# a GML parser
# Here is the GML grammar
# corrected from me because the original at
# http://www.uni-passau.de/Graphlet/GML had some errors
#
# corrections are
# (1) use instring* in string
# (2) add character,lowercase,uppercase definitions
# (3) skip whitespace definition, this is obvious
# (4) use digit+ in mantissa
#
# additions are
# (1) no empty list is allowed
# (2) either intpart or fraction of a real must contain a number
# (3) comments can be on a separate or at the end of the line
# 
#
# gml:        list
# list:       (whitespace* key whitespace+ value)+
# value:      integer | real | string | "[" list "]"
# key:        character (character | digit)*
# integer:    sign digit+
# real:       sign (digit+ "." digit* | digit* "." digit+) mantissa
# string:     """ instring* """
# sign:       "+" | "-" |
# digit:      "0"..."9"
# character:  lowercase | uppercase
# lowercase:  "a"..."z"
# uppercase:  "A"..."Z"
# mantissa:   ("E"|"e") sign digit+ |
# instring:   <ASCII except "&" and """> | "&" character+ ";"
#
# Note that integers and reals can have prefixed zeros, e.g. 001 is 1

_class GMLBaseParser  
_code import GML
_lex GML.GMLLexer()

# the grammar
"""
gml:      list (feddich);
list:     list keyvalue (gml_key_value)| keyvalue;
keyvalue: KEY value (key_value);
value:    INTEGER |
          REAL |
          STRING |
          LSQB list RSQB (gmllist);
"""