Expands minified CSS/Javascript files. No support for Strings or Regex syntax.

src_expander.py

from os.path import abspath, isfile
import sys

def expand(filename):
    "Expands minified Javascript/CSS files."
    
    filename = abspath(filename)
    is_js = filename.endswith(".js")
    is_css = filename.endswith(".css")
    assert isfile(filename) and (is_js or is_css), "Invalid File"
    
    out_filename = filename.split(".",1)
    out_filename = out_filename[0] + "_expanded"
    if is_js: 
        out_filename += ".js"
    elif is_css: 
        out_filename += ".css"
    
    infile = open(filename, "r")
    inscript = infile.read()
    infile.close()
    
    outscript = ""
    indent_spaces = 2
    indents = ""
    ignore_semicolons = False
    for index in xrange(len(inscript)):
        char = inscript[index]
        
        if char == ";" and not ignore_semicolons:
            char += "\n" + indents
            
        elif char == "{":
            indents += " "*indent_spaces
            char += "\n" + indents    
            if ignore_semicolons: 
                ignore_semicolons = False
            
        elif char == "}":
            if len(indents) > indent_spaces:
                indents = indents[0:-indent_spaces]
            else:
                indents = ""
            
            if inscript[index-1] != ";":
                char = "\n" + indents + char
            if not inscript[index+1] == ";":
                char += "\n" + indents
        
        # check if we're in a for-loop statement
        elif is_js \
        and (inscript[index-1 : index+4] == " for " \
        or inscript[index-1 : index+4] == " for(") :
            ignore_semicolons = True
            
        outscript += char
    
    outfile = open(out_filename,"w")
    outfile.write(outscript)
    outfile.close()
    
if __name__ == "__main__":
    for filename in sys.argv[1:]:
        expand(filename)