A practical and space efficient scheme for keeping source location in parse trees

Many CASE tools use graphical notations to represent program source code, which provide an effective visual aid for program analysis. In such systems, it is important that facilities exist for tracing back to source code from, say, a node in a control-flow graph. We describe a scheme by which source code location information is kept with parse trees. The most attractive feature of this scheme is that it requires minimal amount of storage space and it is very simple to implement, particularly well suited for an implementation where an LALR parser generator (e.g., YACC) is used