~ruther/guix-local

5bd00bb54235856dddd11e9f0d03481c5469ca63 — Saku Laesvuori 2 years ago acef524
guix: import: Parse cabal layout blocks correctly

Cabal consideres lines to be part of a layout block if they are indented
at least one space more than the field line the block belongs to.
Previously Guix considered lines to be a part of the block if they were
indented at least as much as the first line in it.

This also makes a workaround that enabled if statements to have multiple
elses redundant and removes it.

Fixes: https://issues.guix.gnu.org/35743

* guix/import/cabal.scm (current-indentation*): Renamed from
current-indentation.
(previous-indentation, current-indentation): New variables.
(make-cabal-parser): Remove outdated comment.
[open]: Use previous-indentation + 1 instead of
current-indentation.
[elif-else]: Split to elif and else to allow only one ELSE in an if
statement.
(read-cabal)[parameterize]: Use current-indentation* and previous-indentation.
* tests/hackage.scm (hackage->guix-package test mixed layout): Expect to
  pass.

Change-Id: I3a1495b1588a022fabbfe8dad9f3231e578af4f3
Signed-off-by: Lars-Dominik Braun <lars@6xq.net>
2 files changed, 19 insertions(+), 25 deletions(-)

M guix/import/cabal.scm
M tests/hackage.scm
M guix/import/cabal.scm => guix/import/cabal.scm +19 -23
@@ 130,8 130,17 @@ to the stack."

(define (context-stack-clear!) ((context-stack) 'clear!))

;; Indentation of the line being parsed.
(define current-indentation (make-parameter 0))
;; Indentation of the line being parsed and that of the previous line.
(define current-indentation* (make-parameter 0))

(define previous-indentation (make-parameter 0))

(define* (current-indentation #:optional value)
  (if value
    (begin
      (previous-indentation (current-indentation*))
      (current-indentation* value))
    (current-indentation*)))

;; Signal to reprocess the beginning of line, in case we need to close more
;; than one indentation level.


@@ 196,27 205,13 @@ to the stack."
                (exprs elif-else)          : (append $1 (list ($2 '(()))))
                (elif-else)                : (list ($1 '(()))))
   ;; LALR(1) parsers prefer to be left-recursive, which make if-statements slightly involved.
   ;; XXX: This technically allows multiple else statements.
   (elif-else   (elif-else ELIF tests OCURLY exprs CCURLY) : (lambda (y) ($1 (list (append (list 'if $3 $5) y))))
                (elif-else ELIF tests open exprs close) : (lambda (y) ($1 (list (append (list 'if $3 $5) y))))
                (elif-else ELSE OCURLY exprs CCURLY) : (lambda (y) ($1 (list $4)))
                ;; The 'open' token after 'tests' is shifted after an 'exprs'
                ;; is found.  This is because, instead of 'exprs' a 'OCURLY'
                ;; token is a valid alternative.  For this reason, 'open'
                ;; pushes a <parse-context> with a line indentation equal to
                ;; the indentation of 'exprs'.
                ;;
                ;; Differently from this, without the rule above this
                ;; comment, when an 'ELSE' token is found, the 'open' token
                ;; following the 'ELSE' would be shifted immediately, before
                ;; the 'exprs' is found (because there are no other valid
                ;; tokens).  The 'open' would therefore create a
                ;; <parse-context> with the indentation of 'ELSE' and not
                ;; 'exprs', creating an inconsistency.  We therefore allow
                ;; mixed style conditionals.
                (elif-else ELSE open exprs close) : (lambda (y) ($1 (list $4)))
   (elif        (elif ELIF tests OCURLY exprs CCURLY) : (lambda (y) ($1 (list (append (list 'if $3 $5) y))))
                (elif ELIF tests open exprs close) : (lambda (y) ($1 (list (append (list 'if $3 $5) y))))
                ;; Terminating rule.
                (if-then) : (lambda (y) (append $1 y)))
   (elif-else   (elif ELSE OCURLY exprs CCURLY) : (lambda (y) ($1 (list $4)))
                (elif ELSE open exprs close)    : (lambda (y) ($1 (list $4)))
                (elif)                          : $1)
   (if-then     (IF tests OCURLY exprs CCURLY) : (list 'if $2 $4)
                (IF tests open exprs close)    : (list 'if $2 $4))
   (tests       (TEST OPAREN ID CPAREN)        : `(,$1 ,$3)


@@ 237,7 232,7 @@ to the stack."
               (OPAREN tests CPAREN)           : $2)
   (open       () : (context-stack-push!
                                   (make-parse-context (context layout)
                                                       (current-indentation))))
                                                       (+ 1 (previous-indentation)))))
   (close      (VCCURLY))))

(define (peek-next-line-indent port)


@@ 655,7 650,8 @@ If #f use the function 'port-filename' to obtain it."
  (let ((cabal-parser (make-cabal-parser)))
    (parameterize ((cabal-file-name
                    (or file-name (port-filename port) "standard input"))
                   (current-indentation 0)
                   (current-indentation* 0)
                   (previous-indentation 0)
                   (check-bol? #f)
                   (context-stack (make-stack)))
      (cabal-parser (make-lexer port) (errorp)))))

M tests/hackage.scm => tests/hackage.scm +0 -2
@@ 306,8 306,6 @@ executable cabal
  ghc-options: -Wall
")

;; Fails: https://debbugs.gnu.org/cgi/bugreport.cgi?bug=35743
(test-expect-fail 1)
(test-assert "hackage->guix-package test mixed layout"
  (eval-test-with-cabal test-cabal-mixed-layout match-ghc-foo))