Improve flow_view_vars()

[moodymudskipper]

several things, by order of difficulty

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(1)

Side effects called are not shown so we might feel like there is dead code when there is not.

For instance:

env <- new.env()
foo <- 1
assign("bar", foo, envir = env)

we could have env -> assign() and foo -> assign() in the diagram, because assign() is at the top level (not a call to <-).

These side effect calls would be leaves by definition (don't create a local variable, explicitly at least), they probably should have a bright color, maybe orange.

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(2) We might provide a list of NSE functions, this means providing a function and the arguments to ignore. Now we special case "quote", "~", "function", "$".

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(3) We might display full calls, or calls of the form foo <- bar(...) using ... when they're too long (we need single line and say <60 char, adjustable), so reading the diagram is much more like reading the actual code.

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(4)

We probably won't ever get there but I wonder if flow_view() and flow_view_vars() can be unified.

• control flows would be represented as functions of the existing variables they use, so we'd have for -> var1 and for -> var2 with green var1 and var2, also for -> i (or relevant variable). and then have a regular flow_view_vars style diagram in a box around it.

• To the for box we'd have var1 -> for_box and var2 -> for_box

• From the for box we'd repeat the the variables used by ulterior code, like for_box -> var1, for_box -> new_var, in default color.

Then we'd have the perfect logical flow, albeit probably very busy.