Add word boundary for true/false literal lexing, close #215

tests/parser-cases/issue_215.thrift

@@ -0,0 +1,6 @@
+struct Test {
+    1: required i64 trueNum;
+}
+
+const bool abool = true
+const i32 falseValue = 123

tests/test_parser.py

@@ -254,3 +254,9 @@ def test_recursive_union():
         6: (TType.MAP, 'object', (TType.STRING, (TType.STRUCT,
                                                  thrift.Dynamic)), False)
     }
+
+
+def test_issue_215():
+    thrift = load('parser-cases/issue_215.thrift')
+    assert thrift.abool is True
+    assert thrift.falseValue == 123

thriftpy/parser/lexer.py

@@ -191,7 +191,7 @@ def t_ignore_COMMENT(t):
 
 
 def t_BOOLCONSTANT(t):
-    r'true|false'
+    r'\btrue\b|\bfalse\b'
     t.value = t.value == 'true'
     return t