On Mar 25, 2010, at 2:33 PM, Ronald Guida wrote: ... a version of map as text ... ... a diagram ... The thing that strikes me forcibly is that the diagram is much bigger than the text. Not only that, but if I am reading it correctly, the text has three lines, a type specification and two cases, and the diagram covers only one of the two cases. This isn't Ronald Guida's fault. In fact his is a very nice looking diagram, and I could figure it out without his explanation of the notation, *given* the textual version to start from. I've seen several visual programming tools, including e-Toys in Squeak, and they tend to be really cool ways to quickly build programs with trivial structures. (I did not say trivial programs: you can build useful programs that do highly non-trivial things, when the things that are primitives _for the notation_ are capable enough. Some data mining products have visual wire-up-these-tools-into-a-workflow, for example.)