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# apicheck.py
# A simple source code scanner for finding patterns of the form
# [ procname1 $arg1 $arg2 ]
# and verifying the number of arguments
#
# Copyright (c) 2004-2016, Paul McGuire
#
from pyparsing import *
# define punctuation and simple tokens for locating API calls
LBRACK, RBRACK, LBRACE, RBRACE = map(Suppress, "[]{}")
ident = Word(alphas, alphanums + "_") | QuotedString("{", endQuoteChar="}")
arg = "$" + 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 = next(api_scanner)
print(f"found {t.procname} on line {lineno(s, test)}")
except ParseSyntaxException as pe:
print(f"invalid arg count on line {pe.lineno}")
print(f"{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
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