[jsinterp] Improve JS language support (#31175)
* operator ??
* operator ?.
* operator **
* accurate operator functions
* `undefined` handling
* object literals {a: 1, "b": expr}
* more tests for weird JS comparisons: see https://github.com/ytdl-org/youtube-dl/issues/31173#issuecomment-1217854397.
This commit is contained in:
dirkf
GitHub
parent
e52e8b8111
commit
b0a60ce203
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@ -8,7 +8,10 @@ import sys
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import unittest
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sys.path.insert(0, os.path.dirname(os.path.dirname(os.path.abspath(__file__))))
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import math
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from youtube_dl.jsinterp import JSInterpreter
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undefined = JSInterpreter.undefined
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class TestJSInterpreter(unittest.TestCase):
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@ -48,6 +51,9 @@ class TestJSInterpreter(unittest.TestCase):
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jsi = JSInterpreter('function f(){return 1 << 5;}')
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self.assertEqual(jsi.call_function('f'), 32)
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jsi = JSInterpreter('function f(){return 2 ** 5}')
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self.assertEqual(jsi.call_function('f'), 32)
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jsi = JSInterpreter('function f(){return 19 & 21;}')
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self.assertEqual(jsi.call_function('f'), 17)
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@ -57,6 +63,15 @@ class TestJSInterpreter(unittest.TestCase):
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jsi = JSInterpreter('function f(){return []? 2+3: 4;}')
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self.assertEqual(jsi.call_function('f'), 5)
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jsi = JSInterpreter('function f(){return 1 == 2}')
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self.assertEqual(jsi.call_function('f'), False)
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jsi = JSInterpreter('function f(){return 0 && 1 || 2;}')
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self.assertEqual(jsi.call_function('f'), 2)
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jsi = JSInterpreter('function f(){return 0 ?? 42;}')
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self.assertEqual(jsi.call_function('f'), 0)
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def test_array_access(self):
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jsi = JSInterpreter('function f(){var x = [1,2,3]; x[0] = 4; x[0] = 5; x[2.0] = 7; return x;}')
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self.assertEqual(jsi.call_function('f'), [5, 2, 7])
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@ -203,6 +218,11 @@ class TestJSInterpreter(unittest.TestCase):
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''')
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self.assertEqual(jsi.call_function('x'), 7)
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jsi = JSInterpreter('''
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function x() { return (l=[0,1,2,3], function(a, b){return a+b})((l[1], l[2]), l[3]) }
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''')
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self.assertEqual(jsi.call_function('x'), 5)
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def test_void(self):
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jsi = JSInterpreter('''
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function x() { return void 42; }
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@ -215,6 +235,100 @@ class TestJSInterpreter(unittest.TestCase):
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''')
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self.assertEqual(jsi.call_function('x')([]), 1)
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def test_null(self):
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jsi = JSInterpreter('''
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function x() { return null; }
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''')
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self.assertIs(jsi.call_function('x'), None)
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jsi = JSInterpreter('''
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function x() { return [null > 0, null < 0, null == 0, null === 0]; }
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''')
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self.assertEqual(jsi.call_function('x'), [False, False, False, False])
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jsi = JSInterpreter('''
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function x() { return [null >= 0, null <= 0]; }
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''')
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self.assertEqual(jsi.call_function('x'), [True, True])
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def test_undefined(self):
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jsi = JSInterpreter('''
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function x() { return undefined === undefined; }
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''')
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self.assertTrue(jsi.call_function('x'))
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jsi = JSInterpreter('''
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function x() { return undefined; }
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''')
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self.assertIs(jsi.call_function('x'), undefined)
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jsi = JSInterpreter('''
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function x() { let v; return v; }
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''')
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self.assertIs(jsi.call_function('x'), undefined)
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jsi = JSInterpreter('''
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function x() { return [undefined === undefined, undefined == undefined, undefined < undefined, undefined > undefined]; }
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''')
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self.assertEqual(jsi.call_function('x'), [True, True, False, False])
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jsi = JSInterpreter('''
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function x() { return [undefined === 0, undefined == 0, undefined < 0, undefined > 0]; }
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''')
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self.assertEqual(jsi.call_function('x'), [False, False, False, False])
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jsi = JSInterpreter('''
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function x() { return [undefined >= 0, undefined <= 0]; }
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''')
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self.assertEqual(jsi.call_function('x'), [False, False])
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jsi = JSInterpreter('''
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function x() { return [undefined > null, undefined < null, undefined == null, undefined === null]; }
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''')
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self.assertEqual(jsi.call_function('x'), [False, False, True, False])
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jsi = JSInterpreter('''
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function x() { return [undefined === null, undefined == null, undefined < null, undefined > null]; }
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''')
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self.assertEqual(jsi.call_function('x'), [False, True, False, False])
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jsi = JSInterpreter('''
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function x() { let v; return [42+v, v+42, v**42, 42**v, 0**v]; }
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''')
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for y in jsi.call_function('x'):
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self.assertTrue(math.isnan(y))
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jsi = JSInterpreter('''
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function x() { let v; return v**0; }
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''')
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self.assertEqual(jsi.call_function('x'), 1)
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jsi = JSInterpreter('''
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function x() { let v; return [v>42, v<=42, v&&42, 42&&v]; }
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''')
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self.assertEqual(jsi.call_function('x'), [False, False, undefined, undefined])
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jsi = JSInterpreter('function x(){return undefined ?? 42; }')
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self.assertEqual(jsi.call_function('x'), 42)
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def test_object(self):
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jsi = JSInterpreter('''
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function x() { return {}; }
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''')
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self.assertEqual(jsi.call_function('x'), {})
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jsi = JSInterpreter('''
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function x() { let a = {m1: 42, m2: 0 }; return [a["m1"], a.m2]; }
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''')
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self.assertEqual(jsi.call_function('x'), [42, 0])
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jsi = JSInterpreter('''
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function x() { let a; return a?.qq; }
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''')
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self.assertIs(jsi.call_function('x'), undefined)
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jsi = JSInterpreter('''
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function x() { let a = {m1: 42, m2: 0 }; return a?.qq; }
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''')
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self.assertIs(jsi.call_function('x'), undefined)
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if __name__ == '__main__':
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unittest.main()
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@ -102,6 +102,10 @@ _NSIG_TESTS = [
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'https://www.youtube.com/s/player/4c3f79c5/player_ias.vflset/en_US/base.js',
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'TDCstCG66tEAO5pR9o', 'dbxNtZ14c-yWyw',
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),
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(
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'https://www.youtube.com/s/player/c81bbb4a/player_ias.vflset/en_US/base.js',
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'gre3EcLurNY2vqp94', 'Z9DfGxWP115WTg',
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),
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]
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@ -7,7 +7,6 @@ import operator
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import re
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from .utils import (
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NO_DEFAULT,
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ExtractorError,
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js_to_json,
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remove_quotes,
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@ -21,6 +20,70 @@ from .compat import (
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_NAME_RE = r'[a-zA-Z_$][\w$]*'
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_UNDEFINED = object()
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def _js_bit_op(op):
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def wrapped(a, b):
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def zeroise(x):
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return 0 if x in (None, _UNDEFINED) else x
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return op(zeroise(a), zeroise(b))
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return wrapped
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def _js_arith_op(op):
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def wrapped(a, b):
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if _UNDEFINED in (a, b):
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return float('nan')
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return op(a or 0, b or 0)
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return wrapped
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def _js_div(a, b):
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if _UNDEFINED in (a, b) or not (a and b):
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return float('nan')
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return float('inf') if not b else operator.truediv(a or 0, b)
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def _js_mod(a, b):
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if _UNDEFINED in (a, b) or not b:
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return float('nan')
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return (a or 0) % b
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def _js_exp(a, b):
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if not b:
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# even 0 ** 0 !!
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return 1
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if _UNDEFINED in (a, b):
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return float('nan')
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return (a or 0) ** b
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def _js_eq_op(op):
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def wrapped(a, b):
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if set((a, b)) <= set((None, _UNDEFINED)):
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return op(a, a)
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return op(a, b)
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return wrapped
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def _js_comp_op(op):
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def wrapped(a, b):
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if _UNDEFINED in (a, b):
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return False
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return op(a or 0, b or 0)
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return wrapped
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# (op, definition) in order of binding priority, tightest first
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# avoid dict to maintain order
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# definition None => Defined in JSInterpreter._operator
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@ -30,40 +93,38 @@ _DOT_OPERATORS = (
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)
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_OPERATORS = (
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('|', operator.or_),
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('^', operator.xor),
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('&', operator.and_),
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('>>', operator.rshift),
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('<<', operator.lshift),
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('+', operator.add),
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('-', operator.sub),
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('*', operator.mul),
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('/', operator.truediv),
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('%', operator.mod),
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('>>', _js_bit_op(operator.rshift)),
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('<<', _js_bit_op(operator.lshift)),
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('+', _js_arith_op(operator.add)),
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('-', _js_arith_op(operator.sub)),
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('*', _js_arith_op(operator.mul)),
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('/', _js_div),
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('%', _js_mod),
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('**', _js_exp),
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)
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_COMP_OPERATORS = (
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('===', operator.is_),
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('==', operator.eq),
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('==', _js_eq_op(operator.eq)),
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('!==', operator.is_not),
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('!=', operator.ne),
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('<=', operator.le),
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('>=', operator.ge),
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('<', operator.lt),
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('>', operator.gt),
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('!=', _js_eq_op(operator.ne)),
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('<=', _js_comp_op(operator.le)),
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('>=', _js_comp_op(operator.ge)),
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('<', _js_comp_op(operator.lt)),
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('>', _js_comp_op(operator.gt)),
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)
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_LOG_OPERATORS = (
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('&', operator.and_),
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('|', operator.or_),
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('^', operator.xor),
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('|', _js_bit_op(operator.or_)),
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('^', _js_bit_op(operator.xor)),
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('&', _js_bit_op(operator.and_)),
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)
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_SC_OPERATORS = (
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('?', None),
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('??', None),
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('||', None),
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('&&', None),
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# TODO: ('??', None),
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)
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_OPERATOR_RE = '|'.join(map(lambda x: re.escape(x[0]), _OPERATORS + _LOG_OPERATORS))
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@ -74,7 +135,7 @@ _QUOTES = '\'"'
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def _ternary(cndn, if_true=True, if_false=False):
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"""Simulate JS's ternary operator (cndn?if_true:if_false)"""
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if cndn in (False, None, 0, ''):
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if cndn in (False, None, 0, '', _UNDEFINED):
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return if_false
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try:
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if math.isnan(cndn): # NB: NaN cannot be checked by membership
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@ -95,6 +156,12 @@ class JS_Continue(ExtractorError):
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class LocalNameSpace(ChainMap):
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def __getitem__(self, key):
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try:
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return super(LocalNameSpace, self).__getitem__(key)
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except KeyError:
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return _UNDEFINED
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def __setitem__(self, key, value):
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for scope in self.maps:
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if key in scope:
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@ -105,6 +172,13 @@ class LocalNameSpace(ChainMap):
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def __delitem__(self, key):
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raise NotImplementedError('Deleting is not supported')
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def __contains__(self, key):
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try:
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super(LocalNameSpace, self).__getitem__(key)
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return True
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except KeyError:
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return False
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def __repr__(self):
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return 'LocalNameSpace%s' % (self.maps, )
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@ -112,6 +186,8 @@ class LocalNameSpace(ChainMap):
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class JSInterpreter(object):
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__named_object_counter = 0
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undefined = _UNDEFINED
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def __init__(self, code, objects=None):
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self.code, self._functions = code, {}
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self._objects = {} if objects is None else objects
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@ -185,12 +261,16 @@ class JSInterpreter(object):
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@staticmethod
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def _all_operators():
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return itertools.chain(
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# Ref: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Operator_Precedence
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_SC_OPERATORS, _LOG_OPERATORS, _COMP_OPERATORS, _OPERATORS)
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def _operator(self, op, left_val, right_expr, expr, local_vars, allow_recursion):
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if op in ('||', '&&'):
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if (op == '&&') ^ _ternary(left_val):
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return left_val # short circuiting
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elif op == '??':
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if left_val not in (None, self.undefined):
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return left_val
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elif op == '?':
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right_expr = _ternary(left_val, *self._separate(right_expr, ':', 1))
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@ -204,12 +284,14 @@ class JSInterpreter(object):
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except Exception as e:
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raise self.Exception('Failed to evaluate {left_val!r} {op} {right_val!r}'.format(**locals()), expr, cause=e)
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def _index(self, obj, idx):
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def _index(self, obj, idx, allow_undefined=False):
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if idx == 'length':
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return len(obj)
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try:
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return obj[int(idx)] if isinstance(obj, list) else obj[idx]
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except Exception as e:
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if allow_undefined:
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return self.undefined
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raise self.Exception('Cannot get index {idx}'.format(**locals()), expr=repr(obj), cause=e)
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def _dump(self, obj, namespace):
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@ -249,8 +331,8 @@ class JSInterpreter(object):
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obj = expr[4:]
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if obj.startswith('Date('):
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left, right = self._separate_at_paren(obj[4:], ')')
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left = self.interpret_expression(left, local_vars, allow_recursion)
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expr = unified_timestamp(left, False)
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expr = unified_timestamp(
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self.interpret_expression(left, local_vars, allow_recursion), False)
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if not expr:
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raise self.Exception('Failed to parse date {left!r}'.format(**locals()), expr=expr)
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expr = self._dump(int(expr * 1000), local_vars) + right
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@ -263,6 +345,14 @@ class JSInterpreter(object):
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if expr.startswith('{'):
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inner, outer = self._separate_at_paren(expr, '}')
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# try for object expression
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sub_expressions = [list(self._separate(sub_expr.strip(), ':', 1)) for sub_expr in self._separate(inner)]
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if all(len(sub_expr) == 2 for sub_expr in sub_expressions):
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return dict(
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(key_expr if re.match(_NAME_RE, key_expr) else key_expr,
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self.interpret_expression(val_expr, local_vars, allow_recursion))
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for key_expr, val_expr in sub_expressions), should_return
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# or statement list
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inner, should_abort = self.interpret_statement(inner, local_vars, allow_recursion)
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if not outer or should_abort:
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return inner, should_abort or should_return
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@ -387,13 +477,13 @@ class JSInterpreter(object):
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(?P<assign>
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(?P<out>{_NAME_RE})(?:\[(?P<index>[^\]]+?)\])?\s*
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(?P<op>{_OPERATOR_RE})?
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=(?P<expr>.*)$
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=(?!=)(?P<expr>.*)$
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)|(?P<return>
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(?!if|return|true|false|null|undefined)(?P<name>{_NAME_RE})$
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)|(?P<indexing>
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(?P<in>{_NAME_RE})\[(?P<idx>.+)\]$
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)|(?P<attribute>
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(?P<var>{_NAME_RE})(?:\.(?P<member>[^(]+)|\[(?P<member2>[^\]]+)\])\s*
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(?P<var>{_NAME_RE})(?:(?P<nullish>\?)?\.(?P<member>[^(]+)|\[(?P<member2>[^\]]+)\])\s*
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)|(?P<function>
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(?P<fname>{_NAME_RE})\((?P<args>.*)\)$
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)'''.format(**globals()), expr)
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@ -405,7 +495,7 @@ class JSInterpreter(object):
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local_vars[m.group('out')] = self._operator(
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m.group('op'), left_val, m.group('expr'), expr, local_vars, allow_recursion)
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return local_vars[m.group('out')], should_return
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elif left_val is None:
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elif left_val in (None, self.undefined):
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raise self.Exception('Cannot index undefined variable ' + m.group('out'), expr=expr)
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idx = self.interpret_expression(m.group('index'), local_vars, allow_recursion)
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@ -424,6 +514,9 @@ class JSInterpreter(object):
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elif expr == 'continue':
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raise JS_Continue()
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|
||||
elif expr == 'undefined':
|
||||
return self.undefined, should_return
|
||||
|
||||
elif md.get('return'):
|
||||
return local_vars[m.group('name')], should_return
|
||||
|
||||
|
|
@ -441,7 +534,9 @@ class JSInterpreter(object):
|
|||
|
||||
for op, _ in self._all_operators():
|
||||
# hackety: </> have higher priority than <</>>, but don't confuse them
|
||||
skip_delim = (op + op) if op in ('<', '>') else None
|
||||
skip_delim = (op + op) if op in '<>*?' else None
|
||||
if op == '?':
|
||||
skip_delim = (skip_delim, '?.')
|
||||
separated = list(self._separate(expr, op, skip_delims=skip_delim))
|
||||
if len(separated) < 2:
|
||||
continue
|
||||
|
|
@ -451,12 +546,10 @@ class JSInterpreter(object):
|
|||
right_expr = '-' + right_expr
|
||||
separated.pop()
|
||||
left_val = self.interpret_expression(op.join(separated), local_vars, allow_recursion)
|
||||
return self._operator(op, 0 if left_val is None else left_val,
|
||||
right_expr, expr, local_vars, allow_recursion), should_return
|
||||
return self._operator(op, left_val, right_expr, expr, local_vars, allow_recursion), should_return
|
||||
|
||||
if md.get('attribute'):
|
||||
variable = m.group('var')
|
||||
member = m.group('member')
|
||||
variable, member, nullish = m.group('var', 'member', 'nullish')
|
||||
if not member:
|
||||
member = self.interpret_expression(m.group('member2'), local_vars, allow_recursion)
|
||||
arg_str = expr[m.end():]
|
||||
|
|
@ -477,15 +570,24 @@ class JSInterpreter(object):
|
|||
'String': compat_str,
|
||||
'Math': float,
|
||||
}
|
||||
obj = local_vars.get(variable, types.get(variable, NO_DEFAULT))
|
||||
if obj is NO_DEFAULT:
|
||||
obj = local_vars.get(variable)
|
||||
if obj in (self.undefined, None):
|
||||
obj = types.get(variable, self.undefined)
|
||||
if obj is self.undefined:
|
||||
try:
|
||||
if variable not in self._objects:
|
||||
self._objects[variable] = self.extract_object(variable)
|
||||
obj = self._objects[variable]
|
||||
except self.Exception:
|
||||
if not nullish:
|
||||
raise
|
||||
|
||||
if nullish and obj is self.undefined:
|
||||
return self.undefined
|
||||
|
||||
# Member access
|
||||
if arg_str is None:
|
||||
return self._index(obj, member)
|
||||
return self._index(obj, member, nullish)
|
||||
|
||||
# Function call
|
||||
argvals = [
|
||||
|
|
@ -660,7 +762,14 @@ class JSInterpreter(object):
|
|||
def build_arglist(cls, arg_text):
|
||||
if not arg_text:
|
||||
return []
|
||||
return list(filter(None, (x.strip() or None for x in cls._separate(arg_text))))
|
||||
|
||||
def valid_arg(y):
|
||||
y = y.strip()
|
||||
if not y:
|
||||
raise cls.Exception('Missing arg in "%s"' % (arg_text, ))
|
||||
return y
|
||||
|
||||
return [valid_arg(x) for x in cls._separate(arg_text)]
|
||||
|
||||
def build_function(self, argnames, code, *global_stack):
|
||||
global_stack = list(global_stack) or [{}]
|
||||
|
|
|
|||
Loading…
Reference in New Issue