/* Variable ID-Entry */
typedef struct {
    unsigned id;    // Identifier index in string table.
    unsigned pt;    // Primitive type.
    unsigned rf;    // Flag: Set if variable is referenced.
} VarEntry;

/* Routine ID-Entry (Function, Procedure) */
typedef struct {
    VarEntry var;   // Variable-Entry details.
    unsigned argc;  // Argument count.
    void **argv;    // Vector of IdEntry table pointers.
} RoutineEntry;

/* Union of possible entry structures. */
typedef union {
    VarEntry var;
    RoutineEntry routine;
} Entry;

/* IdEntry: Symbol Table Entry */
typedef struct {
    unsigned tc;     // Type-class: Routine / Vector / Scalar
    Entry entry;     // Type data.
} IdEntry;