Add number_words.py example; update diagramming code

2 files changed, 105 insertions, 3 deletions

diff --git a/examples/number_words.py b/examples/number_words.py
new file mode 100644
index 0000000..724059f
--- /dev/null
+++ b/examples/number_words.py
@@ -0,0 +1,89 @@
+# number_words.py
+#
+# Copyright 2020, Paul McGuire
+#
+# Parser/evaluator for expressions of numbers as written out in words:
+#  - one
+#  - seven
+#  - twelve
+#  - twenty six
+#  - forty-two
+#  - one hundred and seven
+#
+#
+#  BNF:
+"""
+    optional_and ::= ["and" | "-"]
+    optional_dash ::= ["-"]
+    units ::= one | two | three | ... | nine
+    teens_only ::= eleven | twelve | ... | nineteen
+    teens ::= ten | teens_only
+    tens ::= twenty | thirty | ... | ninety
+    hundreds ::= (units | teens_only | tens optional_dash units) "hundred"
+    one_to_99 ::= units | teens | (tens [optional_dash units])
+    thousands = one_to_99 "thousand"
+
+    number = [thousands] [hundreds] optional_and units | [thousands] optional_and hundreds | thousands
+"""
+import pyparsing as pp
+from operator import mul
+import pyparsing.diagram
+
+def define_numeric_word(s, value):
+    return pp.CaselessKeyword(s).addParseAction(lambda: value)
+
+def define_numeric_word_range(s, vals):
+    if isinstance(s, str):
+        s = s.split()
+    return pp.MatchFirst(define_numeric_word(nm, nm_value) for nm, nm_value in zip(s, vals))
+
+opt_dash = pp.Optional(pp.Suppress("-")).setName("optional '-'")
+opt_and = pp.Optional((pp.CaselessKeyword("and") | "-").suppress()).setName("optional 'and'")
+
+zero = define_numeric_word_range("zero oh", [0, 0])
+one_to_9 = define_numeric_word_range("one two three four five six seven eight nine", range(1, 9 + 1)).setName("1-9")
+eleven_to_19 = define_numeric_word_range("eleven twelve thirteen fourteen fifteen sixteen seventeen eighteen nineteen",
+                                       range(11, 19 + 1)).setName("eleven_to_19")
+ten_to_19 = (define_numeric_word("ten", 10) | eleven_to_19).setName("ten_to_19")
+one_to_19 = (one_to_9 | ten_to_19).setName("1-19")
+tens = define_numeric_word_range("twenty thirty forty fifty sixty seventy eighty ninety", range(20, 90+1, 10))
+hundreds = (one_to_9 | eleven_to_19 | (tens + opt_dash + one_to_9)) + define_numeric_word("hundred", 100)
+one_to_99 = (one_to_19 | (tens + pp.Optional(opt_dash + one_to_9)).addParseAction(sum)).setName("1-99")
+one_to_999 = ((pp.Optional(hundreds + opt_and) + one_to_99 | hundreds).addParseAction(sum)).setName("1-999")
+thousands = one_to_999 + define_numeric_word("thousand", 1000)
+hundreds.setName("100s")
+thousands.setName("1000s")
+
+def multiply(t):
+    return mul(*t)
+hundreds.addParseAction(multiply)
+thousands.addParseAction(multiply)
+
+numeric_expression = (pp.Optional(thousands + opt_and)
+                      + pp.Optional(hundreds + opt_and)
+                      + one_to_99
+                      | pp.Optional(thousands + opt_and)
+                      + hundreds
+                      | thousands
+                      ).setName("numeric_words")
+numeric_expression.addParseAction(sum)
+
+
+if __name__ == '__main__':
+    numeric_expression.runTests("""
+        one
+        seven
+        twelve
+        twenty six
+        forty-two
+        two hundred
+        twelve hundred
+        one hundred and eleven
+        ninety nine thousand nine hundred and ninety nine
+        nine hundred thousand nine hundred and ninety nine
+        nine hundred and ninety nine thousand nine hundred and ninety nine
+        nineteen hundred thousand nineteen hundred and ninety nine
+        """)
+
+    # create railroad diagram
+    numeric_expression.create_diagram("numeric_words_diagram.html")
diff --git a/pyparsing/diagram/__init__.py b/pyparsing/diagram/__init__.py
index e9ad70d..9678368 100644
--- a/pyparsing/diagram/__init__.py
+++ b/pyparsing/diagram/__init__.py
@@ -275,7 +275,7 @@ def _to_diagram_element(
     element: pyparsing.ParserElement,
     parent: Optional[EditablePartial],
     lookup: ConverterState = None,
-    vertical: Union[int, bool] = 5,
+    vertical: Union[int, bool] = 3,
     index: int = 0,
     name_hint: str = None,
 ) -> Optional[EditablePartial]:
@@ -341,9 +341,9 @@ def _to_diagram_element(
             ret = EditablePartial.from_call(railroad.Sequence, items=[])
     elif isinstance(element, (pyparsing.Or, pyparsing.MatchFirst)):
         if _should_vertical(vertical, len(exprs)):
-            ret = EditablePartial.from_call(railroad.HorizontalChoice, items=[])
-        else:
             ret = EditablePartial.from_call(railroad.Choice, 0, items=[])
+        else:
+            ret = EditablePartial.from_call(railroad.HorizontalChoice, items=[])
     elif isinstance(element, pyparsing.Optional):
         ret = EditablePartial.from_call(railroad.Optional, item="")
     elif isinstance(element, pyparsing.OneOrMore):
@@ -424,3 +424,16 @@ def _to_diagram_element(
         )
     else:
         return ret
+
+# monkeypatch .create_diagram method onto ParserElement
+def _create_diagram(expr: pyparsing.ParserElement, output_html):
+    railroad = to_railroad(expr)
+    if isinstance(output_html, str):
+        with open(output_html, "w", encoding="utf-8") as diag_file:
+            diag_file.write(railroad_to_html(railroad))
+    else:
+        # we were passed a file-like object, just write to it
+        output_html.write(railroad_to_html(railroad))
+
+
+pyparsing.ParserElement.create_diagram = _create_diagram