planck 2019-04-02 | Slack Archive

pyrmont02:04:42

@mfikes: Sorry to ping you but I've been trying to figure this out on my own to no avail. I have two questions relating to the form_prompt() function in planck-c/repl.c. (1) Why is the number two subtracted from the namespace length? (2) What significance does the #_ have in the sprintf() call? It doesn't seem to be a formatting character as best as I can tell but it presumably does something. I looked at linenoise.c and it doesn't seem to be part of the API there either.

mfikes15:04:05

@mike858 That's all related to the secondary prompt

cljs.user=> [1
       #_=>  2
012345678901234

In this case, cljs.user has a length of 9, and the space before the #_ has a length of 9 - 2 = 7. (This is where the 2 comes from in the code.) The length of "#_=> " is 5, and adding an extra for the trailing \0, you get 6, the other constant 6 you see in that bit of code.

pyrmont19:04:12

@mfikes: Ahhhhh, now it all makes sense. Thank you!

2019-04-02

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