fix: add unary minus and correct subtraction parsing (GH #315)

[toddr-bot]

What

Subtraction expressions now work correctly in MACRO arguments and all other contexts.

Why

The tokenizer's number regex (-?\d+) greedily consumed - as part of a negative number literal even after identifiers. This caused show(x-2) to tokenize as IDENT:x NUMBER:-2 (two separate args) instead of IDENT:x MINUS NUMBER:2 (a subtraction expression). The macro silently received only x, producing wrong results with no error.

Fixes #315.

How

Three coordinated changes:

• Tokenizer (Parser.pm): Removed -? from the number regex so - is always emitted as a separate operator token
• Grammar (Parser.yp + Grammar.pm.skel): Promoted - from BINOP to its own token (like + and /), added expr '-' expr for binary subtraction and '-' expr %prec UMINUS for unary negation. Widened range rule from sterm TO sterm to expr TO expr so [-2..2] continues to work
• Recompiled Grammar.pm from the updated grammar

Adds 4 S/R conflicts (total 5 S/R + 1 R/R), all correctly resolved by default shift preference — binary minus binds in expression context.

Testing

• All 3192 existing tests pass
• Added t/zz-unary-minus-gh-315.t with 25 tests covering: MACRO subtraction args, unary minus, assignment with negatives, precedence, double negation, negative ranges, negative floats, mixed unary/binary minus

[toddr-bot]

Recreated from #387 (auto-closed when the toddr-bot fork was removed). Original branch is now hosted on this repo.

[toddr]

@toddr-bot rebase

[toddr-bot]

Rebase with requested adjustments

Branch koan.toddr.bot/fix-unary-minus-parsing was rebased onto main and review feedback was applied.

Stats

5 files changed, 4441 insertions(+), 4135 deletions(-)

Actions performed

• Already-solved check: negative (confidence=high, reasoning=No commit in recent main history addresses unary minus parsing, subtraction tokenization, or GH Silent parsing failure when passing expressions to a MACRO #315)
• Resolved merge conflicts (1 round(s))
• Rebased koan.toddr.bot/fix-unary-minus-parsing onto origin/main
• Pre-push CI check: previous run passed
• Force-pushed koan.toddr.bot/fix-unary-minus-parsing to origin
• CI check enqueued in ## CI (async)

CI status

CI will be checked asynchronously.

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