Language Description

starsep-lang is imperative language with functional features. Its grammar is based on Latte with my extensions.

Program Structure

Program is list of functions. The main function is executed.

Functions

• can be recursive
• arguments are passed by value (copy)
• can be passed as arguments

Types

• int
• char
• string (equivalent to list<char>)
• bool
• float
• list type:

  void main() {
    list<int> emptyIntList = int[];
    list<int> append = 5 $ emptyIntList;
    list<int> join = append ++ append;
    list<char> stringList = "abc";
    list<int> listConstructor = int[1, 2, 3, 42 + 5];
  }

• function type:

  void foo1() {}
  void foo2(int x) {}
  int foo3() { return 42; }
  int foo4(int x, int y) { return x + y; }
  void main() {
    fn<void> bar1 = foo1;
    fn<int -> void> bar2 = foo2;
    fn<int> bar3 = foo3;
    fn<int -> int -> int> bar4 = foo4;
  }

Variables

• declared by Type VarName
• can be initiated at declaration by Type VarName = value
• variables can also be declared with auto VarName = value, must be initiated then
• consts are declared by let ConstName = value
• if variable is not initiated then it gets default value: 0 for int, false for bool, empty string for string, 0.0 for float, null char for char

Operators

• arithmetic: + - * / %
• parenthesis ( )
• logical: ! && ||
• comparison: < > <= >= == !=
• assignment: = += -= *= /= %=
• list: $ (append), ++ (join)
• ternary operator (like in C) boolExpr ? expr1 : expr2

Comments

• single line comments start with # or //
• multiline comments C-style, start with /*, end with */

Control flow

• if

 if BoolExpr1 {
    // instructions1
  } elif BoolExpr2 {
    // instructions2
  } else {
    // instructions3
  }

• while

 while BoolExpr {
    // instructions
  }

• loop is equivalent of while true
• for c++-like

 for Oper1; BoolExpr; Oper2 {
    // instructions
  }

• foreach

  for varName in someList {
    // instructions
  }