Number interface methods in source order and check each class against every
implemented interface, reporting missing, private, mismatched, conflicting,
and non-interface implementations at the class declaration.

Generated with Codebuff 🤖
Co-Authored-By: Codebuff <noreply@codebuff.com>

types.s gives every expression a type and applies the spec 3.4/8
conversions, operator table, constant folding and diagnostic spellings.
parser.s records implements lists and init rows in pass 1, carries types
through member chains, groups, calls and indexing in pass 2, and checks
assignments, arguments, returns, conditions, for, print, delete and member
access. A method that declares a result must end in return; a missing one
is E150 at end, and a program return value is E151.

Three older parser fixtures gain true diagnostics. The lexer's host
reference formatter now spells bytes such as {0D} correctly, and the demo
tolerates a missing ERR file.

Verified in x128: 37 parser fixtures, 10 lexer fixtures, the 67-entry
diagnostic catalog, and the Vim-to-N8CHECK demo (good.n8 clean, bad.n8's
four diagnostics).

Generated with Codebuff 🤖
Co-Authored-By: Codebuff <noreply@codebuff.com>

parse_statement parses every spec 7 form (assignment, call, if/else,
while, for/to/step, return, print, delete) and requires the line to end
after it. Expressions use precedence climbing over spec 8's levels: binary
operators left associative, unary not and - nesting rightwards, postfix
member access, calls, and indexing tightest. A syntax error is reported in
pass 1, unwinds to the statement, and skips the line; E03-S02's name,
member, and access checks now run from the parser in pass 2, replacing the
token scan. Expression nesting is bounded at 16 levels (E225).

Verified in x128: 31 fixtures, including the two statement fixtures that
were pending since E03-S01, a postfix trace golden for precedence and
associativity (both mutations caught), every statement form, and 15
independent syntax errors with recovery. Lowest stack pointer $A7. New
diagnostics E038-E042 and E225. The demo passes; its Vim typing is slowed
to 200 ms per key after one doubled keystroke.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

scripts/demo-write-check.ps1 types each demo program into the Vim clone
on x64sc (fresh copy of vim/work.d81), confirms the saved SEQ file matches
its ASCII mirror, then runs demo/n8check.s on x128: a DEMO driver (not
N128C) that asks for a file name and runs the current front end (source
reader, lexer, names, parser) with on-screen diagnostics and NAME.ERR.
good.n8 checks clean; bad.n8 reports its four intended errors.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>