~ruther/guix-local: po: Add procedures to handle '\"', '\t' and '\\' escape sequences.

aff572c9ac80748b86fe22996dc0103a55ee829f — Florian Pelz 6 months ago e16cfd6

po: Add procedures to handle '\"', '\t' and '\\' escape sequences.

They were handled with PEG before.

Now `make download-po` has the same result as before PO files were
minified.

* guix/build/po.scm (interpret-newline-escape): Replace with ...
(interpret-escape): ... this more general procedure.
(replace-escaped-backslashes): New procedure, basically restored from
the past implementation of 'interpret-newline-escape' but
for '\\' escapes.
(interpret-escape-sequences): New procedure to call them all.
(parse-tree->assoc): Use it.

Change-Id: I03226281019fa39ef7bca524278dbc434df95f2e

patch browse .tar.gz

1 files changed, 30 insertions(+), 13 deletions(-)

M guix/build/po.scm

M guix/build/po.scm => guix/build/po.scm +30 -13

@@ 48,6 48,17 @@
   (and (ignore "\"") (* str-chr) (ignore "\"")
        (? (and (ignore (* whitespace)) content))))
 
+(define (replace-escaped-backslashes str)
+  "Replace '\\\\' sequences in STR with a single '\\'."
+  (let loop ((str str)
+             (result '()))
+    (match (string-contains str "\\\\")
+      (#f (string-concatenate-reverse (cons str result)))
+      (index
+       (let ((prefix (string-take str index)))
+         (loop (string-drop str (+ 2 index))
+               (append (list "\\" prefix) result)))))))
+
 (define (final-character-escapes? str last-index)
   "Check if STR ends in an incomplete escape sequence, that is ends in an uneven
 number of backslashes.  LAST-INDEX is the index of its last character."


@@ 55,19 66,29 @@ number of backslashes.  LAST-INDEX is the index of its last character."
        (eqv? (string-ref str last-index) #\\)
        (not (final-character-escapes? str (- last-index 1)))))
 
-(define (interpret-newline-escape str)
-  "Replace unescaped '\\n' sequences in STR with a newline character."
+(define (interpret-escape sequence replacement str)
+  "Replace backslash escape sequence SEQUENCE in STR with REPLACEMENT (a string)
+when SEQUENCE is not escaped itself.  For example, SEQUENCE '\\n' with a
+newline string as REPLACEMENT."
   (let loop ((str str)
              (result '()))
-    (match (string-contains str "\\n")
+    (match (string-contains str sequence)
       (#f (string-concatenate-reverse (cons str result)))
       (index
        (let ((prefix (string-take str index)))
          (loop (string-drop str (+ 2 index))
-               ;; Only add a newline when the backslash is not escaped itself.
+               ;; Only add REPLACEMENT when the backslash is not escaped itself.
                (if (final-character-escapes? str (- index 1))
                    (cons (string-take str (+ 2 index)) result)
-                   (append (list "\n" prefix) result))))))))
+                   (append (list replacement prefix) result))))))))
+
+(define (interpret-escape-sequences str)
+  "Unescape all escape sequences in STR."
+  (replace-escaped-backslashes
+   (interpret-escape "\\n" "\n"
+    (interpret-escape "\\\"" "\""
+     (interpret-escape "\\t" "\t"
+      str)))))
 
 (define (parse-tree->assoc parse-tree)
   "Converts a po PARSE-TREE to an association list, where the key is the msgid


@@ 103,18 124,14 @@ and the value is the msgstr.  The result only contains non fuzzy strings."
        (('entry _ ('msgid msgid) 'msgstr)
         (parse-tree->assoc parse-tree))
        (('entry ('msgid msgid) ('msgstr msgstr))
-        (acons (interpret-newline-escape msgid)
-               (interpret-newline-escape msgstr)
-               (parse-tree->assoc parse-tree)))
-       (('entry ('msgid msgid) ('msgstr msgstr))
-        (acons (interpret-newline-escape msgid)
-               (interpret-newline-escape msgstr)
+        (acons (interpret-escape-sequences msgid)
+               (interpret-escape-sequences msgstr)
                (parse-tree->assoc parse-tree)))
        (('entry comments ('msgid msgid) ('msgstr msgstr))
         (if (member 'fuzzy (comments->flags comments))
             (parse-tree->assoc parse-tree)
-            (acons (interpret-newline-escape msgid)
-                   (interpret-newline-escape msgstr)
+            (acons (interpret-escape-sequences msgid)
+                   (interpret-escape-sequences msgstr)
                    (parse-tree->assoc parse-tree))))))))
 
 (define (read-po-file port)