stxparse-info/parse/pre.rkt

47 lines
1.7 KiB
Racket

#lang racket/base
(require "private/sc.rkt"
"private/litconv.rkt"
"private/lib.rkt"
"private/residual.rkt")
(provide (except-out (all-from-out "private/sc.rkt")
define-integrable-syntax-class
syntax-parser/template
parser/rhs)
(all-from-out "private/litconv.rkt")
(all-from-out "private/lib.rkt")
syntax-parse-state-ref
syntax-parse-state-set!
syntax-parse-state-update!
syntax-parse-state-cons!)
(define not-given (gensym))
(define (state-ref who key default)
(define state (current-state))
(if (eq? default not-given)
(if (hash-has-key? state key)
(hash-ref state key)
(error who "no value found for key\n key: ~e" key))
(hash-ref state key default)))
(define (syntax-parse-state-ref key [default not-given])
(state-ref 'syntax-parse-state-ref key default))
(define (check-update who)
(unless (current-state-writable?)
(error who "cannot update syntax-parse state outside of ~~do/#:do block")))
(define (syntax-parse-state-set! key value)
(check-update 'syntax-parse-state-set!)
(current-state (hash-set (current-state) key value)))
(define (syntax-parse-state-update! key update [default not-given])
(check-update 'syntax-parse-state-update!)
(define old (state-ref 'syntax-parse-state-update! key default))
(current-state (hash-set (current-state) key (update old))))
(define (syntax-parse-state-cons! key value [default null])
(check-update 'syntax-parse-state-cons!)
(define old (hash-ref (current-state) key default))
(current-state (hash-set (current-state) key (cons value old))))