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>

lexer.s turns cached source lines into tokens with stable kinds and error
codes (tokens.inc): 32 keywords, identifiers folded across both PETSCII
letter ranges, decimal/hex/binary numbers to 65535, strings and character
literals with escapes, all operators, and comments. An error reports its
exact column, then the rest of the line is skipped.

An independent host reference lexer and the C128 lexer in x128 both
reproduce the reviewed golden token files: 10 fixtures, 1,119 tokens,
including one fixture per error kind. A case-folding mutation is caught.

Spec 2.2 now lists <= and >=, matching section 8. D119 (proposed): the \n
and \r escapes both produce $0D. The monitor helper now reads RAM bank 0,
because BASIC ROM hides $4000+ after a program returns.

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