My solution for <b>graph</b>:

<ol>
	<li> <a href="graph/graph.lex">lexer</a>
	<li> <a href="graph/graph.yacc">parser</a>
	<li> <a href="graph/graph.cpp">syntax tree classes</a>
</ol>
<p>
My solution for <b>edges</b>:
<ol>
	<li> <a href="edges/edges.lex">lexer</a>
	<li> <a href="edges/edges.yacc">parser</a>
</ol>
<p>
The edges solution was simple enough that I could emit the code directly
during the parse and hence did not have to create an abstract syntax tree.