LDPLNOISE

LDPL 4.3 extension with linenoise support. linenoise is a lite version of readline, originally at https://github.com/antirez/linenoise.

This version wraps https://github.com/yhirose/cpp-linenoise.

Usage

There's only one required variable: RL-INPUT. You must declare it before using this extension:

DATA:
RL-INPUT is EXTERNAL TEXT

The optional variables are:

• RL-PROMPT
  • Defaults to > and allows you to customize the prompt shown to users.
• RL-HISTORY-FILE
  • Can be set to the path to the history file for this program.

To actually use the library, call the RL-ACCEPT subroutine to prompt the user for input:

STORE "Type something: " IN RL-PROMPT
CALL EXTERNAL RL-ACCEPT

What the user inputs will be put into the RL-INPUT text variable:

DISPLAY "You entered: " RL-INPUT CRLF

So the above will print:

Type something: <user types Dave and presses >
You entered: Dave

To record history for a single session, call RL-ADD-HISTORY after calling RL-ACCEPT. The content of the RL-INPUT variable will be added to the history.

To persist history across sessions, you need to save and load a history file. To do so, first set the RL-HISTORY-FILE text variable to the location of your history file, then use the RL-LOAD-HISTORY and RL-SAVE-HISTORY subroutines to load/save the history when your LDPL program begins and ends:

# ...program starts...
STORE "history.txt" IN RL-HISTORY
CALL EXTERNAL RL-LOAD-HISTORY
# ...main program code...
CALL EXTERNAL RL-ACCEPT
CALL EXTERNAL RL-ADD-HISTORY
# ...before the program exits...
CALL EXTERNAL RL-SAVE-HISTORY

Setup

The easy way to include LDPLNOISE in your project is to clone this repo into it and tell the the ldpl compiler where to find ldplnoise.cpp:

cd my-great-ldpl-project
git clone https://github.com/xvxx/ldplnoise
ldpl -i=ldplnoise/ldplnoise.cpp my-code.ldpl
./my-code-bin

You can also use the EXTENSION statement in your LDPL files:

EXTENSION "ldplnoise.cpp"

Example

git clone https://github.com/xvxx/ldplnoise
cd ldplnoise
make example

This should launch you into a basic prompt that echos what you type and remembers you history for that session. To exit, just type "quit" or "exit", submit an empty line, or hit Ctrl-C.

Check out example.ldpl to see an example of using the extension.

LDPL API

Variables:

RL-INPUT          # text entered by the user during RL-ACCEPT
RL-PROMPT         # text prompt shown to user. optional
RL-HISTORY-FILE   # text path to history file

Subroutines:

RL-ACCEPT                # main readline()-like prompt function.
RL-LOAD-HISTORY          # load command history from RL-HISTORY-FILE
RL-SAVE-HISTORY          # save command history to RL-HISTORY-FFILE
RL-ADD-HISTORY           # add content of RL-INPUT to the history
                         # should be called after RL-ACCEPT