1 files changed, 55 insertions, 0 deletions
diff --git a/src/examples/apicheck.py b/src/examples/apicheck.py
new file mode 100644
index 0000000..b5b9358
--- /dev/null
+++ b/src/examples/apicheck.py
@@ -0,0 +1,55 @@
+# apicheck.py
+#   A simple source code scanner for finding patterns of the form
+#       [ procname1 $arg1 $arg2 ]
+#  and verifying the number of arguments
+
+from pyparsing import *
+
+# define punctuation and simple tokens for locating API calls
+LBRACK,RBRACK,LBRACE,RBRACE = map(Suppress,"[]{}")
+ident = Word(alphas,alphanums+"_") | QuotedString("{",endQuoteChar="}")
+arg = "$" + ident
+
+# define an API call with a specific number of arguments - using '-' 
+# will ensure that after matching procname, an incorrect number of args will 
+# raise a ParseSyntaxException, which will interrupt the scanString
+def apiProc(name, numargs):
+    return LBRACK + Keyword(name)("procname") - arg*numargs + RBRACK
+
+# create an apiReference, listing all API functions to be scanned for,  and
+# their respective number of arguments.  Beginning the overall expression
+# with FollowedBy allows us to quickly rule out non-api calls while scanning,
+# since all of the api calls begin with a "["
+apiRef = FollowedBy("[") + MatchFirst([
+    apiProc("procname1", 2),
+    apiProc("procname2", 1),
+    apiProc("procname3", 2),
+    ])
+
+test = """[ procname1  $par1 $par2 ]
+          other code here
+          [ procname1 $par1 $par2 $par3 ]
+          more code here
+          [ procname1 $par1 ]
+          [ procname3  ${arg with spaces} $par2 ]"""
+
+
+# now explicitly iterate through the scanner using next(), so that
+# we can trap ParseSyntaxException's that would be raised due to
+# an incorrect number of arguments. If an exception does occur,
+# then see how we reset the input text and scanner to advance to the
+# next line of source code
+api_scanner = apiRef.scanString(test)
+while 1:
+    try:
+        t,s,e = api_scanner.next()
+        print "found %s on line %d" % (t.procname, lineno(s,test))
+    except ParseSyntaxException, pe:
+        print "invalid arg count on line", pe.lineno
+        print pe.lineno,':',pe.line
+        # reset api scanner to start after this exception location
+        test = "\n"*(pe.lineno-1)+test[pe.loc+1:]
+        api_scanner = apiRef.scanString(test)
+    except StopIteration:
+        break
+        
+\ No newline at end of file