FORTRAN namelist parserbased on http://code.google.com/p/fortran-namelist/Updated by Volodymyr Vladymyrov (http://stackoverflow.com/users/1296661/vvladymyrov) to parse format presented in http://stackoverflow.com/questions/14165733/regular-expression-parsing-key-value-pairs-in-namelist-input-file

namelist.py

#!/usr/bin/python
"""
    Parses Fortran Namelists
    based on Fortran Namelist parser for Python prog/scripts by Stephane Chamberland (stephane.chamberland@ec.gc.ca)
    http://code.google.com/p/fortran-namelist/
    Updated by Volodymyr Vladymyrov (http://stackoverflow.com/users/1296661/vvladymyrov) to parse format presented 
      in http://stackoverflow.com/questions/14165733/regular-expression-parsing-key-value-pairs-in-namelist-input-file    
    added support for
    1)
      $NAMELIST
      $END
    2) and parameter names with parentheses
        PLOT(2) = 12
    3) also paramters are stored in ordered dictionary


    Defines
        Namelist class
        
    Usage:
      python namelist.py
      
    Produce the following output:
{
{'PLOTTING': {'par': [OrderedDict([('PLOT', ['T']), ('PLOT(2) =', ['12'])])],
              'raw': ['PLOT=T', 'PLOT(2)=12']},
 'VEHICLES': {'par': [OrderedDict([('TRUCKS', ['0']), ('PLAINS', ['0']), ('TRAINS', ['0']), ('LIB', ['AUTO.DAT']), ('DATA', ['1.2', '2.34', '3.12', '4.56E-2', '6.78'])])],
              'raw': ['TRUCKS = 0',
                      'PLAINS= 0, TRAINS = 0',
                      "LIB='AUTO.DAT'",
                      'DATA=1.2,2.34,3.12',
                      '4.56E-2,6.78']}}
    
    Also see example usage starting from line 242
"""
from collections import OrderedDict


__author__ = 'Volodymyr Vladymyrov (smartkiwi@gmail.com), based on works Stephane Chamberland (stephane.chamberland@ec.gc.ca)'
__version__ = '$Revision: 1.1 $'[11:-2]
__date__ = '$Date: 2013/01/10 17:00:00 $'
__copyright__ = 'Copyright (c) 2013, 2006 RPN'
__license__ = 'LGPL'


import re



class Namelist(dict):
    """
    Namelist class
    Scan a Fortran Namelist file and put Section/Parameters into a dictionary

    Intentiation:

        foo = Namelist(NamelistFile)

        where NamelistFile can be a filename, an URL or a string

    Functions:
        [Pending]

        This is a generic Fortan namelist parser
        it will recognize all namelist in a file with the following format,
        and ignores the rest.

        &namelistname
            opt1 = value1
            ...
        /
    """

    def __init__(self,input_str):
        dict.__init__(self)
        self._setFile = input_str
        self._setContent = input_str
        #print self._setContent
        self.update(self.parse())

    def parse(self):
        """Config file parser, called from the class initialization"""
        varname   = r'\b[a-zA-Z][a-zA-Z0-9_]*\b'
        valueInt  = re.compile(r'[+-]?[0-9]+')
        valueReal = re.compile(r'[+-]?([0-9]+\.[0-9]*|[0-9]*\.[0-9]+)')
        valueNumber = re.compile(r'\b(([\+\-]?[0-9]+)?\.)?[0-9]*([eE][-+]?[0-9]+)?')
        valueBool = re.compile(r"(\.(true|false|t|f)\.)",re.I)
        valueTrue = re.compile(r"(\.(true|t)\.)",re.I)
        spaces = r'[\s\t]*'
        quote = re.compile(r"[\s\t]*[\'\"]")

        namelistname = re.compile(r"^[\s\t]*\$(" + varname + r")[\s\t]*$")
        #namelistname = re.compile(r"^[\s\t]*\$" + varname)
        paramname = re.compile(r"[\s\t]*(" + varname+r')[\s\t]*=[\s\t]*')

        paramname_with_brackets = re.compile(r"[\s\t]*([a-zA-Z][a-zA-Z0-9_\(\)]*)[\s\t]*=[\s\t]*")

        #namlistend = re.compile(r"^" + spaces + r"/" + spaces + r"$")
        namlistend = re.compile(r"^\$END")

        #split sections/namelists
        mynmlfile  = OrderedDict()
        mynmlname  = ''
        items = self.clean(self._setContent.split("\n"),commentexpr=r"^C.*$",cleancomma=1)
        #        print items
        for item in items:
            if re.match(namelistname,item) and not re.match(namlistend,item):
                mynmlname = re.sub(namelistname,r"\1",item)
                mynmlfile[mynmlname] = {
                    'raw' : [],
                    'par' : [OrderedDict()]
                }
            elif re.match(namlistend,item):
                mynmlname = ''
            else:
                if mynmlname:
                    mynmlfile[mynmlname]['raw'].append(item)

        #parse param in each section/namelist
        for mynmlname in mynmlfile.keys():
            #split strings
            bb = []
            for item in mynmlfile[mynmlname]['raw']:
                bb.extend(self.splitstring(item))
                #split comma and =
            aa = []
            for item in bb:
                if not re.match(quote,item):
                    aa.extend(re.sub(r"[\s\t]*=",r" =\n",re.sub(r",+",r"\n",item)).split("\n"))
                else:
                    aa.append(item)
            del(bb)
            aa = self.clean(aa,cleancomma=1)
            #            print aa

            myparname  = ''
            for item in aa:
                if re.search(paramname,item) or re.search(paramname_with_brackets,item):
                    myparname  = re.sub(paramname,r"\1",item)
                    mynmlfile[mynmlname]['par'][0][myparname] = []
                elif paramname:
                    #removed quotes, spaces (then how to distinguish .t. of ".t."?)
                    if re.match(valueBool,item):
                        if re.match(valueTrue,item):
                            mynmlfile[mynmlname]['par'][0][myparname].append('.true.')
                        else:
                            mynmlfile[mynmlname]['par'][0][myparname].append('.false.')
                    else:
                        mynmlfile[mynmlname]['par'][0][myparname].append(re.sub(r"(^[\'\"]|[\'\"]$)",r"",item.strip()).strip())
        return mynmlfile


    #==== Helper functions for Parsing of files
    def clean(self,mystringlist,commentexpr=r"^[\s\t]*\#.*$",spacemerge=0,cleancomma=0):
        """
        Remove leading and trailing blanks, comments/empty lines from a list of strings
        mystringlist = foo.clean(mystringlist,spacemerge=0,commentline=r"^[\s\t]*\#",cleancharlist="")
            commentline: definition of commentline
            spacemerge: if <>0, merge/collapse multi space
            cleancomma: Remove leading and trailing commas
        """
        aa = mystringlist
        if cleancomma:
            aa = [re.sub("(^([\s\t]*\,)+)|((\,[\s\t]*)+$)","",item).strip() for item in aa]
        if commentexpr:
            aa = [re.sub(commentexpr,"",item).strip() for item in aa]
        if spacemerge:
            aa = [re.sub("[\s\t]+"," ",item).strip() for item in aa if len(item.strip()) <> 0]
        else:
            aa = [item.strip() for item in aa if len(item.strip()) <> 0]
        return aa

    def splitstring(self,mystr):
        """
        Split a string in a list of strings at quote boundaries
            Input: String
            Output: list of strings
        """
        dquote=r'(^[^\"\']*)(\"[^"]*\")(.*)$'
        squote=r"(^[^\"\']*)(\'[^']*\')(.*$)"
        mystrarr = re.sub(dquote,r"\1\n\2\n\3",re.sub(squote,r"\1\n\2\n\3",mystr)).split("\n")
        #remove zerolenght items
        mystrarr = [item for item in mystrarr if len(item) <> 0]
        if len(mystrarr) > 1:
            mystrarr2 = []
            for item in mystrarr:
                mystrarr2.extend(self.splitstring(item))
            mystrarr = mystrarr2
        return mystrarr



    #==== Output function
    def sec_string(self,secname):
        """
        Return a string containing the "cleaned" content of a sectionContent
        mysecstring = foo.sec_string(secname)
        """
        try:
            return "\n".join(self[secname]['raw'])
        except:
            return ''

    def param_singleval(self,secname,parname):
        aa = self.param_vallist(secname,parname)
        if aa[0]:
            return self.param_vallist(secname,parname)[0][0]
        else:
            return ''

    def param_vallist(self,secname,parname,subsec=-1):
        """
        Return a list of values for the specified section/param
        myvallist = foo.param_vallist(secname,parname,subsec=-1)
        if subsec is not specified, the list contain the values for param in each subsec
        """
        try:
            if subsec>=0:
                return self[secname]['par'][subsec][parname]
            else:
                return [item[parname] for item in self[secname]['par']]
        except:
            if subsec>=0:
                return []
            else:
                return [[]]

    def param_string(self,secname,parname,subsec=-1):
        """
        Return a string of comma separated list of values for the specified section/param
        myvalliststring = foo.param_string(secname,parname,subsec=-1)
        if subsec is not specified, the list contain the values for param in each subsec
        """
        try:
            return self.param_vallist(secname,parname,subsec).__repr__()[1:-1]
            #alternate way:
            #return "\n".join(self.param_vallist(secname,parname,subsec))
        except:
            return ''


"""Example usage"""
if __name__=='__main__':

    file_str = """
    $VEHICLES
     CARS= 1,
     TRUCKS = 0,
     PLAINS= 0, TRAINS = 0,
     LIB='AUTO.DAT',
    C This is a comment
    C Data variable spans multiple lines
     DATA=1.2,2.34,3.12,
          4.56E-2,6.78,
    $END
    $PLOTTING
     PLOT=T,
     PLOT(2)=12,
    $END
    """

    nl = Namelist(file_str)


    import pprint
    pprint.pprint(nl)


    for param in nl.keys():
        print "Namelist name: %s" % param
        print "\t"+str(nl[param]['par'])