chrisnevers/ocamline

👨🏻‍💻 Command line interface for user input

This library provides a simple interface for reading user input in OCaml programs. The goal of this project is to reduce the burden of reading user input for programming language REPLs.

The feature that makes this library particularly useful is its handling of brackets. Any brackets that are opened must be closed before input is accepted. This library uses ocaml-linenoise to provide rlwrap like functionality, including command history, arrow navigation, etc.

Example

Source Code:

read ~brackets:['(',')'] ~prompt:"lisp>" ()

Command Line:

lisp> (lambda
          (x)
          (+ x 1))
lisp>

API

val read :  ?trim_delim:bool ->
            ?brackets:(char * char) list ->
            ?prompt:string ->
            ?strings:char list ->
            ?history_loc:string ->
            ?hints_callback:(string -> (string * LNoise.hint_color * bool) option) ->
            ?completion_callback:(string -> LNoise.completions -> unit) ->
            ?delim:string ->
            unit ->
            string

Parameter	Description	Default Value
trim_delim	Whether or not to remove the line delimiter from the return value.	false
brackets	Any characters that once opened must be closed before the line is accepted	[]
prompt	Customizes the prompt displayed to the user.	">"
strings	String delimiters. If brackets are in strings, they won't have to be closed.	[]
history_loc	Where to store the history for the user commands	".ocamline_history.txt"
hints_callback	Linenoise's hints callback. See here	No op
completion_callback	Linenoise's completion callback. See here	No op
delim	The string that, when found, halts scanning and returns the input.	"" (* newlines *)

Contributions

Contributions to ocamline are greatly appreciated! ❤️

Please try to keep its implementation unassuming and configurable. 🙂

ocamline's Issues

Should a list of keywords be passed to ocamline such that they are hinted and completed if at the end of the line?

I'm implementing variable/module keyword hinting and completion in the gobba REPL.
A problem may emerge (as it just did) when completion keywords have sub-keywords that depend on data structures external to linenoise/ocamline and previous sections/words in the current line. Parsing and evaluating the whole line at every keystroke is not preferable.
See 0x0f0f0f/gobba#17. Adding a function similar to the gobba keyword lookup function (currently broken) to ocamline and generalizing it for lists of strings (and adding a recursion capable keyword-finding callback as an Ocamline.read argument) would be time saving for future projects using ocamline that may try to implement the same functionality.

Capability to edit previous lines after pressing return in multiline editing.

Use readline-like key bindings (ctrl-a, ctrl-e, left, right that behave like in bash)

Is your feature request related to a problem? Please describe.
No.

Describe the solution you'd like
ctrl-a, ctrl-e, left, right that behave like readline programs (like bash)

Release the new version with linenoise

C^d does not insert EOF anymore after linenoise was introduced [BUG]

If I press CTRL-D, EOF is not propagated from linenoise to ocamline and the empty line is ignored (ocamline tries to read another line)

A labeled argument in the read function to customize "quit" and "help"

Let users customize the completion callback