Comment by DonHopkins

Spreadsheet certainly are visual programming languages: by any measure, by far one of the most common most widely used types of visual programming languages in the world.

Taxonomies of Visual Programming (1990) [pdf] (cmu.edu)

https://news.ycombinator.com/item?id=20417967

Excerpt from "Taxonomies of Visual Programming and Program Visualization", by Brad A Myers, 1990/3/1, Journal of Visual Languages & Computing, Volume 1, Issue 1, pages 97-123:

Spreadsheets, such as those in VisiCalc or Lotus 1-2-3, were designed to help nonprogrammers manage finances. Spreadsheets incorporate programming features and can be made to do general purpose calculations [71] and therefore qualify as a very-high level Visual Programming Language. Some of the reasons that spreadsheets are so popular are (from [43] and [1]):

1. the graphics on the screen use familiar, concrete, and visible representation which directly maps to the user's natural model of the data,

2. they are nonmodal and interpretive and therefore provide immediate feedback,

3. they supply aggregate and high-level operations,

4. they avoid the notion of variables (all data is visible),

5. the inner world of computation is suppressed,

6. each cell typically has a single value throughout the computation,

7. they are nondeclarative and typeless,

8. consistency is automatically maintained, and

9. the order of evaluation (flow of control) is entirely derived from the declared cell dependencies.

The first point differentiates spreadsheets from many other Visual Programming Languages including flowcharts which are graphical representations derived from textual (linear) languages. With spreadsheets, the original representation in graphical and there is no natural textual language.

Action Graphics [41] uses ideas from spreadsheets to try to make it easier to program graphical animations. The 'Forms' system [43] uses a more conventional spreadsheet format, but adds sub-sheets (to provide procedural abstraction) which can have an unbounded size (to handle arbitrary parameters).

A different style of system is SIL-ICON [49], which allows the user to construct 'iconic sentences' consisting of graphics arranged in a meaningful two-dimensional fashion, as shown in Figure 5. The SIL-ICON interpreter then parses the picture to determine what it means. The interpreter itself is generated from a description of the legal pictures, in the same way that conventional compilers can be generated from BNF descriptions of the grammar.

10. Conclusions

Visual Programming and Program Visualization are interesting areas that show promise for improving the programming process, especially for non-programmers, but more work needs to be done. The success of spreadsheets demonstrates that if we find the appropriate paradigms, graphical techniques can revolutionize the way people interact with computers.