bug#27296: [PATCH 33/35] gnu: Add texlive-union.

[Ricardo Wurmus <rekado@elephly.net>]

* gnu/packages/tex.scm (texlive-union): New procedure.
---
 gnu/packages/tex.scm | 77 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 77 insertions(+)

diff --git a/gnu/packages/tex.scm b/gnu/packages/tex.scm
index 0f0c0b7ee..e4ac2f759 100644
--- a/gnu/packages/tex.scm
+++ b/gnu/packages/tex.scm
@@ -1371,6 +1371,83 @@ font metrics.  The bundle as a whole is part of the LaTeX required set of
 packages.")
     (license license:lppl1.2+)))
 
+(define-public texlive-union (lambda* (#:optional (packages '()))
+  "Return 'texlive-union' package which is a union of PACKAGES and the
+standard LaTeX packages."
+  (let ((default-packages
+          (list texlive-bin
+                texlive-dvips
+                texlive-fonts-cm
+                texlive-fonts-latex
+                texlive-metafont-base
+                texlive-latex-base
+                ;; LaTeX packages from the "required" set.
+                texlive-latex-amsmath
+                texlive-latex-amscls
+                texlive-latex-babel
+                texlive-latex-cyrillic
+                texlive-latex-graphics
+                texlive-latex-psnfss
+                texlive-latex-tools)))
+    (package
+      (name "texlive-union")
+      (version (number->string %texlive-revision))
+      (source #f)
+      (build-system trivial-build-system)
+      (arguments
+       '(#:modules ((guix build union)
+                    (guix build utils)
+                    (guix build texlive-build-system)
+                    (guix build gnu-build-system)
+                    (guix build gremlin)
+                    (guix elf))
+         #:builder
+         (begin
+           (use-modules (ice-9 match)
+                        (srfi srfi-26)
+                        (guix build union)
+                        (guix build utils)
+                        (guix build texlive-build-system))
+           (let* ((out       (assoc-ref %outputs "out"))
+                  (texmf.cnf (string-append out "/share/texmf-dist/web2c/texmf.cnf")))
+             ;; Build a modifiable union of all inputs (but exclude bash)
+             (match (filter (match-lambda
+                              ((name . _)
+                               (not (string=? "bash" name))))
+                            %build-inputs)
+               (((names . directories) ...)
+                (union-build (assoc-ref %outputs "out")
+                             directories
+                             #:create-all-directories? #t)))
+
+             ;; The configuration file "texmf.cnf" is provided by the
+             ;; "texlive-bin" package.  We take it and override only the
+             ;; setting for TEXMFROOT and TEXMF.  This file won't be consulted
+             ;; by default, though, so we still need to set TEXMFCNF.
+             (substitute* texmf.cnf
+               (("^TEXMFROOT = .*")
+                (string-append "TEXMFROOT = " out "/share\n"))
+               (("^TEXMF = .*")
+                "TEXMF = $TEXMFROOT/share/texmf-dist\n"))
+             (setenv "PATH" (string-append (assoc-ref %build-inputs "bash")
+                                           "/bin"))
+             (for-each
+              (cut wrap-program <>
+                   `("TEXMFCNF" ":" = (,(dirname texmf.cnf)))
+                   `("TEXMF"    ":" = (,(string-append out "/share/texmf-dist"))))
+              (find-files (string-append out "/bin") ".*"))
+             #t))))
+      (inputs
+       `(("bash" ,bash)
+         ,@(map (lambda (package)
+                  (list (package-name package) package))
+                (append default-packages packages))))
+      (home-page (package-home-page texlive-bin))
+      (synopsis "Union of Texlive packages")
+      (description "This package provides a subset of the Texlive
+distribution.")
+      (license (map package-license (append default-packages packages)))))))
+
 (define texlive-texmf
   (package
    (name "texlive-texmf")
-- 
2.12.2