An LR(k) grammar is clearly unambiguous, since the definition implies every derivation tree must have the same handle, and by induc- tion there is only one possible tree. It is interesting to point out further- more that nearly every grammar which is known to be unambiguous is either an LR(k) grammar, or (dually) is a right-to-left translatable grammar, or is some grammar which is translated using "both ends to- ward the middle." Thus, the LR(k) condition may be regarded as the most powerful general test for nonambiguity that is now available.
