notes/assignment1.md at master · compilers2019/notes · GitHub

update ATG EBNF grammar to introduce global variables. global VAR section. var_name : type (we have only one type now - INTEGER)
update grammar to introduce assignments. only numerical constants can be assigned to variables yet.

for example, if we declared global variable i : INTEGER; then after BEGIN section we can do: i := 42;

correct program which should parse:

PROGRAM testPrg;

VAR
    i: INTEGER;
	j: INTEGER;
	k: INTEGER;

BEGIN
  i := 42;
  j := 23;
  RETURN i;
END testPrg;

add generator module. it creates output assembler file with '.s' extension. it has section for program exit and startup. hint for startup: '.globl _start' hint for exit: 'exit syscall' hint for declaration:
```
.section .bss
.lcomm i, 4
.lcomm j, 4
```
hint for assignment:
```
  movl $42, i
```

assignment link: https://classroom.github.com/a/oKkfo9iF

deadline: 02/20/2019 23:59 +040

make sure ATG is correct
be able to compile a compiler. (main file may be necessary)
make sure the compiled compiler finds mistakes in example source. otherwise change ATG and generate compiler sources again.
add generator module.