bookmarks: abort directly on invalid name
This consolidates the abort message for a bookmark name containing
invalid characters into one place, and renames the valid() method to
checkvalid() to reflect the fact that it's no longer a predicate.
import sys
globalvars = {}
localvars = {}
lines = sys.stdin.readlines()
while lines:
l = lines.pop(0)
if l.startswith('SALT'):
print l[:-1]
elif l.startswith('>>> '):
snippet = l[4:]
while lines and lines[0].startswith('... '):
l = lines.pop(0)
snippet += "\n" + l[4:]
c = compile(snippet, '<heredoc>', 'single')
try:
exec c in globalvars, localvars
except Exception, inst:
print repr(inst)