mirror of
https://github.com/evilhero/mylar
synced 2024-12-23 08:12:41 +00:00
456 lines
16 KiB
Python
456 lines
16 KiB
Python
"""This module translates JS flow into PY flow.
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Translates:
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IF ELSE
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DO WHILE
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WHILE
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FOR 123
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FOR iter
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CONTINUE, BREAK, RETURN, LABEL, THROW, TRY, SWITCH
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"""
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from utils import *
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from jsparser import *
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from nodevisitor import exp_translator
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import random
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TO_REGISTER = []
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CONTINUE_LABEL = 'JS_CONTINUE_LABEL_%s'
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BREAK_LABEL = 'JS_BREAK_LABEL_%s'
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PREPARE = '''HOLDER = var.own.get(NAME)\nvar.force_own_put(NAME, PyExceptionToJs(PyJsTempException))\n'''
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RESTORE = '''if HOLDER is not None:\n var.own[NAME] = HOLDER\nelse:\n del var.own[NAME]\ndel HOLDER\n'''
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TRY_CATCH = '''%stry:\nBLOCKfinally:\n%s''' % (PREPARE, indent(RESTORE))
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def get_continue_label(label):
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return CONTINUE_LABEL%label.encode('hex')
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def get_break_label(label):
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return BREAK_LABEL%label.encode('hex')
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def pass_until(source, start, tokens=(';',)):
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while start < len(source) and source[start] not in tokens:
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start+=1
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return start+1
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def do_bracket_exp(source, start, throw=True):
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bra, cand = pass_bracket(source, start, '()')
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if throw and not bra:
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raise SyntaxError('Missing bracket expression')
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bra = exp_translator(bra[1:-1])
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if throw and not bra:
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raise SyntaxError('Empty bracket condition')
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return bra, cand if bra else start
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def do_if(source, start):
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start += 2 # pass this if
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bra, start = do_bracket_exp(source, start, throw=True)
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statement, start = do_statement(source, start)
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if statement is None:
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raise SyntaxError('Invalid if statement')
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translated = 'if %s:\n'%bra+indent(statement)
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elseif = except_keyword(source, start, 'else')
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is_elseif = False
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if elseif:
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start = elseif
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if except_keyword(source, start, 'if'):
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is_elseif = True
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elseif, start = do_statement(source, start)
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if elseif is None:
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raise SyntaxError('Invalid if statement)')
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if is_elseif:
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translated += 'el' + elseif
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else:
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translated += 'else:\n'+ indent(elseif)
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return translated, start
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def do_statement(source, start):
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"""returns none if not found other functions that begin with 'do_' raise
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also this do_ type function passes white space"""
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start = pass_white(source, start)
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# start is the fist position after initial start that is not a white space or \n
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if not start < len(source): #if finished parsing return None
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return None, start
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if any(startswith_keyword(source[start:], e) for e in {'case', 'default'}):
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return None, start
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rest = source[start:]
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for key, meth in KEYWORD_METHODS.iteritems(): # check for statements that are uniquely defined by their keywords
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if rest.startswith(key):
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# has to startwith this keyword and the next letter after keyword must be either EOF or not in IDENTIFIER_PART
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if len(key)==len(rest) or rest[len(key)] not in IDENTIFIER_PART:
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return meth(source, start)
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if rest[0] == '{': #Block
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return do_block(source, start)
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# Now only label and expression left
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cand = parse_identifier(source, start, False)
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if cand is not None: # it can mean that its a label
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label, cand_start = cand
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cand_start = pass_white(source, cand_start)
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if source[cand_start]==':':
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return do_label(source, start)
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return do_expression(source, start)
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def do_while(source, start):
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start += 5 # pass while
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bra, start = do_bracket_exp(source, start, throw=True)
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statement, start = do_statement(source, start)
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if statement is None:
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raise SyntaxError('Missing statement to execute in while loop!')
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return 'while %s:\n'%bra + indent(statement), start
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def do_dowhile(source, start):
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start += 2 # pass do
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statement, start = do_statement(source, start)
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if statement is None:
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raise SyntaxError('Missing statement to execute in do while loop!')
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start = except_keyword(source, start, 'while')
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if not start:
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raise SyntaxError('Missing while keyword in do-while loop')
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bra, start = do_bracket_exp(source, start, throw=True)
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statement += 'if not %s:\n' % bra + indent('break\n')
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return 'while 1:\n' + indent(statement), start
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def do_block(source, start):
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bra, start = pass_bracket(source, start, '{}')
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#print source[start:], bra
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#return bra +'\n', start
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if bra is None:
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raise SyntaxError('Missing block ( {code} )')
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code = ''
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bra = bra[1:-1]+';'
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bra_pos = 0
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while bra_pos<len(bra):
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st, bra_pos = do_statement(bra, bra_pos)
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if st is None:
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break
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code += st
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bra_pos = pass_white(bra, bra_pos)
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if bra_pos<len(bra):
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raise SyntaxError('Block has more code that could not be parsed:\n'+bra[bra_pos:])
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return code, start
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def do_empty(source, start):
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return 'pass\n', start + 1
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def do_expression(source, start):
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start = pass_white(source, start)
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end = pass_until(source, start, tokens=(';',))
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if end==start+1: #empty statement
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return 'pass\n', end
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# AUTOMATIC SEMICOLON INSERTION FOLLOWS
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# Without ASI this function would end with: return exp_translator(source[start:end].rstrip(';'))+'\n', end
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# ASI makes things a bit more complicated:
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# we will try to parse as much as possible, inserting ; in place of last new line in case of error
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rev = False
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rpos = 0
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while True:
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try:
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code = source[start:end].rstrip(';')
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cand = exp_translator(code)+'\n', end
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just_to_test = compile(cand[0], '', 'exec')
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return cand
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except Exception as e:
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if not rev:
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rev = source[start:end][::-1]
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lpos = rpos
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while True:
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rpos = pass_until(rev, rpos, LINE_TERMINATOR)
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if rpos>=len(rev):
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raise
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if filter(lambda x: x not in SPACE, rev[lpos:rpos]):
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break
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end = start + len(rev) - rpos + 1
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def do_var(source, start):
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#todo auto ; insertion
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start += 3 #pass var
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end = pass_until(source, start, tokens=(';',))
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defs = argsplit(source[start:end-1]) # defs is the list of defined vars with optional initializer
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code = ''
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for de in defs:
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var, var_end = parse_identifier(de, 0, True)
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TO_REGISTER.append(var)
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var_end = pass_white(de, var_end)
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if var_end<len(de): # we have something more to parse... It has to start with =
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if de[var_end] != '=':
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raise SyntaxError('Unexpected initializer in var statement. Expected "=", got "%s"'%de[var_end])
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code += exp_translator(de) + '\n'
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if not code.strip():
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code = 'pass\n'
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return code, end
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def do_label(source, start):
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label, end = parse_identifier(source, start)
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end = pass_white(source, end)
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#now source[end] must be :
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assert source[end]==':'
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end += 1
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inside, end = do_statement(source, end)
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if inside is None:
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raise SyntaxError('Missing statement after label')
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defs = ''
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if inside.startswith('while ') or inside.startswith('for ') or inside.startswith('#for'):
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# we have to add contine label as well...
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# 3 or 1 since #for loop type has more lines before real for.
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sep = 1 if not inside.startswith('#for') else 3
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cont_label = get_continue_label(label)
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temp = inside.split('\n')
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injected = 'try:\n'+'\n'.join(temp[sep:])
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injected += 'except %s:\n pass\n'%cont_label
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inside = '\n'.join(temp[:sep])+'\n'+indent(injected)
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defs += 'class %s(Exception): pass\n'%cont_label
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break_label = get_break_label(label)
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inside = 'try:\n%sexcept %s:\n pass\n'% (indent(inside), break_label)
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defs += 'class %s(Exception): pass\n'%break_label
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return defs + inside, end
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def do_for(source, start):
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start += 3 # pass for
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entered = start
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bra, start = pass_bracket(source, start , '()')
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inside, start = do_statement(source, start)
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if inside is None:
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raise SyntaxError('Missing statement after for')
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bra = bra[1:-1]
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if ';' in bra:
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init = argsplit(bra, ';')
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if len(init)!=3:
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raise SyntaxError('Invalid for statement')
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args = []
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for i, item in enumerate(init):
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end = pass_white(item, 0)
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if end==len(item):
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args.append('' if i!=1 else '1')
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continue
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if not i and except_keyword(item, end, 'var') is not None:
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# var statement
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args.append(do_var(item, end)[0])
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continue
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args.append(do_expression(item, end)[0])
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return '#for JS loop\n%swhile %s:\n%s%s\n' %(args[0], args[1].strip(), indent(inside), indent(args[2])), start
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# iteration
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end = pass_white(bra, 0)
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register = False
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if bra[end:].startswith('var '):
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end+=3
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end = pass_white(bra, end)
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register = True
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name, end = parse_identifier(bra, end)
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if register:
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TO_REGISTER.append(name)
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end = pass_white(bra, end)
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if bra[end:end+2]!='in' or bra[end+2] in IDENTIFIER_PART:
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#print source[entered-10:entered+50]
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raise SyntaxError('Invalid "for x in y" statement')
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end+=2 # pass in
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exp = exp_translator(bra[end:])
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res = 'for temp in %s:\n' % exp
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res += indent('var.put(%s, temp)\n' % name.__repr__()) + indent(inside)
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return res, start
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# todo - IMPORTANT
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def do_continue(source, start, name='continue'):
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start += len(name) #pass continue
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start = pass_white(source, start)
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if start<len(source) and source[start] == ';':
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return '%s\n'%name, start+1
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# labeled statement or error
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label, start = parse_identifier(source, start)
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start = pass_white(source, start)
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if start<len(source) and source[start] != ';':
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raise SyntaxError('Missing ; after label name in %s statement'%name)
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return 'raise %s("%s")\n' % (get_continue_label(label) if name=='continue' else get_break_label(label), name), start+1
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def do_break(source, start):
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return do_continue(source, start, 'break')
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def do_return(source, start):
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start += 6 # pass return
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end = source.find(';', start)+1
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if end==-1:
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end = len(source)
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trans = exp_translator(source[start:end].rstrip(';'))
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return 'return %s\n' % (trans if trans else "var.get('undefined')"), end
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# todo later?- Also important
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def do_throw(source, start):
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start += 5 # pass throw
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end = source.find(';', start)+1
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if not end:
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end = len(source)
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trans = exp_translator(source[start:end].rstrip(';'))
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if not trans:
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raise SyntaxError('Invalid throw statement: nothing to throw')
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res = 'PyJsTempException = JsToPyException(%s)\nraise PyJsTempException\n' % trans
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return res, end
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def do_try(source, start):
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start += 3 # pass try
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block, start = do_block(source, start)
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result = 'try:\n%s' %indent(block)
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catch = except_keyword(source, start, 'catch')
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if catch:
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bra, catch = pass_bracket(source, catch, '()')
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bra = bra[1:-1]
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identifier, bra_end = parse_identifier(bra, 0)
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holder = 'PyJsHolder_%s_%d'%(identifier.encode('hex'), random.randrange(1e8))
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identifier = identifier.__repr__()
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bra_end = pass_white(bra, bra_end)
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if bra_end<len(bra):
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raise SyntaxError('Invalid content of catch statement')
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result += 'except PyJsException as PyJsTempException:\n'
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block, catch = do_block(source, catch)
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# fill in except ( catch ) block and remember to recover holder variable to its previous state
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result += indent(TRY_CATCH.replace('HOLDER', holder).replace('NAME', identifier).replace('BLOCK', indent(block)))
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start = max(catch, start)
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final = except_keyword(source, start, 'finally')
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if not (final or catch):
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raise SyntaxError('Try statement has to be followed by catch or finally')
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if not final:
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return result, start
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# translate finally statement
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block, start = do_block(source, final)
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return result + 'finally:\n%s' % indent(block), start
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def do_debugger(source, start):
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start += 8 # pass debugger
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end = pass_white(source, start)
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if end<len(source) and source[end]==';':
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end += 1
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return 'pass\n', end #ignore errors...
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# todo automatic ; insertion. fuck this crappy feature
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# Least important
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def do_switch(source, start):
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start += 6 # pass switch
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code = 'while 1:\n' + indent('SWITCHED = False\nCONDITION = (%s)\n')
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# parse value of check
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val, start = pass_bracket(source, start, '()')
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if val is None:
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raise SyntaxError('Missing () after switch statement')
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if not val.strip():
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raise SyntaxError('Missing content inside () after switch statement')
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code = code % exp_translator(val)
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bra, start = pass_bracket(source, start, '{}')
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if bra is None:
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raise SyntaxError('Missing block {} after switch statement')
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bra_pos = 0
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bra = bra[1:-1] + ';'
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while True:
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case = except_keyword(bra, bra_pos, 'case')
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default = except_keyword(bra, bra_pos, 'default')
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assert not (case and default)
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if case or default: # this ?: expression makes things much harder....
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case_code = None
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if case:
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case_code = 'if SWITCHED or PyJsStrictEq(CONDITION, %s):\n'
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# we are looking for a first : with count 1. ? gives -1 and : gives +1.
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count = 0
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for pos, e in enumerate(bra[case:], case):
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if e=='?':
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count -= 1
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elif e==':':
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count += 1
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if count==1:
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break
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else:
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raise SyntaxError('Missing : token after case in switch statement')
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case_condition = exp_translator(bra[case:pos]) # switch {case CONDITION: statements}
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case_code = case_code % case_condition
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case = pos + 1
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if default:
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case = except_token(bra, default, ':')
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case_code = 'if True:\n'
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# now parse case statements (things after ':' )
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cand, case = do_statement(bra, case)
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while cand:
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case_code += indent(cand)
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cand, case = do_statement(bra, case)
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case_code += indent('SWITCHED = True\n')
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code += indent(case_code)
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bra_pos = case
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else:
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break
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# prevent infinite loop :)
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code += indent('break\n')
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return code, start
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def do_pyimport(source, start):
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start += 8
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lib, start = parse_identifier(source, start)
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jlib = 'PyImport_%s' % lib
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code = 'import %s as %s\n' % (lib, jlib)
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#check whether valid lib name...
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try:
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compile(code, '', 'exec')
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except:
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raise SyntaxError('Invalid Python module name (%s) in pyimport statement'%lib)
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# var.pyimport will handle module conversion to PyJs object
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code += 'var.pyimport(%s, %s)\n' % (repr(lib), jlib)
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return code, start
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def do_with(source, start):
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raise NotImplementedError('With statement is not implemented yet :(')
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KEYWORD_METHODS = {'do': do_dowhile,
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'while': do_while,
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'if': do_if,
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'throw': do_throw,
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'return': do_return,
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'continue': do_continue,
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'break': do_break,
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'try': do_try,
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'for': do_for,
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'switch': do_switch,
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'var': do_var,
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'debugger': do_debugger, # this one does not do anything
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'with': do_with,
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'pyimport': do_pyimport
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}
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#Also not specific statements (harder to detect)
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# Block {}
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# Expression or Empty Statement
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# Label
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#
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# Its easy to recognize block but harder to distinguish between label and expression statement
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def translate_flow(source):
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"""Source cant have arrays, object, constant or function literals.
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Returns PySource and variables to register"""
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global TO_REGISTER
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TO_REGISTER = []
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return do_block('{%s}'%source, 0)[0], TO_REGISTER
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if __name__=='__main__':
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#print do_dowhile('do {} while(k+f)', 0)[0]
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#print 'e: "%s"'%do_expression('++(c?g:h); mj', 0)[0]
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print translate_flow('a; yimport test')[0]
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