Run calculations using libqalculate from a rofi menu.

Compared to rofi-calc, which calls the libqalculate CLI, rofi-qalc interfaces with the qalculate library.

This provides a number of benefits:

• Plotting works --- a single GNUplot window is updated in the background;
• Variables can be used --- but see the note at the end of this section;
• Marginally faster --- while not a goal of mine, maybe it matters to someone else.

Not very well tested as of yet, but give it a try if you missed any of the same features I did. Uses the same history file as rofi-calc, so if you have anything important there then back it up just-in-case.

A note on variables: since rofi doesn't provide a way to clear the filter textbox contents then using variables is a bit iffy when disabling the filter auto-clear. To use variables you first must type the expression, e.g. ten = 10 and then clear the textbox by pressing Ctrl-F.

When you clear the textbox by deleting the text gradually then rofi will at some point call the rofi-qalc mode with ten =, which is parsed by libqalculate as ten = 0, zeroing out the variable.

Variables are not persistent throughout multiple sessions.

First install libqalculate and rofi, as this project depends on them.

If you're using an older version of rofi (not built from next branch) then you'll also need to set the option use_rofi_next to false during config.

# Generate project files
meson setup build \
    --buildtype=release \
    --optimization=3 \
    -Dstrip=true \
    -Dlibdir=lib/rofi \
    -Dprefix=/usr
# If using older rofi then also add:
#   -Duse_rofi_next=false

# Compile the project
meson compile -C build

Arch Linux users can make use of the provided PKGBUILD file and install the resulting package.

To try out rofi-qalc you can provide the plugin search path as a command line argument, e.g.:

cd /path/to/rofi-qalc
# configure, build, etc..
rofi -plugin-path ./build -show "qalc"

For development purposes it might be worthwhile to enable logging for the rofi-qalc module, e.g.:

G_MESSAGES_DEBUG=rq rofi -show "qalc"

Enter your expression in the filter box.

Select the "Add to history" option to add the result to history. Ctrl-Enter on the "Add to history" option will add the result to history without saving it (will only be displayed during current session, indicated by (tmp) prefix).

This mode supports the following command-line arguments:

• -eval-timeout-ms --- evaluation timeout passed to libqalculate;
• -no-history --- disables history file access;
• -automatic-save-to-history --- auto-save last entered expression to history when quitting;
• -history-only-save-results --- disables saving of expressions to history (e.g. instead of 2*10 = 20 the history will show just 20);
• -history-length --- maximum number of lines of history to keep;
• -no-auto-clear-filter --- disables automatic clearing of the filter textbox;