Allow the user to specify which LaTeX compiler to use (#8)

We were using pdflatex as a default LaTeX compiler. This PR allows the user to specify any of the ones shipped with TeXLive.

This is particularly important because some applications require, e.g., Times New Roman font. In PDFLatex, it looks like it's basically impossible to guarantee this. In XeLaTeX and LuaLaTeX it seems to be possible. So having the option to switch between them can be useful.

3 files changed, 9 insertions, 3 deletions

diff --git a/README.md b/README.md
index f5051d7..c13f0b3 100644
--- a/README.md
+++ b/README.md
@@ -74,6 +74,9 @@ latex_document(
     main = "main.tex",
 )
 ```
+By default, the `latex_document` rule will compiler the PDF with the `pdflatex`
+program. You can instruct it to use another compiler, such as `xelatex`, by
+passing the optional `compiler` option.
 
 ### Step 3: Building your Paper
 Every `latex_document` rule creates multiple targets:
diff --git a/latex.bzl b/latex.bzl
index d496397..868d7bb 100644
--- a/latex.bzl
+++ b/latex.bzl
@@ -15,6 +15,7 @@ def _latex_pdf_impl(ctx):
             ctx.files._run_script[0].path,
             texlive_path,
             ctx.files._latexrun[0].path,
+            ctx.attr.compiler,
             ctx.label.name,
             ctx.files.main[0].path,
             ctx.outputs.out.path,
@@ -30,6 +31,7 @@ _latex_pdf = rule(
     attrs = {
         "main": attr.label(allow_files = True),
         "srcs": attr.label_list(allow_files = True),
+        "compiler": attr.string(default = "pdflatex"),
         "_latexrun": attr.label(
             allow_files = True,
             default = "@bazel_latex_latexrun//:latexrun",
@@ -98,7 +100,7 @@ _arxivable = rule(
     implementation = _arxivable_impl,
 )
 
-def latex_document(name, main, srcs = []):
+def latex_document(name, main, srcs = [], compiler = "pdflatex"):
     """Given a TeX file, add rules for compiling and archiving it.
     """
 
@@ -107,6 +109,7 @@ def latex_document(name, main, srcs = []):
         name = name,
         srcs = srcs,
         main = main,
+        compiler = compiler,
     )
 
     # Convenience rule for viewing PDFs.
diff --git a/run_latex.py b/run_latex.py
index 9f4b75e..32b44cf 100644
--- a/run_latex.py
+++ b/run_latex.py
@@ -21,7 +21,7 @@ import shutil
 import subprocess
 import sys
 
-texlive, latexrun, job_name, main_file, output_file = sys.argv[1:6]
+texlive, latexrun, compiler, job_name, main_file, output_file = sys.argv[1:7]
 sources = sys.argv[6:]
 if output_file == "--":
     run_after = sources[sources.index("--"):][1:]
@@ -48,7 +48,7 @@ return_code = subprocess.call(
         "python3",
         latexrun,
         "--latex-args=-jobname=" + job_name,
-        "--latex-cmd=pdflatex",
+        "--latex-cmd=" + compiler,
         "--bibtex-cmd=bibtex",
         "-Wall",
         main_file,