dig/src/dig/dot/read.js

Graph algorithms

var dig_dot_read = dig.dot.read = function(dot) {
  var parseTree = dig_dot_parser.parse(dot);
  var graph = parseTree.type === "digraph" ? new dig.DiGraph() : new dig.UGraph();

  function handleStmt(stmt) {
    switch (stmt.type) {
      case "node":
        var id = stmt.id;
        graph.addNode(id, stmt.attrs);
        break;
      case "edge":
        var prev;
        dig_util_forEach(stmt.elems, function(elem) {
          handleStmt(elem);

          switch(elem.type) {
            case "node":
              if (prev) {
                graph.addEdge(prev, elem.id, stmt.attrs);
              }
              prev = elem.id; 
              break;
            default:
              // We don't currently support subgraphs incident on an edge
              throw new Error("Unsupported type incident on edge: " + elem.type);
          }
        });
        break;
      case "attr":
        // Ignore attrs
        break;
      default:
        throw new Error("Unsupported statement type: " + stmt.type);
    }
  }

  dig_util_forEach(parseTree.stmts, function(stmt) {
    handleStmt(stmt);
  });
  return graph;
}