tweak docs; fix reference to _LogicParser

nltk/sem/__init__.py

@@ -17,7 +17,7 @@ set-theoretic models.
 
 The package has two main components:
 
- - ``logic`` provides a parser for analyzing expressions of First
+ - ``logic`` provides support for analyzing expressions of First
    Order Logic (FOL).
  - ``evaluate`` allows users to recursively determine truth in a
    model for formulas of FOL.

nltk/test/logic.doctest

@@ -348,7 +348,7 @@ Test Parser
     x(john)
     ^
 
-    >>> lpq = LogicParser()
+    >>> lpq = _LogicParser()
     >>> lpq.quote_chars = [("'", "'", "\\", False)]
     >>> print(lpq.parse(r"(man(x) & 'tall\'s,' (x) & walks (x) )"))
     (man(x) & tall's,(x) & walks(x))