How to allow stdin prompts when running an app with runMain?

[ldeck]

If I run sbt via a standard terminal and runMain my.MainObject I can provide stdin if prompted. Doing the same in emacs with sbt-start, once running the app as above the buffer is seemingly read-only. How do you provide input?

[hvesalai]

sbt-mode uses comint for terminal interaction. Comint puts the terminal to read-only when not on a line that has a prompt.

Read about it here: https://www.gnu.org/software/emacs/manual/html_node/emacs/Shell-Prompts.html

So you have some options:

• use the sbt-clear command to clear the buffer (M-x sbt-clear). This also clears the read-only status.
• temporarily set the comint-prompt-regexp variable to Nil (use M-x set-variable)
• if it is your project, make the MainObject output a prompt that is compatible with the propt regex (see https://github.com/hvesalai/emacs-sbt-mode/blob/master/sbt-mode-comint.el#L36), such as, for example, >. However, this might make things funny.

[ldeck]

Thanks @hvesalai for the hints. sbt-clear certainly works, though I wonder: is there also a function to merely clear the read-only status without clearing the buffer?

Setting comint-use-prompt-regexp to nil from t doesn't appear to help, not clearing the regex itself.