diff options
| -rw-r--r-- | guix/read-print.scm | 46 | ||||
| -rw-r--r-- | tests/read-print.scm | 22 |
2 files changed, 65 insertions, 3 deletions
diff --git a/guix/read-print.scm b/guix/read-print.scm index 2b626ba281..33ed6e3dbe 100644 --- a/guix/read-print.scm +++ b/guix/read-print.scm @@ -35,6 +35,9 @@ vertical-space-height canonicalize-vertical-space + page-break + page-break? + comment comment? comment->string @@ -83,6 +86,18 @@ "Return a vertical space corresponding to a single blank line." unit))) +(define <page-break> + (make-record-type '<page-break> '() + #:parent <blank> + #:extensible? #f)) + +(define page-break? (record-predicate <page-break>)) +(define page-break + (let ((break ((record-type-constructor <page-break>)))) + (lambda () + break))) + + (define <comment> ;; Comments. (make-record-type '<comment> '(str margin?) @@ -105,12 +120,17 @@ end with newline, otherwise an error is raised." (&message (message "invalid comment string"))))) (string->comment str margin?)) +(define char-set:whitespace-sans-page-break + ;; White space, excluding #\page. + (char-set-difference char-set:whitespace (char-set #\page))) + +(define (space? chr) + "Return true if CHR is white space, except for page breaks." + (char-set-contains? char-set:whitespace-sans-page-break chr)) + (define (read-vertical-space port) "Read from PORT until a non-vertical-space character is met, and return a single <vertical-space> record." - (define (space? chr) - (char-set-contains? char-set:whitespace chr)) - (let loop ((height 1)) (match (read-char port) (#\newline (loop (+ 1 height))) @@ -118,6 +138,15 @@ single <vertical-space> record." ((? space?) (loop height)) (chr (unread-char chr port) (vertical-space height))))) +(define (read-until-end-of-line port) + "Read white space from PORT until the end of line, included." + (let loop () + (match (read-char port) + (#\newline #t) + ((? eof-object?) #t) + ((? space?) (loop)) + (chr (unread-char chr port))))) + (define (read-with-comments port) "Like 'read', but include <blank> objects when they're encountered." ;; Note: Instead of implementing this functionality in 'read' proper, which @@ -148,6 +177,11 @@ single <vertical-space> record." (if blank-line? (read-vertical-space port) (loop #t return))) + ((eqv? chr #\page) + ;; Assume that a page break is on a line of its own and read + ;; subsequent white space and newline. + (read-until-end-of-line port) + (page-break)) ((char-set-contains? char-set:whitespace chr) (loop blank-line? return)) ((memv chr '(#\( #\[)) @@ -444,6 +478,12 @@ FORMAT-VERTICAL-SPACE; a useful value of 'canonicalize-vertical-space'." (loop (- i 1)))) (display (make-string indent #\space) port) indent) + ((? page-break?) + (unless delimited? (newline port)) + (display #\page port) + (newline port) + (display (make-string indent #\space) port) + indent) (('quote lst) (unless delimited? (display " " port)) (display "'" port) diff --git a/tests/read-print.scm b/tests/read-print.scm index f915b7e2d2..70be7754f8 100644 --- a/tests/read-print.scm +++ b/tests/read-print.scm @@ -70,6 +70,21 @@ (read-with-comments port) (read-with-comments port))))) +(test-equal "read-with-comments: top-level page break" + (list (comment ";; Begin.\n") (vertical-space 1) + (page-break) + (comment ";; End.\n")) + (call-with-input-string "\ +;; Begin. + + +;; End.\n" + (lambda (port) + (list (read-with-comments port) + (read-with-comments port) + (read-with-comments port) + (read-with-comments port))))) + (test-pretty-print "(list 1 2 3 4)") (test-pretty-print "((a . 1) (b . 2))") (test-pretty-print "(a b c . boom)") @@ -229,6 +244,13 @@ mnopqrstuvwxyz.\")" ;; Comment after blank line. two)") +(test-pretty-print "\ +(begin + break + + ;; page break above + end)") + (test-equal "pretty-print-with-comments, canonicalize-comment" "\ (list abc |