giäl

giäl is a BASIC-inspired programming language imitating the Rauma dialect. In rauma the term for 'language' is 'giäl' - hence the name of language. Apologies in advance to native speakers of Rauma.

The project is actually a translator: it translates giäl to assembly for x86. The assembler targeted is NASM. It is written in C++.

The project started with Jack Crenshaws's Let's Build a Compiler article series. Jack writes in Turbo Pascal and targets 68000, so code's been re-written, but I've stolen some of the ideas. Unlike Jack's compiler, giäl represents the parsed program as a tree-like structure before translation.

Online compiler

You can try gial using the online compiler here. The online compiler is possible with WASM (see ./wasm/).

Hello, world! / Terveissi!

The canonical hello world! -example in giäl is simply:

SAN NY 'hello world!'

To illustrate the use giäl, let's extend the example by translating "hello world" into Rauma (it's terveissi!) and print it five times using a while-loop: That would look something like this in pseudocode:

i = 0
WHILE (i < 5)
    PRINT 'Terveissi!
    PRINT
    i = i + 1
END WHILE

The output being (of course) the string 'Terveissi!' printed out five times.

In giäl the same can be achieved with:

LUGU i = 0
GUHA (i < 5)
    SAN NY 'Terveissi!'
    SIKSES
    i = i + 1    
NYLOPPUS

Alternatively one can use a construct for repeating a block of code N-times:

TOIST 5 
    SAN NY 'Terveissi!'
    SIKSES
NYLOPPUS

Features

Giäl can do:

• Integer arithmetic with operators +, -, * and /
• Complex expressions, eg. ((1*3) + 2)/5
• Boolean expressions with operators ==, !=, <, >, <= and >=, eg. ( ((1==1) AND 1 > 5) OR 8 < 9)
• Control structures like IF, IF ELSE, WHILE
• String indexing (see examples, RaumTranslator.gl)
• Arrays (see examples arrays.gl)
• I/O, atm. only through stdio and stdout

Syntax

In giäl, keywords are written in CAPS. The following table lists keywords of giäl and the corresponding term in "conventional programming wisdom" (whatever that means). If there's no corresponding term, an english translation is provided.

conventional term/expression	giäl
PRINT \n	SIKSES
PRINT	SAN NY
INPUT	SAN SNÄÄ
AND	JA
OR	TAI
IF	JOS
END	NYLOPPUS
WHILE	GUHA
STRING	SANAMBÄTK
INTEGER	LUGU
REPEAT	TOIST
FOR x = 0 TO 10 STEP 1	TOST x = 0 TOHO 10 HYBYL 1

(If you have trouble with the encoding you can replace 'Ä' with 'A' in the keywords. This is what the compiler does anyways. So SAN SNÄÄ is equal to SAN SNAA.)

Compiling

Assuming you have g++ and nasm at your disposal, follow these steps.

First, create a folder 'build' and run make:

mkdir -p build && make

Next, translate the example program written in giäl and pipe the result into an .asm file:

./build/gl example/terveissi.gl > ./build/terveissi.asm

Assemble and link with ASCII:

nasm -f elf64 asm/ASCII.asm -o build/ASCII.o
nasm -f elf64 build/terveissi.asm -o build/terveissi.o
ld -o ./build/terveissi.out ./build/terveissi.o ./build/ASCII.o

And you're done. Run the program:

./build/terveissi.out

Testing

Testing is implemented with BATS (included as a submodule).

Get submodule

git submodule update --init --recursive

To run all tests:

make tests

To test for memory leaks, use:

make memcheck