Fixing PR12779

original commit: 8b035f3c736d92c5e8ae896b3044eb2e32f44c8a

collects/scriblib/bibtex.rkt

@@ -17,7 +17,7 @@
     (list->string
      (let loop ()
        (match (peek-char ip)
-         [(? pred)
+         [(and (? char?) (? pred))
           (cons (read-char ip)
                 (loop))]
          [_
@@ -41,10 +41,13 @@
       [(? eof-object?)
        (void)]
       [c
-       (perror ip 'read-entries "Expected % or @, got ~v" c)]))
+       ;; All other characters are comments.
+       (read-entries ip)]))
 
   (define (read-entry ip)
-    (match (read-until (λ (c) (char=? c #\{)) ip)
+    (match (read-until (λ (c) (or (char=? c #\{)
+                                  (char=? c #\()))
+                       ip)
       [(app string-downcase "string")
        (slurp-whitespace ip)
        (match (read-char ip)
@@ -84,11 +87,17 @@
          (let loop ()
            (slurp-whitespace ip)
            (define atag (read-tag ip))
+           (cond
+             [(string=? "" atag)
+              (read-char ip)
+              (hash)]
+             [else
               (slurp-whitespace ip)
               (match (read-char ip)
                 [#\=
                  (slurp-whitespace ip)
                  (define aval (read-value ip))
+                 (slurp-whitespace ip)
                  (match (read-char ip)
                    [#\,
                     (hash-set (loop) atag aval)]
@@ -97,7 +106,7 @@
                    [c
                     (perror ip 'read-entry "Parsing entry, expected , or }, got ~v; label is ~v; atag is ~v; aval is ~v" c label atag aval)])]
                 [c
-              (perror ip 'read-entry "Parsing entry tag, expected =, got ~v; label is ~v; atag is ~v" c label atag)])))
+                 (perror ip 'read-entry "Parsing entry tag, expected =, got ~v; label is ~v; atag is ~v" c label atag)])])))
        (hash-set! ENTRY-DB label
                   (hash-set alist 'type typ))]))
 
@@ -106,13 +115,12 @@
     (string-downcase
      (read-until
       (λ (c) (or (char-whitespace? c)
-                 (char=? c #\=)))
+                 (char=? c #\=)
+                 (char=? c #\{)
+                 (char=? c #\})))
       ip)))
 
-  (define (read-value ip)
+  (define (read-braced-value ip)
-    (slurp-whitespace ip)
-    (match (peek-char ip)
-      [#\{
     (read-char ip)
     (let loop ()
       (define first-part (read-until (λ (c) (or (char=? c #\{) (char=? c #\})))
@@ -121,12 +129,42 @@
         [#\{
          (string-append first-part (read-value ip) (loop))]
         [#\}
+         (read-char ip)
+         first-part])))
+
+  (define (read-value ip)
+    (slurp-whitespace ip)
+    (define first-part (read-value-single ip))
+    (slurp-whitespace ip)
+    (match (peek-char ip)
+      [#\#
+       (read-char ip)
+       (string-append first-part (read-value ip))]
+      [_
+       first-part]))
+
+  (define (read-value-single ip)
+    (slurp-whitespace ip)
+    (match (peek-char ip)
+      [#\{
+       (read-braced-value ip)]
+      [#\"
+       (read-char ip)
+       (let loop ()
+         (define first-part (read-until (λ (c) (or (char=? c #\{) (char=? c #\")))
+                                        ip))
+         (match (peek-char ip)
+           [#\{
+            (string-append first-part (read-braced-value ip) (loop))]
+           [#\"
             (read-char ip)
             first-part]))]
       [(? char-numeric?)
        (read-while char-numeric? ip)]
       [(? char-alphabetic?)
-       (define string-tag (read-until (λ (c) (char=? c #\,)) ip))
+       (define string-tag (read-until (λ (c) (or (char-whitespace? c)
+                                                 (char=? c #\,)))
+                                      ip))
        (hash-ref STRING-DB string-tag
                  (λ () string-tag))]
       [c
@@ -238,4 +276,7 @@
                  [_
                   (make-bib #:title (format "~v" the-raw))]))))
 
-(provide define-bibtex-cite)
+(provide (struct-out bibdb)
+         path->bibdb
+         bibtex-parse
+         define-bibtex-cite)

collects/scriblib/scribblings/bibtex.scrbl

@@ -18,3 +18,18 @@ Uses @racket[define-cite] from @racketmodname[scriblib/autobib], but augments th
 Each string is broken along spaces into citations keys that are looked up in the BibTeX database and turned into @racket[bib?] structures.
 
 }
+
+@defstruct*[bibdb ([raw (hash/c string? (hash/c string? string?))]
+                   [bibs (hash/c string? bib?)])]{
+                                             Represents a BibTeX database. The @racket[_raw] hash table maps the labels in the file to hash tables of the attributes and their values. The @racket[_bibs] hash table maps the same labels to Scribble data-structures representing the same information.
+                                             }
+
+@defproc[(path->bibdb [path path-string?])
+         bibdb?]{
+                 Parses a path into a BibTeX database.
+                 }
+
+@defproc[(bibtex-parse [ip input-port?])
+         bibdb?]{
+                 Parses an input port into a BibTeX database.
+                 }

collects/tests/scriblib/bibtex.rkt

@@ -6,6 +6,15 @@
 (define-runtime-path example.bib "example.bib")
 
 (test
+ (let ()
+   (define example (path->bibdb example.bib))
+   (define raw (bibdb-raw example))
+
+   (test
+    (hash-ref (hash-ref raw "sweig42") "month") => "march"
+    (hash-ref (hash-ref raw "sweig42a") "month") => "1~mar"
+    (hash-ref (hash-ref raw "sweig42b") "month") => "1~march"
+    (hash-ref (hash-ref raw "sweig42c") "month") => "1~marcha"))
  (let ()
    (define-bibtex-cite example.bib
      ~cite-id citet-id generate-bibliography-id)

collects/tests/scriblib/example.bib

@@ -309,3 +309,91 @@
 	Year = {1987},
 	Bdsk-Url-1 = {http://doi.acm.org/10.1145/41625.41654}}
 
+@article{hochreiter_long_1997,
+    author = {Hochreiter, S. and Schmidhuber, J.},
+    title = {Long {Short-Term} Memory},
+    volume = {9},
+    number = {8},
+    journal = {Neural Computation},
+    year = {1997},
+    pages = {1735--1780}
+}
+
+@Article{py03,
+     author = {Xavier D\'ecoret},
+     title  = "PyBiTex",
+     year   = 2003
+}
+
+@Article{key03,
+  title = "A {bunch {of} braces {in}} title"
+}
+
+@Article{key01,
+  author = "Simon {"}the {saint"} Templar", 
+}
+
+@Article{key01,
+  title = "The history of @ sign"
+}
+
+Some {{comments} with unbalanced braces
+....and a "commented" entry...
+
+Book{landru21,
+  author =	 {Landru, Henri D\'esir\'e},
+  title =	 {A hundred recipes for you wife},
+  publisher =	 {Culinary Expert Series},
+  year =	 1921
+}
+
+..some other comments..before a valid entry...
+
+@Book{steward03,
+  author =	 { Martha Steward },
+  title =	 {Cooking behind bars},
+  publisher =	 {Culinary Expert Series},
+  year =	 2003
+}
+
+...and finally an entry commented by the use of the special @Comment entry type.
+
+@Comment{steward03,
+  author =	 {Martha Steward},
+  title =	 {Cooking behind bars},
+  publisher =	 {Culinary Expert Series},
+  year =	 2003
+}
+
+@Comment{
+  @Book{steward03,
+    author =	 {Martha Steward},
+    title =	 {Cooking behind bars},
+    publisher =	 {Culinary Expert Series},
+    year =	 2003
+  }
+}
+
+@String{mar = "march"}
+
+@Book{sweig42,
+  Author =	 { Stefan Sweig },
+  title =	 { The impossible book },
+  publisher =	 { Dead Poet Society},
+  year =	 1942,
+  month =        mar
+}
+
+@Book{sweig42a,
+  month =        "1~mar"
+}
+
+@Book{sweig42b,
+  month =        "1~" # mar
+}
+
+@Book{sweig42c,
+  month =        "1~" # mar # "a"
+}
+
+@preamble{"This bibliography was generated on \today"}