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read-print: Read and render vertical space. 

* guix/read-print.scm (<vertical-space>, vertical-space?)
(vertical-space, vertical-space-height): New variables.
(combine-vertical-space, canonicalize-vertical-space)
(read-vertical-space): New procedures.
(read-with-comments): Use it in the #\newline case.
(pretty-print-with-comments): Add #:format-vertical-space and honor it.
Add case for 'vertical-space?'.
* guix/scripts/style.scm (format-package-definition): Pass
 #:format-vertical-space to 'object->string*'.
* tests/read-print.scm ("read-with-comments: list with blank line")
("read-with-comments: list with multiple blank lines")
("read-with-comments: top-level blank lines")
("pretty-print-with-comments, canonicalize-vertical-space"): New tests.
Add a couple of additional round-trip tests.
Ludovic Courtès 2022-08-02 11:57:39 +02:00
parent 3eb3901d7f
commit f687e27e03
No known key found for this signature in database
GPG Key ID: 090B11993D9AEBB5
3 changed files with 129 additions and 4 deletions
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54
guix/read-print.scm
View File

@ -30,6 +30,11 @@
blank?
vertical-space
vertical-space?
vertical-space-height
canonicalize-vertical-space
comment
comment?
comment->string
@ -58,6 +63,26 @@
(define blank? (record-predicate <blank>))
(define <vertical-space>
(make-record-type '<vertical-space> '(height)
#:parent <blank>
#:extensible? #f))
(define vertical-space? (record-predicate <vertical-space>))
(define vertical-space (record-type-constructor <vertical-space>))
(define vertical-space-height (record-accessor <vertical-space> 'height))
(define (combine-vertical-space x y)
"Return vertical space as high as the combination of X and Y."
(vertical-space (+ (vertical-space-height x)
(vertical-space-height y))))
(define canonicalize-vertical-space
(let ((unit (vertical-space 1)))
(lambda (space)
"Return a vertical space corresponding to a single blank line."
unit)))
(define <comment>
;; Comments.
(make-record-type '<comment> '(str margin?)
@ -80,6 +105,19 @@ end with newline, otherwise an error is raised."
(&message (message "invalid comment string")))))
(string->comment str margin?))
(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)))
((? eof-object?) (vertical-space height))
((? space?) (loop height))
(chr (unread-char chr port) (vertical-space height)))))
(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
@ -107,7 +145,9 @@ end with newline, otherwise an error is raised."
eof) ;oops!
(chr
(cond ((eqv? chr #\newline)
(loop #t return))
(if blank-line?
(read-vertical-space port)
(loop #t return)))
((char-set-contains? char-set:whitespace chr)
(loop blank-line? return))
((memv chr '(#\( #\[))
@ -297,6 +337,7 @@ semicolons."
(define* (pretty-print-with-comments port obj
#:key
(format-comment identity)
(format-vertical-space identity)
(indent 0)
(max-width 78)
(long-list 5))
@ -306,7 +347,8 @@ included in the output.
Lists longer than LONG-LIST are written as one element per line. Comments are
passed through FORMAT-COMMENT before being emitted; a useful value for
FORMAT-COMMENT is 'canonicalize-comment'."
FORMAT-COMMENT is 'canonicalize-comment'. Vertical space is passed through
FORMAT-VERTICAL-SPACE; a useful value of 'canonicalize-vertical-space'."
(define (list-of-lists? head tail)
;; Return true if HEAD and TAIL denote a list of lists--e.g., a list of
;; 'let' bindings.
@ -394,6 +436,14 @@ FORMAT-COMMENT is 'canonicalize-comment'."
port)))
(display (make-string indent #\space) port)
indent)
((? vertical-space? space)
(unless delimited? (newline port))
(let loop ((i (vertical-space-height (format-vertical-space space))))
(unless (zero? i)
(newline port)
(loop (- i 1))))
(display (make-string indent #\space) port)
indent)
(('quote lst)
(unless delimited? (display " " port))
(display "'" port)

3
guix/scripts/style.scm
View File

@ -316,7 +316,8 @@ PACKAGE."
(object->string* exp
(location-column
(package-definition-location package))
#:format-comment canonicalize-comment)))))
#:format-comment canonicalize-comment
#:format-vertical-space canonicalize-vertical-space)))))
(define (package-location<? p1 p2)
"Return true if P1's location is \"before\" P2's."

76
tests/read-print.scm
View File

@ -19,7 +19,8 @@
(define-module (tests-style)
#:use-module (guix read-print)
#:use-module (guix gexp) ;for the reader extensions
#:use-module (srfi srfi-64))
#:use-module (srfi srfi-64)
#:use-module (ice-9 match))
(define-syntax-rule (test-pretty-print str args ...)
"Test equality after a round-trip where STR is passed to
@ -40,6 +41,35 @@
(call-with-input-string "(a . b)"
read-with-comments))
(test-equal "read-with-comments: list with blank line"
`(list with ,(vertical-space 1) blank line)
(call-with-input-string "\
(list with
blank line)\n"
read-with-comments))
(test-equal "read-with-comments: list with multiple blank lines"
`(list with ,(comment ";multiple\n" #t)
,(vertical-space 3) blank lines)
(call-with-input-string "\
(list with ;multiple
blank lines)\n"
read-with-comments))
(test-equal "read-with-comments: top-level blank lines"
(list (vertical-space 2) '(a b c) (vertical-space 2))
(call-with-input-string "
(a b c)\n\n"
(lambda (port)
(list (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)")
@ -181,6 +211,24 @@ mnopqrstuvwxyz.\")"
`(cons \"--without-any-problem\"
,flags)))")
(test-pretty-print "\
(vertical-space one:
two:
three:
end)")
(test-pretty-print "\
(vertical-space one
;; Comment after blank line.
two)")
(test-equal "pretty-print-with-comments, canonicalize-comment"
"\
(list abc
@ -206,4 +254,30 @@ mnopqrstuvwxyz.\")"
#:format-comment
canonicalize-comment)))))
(test-equal "pretty-print-with-comments, canonicalize-vertical-space"
"\
(list abc
def
;; last one
ghi)"
(let ((sexp (call-with-input-string
"\
(list abc
def
;; last one
ghi)"
read-with-comments)))
(call-with-output-string
(lambda (port)
(pretty-print-with-comments port sexp
#:format-vertical-space
canonicalize-vertical-space)))))
(test-end)