diff options
| -rw-r--r-- | pexpect/pexpect.py | 29 |
1 files changed, 29 insertions, 0 deletions
diff --git a/pexpect/pexpect.py b/pexpect/pexpect.py index c313f46..b234273 100644 --- a/pexpect/pexpect.py +++ b/pexpect/pexpect.py @@ -695,6 +695,33 @@ class spawn: self.match = None self.buffer = '' raise + + def expect_lookahead(self,pattern, timeout = -1): + """ + This function works exactly like the expect() function, + taking the same arguments, returning the same results, + and causing the same side effects except for one thing. + This function leaves all the data on the buffer. It does + not strip off everything up to the end of the match. + This is useful in situations where you have multiple possible + sequences that you may have to interact with, for which you + have pexpect proceedures, but you can't know which one applies + until you look to see which one is starting. The problem with + expect is that once you've looked to see which one is starting, + you have no way to use your existing proceedures, because expect + strips off of the buffer the very data your proceedures need to + get them going. + """ + + #Do a normal expect process + index = self.expect(pattern,timeout) + #Put back the part of the buffer stripped off + if ( self.match != None ): + self.buffer = self.before + self.match.group() + self.buffer + else: + self.buffer = self.before + self.buffer + #Return the index + return index def expect_list(self, pattern_list, timeout = -1): """ @@ -739,6 +766,7 @@ class spawn: except EOF: self.before = incoming self.after = EOF + self.match = None if EOF in pattern_list: #self.buffer = '' return pattern_list.index(EOF) @@ -747,6 +775,7 @@ class spawn: except TIMEOUT: self.before = incoming self.after = TIMEOUT + self.match = None if TIMEOUT in pattern_list: #self.buffer = '' return pattern_list.index(TIMEOUT) |