Head words are attached to its corresponding dependent words as early as possible. The transition operations on the words are LEFTARC ,RIGHTARC, SHIFT and REDUCE.

LEFTARC: Assert a head-dependent relation between the word at the front of the input buffer and the word at the top of the stack; pop the stack.

RIGHTARC: Assert a head-dependent relation between the word on the top of the stack and the word at front of the input buffer; shift the word at the front of the input buffer to the stack.

SHIFT: Remove the word from the front of the input buffer and push it onto the stack.

REDUCE: Pop the stack.