Initial commit: WAFER (WebAssembly Forth Engine in Rust)

Optimizing Forth 2012 compiler targeting WebAssembly with IR-based
compilation pipeline, multi-typed stack inference, subroutine threading,
and JIT/consolidation modes. Rust kernel with ~35 primitives and Forth
standard library for core/core-ext word sets.

forth/boot.fth

@@ -0,0 +1,23 @@
+\ WAFER Boot - Minimal bootstrap loaded first after primitives
+\ This file defines the most fundamental derived words needed
+\ before the rest of the standard library can load.
+
+\ These words are defined in terms of the ~35 Rust primitives.
+\ They form the foundation for core.fth and all subsequent files.
+
+\ TODO: Step 7/8 - Populate with bootstrap definitions once
+\ the compiler and outer interpreter are working.
+\ For now this file documents what will go here:
+
+\ Derived stack operations:
+\ : NIP    ( x1 x2 -- x2 )       SWAP DROP ;
+\ : TUCK   ( x1 x2 -- x2 x1 x2 ) SWAP OVER ;
+\ : 2DUP   ( x1 x2 -- x1 x2 x1 x2 ) OVER OVER ;
+\ : 2DROP  ( x1 x2 -- )          DROP DROP ;
+\ : ?DUP   ( x -- 0 | x x )      DUP IF DUP THEN ;
+
+\ Basic arithmetic derived from primitives:
+\ : 1+     ( n -- n+1 )          1 + ;
+\ : 1-     ( n -- n-1 )          1 - ;
+\ : NEGATE ( n -- -n )           0 SWAP - ;
+\ : ABS    ( n -- |n| )          DUP 0< IF NEGATE THEN ;