Simplang

Simplang is a simple and lightweight, dynamically-typed interpreted scripting language meant to teach the basic concepts of logic and control-flow to beginning programmers without the cognitive overhead of trying to learn a general-purpose language.

Official course coming soon to simplang.dev

See the new official VSCode plugin here!

Usage

Simplang supports executing script files or operating as a repl interactively. To execute a script, use #!/usr/bin/env simplang as your shebang, or run simplang <script file>, and to use the repl, just run simplang with no arguments. You can pass integers to your Simplang scripts as command line arguments, and the script will run with its int registers pre-initialized to the supplied values, sequentially starting from r0.

Here's an example Simplang script:

#!/usr/bin/env simplang

assign welcome_msg "Welcome to Simplang!"
print welcome_msg
assign num1 6
assign num2 3
add num1 num2
print num1
done

Running this script will print "Welcome to Simplang!" on one line, followed by 9 on the next.

All Simplang scripts need to end with done on the last line. Simplang supports up to 24 uniquely named variables, which can either be integers or strings. Comments begin with ;. They must be on their own line, but may be indented, and there must be at at least one whitespace character between the semicolon and the comment text.

There are more examples that you can run in the tests/ directory.

Building/Installing

git clone https://github.com/calebstein1/simplang
cd simplang
make
sudo make install

This will produce a simplang binary in the bin/ directory. There are no dependencies outside of the C standard library. Simplang is self-contained in a single binary, make install copies this binary to /usr/local/bin, and make uninstall deletes it.

Reference

assign <a1> <a2> - stores the value specified by a2 in the variable specified by a1

new_array <a1> <a2> - create a new array named a1 of size a2

random <a1> <a2> - stores a pseudo-randomly generated number in the variable specified by a1 between 0 and a2 - 1

get_input <a1> <a2> - prints a string literal prompt specified by a2 and gets and input from the user to store in the variable specified by a1 if that variable hasn't already been filled

(add, subtract, multiply, divide, modulo) <a1> <a2> - perform the arithmetic operation specified on the value stored in the a1 variable with the number specified by a2, then store the result back in a1

(increment, decrement) <a1> - increment or decrement the value stored at the variable specified by a1

swap <a1> <a2> - swap the values stored in the variables specified by a1 and a2

begin_loop - begins a loop

for_each <a1> in <a3> - iterate over each item in the array a3, with a1 being the named reference to the current item and "next" being the next item

continue - jump back to the beginning of the current loop

end_loop - end a for_each loop

(end_loop_if_equal, end_loop_if_not_equal, end_loop_if_less, end_loop_if_less_or_equal, end_loop_if_greater, end_loop_if_greater_or_equal) <a1> <a2> - ends execution of a loop based on the condition comparing a1 and a2, otherwise jump back to beglp

(if_equal, if_not_equal, if_less, if_less_or_equal, if_greater, if_greater_or_equal) <a1> <a2> - executes the following code block based on the condition comparing a1 and a2, otherwise jump ahead to the next end_if

end_if - signifies the end of an if block

print <a1>...<aMax> - prints the integer value or string stored in each argument, separated by a space

print_array <a1> - prints the array specified by a1 as a string

done - ends execution of the program

Known Bugs:

• Trying to assign a variable to a constant number within a loop doesn't seem to be working properly in certain cases