nx_glsl_tok_lib.nx

nx_glsl_tok_lib.nx -- THE SHADER TOKEN RULER (gameengine S12c accept-rule instrument, 2026-09-05). WHY: the cast port's pre-declared accept rule says the IR-emitted GLSL must match the hand-written MVS/MFS at ZERO normalised-token distance before its WGSL twin is trusted. A byte diff cannot be that ruler (the hand shader has formatting freedom, comments, `.5` for `0.5`, `br/=nr` for `br=br/nr`) and a string-run ruler cannot either (it has no grammar). This lib is ONE tokenizer + ONE canonicaliser + ONE compound-assignment expander + ONE differ, composed in-process by nx_glsl_tokdiff (the program) and nx_glsl_tokdiff_gate (planted fixtures, both directions). NORMALISATIONS, each named: whitespace and comments dropped; numeric literals canonicalised (`.5`->`0.5`, `1.`->`1.0`, trailing f/F/u/U dropped); `x op= y` expanded to `x = x op y` for op in + - * / where x is an lvalue of the grammar ident ( '.' ident | '[' ... ']' )* -- any other shape is left literal and COUNTED (expand_refused=), never guessed. Everything else must match token for token: a renamed identifier, a moved parenthesis, a changed constant is a DIFF, and the first differing token is named with both spellings. Token = 3 words (start, len, kind); kinds 1 ident, 2 number, 3 operator/punct. Buffers are sized from the input (one token cannot be shorter than one byte, so 3*n words is a bound that cannot overflow -- no guessed cap). license_tier: ORIGINAL No hw writes (Rule 26).