--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/python/libs/compiler/frontends/ksparser.py	Mon Oct 29 20:24:29 2012 +0100
@@ -0,0 +1,183 @@
+"""
+  This module define a grammar for the 'K#' language.
+"""
+
+from .nodes import *
+from .errors import CompilerException, Error
+from .modules import loadModule
+from .display import printNode
+from .builtin import *
+from . import assembler
+
+class Grammar:
+   # TODO: implement some base class?
+   pass
+
+class Parser:
+   #TODO
+   pass
+
+class KsParser(Parser):
+   def __init__(self):
+      self.loadGrammar(KsGrammar)
+
+# For now, try to parse an expression as test case:
+class KsGrammer(Grammar):
+
+   def __init__(self):
+      pass
+
+   # Parsing expressions:
+   """
+     grammar of expressions:
+     expression       = term { addoperator term }
+     addoperator      = '+' | '-'
+     term             = factor { muloperator factor }
+     muloperator      = '*' | '/'
+     factor           = number | "(" expression ")"
+   """
+
+   @rule(Term)
+   def Expression1(self, term):
+      return Expression(term)
+
+   @rule(Term, AddOperator, Term)
+   def Expression2(self, term1, op, term2):
+      return Expression(term1, op, term2)
+
+   # Parsing arithmatic expressions:
+   def parseTerm(self):
+       a = self.parseFactor()
+       while self.token.typ in ['*', '/', 'mod', 'div', 'and']:
+           loc = self.getLocation()
+           op = self.Consume()
+           b = self.parseTerm()
+           # Type determination and checking:
+           if op in ['mod', 'div']:
+              if not isType(a.typ, integer):
+                 self.Error('First operand should be integer, not {0}'.format(a.typ))
+              if not isType(b.typ, integer):
+                 self.Error('Second operand should be integer, not {0}'.format(b.typ))
+              typ = integer
+           elif op == '*':
+              if isType(a.typ, integer) and isType(b.typ, integer):
+                 typ = integer
+              elif isType(a.typ, real) or isType(b.typ, real):
+                 if isType(a.typ, integer):
+                    # Automatic type cast
+                    a = Unop(a, 'INTTOREAL', real)
+                 if isType(b.typ, integer):
+                    b = Unop(b, 'INTTOREAL', real)
+                 if not isType(a.typ, real):
+                    self.Error('first operand must be a real!')
+                 if not isType(b.typ, real):
+                    self.Error('second operand must be a real!')
+                 typ = real
+              else:
+                 self.Error('Unknown operands for multiply: {0}, {1}'.format(a, b))
+           elif op == '/':
+              # Division always yields a real result, for integer division use div
+              if isType(a.typ, integer):
+                 # Automatic type cast
+                 a = Unop(a, 'INTTOREAL', real)
+              if isType(b.typ, integer):
+                 b = Unop(b, 'INTTOREAL', real)
+              if not isType(a.typ, real):
+                 self.Error('first operand must be a real!')
+              if not isType(b.typ, real):
+                 self.Error('second operand must be a real!')
+              typ = real
+           elif op == 'and':
+              if not isType(a.typ, boolean):
+                 self.Error('First operand of and must be boolean')
+              if not isType(b.typ, boolean):
+                 self.Error('Second operand of and must be boolean')
+              typ = boolean
+           else:
+              self.Error('Unknown operand {0}'.format(op))
+
+           a = self.setLocation(Binop(a, op, b, typ), loc)
+       return a
+
+   @rule(
+   def parseFactor(self):
+      if self.hasConsumed('('):
+         e = self.parseExpression()
+         self.Consume(')')
+         return e
+      elif self.token.typ == 'NUMBER':
+         loc = self.getLocation() 
+         val = self.Consume('NUMBER')
+         return self.setLocation(Constant(val, integer), loc)
+      elif self.token.typ == 'REAL':
+         loc = self.getLocation()
+         val = self.Consume('REAL')
+         return self.setLocation(Constant(val, real), loc)
+      elif self.token.typ == 'CHAR':
+          val = self.Consume('CHAR')
+          return Constant(val, char)
+      elif self.token.typ in ['true', 'false']:
+         val = self.Consume()
+         val = True if val == 'true' else False
+         return Constant(val, boolean)
+      elif self.hasConsumed('nil'):
+         return Constant(0, NilType())
+      elif self.hasConsumed('not'):
+         f = self.parseFactor()
+         if not isType(f.typ, boolean):
+            self.Error('argument of boolean negation must be boolean type')
+         return Unop(f, 'not', boolean)
+      elif self.token.typ == 'ID':
+          designator = self.parseDesignator()
+          # TODO: handle functions different here?
+          if self.token.typ == '(' and type(designator.typ) is ProcedureType:
+             return self.parseProcedureCall(designator)
+          else:
+             return designator
+      else:
+         self.Error('Expected NUMBER, ID or ( expr ), got'+str(self.token))
+
+   def parseSimpleExpression(self):
+      """ Arithmatic expression """
+      if self.token.typ in ['+', '-']:
+         # Handle the unary minus
+         op = self.Consume()
+         a = self.parseTerm()
+         typ = a.typ
+         if not isType(typ,real) and not isType(typ, integer):
+            self.Error('Unary minus or plus can be only applied to real or integers')
+         if op == '-':
+            a = Unop(a, op, typ)
+      else:
+         a = self.parseTerm()
+      while self.token.typ in ['+', '-', 'or']:
+           loc = self.getLocation()
+           op = self.Consume()
+           b = self.parseTerm()
+           if op in ['+', '-']:
+              if isType(a.typ, real) or isType(b.typ, real):
+                 typ = real
+                 if isType(a.typ, integer):
+                    # Automatic type cast
+                    a = Unop(a, 'INTTOREAL', real)
+                 if not isType(a.typ, real):
+                    self.Error('first operand must be a real!')
+                 if isType(b.typ, integer):
+                    b = Unop(b, 'INTTOREAL', real)
+                 if not isType(b.typ, real):
+                    self.Error('second operand must be a real!')
+              elif isType(a.typ, integer) and isType(b.typ, integer):
+                 typ = integer
+              else:
+                 self.Error('Invalid types {0} and {1}'.format(a.typ, b.typ))
+           elif op == 'or':
+              if not isType(a.typ, boolean):
+                 self.Error('first operand must be boolean for or operation')
+              if not isType(b.typ, boolean):
+                 self.Error('second operand must be boolean for or operation')
+              typ = boolean
+           else:
+              self.Error('Unknown operand {0}'.format(op))
+           a = self.setLocation(Binop(a, op, b, typ), loc)
+      return a
+