def_list & defs(); const def_list & defs();
These functions get and set the definition list for the unitNode. This is the list of global function and variable declarations and definitions.
suespec_list & suespecs();
Each unit has its own list of suespecNodes. These are the definitions to which sueNodes refer, i.e., this is where the actual definitions of structs, unions and enums reside, as opposed to having to duplicate their definitions for each struct/union/enum declaration and derived type node.