Method addDef

chapter04/src/main/java/com/seaofnodes/simple/node/Node.java:161–168

Add a new def to an existing Node. Keep the edges correct by adding the corresponding def->use edge. @param new_def the new definition, appended to the end of existing definitions @return new_def for flow coding

(Node new_def)

     * @return new_def for flow coding
     */
    Node addDef(Node new_def) {
        // Add use->def edge
        _inputs.add(new_def);
        // If new def is not null, add the corresponding def->use edge
        if( new_def != null )
            new_def.addUse(this);
        return new_def;
    }

    // Breaks the edge invariants, used temporarily
    protected <N extends Node> void addUse(N n) { _outputs.add(n); }