CODEWITHSUNDEEP
haskellemacsintero
Mike Flynn
Mike Flynn

Reputation: 1027

Haskell / Intero - send lines to Intero REPL buffer

I've been attempting to use Haskell for running a simple production process. Like many production processes, it involves changing the states of things all over the place. For this reason, it would be really handy for me to have a script file where I could keep track of things and selectively run commands into interactive Haskell, something like

-- to start the process
process <- startProcess

-- to stop process
stopProcess

-- to check how things are going
summary <- checkStuff
summary 

-- optionally restart bad processes
restartProcesses (getBadProcesses summary)

-- send summary emails
sendSummaryEmails summary ["[email protected]", "[email protected]", 
                           "[email protected]" "[email protected]",
                           "[email protected]"]

-- set up something big that I don't want to have to retype/paste every time
studentGrades <- getStudentGrades "John Peterson"
gen <- getStdGen
let (randomTest, gen') = generateRandomTest studentGrades gen
compilePdf randomTest
answers <- getAnswers
gradeTest randomTest answers "John Peterson"

It would be really cool if, like with ESS (Emacs speaks statistics) in R, if you could press a button to send these lines to the repl process. Maybe seperate buttons for line, paragraph, region. Is there already a way to do this?

For example with ESS, C-Ret sends the line, C-c C-c sends a paragraph, and C-c C-r sends a region.

Upvotes: 4

Views: 650

Answers (1)

V. Semeria
V. Semeria

Reputation: 3256

This emacs lisp function will send a command to haskell's repl

(defun haskell-send-command (cmd)
  (process-send-string (inferior-haskell-process) (concat cmd "\n")))

and this will call the previous one with the current selection 

(defun haskell-send-selection ()
  (interactive)
  (haskell-send-command (x-selection)))

You can assign it a keyboard shortcut with global-set-key. Then you need to figure out how to quickly select what you want to send. For instance M-h is mark-paragraph. Or just recode the ESS functions you like :

(defun haskell-send-paragraph ()
  (interactive)
  (mark-paragraph)
  (haskell-send-selection))

I actually used those to build a small debugging GUI for Haskell in emacs. I have shortcuts for setting breakpoints and stepping, and the position of the debugger highlights directly in the haskell code.

Upvotes: 1

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