiation
return left**right
# Bitwise
if node.op.id == Id.Arith_Amp:
return left & right
if node.op.id == Id.Arith_Pipe:
return left | right
if node.op.id == Id.Expr_Xor:
return left ^ right
if node.op.id == Id.Arith_DGreat:
return left >> right
if node.op.id == Id.Arith_DLess:
return left << right
# Logical
if node.op.id == Id.Expr_And:
return left and right
if node.op.id == Id.Expr_Or:
return left or right
raise NotImplementedError(node.op.id)
if node.tag == expr_e.Range: # 1:10 or 1:10:2
lower = self.EvalExpr(node.lower)
upper = self.EvalExpr(node.upper)
return xrange(lower, upper)
if node.tag == expr_e.Slice: # a[:0]
lower = self.EvalExpr(node.lower) if node.lower else None
upper = self.EvalExpr(node.upper) if node.upper else None
return slice(lower, upper)
if node.tag == expr_e.Compare:
left = self.EvalExpr(node.left)
result = True # Implicit and
for op, right_expr in zip(node.ops, node.comparators):
right = self.EvalExpr(right_expr)
if op.id == Id.Arith_Less:
result = left < right
elif op.id == Id.Arith_Great:
result = left > right
elif op.id == Id.Arith_GreatEqual:
result = left >= right
elif op.id == Id.Arith_LessEqual:
result = left <= right
elif op.id == Id.Arith_DEqual:
result = left == right
elif op.id == Id.Expr_In:
result = left in right
elif op.id == Id.Node_NotIn:
result = left not in right
elif op.id == Id.Expr_Is:
result = left is right
elif op.id == Id.Node_IsNot:
result = left is not right
else:
try:
if op.id == Id.Arith_Tilde:
result = self._EvalMatch(left, right, True)
elif op.id == Id.Expr_NotTilde:
result = not self._EvalMatch(left, right, False)
else:
raise AssertionError(op.id)
except RuntimeError as e:
# Status 2 indicates a regex parse error. This is fatal in OSH but
# not in bash, which treats [[ like a command with an exit code.
e_die("Invalid regex %r",
right,
span_id=op.span_id,
status=2)
if not result:
return result
left = right
return result
if node.tag == expr_e.IfExp:
b = self.EvalExpr(node.test)
if b:
return self.EvalExpr(node.body)
else:
return self.EvalExpr(node.orelse)
if node.tag == expr_e.List:
return [self.EvalExpr(e) for e in node.elts]
if node.tag == expr_e.Tuple:
return tuple(self.EvalExpr(e) for e in node.elts)
if node.tag == expr_e.Dict:
# NOTE: some keys are expr.Const
keys = [self.EvalExpr(e) for e in node.keys]
values = []
for i, e in enumerate(node.values):
if e.tag == expr_e.Implicit:
v = self.LookupVar(keys[i]) # {name}
else:
v = self.EvalExpr(e)
values.append(v)
return dict(zip(keys, values))
if node.tag == expr_e.ListComp:
# TODO:
# - Consolidate with command_e.OilForIn in osh/cmd_exec.py?
# - Do I have to push a temp frame here?
# Hm... lexical or dynamic scope is an issue.
result = []
comp = node.generators[0]
obj = self.EvalExpr(comp.iter)
# TODO: Handle x,y etc.
iter_name = comp.lhs[0].name.val
if isinstance(obj, str):
e_die("Strings aren't iterable")
else:
it = obj.__iter__()
while True:
try:
loop_val = it.next() # e.g. x
except StopIteration:
break
self.mem.SetVar(lvalue.Named(iter_name), value.Obj(loop_val),
scope_e.LocalOnly)
if comp.cond:
b = self.EvalExpr(comp.cond)
else:
b = True
if b:
item = self.EvalExpr(node.elt) # e.g. x*2
result.append(item)
return result
if node.tag == expr_e.GeneratorExp:
comp = node.generators[0]
obj = self.EvalExpr(comp.iter)
# TODO: Support (x for x, y in ...)
iter_name = comp.lhs[0].name.val
it = obj.__iter__()
# TODO: There is probably a much better way to do this!
# The scope of the loop variable is wrong, etc.
def _gen():
while True:
try:
loop_val = it.next() # e.g. x
except StopIteration:
break
self.mem.SetVar(lvalue.Named(iter_name),
value.Obj(loop_val), scope_e.LocalOnly)
if comp.cond:
b = self.EvalExpr(comp.cond)
else:
b = True
if b:
item = self.EvalExpr(node.elt) # e.g. x*2
yield item
return _gen()
if node.tag == expr_e.Lambda:
return objects.Lambda(node, self.ex)
if node.tag == expr_e.FuncCall:
func = self.EvalExpr(node.func)
pos_args, named_args = self.EvalArgList(node.args)
ret = func(*pos_args, **named_args)
return ret
if node.tag == expr_e.Subscript:
obj = self.EvalExpr(node.obj)
index = self._EvalIndices(node.indices)
return obj[index]
# TODO: obj.method() should be separate
if node.tag == expr_e.Attribute: # obj.attr
o = self.EvalExpr(node.obj)
id_ = node.op.id
if id_ == Id.Expr_Dot:
name = node.attr.val
# TODO: Does this do the bound method thing we do NOT want?
return getattr(o, name)
if id_ == Id.Expr_RArrow: # d->key is like d['key']
name = node.attr.val
return o[name]
if id_ == Id.Expr_DColon: # StaticName::member
raise NotImplementedError(id_)
# TODO: We should prevent virtual lookup here? This is a pure static
# namespace lookup?
# But Python doesn't any hook for this.
# Maybe we can just check that it's a module? And modules don't lookup
# in a supertype or __class__, etc.
raise AssertionError(id_)
if node.tag == expr_e.RegexLiteral: # obj.attr
# TODO: Should this just be an object that ~ calls?
return objects.Regex(self.EvalRegex(node.regex))
if node.tag == expr_e.ArrayLiteral: # obj.attr
items = [self.EvalExpr(item) for item in node.items]
if items:
# Determine type at runtime? If we have something like @[(i) (j)]
# then we don't know its type until runtime.
first = items[0]
if isinstance(first, bool):
return objects.BoolArray(bool(x) for x in items)
elif isinstance(first, int):
return objects.IntArray(int(x) for x in items)
elif isinstance(first, float):
return objects.FloatArray(float(x) for x in items)
elif isinstance(first, str):
return objects.StrArray(str(x) for x in items)
else:
raise AssertionError(first)
else:
# TODO: Should this have an unknown type?
# What happens when you mutate or extend it? You have to make sure
# that the type tags match?
return objects.BoolArray(items)
raise NotImplementedError(node.__class__.__name__)
def EvalExpr(self, node):
# type: (expr_t) -> Any
"""
This is a naive PyObject evaluator! It uses the type dispatch of the host
Python interpreter.
Returns:
A Python object of ANY type. Should be wrapped in value.Obj() for
storing in Mem.
"""
if 0:
print('EvalExpr()')
node.PrettyPrint()
print('')
if node.tag == expr_e.Const:
id_ = node.c.id
if id_ == Id.Expr_DecInt:
return int(node.c.val)
elif id_ == Id.Expr_BinInt:
return int(node.c.val, 2)
elif id_ == Id.Expr_OctInt:
return int(node.c.val, 8)
elif id_ == Id.Expr_HexInt:
return int(node.c.val, 16)
elif id_ == Id.Expr_Float:
return float(node.c.val)
elif id_ == Id.Expr_Null:
return None
elif id_ == Id.Expr_True:
return True
elif id_ == Id.Expr_False:
return False
elif id_ == Id.Expr_Name:
# for {name: 'bob'}
# Maybe also :Symbol?
return node.c.val
raise AssertionError(id_)
if node.tag == expr_e.Var:
return self.LookupVar(node.name.val)
if node.tag == expr_e.CommandSub:
return self.ex.RunCommandSub(node.command_list)
if node.tag == expr_e.ShArrayLiteral:
words = braces.BraceExpandWords(node.words)
strs = self.word_ev.EvalWordSequence(words)
#log('ARRAY LITERAL EVALUATED TO -> %s', strs)
return objects.StrArray(strs)
if node.tag == expr_e.DoubleQuoted:
# In an ideal world, I would *statically* disallow:
# - "$@" and "${array[@]}"
# - backticks like `echo hi`
# - $(( 1+2 )) and $[] -- although useful for refactoring
# - not sure: ${x%%} -- could disallow this
# - these enters the ArgDQ state: "${a:-foo bar}" ?
# But that would complicate the parser/evaluator. So just rely on
# strict_array to disallow the bad parts.
return self.word_ev.EvalDoubleQuotedToString(node)
if node.tag == expr_e.SingleQuoted:
return word_eval.EvalSingleQuoted(node)
if node.tag == expr_e.BracedVarSub:
return self.word_ev.EvalBracedVarSubToString(node)
if node.tag == expr_e.SimpleVarSub:
return self.word_ev.EvalSimpleVarSubToString(node.token)
if node.tag == expr_e.Unary:
child = self.EvalExpr(node.child)
if node.op.id == Id.Arith_Minus:
return -child
if node.op.id == Id.Arith_Tilde:
return ~child
if node.op.id == Id.Expr_Not:
return not child
raise NotImplementedError(node.op.id)
if node.tag == expr_e.Binary:
left = self.EvalExpr(node.left)
right = self.EvalExpr(node.right)
if node.op.id == Id.Arith_Plus:
return left + right
if node.op.id == Id.Arith_Minus:
return left - right
if node.op.id == Id.Arith_Star:
return left * right
if node.op.id == Id.Arith_Slash:
# NOTE: from __future__ import division changes 5/2!
# But just make it explicit.
return float(left) / right # floating point division
if node.op.id == Id.Expr_Div:
return left // right # integer divison
if node.op.id == Id.Arith_Percent:
return left % right
if node.op.id == Id.Arith_Caret: # Exponentiation
return left**right
# Bitwise
if node.op.id == Id.Arith_Amp:
return left & right
if node.op.id == Id.Arith_Pipe:
return left | right
if node.op.id == Id.Expr_Xor:
return left ^ right
if node.op.id == Id.Arith_DGreat:
return left >> right
if node.op.id == Id.Arith_DLess:
return left << right
# Logical
if node.op.id == Id.Expr_And:
return left and right
if node.op.id == Id.Expr_Or:
return left or right
raise NotImplementedError(node.op.id)
if node.tag == expr_e.Compare:
left = self.EvalExpr(node.left)
result = True # Implicit and
for op, right_expr in zip(node.ops, node.comparators):
right = self.EvalExpr(right_expr)
if op.id == Id.Arith_Less:
result = left < right
elif op.id == Id.Arith_Great:
result = left > right
elif op.id == Id.Arith_GreatEqual:
result = left >= right
elif op.id == Id.Arith_LessEqual:
result = left <= right
elif op.id == Id.Arith_DEqual:
result = left == right
elif op.id == Id.Expr_In:
result = left in right
elif op.id == Id.Node_NotIn:
result = left not in right
elif op.id == Id.Expr_Is:
result = left is right
elif op.id == Id.Node_IsNot:
result = left is not right
else:
try:
if op.id == Id.Arith_Tilde:
result = self._EvalMatch(left, right, True)
elif op.id == Id.Expr_NotTilde:
result = not self._EvalMatch(left, right, False)
else:
raise AssertionError(op.id)
except RuntimeError as e:
# Status 2 indicates a regex parse error. This is fatal in OSH but
# not in bash, which treats [[ like a command with an exit code.
e_die("Invalid regex %r",
right,
span_id=op.span_id,
status=2)
if not result:
return result
left = right
return result
if node.tag == expr_e.IfExp:
b = self.EvalExpr(node.test)
if b:
return self.EvalExpr(node.body)
else:
return self.EvalExpr(node.orelse)
if node.tag == expr_e.List:
return [self.EvalExpr(e) for e in node.elts]
if node.tag == expr_e.Tuple:
return tuple(self.EvalExpr(e) for e in node.elts)
if node.tag == expr_e.Dict:
# NOTE: some keys are expr.Const
keys = [self.EvalExpr(e) for e in node.keys]
values = []
for i, e in enumerate(node.values):
if e.tag == expr_e.Implicit:
v = self.LookupVar(keys[i]) # {name}
else:
v = self.EvalExpr(e)
values.append(v)
return dict(zip(keys, values))
if node.tag == expr_e.ListComp:
# TODO:
# - Consolidate with command_e.OilForIn in osh/cmd_exec.py?
# - Do I have to push a temp frame here?
# Hm... lexical or dynamic scope is an issue.
result = []
comp = node.generators[0]
obj = self.EvalExpr(comp.iter)
# TODO: Handle x,y etc.
iter_name = comp.target.name.val
if isinstance(obj, str):
e_die("Strings aren't iterable")
else:
it = iter(obj)
while True:
try:
loop_val = next(it) # e.g. x
except StopIteration:
break
self.mem.SetVar(lvalue.Named(iter_name), value.Obj(loop_val),
(), scope_e.LocalOnly)
if comp.ifs:
b = self.EvalExpr(comp.ifs[0])
else:
b = True
if b:
item = self.EvalExpr(node.elt) # e.g. x*2
result.append(item)
return result
if node.tag == expr_e.FuncCall:
# TODO:
#
# Let Python handle type errors for now?
# TODO: Lookup in equivalent of __builtins__
#
# shopt -s namespaces
#
# builtin log "hello"
# builtin log "hello"
#node.PrettyPrint()
# TODO: All functions called like f(x, y) must be in 'mem'.
# Only 'procs' are in self.funcs
# First look up the name in 'funcs'. And then look it up
# in 'mem' for first-class functions?
#if node.func.tag == expr_e.Var:
# func = self.funcs.get(node.func.name.val)
func = self.EvalExpr(node.func)
args = [self.EvalExpr(a) for a in node.args]
ret = func(*args)
return ret
if node.tag == expr_e.Subscript:
collection = self.EvalExpr(node.collection)
# TODO: handle multiple indices like a[i, j]
index = self.EvalExpr(node.indices[0])
return collection[index]
# TODO: obj.method() should be separate
if node.tag == expr_e.Attribute: # obj.attr
o = self.EvalExpr(node.value)
id_ = node.op.id
if id_ == Id.Expr_Dot:
name = node.attr.val
# TODO: Does this do the bound method thing we do NOT want?
return getattr(o, name)
if id_ == Id.Expr_RArrow: # d->key is like d['key']
name = node.attr.val
return o[name]
if id_ == Id.Expr_DColon: # StaticName::member
raise NotImplementedError(id_)
# TODO: We should prevent virtual lookup here? This is a pure static
# namespace lookup?
# But Python doesn't any hook for this.
# Maybe we can just check that it's a module? And modules don't lookup
# in a supertype or __class__, etc.
raise AssertionError(id_)
if node.tag == expr_e.RegexLiteral: # obj.attr
# TODO: Should this just be an object that ~ calls?
return objects.Regex(self.EvalRegex(node.regex))
raise NotImplementedError(node.__class__.__name__)