def parse_tree_walker(tree):
if tree.symbol == NonTerminalSymbol("S"):
return parse_tree_walker(tree.childlist[0])
if tree.symbol == NonTerminalSymbol("E"):
return to_number(tree.childlist[0].symbol.gd) + to_number(
tree.childlist[2].symbol.gd)
raise Exception
def testFirstLookup(self):
from pydsl.Grammar.Symbol import NonTerminalSymbol, TerminalSymbol
from pydsl.Grammar.PEG import Choice
self.grammardef.first_lookup(NonTerminalSymbol("exp"))[0]
self.assertEqual(
self.grammardef.first_lookup(NonTerminalSymbol("exp")),
Choice([String("S")]))
def parse_tree_walker(tree):
from pydsl.Grammar.Symbol import NonTerminalSymbol
if tree.symbol == NonTerminalSymbol("S"):
return parse_tree_walker(tree.childlist[0])
if tree.symbol == NonTerminalSymbol("E"):
return int(str(tree.childlist[0].content)) + int(
str(tree.childlist[2].content))
else:
raise Exception
def tree_translator(tree):
from pydsl.Grammar.Symbol import NonTerminalSymbol
if tree.symbol == NonTerminalSymbol("E"):
return int(str(tree.childlist[0].content)) + int(
str(tree.childlist[2].content))
elif len(tree.childlist) == 1:
return tree_translator(tree.childlist[0])
else:
raise Exception
def read_nonterminal_production(line, symboldict):
sidesarray = line.split("::=")
if len(sidesarray) < 2 or len(sidesarray) > 3:
raise ValueError("Error reading nonterminal production rule")
leftside = sidesarray[0].strip()
#leftside contains at least one NonTerminalSymbol
#FIXME supports only one symbol
symboldict[leftside] = NonTerminalSymbol(leftside)
rightside = sidesarray[1]
alternatives = [alt.rstrip() for alt in rightside.split("|")]
result = []
n = 0
for alternative in alternatives:
symbollist = alternative.split()
symbolinstancelist = []
for symbol in symbollist:
symbolinstancelist.append(symboldict[symbol])
result.append(Production([symboldict[leftside]], symbolinstancelist))
n += 1
return result
from pydsl.Grammar.Symbol import TerminalSymbol, NonTerminalSymbol, NullSymbol
from pydsl.Grammar.BNF import Production, BNFGrammar
from pydsl.File.BNF import strlist_to_production_set
from pydsl.File.Python import load_python_file
from pydsl.Grammar.Definition import String, RegularExpression
br = "max"
leftrecursive=["S ::= E","E ::= E dot | dot","dot := String,."]
rightrecursive=["S ::= E","E ::= dot E | dot","dot := String,."]
centerrecursive=["S ::= E","E ::= dot E dot | dot","dot := String,."]
#productionset0 definition
symbol1 = TerminalSymbol(String("S"))
symbol2 = TerminalSymbol(String("R"))
final1 = NonTerminalSymbol("exp")
rule1 = Production([final1], (symbol1, symbol2))
productionset0 = BNFGrammar(final1, (rule1,symbol1,symbol2))
p0good = "SR"
p0bad = "SRL"
#productionset1 definition
symbol1 = TerminalSymbol(String("S"))
symbol2 = TerminalSymbol(String("R"))
symbol3 = TerminalSymbol(String(":"))
symbol4 = TerminalSymbol(RegularExpression("^[0123456789]*$"), None, br)
symbol5 = TerminalSymbol(load_python_file('pydsl/contrib/grammar/cstring.py'), None, br)
final1 = NonTerminalSymbol("storeexp")
final2 = NonTerminalSymbol("retrieveexp")
final3 = NonTerminalSymbol("exp")
#You should have received a copy of the GNU General Public License
#along with pydsl. If not, see <http://www.gnu.org/licenses/>.
"""SLR0 unfinished implementation"""
__author__ = "Nestor Arocha"
__copyright__ = "Copyright 2008-2013, Nestor Arocha"
__email__ = "*****@*****.**"
import logging
LOG = logging.getLogger(__name__)
from pydsl.Parser.Parser import BottomUpParser
from pydsl.Grammar.Symbol import NonTerminalSymbol, TerminalSymbol, EndSymbol
from pydsl.Grammar.BNF import Production
Extended_S = NonTerminalSymbol("EI")
def _build_item_closure(itemset, productionset):
"""Build input itemset closure """
#For every item inside current itemset, if we have the following rule:
# xxx <cursor><nonterminalSymbol> xxx append every rule from self._productionruleset that begins with that NonTerminalSymbol
LOG.debug("_build_item_closure: Begin")
if not isinstance(itemset, LR0ItemSet):
raise TypeError
import copy
resultset = copy.copy(itemset)
changed = True
while changed:
changed = False
for currentitem in resultset.itemlist:
nextsymbol = currentitem.next_symbol()
def testNextLookup(self):
from pydsl.Grammar.Symbol import NonTerminalSymbol, EndSymbol
self.grammardef.next_lookup(NonTerminalSymbol("exp"))[0]
self.assertListEqual(
self.grammardef.next_lookup(NonTerminalSymbol("exp")),
[EndSymbol()])