#! python:
#w#VIC variables.py module
#
# Copyright 2002, 2003 by Timothy Rue <3seas@threeseas.net>
#
# VIC variables.py module: version 0.5.1.python (BETA)
#
#
# This program is free software; you can redistribute it and/or
# modify it under the terms of the GNU General Public License
# as published by the Free Software Foundation version 2
# of the License. http://www.gnu.org/copyleft/gpl.html
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
# Or access http://www.gnu.org/copyleft/gpl.html
##########################################################################
#August 29, 2003 made file IQ parseable 0.5.1
#July 24, 2003 initial release 0.5
#
##########################################################################
#s#system module
import string

#s#local module
import files

###
#w# Module for doing variable substitution in a command line
### or other string.  Variables are of the form $foo or $Bar
### They are case sesnsetive.  '\$varname' is not a variable
### name, and to embed them use a notation like ${bar}bar
### where the variable name is encased in '{}' (otherwise
### It's not possible to tell if the var is 'bar' or 'barbar')
### Variables have a default value of empty-string, that is
### if the given variable dictionary has no entry for a
### particular name, then it is replaced with an empty string
###


#s#def varVal
###
### It's in the dictionary, or it's an empty string
### First check the focused VIC's variable table, and if
### not found then check the global variables.
###
def varVal(var_dict,global_dict,key):
    content = ""
    if (var_dict.has_key(key)):
        content = var_dict[key]
    elif (global_dict.has_key(key)):
        content = global_dict[key]

    ### if the variable content is stored in a file, read & return it
    if (len(content) > 0 and content[0] == '@'):
        content = files.gulpFile(content[1:len(content)])

    return content


#s#def replaceVars
###
### Given a command line (or any string really), subsititute variables
### with either a known content or an empty string.  Variables are
### defined as $name or ${name}  but NOT \$anything
###
def replaceVars(command,var_dict,global_dict):
    output = ""
    varchars = "_1234567890abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ"

    var_start_index = -1
    cursor = 0
    while (1):
        if (var_start_index >= 0):
            ### inside a variable
            if (cursor == len(command)):
                ### Ran out of string, so close off variable
                var_name = command[var_start_index+1:cursor]
                output = output + varVal(var_dict,global_dict,var_name)
            elif (not command[cursor] in varchars):
                if (command[cursor] == '{' and command[cursor-1] == '$'):
                    var_start_index = cursor
                else:
                    ### Var has ended - output it
                    #print "VAR: ["+command[var_start_index+1:cursor]+"]"
                    var_name = command[var_start_index+1:cursor]
                    output = output + varVal(var_dict,global_dict,var_name)
                    var_start_index = -1
                    if (command[cursor] != '}'):
                        cursor = cursor - 1  ### Skip back a space to re-process without var processing

        elif (cursor < len(command)):
            ### not inside a variable
            if (command[cursor] == '$'):
                if (cursor == 0 or (cursor > 0 and command[cursor-1] != '\\')):
                    ### new variable starts
                    var_start_index = cursor
                elif (cursor > 0 and command[cursor-1] == '\\'):
                    ### Handle escaped dollar '\$'
                    output = output[0:len(output)-1]
                    output = output + '$'
            else:
                output = output + command[cursor]

        ### Step to the next chaaracter in the input
        cursor = cursor + 1

        ### Game over
        if (cursor == len(command)+1):
            break

    return output