Summing lists in directory structure

[DavidM]

Here's an additional example of one way to approach this.

As written, the following RPL program needs to be saved in the root of your HOME directory (or in a library) so that it can be accessed appropriately. It could be saved somewhere else if you make a minor change to it, though I'll leave that as an exercise for the reader.

Code:

DODIRS
\<<
  \-> prog      @ save the program given as an argument in a local variable
  \<<
    prog EVAL   @ execute the program in the current directory
    15 TVARS    @ obtain a list of any subdirectories in the current directory
    IF { } OVER SAME NOT THEN             @ if any subdirectories exist...
      1 \<< EVAL prog DODIRS \>> DOSUBS   @ execute DODIRS on all of them
    ELSE        @ else there weren't any subdirectories
      DROP      @ drop the empty list; nothing further to process
    END
  \>>
\>>

DODIRS takes another RPL program in stack level 1 as an argument, then executes it in the current directory and each "child" subdirectory to the current one.

As an example, let's say that you wanted to obtain a list of all of the directories currently defined in your directory tree. You can do this simply by setting HOME as your current directory, then passing a simple program to DODIRS which updates a result list as the directory tree is traversed:

Code:

TestDODIRS
\<<
  {} PATH \-> result cd
  \<<
    HOME
    \<<
      PATH 1 \->LIST 'result' SWAP STO+
    \>>
    DODIRS
    result
    cd EVAL
  \>>
\>>

Hopefully the combination of Pier's and these examples will spark some ideas for you.