Add Y-lang prime number calculator: parser <=, assignment coercion, stdlib/primes

[Copilot]

Implements a Y-lang program that computes and prints the first 1000 prime numbers to stdout, compiled to a native Linux binary and verified against a Go-computed reference. Three blocking issues required fixes before the program could compile and run correctly.

Compiler / Parser Fixes

• parser/parser.go: <= (TokenTypeLessThanEqual) was lexed and codegen-handled but never registered as an infix operator — added to precedence table (LESSGREATER) and infix dispatch. Without this, while (i * i <= n) failed to parse.
• compiler/generator/assignment.go: Stores to typed pointer targets (e.g. i8* from mmap) now truncate or sign-extend the RHS to match the element type before emitting store. Enables byte-buffer writes:

  let buf = syscall(9, 0, 8, 3, 34, -1, 0);
  buf[0] = d + 48;  // i32 truncated to i8 before store

New stdlib Module

• lib/stdlib/primes/primes.y: Pure Y-lang stdlib module using Linux x86-64 syscalls only (no C runtime):
  • isPrime(n) — trial division; modulo emulated as n - (n/i)*i
  • print_digit(d) — single digit via mmap scratch buffer + SYS_write + munmap
  • print_int(n) — recursive decimal printer
  • print_primes(count) — iterates candidates, prints first count primes

Integration Test

• primes_test.go: Lexes → parses → compiles to LLVM IR → clang → runs binary → verifies all 1000 output lines against firstNPrimes(1000) computed in Go (first: 2, 1000th: 7919).

---

🔒 GitHub Advanced Security automatically protects Copilot coding agent pull requests. You can protect all pull requests by enabling Advanced Security for your repositories. Learn more about Advanced Security.