ParsingCompiler

VŠB-TUO — School project · Programming Languages and Compilers (PJP)

A complete compiler and interpreter for a custom statically-typed programming language, built with ANTLR4. The pipeline covers four stages: parsing, type checking, stack-based code generation, and interpretation.

 

Pipeline

Stage	Description
Parser	ANTLR4 lexer + parser, reports all syntax errors
Type checker	Semantic analysis, validates type compatibility
Code generator	Produces 26-instruction stack-based bytecode
Interpreter	Executes the generated bytecode

Language Specification

Types and literals

Type	Literal	Default
int	sequence of digits	0
float	digits with .	0.0
bool	true / false	false
string	"text"	""

Variables must be declared before use. Repeated declaration is an error. int values automatically promote to float where needed — there is no reverse conversion.

Statements

• type var1, var2; — variable declaration
• expression; — expression statement (assignment has side effects)
• read var1, var2; — read values from stdin
• write expr1, expr2; — write values to stdout, newline after last
• { ... } — block
• if (cond) stmt [else stmt] — conditional
• while (cond) stmt — loop
• // — single-line comment

Operators (lowest to highest precedence)

Operator	Signature
=	x × x → x (right-assoc)
||	B × B → B
&&	B × B → B
== !=	x × x → B
< >	x × x → B (numeric)
+ - .	arithmetic / string concat
* / %	I × I → I or F × F → F
!	B → B
unary -	I → I or F → F

Instruction set (stack-based VM)

Instruction	Description
push T x	Push value x of type T (I/F/S/B)
pop	Discard top of stack
load id	Push variable value
save id	Pop and store into variable
add sub mul div mod	Binary arithmetic
uminus	Unary minus
concat	String concatenation
and or not	Boolean logic
gt lt eq	Comparisons
itof	Convert int to float
label n	Mark jump target
jmp n	Unconditional jump
fjmp n	Jump if top of stack is false
print n	Pop and print n values
read T	Read value of type T from stdin

Requirements

• Java 21+
• Maven 3.8.1+ (ANTLR 4.9.2 managed automatically)

Setup

1. Clone the repository:

   git clone https://github.com/Firestone82/ParsingCompiler.git
   cd ParsingCompiler

2. Build:

   mvn clean package

3. Run a program:

   java -jar target/ParsingCompiler-*.jar path/to/program.lang

Sample programs and error examples are in the src/main/antlr4/Project/ directory.

License

This project was created as a school assignment at VŠB-TUO.