Adds Go unary prefix operators per Go spec § Operators:
+x -x !x ^x *p &v <-ch
gp-parse-unary is recursive (so !!x and -^x chain correctly) and
sits between gp-parse-expr and gp-parse-primary — unary therefore
always binds tighter than any binary op without needing a unary
entry in the precedence table.
Symbols +, -, *, &, ^ are shared between unary and binary forms;
the positional split (expression-start sees unary, mid-expression
sees binary) disambiguates them cleanly with no lookback.
Unary nodes are single-arg ast-app:
(ast-app (ast-var OP) (list OPERAND))
parse 37/37, total 166/166.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
gp-parse-expr / gp-pratt-loop implement classic Pratt climbing
against go-precedence-table (entry shape from lib/guest/pratt.sx).
The kit gives us pratt-op-lookup + accessors; the climbing loop
itself stays per-language (per kit header — Lua and Prolog have
opposite conventions).
Left-associative ops raise the right-recursion min by 1; right-
associative would keep prec. All Go binary operators are left-assoc.
AST shape: a binary node is emitted as
(ast-app (ast-var OP) [LHS RHS])
— canonical ast-app rather than a Go-specific binary node, since a
future evaluator can recognise operator-named apps without losing
information.
Coverage: equal-prec left-to-right, * tighter than +, && tighter
than ||, comparison tighter than &&, long left-assoc chains, mixed
literal+ident operands.
parse 26/26, total 155/155.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Starts Phase 2. lib/go/parse.sx defines:
* go-precedence-table — Go's five operator-precedence levels in the
(NAME PREC ASSOC) entry shape from lib/guest/pratt.sx, ready for the
binary-operator iteration to consume via pratt-op-lookup.
* go-parse(src) — tokenises and parses ONE primary expression: int,
float, imag, string, rune literals become (ast-literal VALUE);
identifiers become (ast-var NAME). Built directly on lib/guest/ast.sx
constructors — no intermediate AST shape.
Conformance.sh extended to load lib/guest/{ast,pratt}.sx and run the
new parse suite. Scoreboard cleanup: drop the "pending" parse row since
the suite is now real.
parse 17/17 (lex still 129/129). Total 146/146.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
