I'm using a command-line interface of Mathematica, or /usr/bin/wolfram. In wrapping this cui program with GNU Readline library, I would like to omit the In[n] := prompt. In other words, I'd like to change

~ $ /usr/bin/wolfram
Wolfram Language 11.3.0 Engine for Linux ARM (32-bit)
Copyright 1988-2018 Wolfram Research, Inc.

In[1]:= 3 + 5                                                                                           

Out[1]= 8

In[2]:= f[x_] := x^


~ $ /usr/bin/wolfram
Wolfram Language 11.3.0 Engine for Linux ARM (32-bit)
Copyright 1988-2018 Wolfram Research, Inc.

3 + 5                                                                                           

Out[1]= 8

f[x_] := x^

Is there any options which omit or change the prompt?


-noprompt command line option gives this.

~ $ /usr/bin/wolfram -noprompt
3 + 5                                                                                           
f[x_] := x^

This also omits the Out[n]= prompt and a blank line, both of which I don't want to remove. (If these can be shown in some way, the -noprompt options is enough for me.)

Finally, thanks to the really great help of Somos' answer, I came true what I wanted to do by writing the code below to the configuration file ~/.WolframEngine/Kernel/init.m.

ST[] :=
        input = InputString[""];
        If[input == EndOfFile, Quit[]];
        If[input == "", Continue[]];
        Print["Out[", ++$Line, "]= ", ToExpression[input]];

What I get now: enter image description here

By combining wolfram command and GNU Readline Library, you can equip mathematica with a highly functional line editor. As shown in the gif file above,

  • completion of words
  • highlighting an opening bracket when the corresponding closing bracket is typed
  • rapid cursor movement not only to line's head or tail but also to any position like "next word" or "next occurrence of an alphabet Z".
  • partly editing a line (e.g. delete next two words from the current position, or delete from this opening bracket to the corresponding closing bracket)
  • history search (not shown in the gif)
  • etc.

are realized with custom key-binding which you like (e.g. I'm using wolfram command with vim-like keybindings).

(rlwrap suggested in MATHEMATICA - Completion in terminal? doesn't work well with recent wolfram command. Also JMath: A GNU Readline based frontend for Mathematica is out-dated. What I did is similar to Mathematica with a GNU readline input (Python recipe), though I write a longer C++ code to explicitly use Readline library and turn on additional functionality like completion.)

  • $\begingroup$ What do you mean exactly by "wrapping this cui program with GNU Readline library"? $\endgroup$ – Somos Jun 22 '19 at 7:05
  • $\begingroup$ "wrap" is a general word (at least in linux community I reside in) that means "to program a functional or user-friendly interface for some hard-to-use or too-complicated program". In my case, by using GNU Readline library, I wanted to compensate the non-sophisticated line editing functionality of wolfram command. $\endgroup$ – ynn Jun 22 '19 at 10:33
  • $\begingroup$ And you plan to do this with the "rlwrap" program perhaps? Or some other way to get Mathematica to use "readline"? $\endgroup$ – Somos Jun 22 '19 at 10:36
  • $\begingroup$ @Somos No. There is no "plan" any more. Thanks to your help, I succeeded in using Readline with mathematica. (Actually In[] := prompt interferes with Readline, so I wanted to omit this to make my program more useful.) $\endgroup$ – ynn Jun 22 '19 at 10:42
  • $\begingroup$ Surprising to me, I just discovered that the Mathematica CLI that I was using already has "readline" editing and history, but no tab completion. How strange. $\endgroup$ – Somos Jun 22 '19 at 11:02

You may be able to use some code like this

repl[prompt_: ""] := Module[{input}, Print[]; While[True,
  input = InputString[prompt]; If[input == "quit", Break[],
     Print[]; Print["Out[", ++$Line, "]= ",   
       ToExpression@input]]; Print[]]];

an example of a Read-eval-print loop function which may do what you want and can be easily customized.

An example session is as follows

Mathematica 10.2.0 for Microsoft Windows (32-bit)
Copyright 1988-2015 Wolfram Research, Inc.

In[1]:= repl[prompt_: ""] := Module[
       {input}, Print[]; While[True,
        input = InputString[prompt];
        If[input == "quit", Break[], Print[];
         Print["Out[", $Line++, "]= ",   
           ToExpression@input]]; Print[]]]];

In[2]:= repl["? "]

? 3 + 5

Out[3]= 8

? f[x_] := x^2;

Out[4]= Null

? f[3 + 5]

Out[5]= 64

? quit

  • $\begingroup$ Thank you very much. This is truly what I wanted. By the way, do I have to call repl[] explicitly every time I start wolfram command? ($Line variable is not available before the first In[1]:= prompt is displayed, so I couldn't call repl[] in the configuration file.) $\endgroup$ – ynn Jun 22 '19 at 10:36
  • 1
    $\begingroup$ The example session was just an example. I don't have access to Wolfram Language engine so I can't test it out for myself. There is probably a way to get repl[] defined and called at startup. I don't know any details. I don't think it is a problem to call repl[] in a config file. Also I am not sure about $Line. You can also use your own line counter. $\endgroup$ – Somos Jun 22 '19 at 10:41
  • $\begingroup$ By using my own line counter, now I can call repl[] from the config file. That's perfect. Thank you :) $\endgroup$ – ynn Jun 22 '19 at 11:04

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