README.md

Alpha Compiler

For the project of HY340 (@CSD) we created a compiler intended for the alpha programming language, and a virtual machine (Implemented in C) wich runs out generated target code.

Project Stracture

The project contains the following directories

• inc (The header files used)
  • parser
  • vm
• pdfs (The course's pdfs)
• src (The source directory of the project)
  • parser (lexer, parser and intermidiate/target code generator)
  • vm (Virtual machine in C intended for our parser's target code)
• tests (some example testfiles)

Compiling the project

• First of all, you should compile the project using the make command
  
• The ./bin directory should have been created, containing two executables: acomp and avm. This sohould mean the project has compiled succesfully! (Addidtional information about the compilation process can be found in the terminal)
• After the project is compiled you can compile and run your alpha code files by using the make rule make <input file>.asc

Runing the Compiler

The compiler executable syntax is as followed:

./bin/acmop <input file>

Our compiler creates three files:

• output.txt (Contains the easily readable quads)
• alpha.out (Binary file intended for the virtual machine)
• output_comparison/parser_generated.txt (A readable version from the contents of the binary file as the parser genrated it)

Running the Virtual Machine

The virtual machine executable syntax is as followed:

./bin/avm <input file (alpha.out)>

Our virtual machine creates:

• output_comparison/vm_parsed.txt (A readable version from the contents of the binary file as the virtual macined parsed it)

Demonstration

You can run (Compile and Run) all the original testfiles by using the following make rule:

make tests

Alpha programming language syntax

Specifics about the alpha language syntax can be found on pdfs/assignments/2_syntax_analysis.pdf

The Alpha language grammar is as follows:

program     ->  stmt*
stmt        ->  expr ;
                | ifstmt
                | whilestmt
                | forstmt
                | returnstmt
                | break ;
                | continue;
                | block
                | funcdef
                |;

expr        ->  assignexpr
                | expr + expr
                | expr - expr
                | expr * expr
                | expr / expr
                | expr % expr
                | expr > expr
                | expr >= expr
                | expr < expr
                | expr <= expr
                | expr == expr
                | expr != expr
                | expr and expr
                | expr or expr
                | term

term        ->  ( expr )
                | - expr
                | not expr
                | ++lvalue
                | lvalue++
                | --lvalue
                | lvalue--
                | primary

assginexpr  ->  lvalue = expr

primary     ->  lvalue
                | call
                | objectdef
                | ( funcdef )
                | const

lvalue      ->  id
                | local id
                | :: id
                | member

member      ->  lvalue . id
                | lvalue [ expr ]
                | call . id
                | call [ expr ]

call        ->  call ( elist )
                | lvalue callsuffix
                | ( funcdef) ( elist )

callsuffix  ->  normcall
                | methodcall

normcall    ->  ( elist )

methodcall  ->  .. id ( elist ) // equivalent to lvalue.id(lvalue, elist)

elist       ->  [ expr [, expr] * ]

objectdef   ->  [ [elist | indexed] ]
indexed     ->  [indexedelem [, indexedelem] * ]
indexedelem ->  { expr : expr }

block       ->  { [stmt*] }
funcdef     ->  function [id] (idlist) block

const       ->  number | string | nil | true | false
idlist      ->  [id [, id] * ]

ifstmt      ->  if ( expr ) stmt [ else stmt ]

whilestmt   ->  while ( expr ) stmt

forstmt     ->  for ( elist; expr; elist) stmt
returnstmt  -> return [expr];

Debugging

Debugging the compiler

In order for the compiler to print debug information on the terminal, tou have to set yydebug to 1 at src/parser/bison_parser.y:1308.
While compiling, the compiler will display reduction information.

Debugging the Virtual Machine

To debug the VM, you have to set AVMDEBUG definition to 1 at src/vm/alphavm.h:17 That way, the virtual machine will display execution details in the terminal.

Co owners

Orestis Chiotakis
Dimitris Bisias