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mylar/lib/js2py/translators/translator.py

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Python

from . import pyjsparser
#from pyesprima import esprima
from . import translating_nodes
import hashlib
import re
# the re below is how we'll recognise numeric constants.
# it finds any 'simple numeric that is not preceded with an alphanumeric character
# the numeric can be a float (so a dot is found) but
# it does not recognise notation such as 123e5, 0xFF, infinity or NaN
CP_NUMERIC_RE = re.compile(r'(?<![a-zA-Z0-9_"\'])([0-9\.]+)')
CP_NUMERIC_PLACEHOLDER = '__PyJsNUM_%i_PyJsNUM__'
CP_NUMERIC_PLACEHOLDER_REVERSE_RE = re.compile(
CP_NUMERIC_PLACEHOLDER.replace('%i', '([0-9\.]+)')
)
# the re below is how we'll recognise string constants
# it finds a ' or ", then reads until the next matching ' or "
# this re only services simple cases, it can not be used when
# there are escaped quotes in the expression
#CP_STRING_1 = re.compile(r'(["\'])(.*?)\1') # this is how we'll recognise string constants
CP_STRING = '"([^\\\\"]+|\\\\([bfnrtv\'"\\\\]|[0-3]?[0-7]{1,2}|x[0-9a-fA-F]{2}|u[0-9a-fA-F]{4}))*"|\'([^\\\\\']+|\\\\([bfnrtv\'"\\\\]|[0-3]?[0-7]{1,2}|x[0-9a-fA-F]{2}|u[0-9a-fA-F]{4}))*\''
CP_STRING_RE = re.compile(CP_STRING) # this is how we'll recognise string constants
CP_STRING_PLACEHOLDER = '__PyJsSTR_%i_PyJsSTR__'
CP_STRING_PLACEHOLDER_REVERSE_RE = re.compile(
CP_STRING_PLACEHOLDER.replace('%i', '([0-9\.]+)')
)
cache = {}
# This crap is still needed but I removed it for speed reasons. Have to think of better idea
# import js2py.pyjs, sys
# # Redefine builtin objects... Do you have a better idea?
# for m in list(sys.modules):
# if m.startswith('js2py'):
# del sys.modules[m]
# del js2py.pyjs
# del js2py
DEFAULT_HEADER = u'''from js2py.pyjs import *
# setting scope
var = Scope( JS_BUILTINS )
set_global_object(var)
# Code follows:
'''
def dbg(x):
"""does nothing, legacy dummy function"""
return ''
def translate_js(js, HEADER=DEFAULT_HEADER, use_compilation_plan=False):
"""js has to be a javascript source code.
returns equivalent python code."""
if use_compilation_plan and not '//' in js and not '/*' in js:
return translate_js_with_compilation_plan(js, HEADER=HEADER)
parser = pyjsparser.PyJsParser()
parsed = parser.parse(js) # js to esprima syntax tree
# Another way of doing that would be with my auto esprima translation but its much slower and causes import problems:
# parsed = esprima.parse(js).to_dict()
translating_nodes.clean_stacks()
return HEADER + translating_nodes.trans(parsed) # syntax tree to python code
class match_unumerator(object):
"""This class ise used """
matchcount = -1
def __init__(self, placeholder_mask):
self.placeholder_mask = placeholder_mask
self.matches = []
def __call__(self, match):
self.matchcount += 1
self.matches.append(match.group(0))
return self.placeholder_mask%self.matchcount
def __repr__(self):
return '\n'.join(self.placeholder_mask%counter + '=' + match for counter, match in enumerate(self.matches))
def wrap_up(self, output):
for counter, value in enumerate(self.matches):
output = output.replace("u'" + self.placeholder_mask%(counter) + "'", value, 1)
return output
def get_compilation_plan(js):
match_increaser_str = match_unumerator(CP_STRING_PLACEHOLDER)
compilation_plan = re.sub(
CP_STRING, match_increaser_str, js
)
match_increaser_num = match_unumerator(CP_NUMERIC_PLACEHOLDER)
compilation_plan = re.sub(CP_NUMERIC_RE, match_increaser_num, compilation_plan)
# now put quotes, note that just patching string replaces is somewhat faster than
# using another re:
compilation_plan = compilation_plan.replace('__PyJsNUM_', '"__PyJsNUM_').replace('_PyJsNUM__', '_PyJsNUM__"')
compilation_plan = compilation_plan.replace('__PyJsSTR_', '"__PyJsSTR_').replace('_PyJsSTR__', '_PyJsSTR__"')
return match_increaser_str, match_increaser_num, compilation_plan
def translate_js_with_compilation_plan(js, HEADER=DEFAULT_HEADER):
"""js has to be a javascript source code.
returns equivalent python code.
compile plans only work with the following restrictions:
- only enabled for oneliner expressions
- when there are comments in the js code string substitution is disabled
- when there nested escaped quotes string substitution is disabled, so
cacheable:
Q1 == 1 && name == 'harry'
not cacheable:
Q1 == 1 && name == 'harry' // some comment
not cacheable:
Q1 == 1 && name == 'o\'Reilly'
not cacheable:
Q1 == 1 && name /* some comment */ == 'o\'Reilly'
"""
match_increaser_str, match_increaser_num, compilation_plan = get_compilation_plan(js)
cp_hash = hashlib.md5(compilation_plan.encode('utf-8')).digest()
try:
python_code = cache[cp_hash]['proto_python_code']
except:
parser = pyjsparser.PyJsParser()
parsed = parser.parse(compilation_plan) # js to esprima syntax tree
# Another way of doing that would be with my auto esprima translation but its much slower and causes import problems:
# parsed = esprima.parse(js).to_dict()
translating_nodes.clean_stacks()
python_code = translating_nodes.trans(parsed) # syntax tree to python code
cache[cp_hash] = {
'compilation_plan': compilation_plan,
'proto_python_code': python_code,
}
python_code = match_increaser_str.wrap_up(python_code)
python_code = match_increaser_num.wrap_up(python_code)
return HEADER + python_code
def trasnlate(js, HEADER=DEFAULT_HEADER):
"""js has to be a javascript source code.
returns equivalent python code.
Equivalent to translate_js"""
return translate_js(js, HEADER)
syntax_tree_translate = translating_nodes.trans
if __name__=='__main__':
PROFILE = False
import js2py
import codecs
def main():
with codecs.open("esprima.js", "r", "utf-8") as f:
d = f.read()
r = js2py.translate_js(d)
with open('res.py','wb') as f2:
f2.write(r)
exec(r, {})
if PROFILE:
import cProfile
cProfile.run('main()', sort='tottime')
else:
main()