PINSCompiler

A Java compiler made for PINS Language (a made up language) as part of undergraduate Compilers class.

Usage

"example" files in the root directory are examples of valid source codes in PINS Language.

To compile source file: PINS example.

Use --exec <phase> to execute only phases up to selected phase. Options are: LEX, SYN, AST, NAME, TYP, FRM, IMC, INT.

Compiler phases

1. Lexical analysis - break down the source code into tokens and remove comments and whitespace
2. Syntax analysis - parse tokens employing the context-free grammar described below
3. Abstract syntax - create an abstract syntax tree (AST) to represent the syntactic structure
4. Semantic analysis - check types, scope (using double pass), names
5. Stack frame generation - create stack frames for function calls (allocate memory on call stack for local variables, parameters, return addresses)
6. Intermediate code generation - translate AST into IM (intermediate code) that is more platform independent and suitable for optimization
7. Interpreter - execute generated intermediate code

PINS Language

Defined in pins.pdf (in Slovenian). Supported types are logical, integer, string and arrays (multi-dimensional). To create a new scope, use expression { WHERE definitons}. A name is visible in entire scope. Standard library is also implemented (print_int, print_str, print_log, rand_int, seed).

Context-free grammar (CFG)

source -> defs .

defs -> def defs2 .
defs2 -> ';' def defs2 .
defs2 -> .

def -> type_def .
def -> fun_def .
def -> var_def .

type_def -> typ id ':' type .
type -> id .
type -> logical .
type -> integer .
type -> string .
type -> arr '['int_const']' type .

fun_def -> fun id '('params')' ':' type '=' expr .

params -> param params2 .
params2 -> ',' param params2 .
params2 -> .

param -> id ':' type .

expr -> logical_ior_expr expr2 .
expr2 -> .
expr2 -> '{' WHERE defs '}' .

logical_ior_expr -> logical_and_expr logical_ior_expr2 .
logical_ior_expr2 -> '|' logical_and_expr logical_ior_expr2 .
logical_ior_expr2 -> .

logical_and_expr -> compare_expr logical_and_expr2 .
logical_and_expr2 -> '&' compare_expr logical_and_expr2 .
logical_and_expr2 -> .

compare_expr -> add_expr compare_expr2 .
compare_expr2 -> '==' add_expr .
compare_expr2 -> '!=' add_expr .
compare_expr2 -> '<=' add_expr .
compare_expr2 -> '>=' add_expr .
compare_expr2 -> '<' add_expr .
compare_expr2 -> '>' add_expr .
compare_expr2 -> .

add_expr -> mul_expr add_expr2 .
add_expr2 -> '+' mul_expr add_expr2 .
add_expr2 -> '-' mul_expr add_expr2 .
add_expr2 -> .

mul_expr -> pre_expr mul_expr2 .
mul_expr2 -> '*' pre_expr mul_expr2 .
mul_expr2 -> '/' pre_expr mul_expr2 .
mul_expr2 -> '%' pre_expr mul_expr2 .
mul_expr2 -> .

pre_expr -> '+'pre_expr .
pre_expr -> '-'pre_expr .
pre_expr -> '!'pre_expr .
pre_expr -> post_expr .

post_expr -> atom_expr post_expr2 .
post_expr2 -> '[' expr ']' post_expr2 .
post_expr2 -> .

atom_expr -> log_constant .
atom_expr -> int_constant .
atom_expr -> str_constant .
atom_expr -> id atom_expr2 .
atom_expr2 -> .
atom_expr2 -> '(' exprs ')' .


atom_expr -> '{' atom_expr3 .
atom_expr3 -> if expr then expr atom_expr4 .
atom_expr4 -> '}' .
atom_expr4 -> else expr '}' .
atom_expr3 -> while expr ':' expr '}' .
atom_expr3 -> for id '=' expr ',' expr ',' expr ':' expr '}' .
atom_expr3 -> expr '=' expr '}' .

atom_expr -> '(' exprs ')' .

exprs -> expr exprs2 .
exprs2 -> ',' expr exprs2 .
exprs2 -> .

var_def -> var id ':' type .