guix/guix/scripts/style.scm
Ludovic Courtès c9cded0955
style: Correctly read dots in pairs and improper lists.
Until now dots were read as symbols.

* guix/scripts/style.scm (read-with-comments)[dot]: New variable.
[dot?, reverse/dot]: New procedures.
Use 'reverse/dot' instead of 'reverse' when reading lists.
* tests/style.scm ("read-with-comments: dot notation")
("((a . 1) (b . 2))", "(a b c . boom)"): New tests.
2022-04-14 14:48:20 +02:00

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;;; GNU Guix --- Functional package management for GNU
;;; Copyright © 2021-2022 Ludovic Courtès <ludo@gnu.org>
;;;
;;; This file is part of GNU Guix.
;;;
;;; GNU Guix is free software; you can redistribute it and/or modify it
;;; under the terms of the GNU General Public License as published by
;;; the Free Software Foundation; either version 3 of the License, or (at
;;; your option) any later version.
;;;
;;; GNU Guix is distributed in the hope that it will be useful, but
;;; WITHOUT ANY WARRANTY; without even the implied warranty of
;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
;;; GNU General Public License for more details.
;;;
;;; You should have received a copy of the GNU General Public License
;;; along with GNU Guix. If not, see <http://www.gnu.org/licenses/>.
;;; Commentary:
;;;
;;; This script updates package definitions so they use the "simplified" style
;;; for input lists, as in:
;;;
;;; (package
;;; ;; ...
;;; (inputs (list foo bar baz)))
;;;
;;; Code:
(define-module (guix scripts style)
#:autoload (gnu packages) (specification->package fold-packages)
#:use-module (guix scripts)
#:use-module ((guix scripts build) #:select (%standard-build-options))
#:use-module (guix combinators)
#:use-module (guix ui)
#:use-module (guix packages)
#:use-module (guix utils)
#:use-module (guix i18n)
#:use-module (guix diagnostics)
#:use-module (ice-9 control)
#:use-module (ice-9 match)
#:use-module (ice-9 rdelim)
#:use-module (ice-9 vlist)
#:use-module (srfi srfi-1)
#:use-module (srfi srfi-9)
#:use-module (srfi srfi-26)
#:use-module (srfi srfi-37)
#:export (pretty-print-with-comments
read-with-comments
canonicalize-comment
guix-style))
;;;
;;; Comment-preserving reader.
;;;
;; A comment.
(define-record-type <comment>
(comment str margin?)
comment?
(str comment->string)
(margin? comment-margin?))
(define (read-with-comments port)
"Like 'read', but include <comment> objects when they're encountered."
;; Note: Instead of implementing this functionality in 'read' proper, which
;; is the best approach long-term, this code is a layer on top of 'read',
;; such that we don't have to rely on a specific Guile version.
(define dot (list 'dot))
(define (dot? x) (eq? x dot))
(define (reverse/dot lst)
;; Reverse LST and make it an improper list if it contains DOT.
(let loop ((result '())
(lst lst))
(match lst
(() result)
(((? dot?) . rest)
(let ((dotted (reverse rest)))
(set-cdr! (last-pair dotted) (car result))
dotted))
((x . rest) (loop (cons x result) rest)))))
(let loop ((blank-line? #t)
(return (const 'unbalanced)))
(match (read-char port)
((? eof-object? eof)
eof) ;oops!
(chr
(cond ((eqv? chr #\newline)
(loop #t return))
((char-set-contains? char-set:whitespace chr)
(loop blank-line? return))
((memv chr '(#\( #\[))
(let/ec return
(let liip ((lst '()))
(liip (cons (loop (match lst
(((? comment?) . _) #t)
(_ #f))
(lambda ()
(return (reverse/dot lst))))
lst)))))
((memv chr '(#\) #\]))
(return))
((eq? chr #\')
(list 'quote (loop #f return)))
((eq? chr #\`)
(list 'quasiquote (loop #f return)))
((eq? chr #\,)
(list (match (peek-char port)
(#\@
(read-char port)
'unquote-splicing)
(_
'unquote))
(loop #f return)))
((eqv? chr #\;)
(unread-char chr port)
(comment (read-line port 'concat)
(not blank-line?)))
(else
(unread-char chr port)
(match (read port)
((and token '#{.}#)
(if (eq? chr #\.) dot token))
(token token))))))))
;;;
;;; Comment-preserving pretty-printer.
;;;
(define-syntax vhashq
(syntax-rules (quote)
((_) vlist-null)
((_ (key (quote (lst ...))) rest ...)
(vhash-consq key '(lst ...) (vhashq rest ...)))
((_ (key value) rest ...)
(vhash-consq key '((() . value)) (vhashq rest ...)))))
(define %special-forms
;; Forms that are indented specially. The number is meant to be understood
;; like Emacs' 'scheme-indent-function' symbol property. When given an
;; alist instead of a number, the alist gives "context" in which the symbol
;; is a special form; for instance, context (modify-phases) means that the
;; symbol must appear within a (modify-phases ...) expression.
(vhashq
('begin 1)
('lambda 2)
('lambda* 2)
('match-lambda 1)
('match-lambda* 2)
('define 2)
('define* 2)
('define-public 2)
('define*-public 2)
('define-syntax 2)
('define-syntax-rule 2)
('define-module 2)
('define-gexp-compiler 2)
('let 2)
('let* 2)
('letrec 2)
('letrec* 2)
('match 2)
('when 2)
('unless 2)
('package 1)
('origin 1)
('operating-system 1)
('modify-inputs 2)
('modify-phases 2)
('add-after '(((modify-phases) . 3)))
('add-before '(((modify-phases) . 3)))
('replace '(((modify-phases) . 2))) ;different from 'modify-inputs'
('substitute* 2)
('substitute-keyword-arguments 2)
('call-with-input-file 2)
('call-with-output-file 2)
('with-output-to-file 2)
('with-input-from-file 2)))
(define %newline-forms
;; List heads that must be followed by a newline. The second argument is
;; the context in which they must appear. This is similar to a special form
;; of 1, except that indent is 1 instead of 2 columns.
(vhashq
('arguments '(package))
('sha256 '(origin source package))
('base32 '(sha256 origin))
('git-reference '(uri origin source))
('search-paths '(package))
('native-search-paths '(package))
('search-path-specification '())))
(define (prefix? candidate lst)
"Return true if CANDIDATE is a prefix of LST."
(let loop ((candidate candidate)
(lst lst))
(match candidate
(() #t)
((head1 . rest1)
(match lst
(() #f)
((head2 . rest2)
(and (equal? head1 head2)
(loop rest1 rest2))))))))
(define (special-form-lead symbol context)
"If SYMBOL is a special form in the given CONTEXT, return its number of
arguments; otherwise return #f. CONTEXT is a stack of symbols lexically
surrounding SYMBOL."
(match (vhash-assq symbol %special-forms)
(#f #f)
((_ . alist)
(any (match-lambda
((prefix . level)
(and (prefix? prefix context) (- level 1))))
alist))))
(define (newline-form? symbol context)
"Return true if parenthesized expressions starting with SYMBOL must be
followed by a newline."
(match (vhash-assq symbol %newline-forms)
(#f #f)
((_ . prefix)
(prefix? prefix context))))
(define (escaped-string str)
"Return STR with backslashes and double quotes escaped. Everything else, in
particular newlines, is left as is."
(list->string
`(#\"
,@(string-fold-right (lambda (chr lst)
(match chr
(#\" (cons* #\\ #\" lst))
(#\\ (cons* #\\ #\\ lst))
(_ (cons chr lst))))
'()
str)
#\")))
(define (string-width str)
"Return the \"width\" of STR--i.e., the width of the longest line of STR."
(apply max (map string-length (string-split str #\newline))))
(define (canonicalize-comment c)
"Canonicalize comment C, ensuring it has the \"right\" number of leading
semicolons."
(let ((line (string-trim-both
(string-trim (comment->string c) (char-set #\;)))))
(comment (string-append
(if (comment-margin? c)
";"
(if (string-null? line)
";;" ;no trailing space
";; "))
line "\n")
(comment-margin? c))))
(define* (pretty-print-with-comments port obj
#:key
(format-comment identity)
(indent 0)
(max-width 78)
(long-list 5))
"Pretty-print OBJ to PORT, attempting to at most MAX-WIDTH character columns
and assuming the current column is INDENT. Comments present in OBJ are
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'."
(let loop ((indent indent)
(column indent)
(delimited? #t) ;true if comes after a delimiter
(context '()) ;list of "parent" symbols
(obj obj))
(define (print-sequence context indent column lst delimited?)
(define long?
(> (length lst) long-list))
(let print ((lst lst)
(first? #t)
(delimited? delimited?)
(column column))
(match lst
(()
column)
((item . tail)
(define newline?
;; Insert a newline if ITEM is itself a list, or if TAIL is long,
;; but only if ITEM is not the first item. Also insert a newline
;; before a keyword.
(and (or (pair? item) long?
(and (keyword? item)
(not (eq? item #:allow-other-keys))))
(not first?) (not delimited?)
(not (comment? item))))
(when newline?
(newline port)
(display (make-string indent #\space) port))
(let ((column (if newline? indent column)))
(print tail #f
(comment? item)
(loop indent column
(or newline? delimited?)
context
item)))))))
(define (sequence-would-protrude? indent lst)
;; Return true if elements of LST written at INDENT would protrude
;; beyond MAX-WIDTH. This is implemented as a cheap test with false
;; negatives to avoid actually rendering all of LST.
(find (match-lambda
((? string? str)
(>= (+ (string-width str) 2 indent) max-width))
((? symbol? symbol)
(>= (+ (string-width (symbol->string symbol)) indent)
max-width))
((? boolean?)
(>= (+ 2 indent) max-width))
(()
(>= (+ 2 indent) max-width))
(_ ;don't know
#f))
lst))
(define (special-form? head)
(special-form-lead head context))
(match obj
((? comment? comment)
(if (comment-margin? comment)
(begin
(display " " port)
(display (comment->string (format-comment comment))
port))
(begin
;; When already at the beginning of a line, for example because
;; COMMENT follows a margin comment, no need to emit a newline.
(unless (= column indent)
(newline port)
(display (make-string indent #\space) port))
(display (comment->string (format-comment comment))
port)))
(display (make-string indent #\space) port)
indent)
(('quote lst)
(unless delimited? (display " " port))
(display "'" port)
(loop indent (+ column (if delimited? 1 2)) #t context lst))
(('quasiquote lst)
(unless delimited? (display " " port))
(display "`" port)
(loop indent (+ column (if delimited? 1 2)) #t context lst))
(('unquote lst)
(unless delimited? (display " " port))
(display "," port)
(loop indent (+ column (if delimited? 1 2)) #t context lst))
(('unquote-splicing lst)
(unless delimited? (display " " port))
(display ",@" port)
(loop indent (+ column (if delimited? 2 3)) #t context lst))
(('gexp lst)
(unless delimited? (display " " port))
(display "#~" port)
(loop indent (+ column (if delimited? 2 3)) #t context lst))
(('ungexp obj)
(unless delimited? (display " " port))
(display "#$" port)
(loop indent (+ column (if delimited? 2 3)) #t context obj))
(('ungexp-native obj)
(unless delimited? (display " " port))
(display "#+" port)
(loop indent (+ column (if delimited? 2 3)) #t context obj))
(('ungexp-splicing lst)
(unless delimited? (display " " port))
(display "#$@" port)
(loop indent (+ column (if delimited? 3 4)) #t context lst))
(('ungexp-native-splicing lst)
(unless delimited? (display " " port))
(display "#+@" port)
(loop indent (+ column (if delimited? 3 4)) #t context lst))
(((? special-form? head) arguments ...)
;; Special-case 'let', 'lambda', 'modify-inputs', etc. so the second
;; and following arguments are less indented.
(let* ((lead (special-form-lead head context))
(context (cons head context))
(head (symbol->string head))
(total (length arguments)))
(unless delimited? (display " " port))
(display "(" port)
(display head port)
(unless (zero? lead)
(display " " port))
;; Print the first LEAD arguments.
(let* ((indent (+ column 2
(if delimited? 0 1)))
(column (+ column 1
(if (zero? lead) 0 1)
(if delimited? 0 1)
(string-length head)))
(initial-indent column))
(define new-column
(let inner ((n lead)
(arguments (take arguments (min lead total)))
(column column))
(if (zero? n)
(begin
(newline port)
(display (make-string indent #\space) port)
indent)
(match arguments
(() column)
((head . tail)
(inner (- n 1) tail
(loop initial-indent column
(= n lead)
context
head)))))))
;; Print the remaining arguments.
(let ((column (print-sequence
context indent new-column
(drop arguments (min lead total))
#t)))
(display ")" port)
(+ column 1)))))
((head tail ...)
(let* ((overflow? (>= column max-width))
(column (if overflow?
(+ indent 1)
(+ column (if delimited? 1 2))))
(newline? (newline-form? head context))
(context (cons head context)))
(if overflow?
(begin
(newline port)
(display (make-string indent #\space) port))
(unless delimited? (display " " port)))
(display "(" port)
(let* ((new-column (loop column column #t context head))
(indent (if (or (>= new-column max-width)
(not (symbol? head))
(sequence-would-protrude?
(+ new-column 1) tail)
newline?)
column
(+ new-column 1))))
(when newline?
;; Insert a newline right after HEAD.
(newline port)
(display (make-string indent #\space) port))
(let ((column
(print-sequence context indent
(if newline? indent new-column)
tail newline?)))
(display ")" port)
(+ column 1)))))
(_
(let* ((str (if (string? obj)
(escaped-string obj)
(object->string obj)))
(len (string-width str)))
(if (and (> (+ column 1 len) max-width)
(not delimited?))
(begin
(newline port)
(display (make-string indent #\space) port)
(display str port)
(+ indent len))
(begin
(unless delimited? (display " " port))
(display str port)
(+ column (if delimited? 0 1) len))))))))
(define (object->string* obj indent . args)
(call-with-output-string
(lambda (port)
(apply pretty-print-with-comments port obj
#:indent indent
args))))
;;;
;;; Simplifying input expressions.
;;;
(define (label-matches? label name)
"Return true if LABEL matches NAME, a package name."
(or (string=? label name)
(and (string-prefix? "python-" label)
(string-prefix? "python2-" name)
(string=? (string-drop label (string-length "python-"))
(string-drop name (string-length "python2-"))))))
(define* (simplify-inputs location package str inputs
#:key (label-matches? label-matches?))
"Simplify the inputs field of PACKAGE (a string) at LOCATION; its current
value is INPUTS the corresponding source code is STR. Return a string to
replace STR."
(define (simplify-input-expression return)
(match-lambda
((label ('unquote symbol)) symbol)
((label ('unquote symbol) output)
(list 'quasiquote
(list (list 'unquote symbol) output)))
(_
;; Expression doesn't look like a simple input.
(warning location (G_ "~a: complex expression, \
bailing out~%")
package)
(return str))))
(define (simplify-input exp input return)
(define package* package)
(match input
((or ((? string? label) (? package? package))
((? string? label) (? package? package)
(? string?)))
;; If LABEL doesn't match PACKAGE's name, then simplifying would incur
;; a rebuild, and perhaps it would break build-side code relying on
;; this specific label.
(if (label-matches? label (package-name package))
((simplify-input-expression return) exp)
(begin
(warning location (G_ "~a: input label \
'~a' does not match package name, bailing out~%")
package* label)
(return str))))
(_
(warning location (G_ "~a: non-trivial input, \
bailing out~%")
package*)
(return str))))
(define (simplify-expressions exp inputs return)
;; Simplify the expressions in EXP, which correspond to INPUTS, and return
;; a list of expressions. Call RETURN with a string when bailing out.
(let loop ((result '())
(exp exp)
(inputs inputs))
(match exp
(((? comment? head) . rest)
(loop (cons head result) rest inputs))
((head . rest)
(match inputs
((input . inputs)
;; HEAD (an sexp) and INPUT (an input tuple) are correlated.
(loop (cons (simplify-input head input return) result)
rest inputs))
(()
;; If EXP and INPUTS have a different length, that
;; means EXP is a non-trivial input list, for example
;; with input-splicing, conditionals, etc.
(warning location (G_ "~a: input expression is too short~%")
package)
(return str))))
(()
;; It's possible for EXP to contain fewer elements than INPUTS, for
;; example in the case of input splicing. No bailout here. (XXX)
(reverse result)))))
(define inputs-exp
(call-with-input-string str read-with-comments))
(match inputs-exp
(('list _ ...) ;already done
str)
(('modify-inputs _ ...) ;already done
str)
(('quasiquote ;prepending inputs
(exp ...
('unquote-splicing
((and symbol (or 'package-inputs 'package-native-inputs
'package-propagated-inputs))
arg))))
(let/ec return
(object->string*
(let ((things (simplify-expressions exp inputs return)))
`(modify-inputs (,symbol ,arg)
(prepend ,@things)))
(location-column location))))
(('quasiquote ;replacing an input
((and exp ((? string? to-delete) ('unquote replacement)))
('unquote-splicing
('alist-delete (? string? to-delete)
((and symbol
(or 'package-inputs 'package-native-inputs
'package-propagated-inputs))
arg)))))
(let/ec return
(object->string*
(let ((things (simplify-expressions (list exp)
(list (car inputs))
return)))
`(modify-inputs (,symbol ,arg)
(replace ,to-delete ,replacement)))
(location-column location))))
(('quasiquote ;removing an input
(exp ...
('unquote-splicing
('alist-delete (? string? to-delete)
((and symbol
(or 'package-inputs 'package-native-inputs
'package-propagated-inputs))
arg)))))
(let/ec return
(object->string*
(let ((things (simplify-expressions exp inputs return)))
`(modify-inputs (,symbol ,arg)
(delete ,to-delete)
(prepend ,@things)))
(location-column location))))
(('fold 'alist-delete ;removing several inputs
((and symbol
(or 'package-inputs 'package-native-inputs
'package-propagated-inputs))
arg)
('quote ((? string? to-delete) ...)))
(object->string*
`(modify-inputs (,symbol ,arg)
(delete ,@to-delete))
(location-column location)))
(('quasiquote ;removing several inputs and adding others
(exp ...
('unquote-splicing
('fold 'alist-delete
((and symbol
(or 'package-inputs 'package-native-inputs
'package-propagated-inputs))
arg)
('quote ((? string? to-delete) ...))))))
(let/ec return
(object->string*
(let ((things (simplify-expressions exp inputs return)))
`(modify-inputs (,symbol ,arg)
(delete ,@to-delete)
(prepend ,@things)))
(location-column location))))
(('quasiquote (exp ...))
(let/ec return
(object->string*
`(list ,@(simplify-expressions exp inputs return))
(location-column location))))
(_
(warning location (G_ "~a: unsupported input style, \
bailing out~%")
package)
str)))
(define (edit-expression/dry-run properties rewrite-string)
"Like 'edit-expression' but display what would be edited without actually
doing it."
(edit-expression properties
(lambda (str)
(unless (string=? (rewrite-string str) str)
(info (source-properties->location properties)
(G_ "would be edited~%")))
str)))
(define (absolute-location loc)
"Replace the file name in LOC by an absolute location."
(location (if (string-prefix? "/" (location-file loc))
(location-file loc)
(search-path %load-path (location-file loc)))
(location-line loc)
(location-column loc)))
(define* (simplify-package-inputs package
#:key (policy 'silent)
(edit-expression edit-expression))
"Edit the source code of PACKAGE to simplify its inputs field if needed.
POLICY is a symbol that defines whether to simplify inputs; it can one of
'silent (change only if the resulting derivation is the same), 'safe (change
only if semantics are known to be unaffected), and 'always (fearlessly
simplify inputs!). Call EDIT-EXPRESSION to actually edit the source of
PACKAGE."
(for-each (lambda (field-name field)
(match (field package)
(()
#f)
(inputs
(match (package-field-location package field-name)
(#f
;; If the location of FIELD-NAME is not found, it may be
;; that PACKAGE inherits from another package.
#f)
(location
(edit-expression
(location->source-properties (absolute-location location))
(lambda (str)
(define matches?
(match policy
('silent
;; Simplify inputs only when the label matches
;; perfectly, such that the resulting derivation
;; is unchanged.
label-matches?)
('safe
;; If PACKAGE has no arguments, labels are known
;; to have no effect: this is a "safe" change, but
;; it may change the derivation.
(if (null? (package-arguments package))
(const #t)
label-matches?))
('always
;; Assume it's gonna be alright.
(const #t))))
(simplify-inputs location
(package-name package)
str inputs
#:label-matches? matches?))))))))
'(inputs native-inputs propagated-inputs)
(list package-inputs package-native-inputs
package-propagated-inputs)))
;;;
;;; Formatting package definitions.
;;;
(define* (format-package-definition package
#:key policy
(edit-expression edit-expression))
"Reformat the definition of PACKAGE."
(unless (package-definition-location package)
(leave (package-location package)
(G_ "no definition location for package ~a~%")
(package-full-name package)))
(edit-expression
(location->source-properties
(absolute-location (package-definition-location package)))
(lambda (str)
(let ((exp (call-with-input-string str
read-with-comments)))
(object->string* exp
(location-column
(package-definition-location package))
#:format-comment canonicalize-comment)))))
(define (package-location<? p1 p2)
"Return true if P1's location is \"before\" P2's."
(let ((loc1 (package-location p1))
(loc2 (package-location p2)))
(and loc1 loc2
(if (string=? (location-file loc1) (location-file loc2))
(< (location-line loc1) (location-line loc2))
(string<? (location-file loc1) (location-file loc2))))))
;;;
;;; Options.
;;;
(define %options
;; Specification of the command-line options.
(list (find (lambda (option)
(member "load-path" (option-names option)))
%standard-build-options)
(option '(#\n "dry-run") #f #f
(lambda (opt name arg result)
(alist-cons 'dry-run? #t result)))
(option '(#\e "expression") #t #f
(lambda (opt name arg result)
(alist-cons 'expression arg result)))
(option '(#\S "styling") #t #f
(lambda (opt name arg result)
(alist-cons 'styling-procedure
(match arg
("inputs" simplify-package-inputs)
("format" format-package-definition)
(_ (leave (G_ "~a: unknown styling~%")
arg)))
result)))
(option '("input-simplification") #t #f
(lambda (opt name arg result)
(let ((symbol (string->symbol arg)))
(unless (memq symbol '(silent safe always))
(leave (G_ "~a: invalid input simplification policy~%")
arg))
(alist-cons 'input-simplification-policy symbol
result))))
(option '(#\h "help") #f #f
(lambda args
(show-help)
(exit 0)))
(option '(#\V "version") #f #f
(lambda args
(show-version-and-exit "guix style")))))
(define (show-help)
(display (G_ "Usage: guix style [OPTION]... [PACKAGE]...
Update package definitions to the latest style.\n"))
(display (G_ "
-S, --styling=RULE apply RULE, a styling rule"))
(newline)
(display (G_ "
-n, --dry-run display files that would be edited but do nothing"))
(display (G_ "
-L, --load-path=DIR prepend DIR to the package module search path"))
(display (G_ "
-e, --expression=EXPR consider the package EXPR evaluates to"))
(display (G_ "
--input-simplification=POLICY
follow POLICY for package input simplification, one
of 'silent', 'safe', or 'always'"))
(newline)
(display (G_ "
-h, --help display this help and exit"))
(display (G_ "
-V, --version display version information and exit"))
(newline)
(show-bug-report-information))
(define %default-options
;; Alist of default option values.
`((input-simplification-policy . silent)
(styling-procedure . ,format-package-definition)))
;;;
;;; Entry point.
;;;
(define-command (guix-style . args)
(category packaging)
(synopsis "update the style of package definitions")
(define (parse-options)
;; Return the alist of option values.
(parse-command-line args %options (list %default-options)
#:build-options? #f))
(let* ((opts (parse-options))
(packages (filter-map (match-lambda
(('argument . spec)
(specification->package spec))
(('expression . str)
(read/eval str))
(_ #f))
opts))
(edit (if (assoc-ref opts 'dry-run?)
edit-expression/dry-run
edit-expression))
(style (assoc-ref opts 'styling-procedure))
(policy (assoc-ref opts 'input-simplification-policy)))
(with-error-handling
(for-each (lambda (package)
(style package #:policy policy
#:edit-expression edit))
;; Sort package by source code location so that we start editing
;; files from the bottom and going upward. That way, the
;; 'location' field of <package> records is not invalidated as
;; we modify files.
(sort (if (null? packages)
(fold-packages cons '() #:select? (const #t))
packages)
(negate package-location<?))))))