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(zilch lang rust): document

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Change-Id: I6a6a6964c8aaff8d5f3e18bc5c7486746b5a2952
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puck 2025-06-23 12:22:20 +00:00
parent ae774da043
commit 0340f6e830
10 changed files with 597 additions and 82 deletions
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10
lang/rust/src/cfg.sld
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@ -1,3 +1,5 @@
;; Procedures to parse `cfg` attributes, as well as match them against
;; conditionals found in crate definitions.
(define-library (zilch lang rust cfg)
(import
(scheme base)
@ -35,6 +37,12 @@
(let ((end (or (string-skip strval is-ident-rest (+ index 1)) (string-length strval))))
(tokenize-cfg strval end (cons (cons 'ident (string-copy strval index end)) tail)))
(error "Unexpected character in cfg() string" strval))))))
;; Parses a configuration string or expression.
;;
;; - `key="value"` is represented as `('value . (key . value))`, where value can be `#f`.
;; - `all` and `any` are represented as `('all/'any . items)`, where `items` is a list of sub-expressions.
;; - `not(...)` is represented as `('not . value)`, where `value` is a sub-expression.
(define (cfg-parse str)
(define tokens (tokenize-cfg str 0 '()))
(define (expect token)
@ -100,6 +108,8 @@
(cons 'value (cons left right))))))
(parse-expr))
;; Checks whether the parsed expression `expr` matches against the list of
;; config value pairs in `cfgs`.
(define (cfg-matches expr cfgs)
(define (parse-any tail)
(cond