Adds postfix expression forms per Go spec:
f() f(x) f(x, y, z) — function calls
x.y x.y.z obj.method(x) — selector / member access
gp-parse-postfix sits between gp-parse-unary and gp-parse-primary,
so calls and selectors bind tighter than any unary prefix — `-f(x)`
parses as `-(f(x))`, not `(-f)(x)`. Postfix is left-associative
(`x.y.z` = `(x.y).z`), so the loop iterates rather than recurses
on the LHS.
AST shapes:
Call: (ast-app FN ARGS) — canonical
Selector: (list :select OBJ "field") — Go-specific tag
The selector shape is a kit gap — lib/guest/ast.sx ships ast-app but
no ast-select, despite `obj.field` being universal across Go, Rust,
Swift, TS, JS, Python, Ruby, Java, C#. Logged in Blockers; tagging
[proposes-ast]. Worth promoting on the next nominally-typed guest.
parse 49/49, total 178/178.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
giles
e1c5fdae53