Question

I’m getting IOError: [Errno 13] Permission denied and I don’t know what is wrong wit this code.

I’m trying to read a file given an absolute path (meaning only file.asm),

and a relative path (meaning /.../file.asm), and I want the program to write the file to whatever path is given – if it is absolute, it should write it to the current dir; otherwise, to the path given.

the code:

#call to main function
if __name__ == '__main__':
    assem(sys.argv[1])


import sys

def assem(myFile):
    from myParser import Parser
    import code
    from symbolTable import SymbolTable

    table=SymbolTable()

    # max size of each word
    WORD_SIZE = 16
    # rom address to save to
    rom_addrs = 0
    # variable address to save to
    var_addrs = 16

    # new addition
    if (myFile[-4:] == ".asm"):
        newFile = myFile[:4]+".hack"

    output = open(newFile, 'w') <==== ERROR

the error given:

IOError: [Errno 13] Permission denied: '/Use.hack'

the way I execute the code :

python assembler.py Users/***/Desktop/University/Add.asm 

What am I doing wrong here?

Answer 1

It looks like you’re trying to replace the extension with the following code:

if (myFile[-4:] == ".asm"):
    newFile = myFile[:4]+".hack"

However, you appear to have the array indexes mixed up. Try the following:

if (myFile[-4:] == ".asm"):
    newFile = myFile[:-4]+".hack"

Note the use of -4 instead of just 4 in the second line of code. This explains why your program is trying to create /Use.hack, which is the first four characters of your file name (/Use), with .hack appended to it.