- Adjusted Arithmetic example a bit more...

dhparser.py

@@ -16,7 +16,7 @@ distributed under the License is distributed on an "AS IS" BASIS,
 WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
 implied.  See the License for the specific language governing
 permissions and limitations under the License.
-"""3
+"""
 
 #  TODO: This is still a stub...
 

examples/Arithmetic/Arithmetic.ebnf

@@ -6,11 +6,11 @@
 #
 #######################################################################
 
-@ whitespace  = vertical        # implicit whitespace, includes any number of line feeds
-@ literalws   = right           # literals have implicit whitespace on the right hand side
-@ comment     = /#.*/           # comments range from a '#'-character to the end of the line
-@ ignorecase  = False           # literals and regular expressions are case-sensitive
-@ drop        = whitespace      # drop anonymous whitespace
+@ whitespace  = vertical           # implicit whitespace, includes any number of line feeds
+@ literalws   = right              # literals have implicit whitespace on the right hand side
+@ comment     = /#.*/              # comments range from a '#'-character to the end of the line
+@ ignorecase  = False              # literals and regular expressions are case-sensitive
+@ drop        = whitespace, token  # drop anonymous whitespace
 
 #######################################################################
 #
@@ -18,16 +18,20 @@
 #
 #######################################################################
 
-expression = term  { ("+" | "-") term}
-term       = factor  { ("*" | "/") factor}
-factor     = [/-/] ( NUMBER | VARIABLE | group ) { VARIABLE | group }
+expression = term  { EXPR_OP term}
+term       = factor  { TERM_OP factor}
+factor     = [SIGN] ( NUMBER | VARIABLE | group ) { VARIABLE | group }
 group      = "(" expression ")"
 
 #######################################################################
 #
-#  Regular Expressions
+# "Leaf"-Expressions
 #
 #######################################################################
 
+EXPR_OP    = "+" | "-"
+TERM_OP    = "*" | "/"
+SIGN       = /-/
+
 NUMBER     = /(?:0|(?:[1-9]\d*))(?:\.\d+)?/~
 VARIABLE   = /[A-Za-z]/~

examples/Arithmetic/ArithmeticCompiler.py

@@ -59,7 +59,7 @@ class ArithmeticGrammar(Grammar):
     r"""Parser for an Arithmetic source file.
     """
     expression = Forward()
-    source_hash__ = "a94242482d508901d1692b82c48ba903"
+    source_hash__ = "5a5e8df98d9c78186acdd7f602aa51da"
     parser_initialization__ = ["upon instantiation"]
     resume_rules__ = {}
     COMMENT__ = r'#.*'
@@ -69,10 +69,13 @@ class ArithmeticGrammar(Grammar):
     wsp__ = Whitespace(WSP_RE__)
     VARIABLE = Series(RegExp('[A-Za-z]'), dwsp__)
     NUMBER = Series(RegExp('(?:0|(?:[1-9]\\d*))(?:\\.\\d+)?'), dwsp__)
-    group = Series(Series(Token("("), dwsp__), expression, Series(Token(")"), dwsp__))
-    factor = Series(Option(RegExp('-')), Alternative(NUMBER, VARIABLE, group), ZeroOrMore(Alternative(VARIABLE, group)))
-    term = Series(factor, ZeroOrMore(Series(Alternative(Series(Token("*"), dwsp__), Series(Token("/"), dwsp__)), factor)))
-    expression.set(Series(term, ZeroOrMore(Series(Alternative(Series(Token("+"), dwsp__), Series(Token("-"), dwsp__)), term))))
+    SIGN = RegExp('-')
+    TERM_OP = Alternative(Series(DropToken("*"), dwsp__), Series(DropToken("/"), dwsp__))
+    EXPR_OP = Alternative(Series(DropToken("+"), dwsp__), Series(DropToken("-"), dwsp__))
+    group = Series(Series(DropToken("("), dwsp__), expression, Series(DropToken(")"), dwsp__))
+    factor = Series(Option(SIGN), Alternative(NUMBER, VARIABLE, group), ZeroOrMore(Alternative(VARIABLE, group)))
+    term = Series(factor, ZeroOrMore(Series(TERM_OP, factor)))
+    expression.set(Series(term, ZeroOrMore(Series(EXPR_OP, term))))
     root__ = expression
     
 def get_grammar() -> ArithmeticGrammar: