LRXplain -- Explaining LALR (bison) conflicts

Dick Grune

The progam LRXplain tries to assist the user in finding the underlying causes of LALR conflicts in *.y (bison) grammars. Such conflicts can be notoriously puzzling, and the program supplies for each conflict state S:

  • A short input sequence which brings the parser in the conflict state S, and the look-ahead involved. A marker # in this sequence indicates the point in which the choice arises that could not be resolved in state S.
  • Two sets of core items valid at #, one for each of the choices.

This information is often suffcient to bring the needed insight. The program has options to ask for more details. These are described in the Manual.

Download the C code as zip archive.

[Home Page]
LRXplain / Dick Grune /

... and my name is not Richard ...