From 412b478f5c208bcf493df339f9a51f60c3246176 Mon Sep 17 00:00:00 2001
From: Luca Heltai <luca.heltai@sissa.it>
Date: Tue, 28 Apr 2020 23:05:07 +0200
Subject: [PATCH] Added print_parameters with string and style.

---
 include/deal.II/base/parameter_handler.h | 26 +++++++++++++++++++++++
 source/base/parameter_handler.cc         | 27 ++++++++++++++++++++++++
 2 files changed, 53 insertions(+)

diff --git a/include/deal.II/base/parameter_handler.h b/include/deal.II/base/parameter_handler.h
index 2699965e4f..e91a3517bc 100644
--- a/include/deal.II/base/parameter_handler.h
+++ b/include/deal.II/base/parameter_handler.h
@@ -1475,6 +1475,32 @@ public:
   std::ostream &
   print_parameters(std::ostream &out, const OutputStyle style) const;
 
+
+
+  /**
+   * Print all parameters with the given @p style to the file given by
+   * @p filename.
+   *
+   * This function deduces the output format from the extension of the specified
+   * filename. Supported extensions are `prm`, `xml`, `tex`, and `json`.
+   * If a different extensions is used, then an output style is deduced from the
+   * @p style argument.
+   *
+   * Notice that specifying a supported file extension is equivalent to
+   * specifying the corresponding ParameterHandler::OutputStyle format. In
+   * particular, any  (optional) format specification specified in the @p style
+   * parameter  must be compatible with the given extension.
+   *
+   * If the format is not supported, and @p output_style does not contain a
+   * format specification, an assertion is thrown.
+   *
+   * @param filename The output file name.
+   * @param style The style with which output is produced.
+   */
+  void
+  print_parameters(const std::string &filename,
+                   const OutputStyle  style = DefaultStyle) const;
+
   /**
    * Print parameters to a logstream. This function allows to print all
    * parameters into a log-file. Sections will be indented in the usual log-
diff --git a/source/base/parameter_handler.cc b/source/base/parameter_handler.cc
index 2f3f157607..07716b8826 100644
--- a/source/base/parameter_handler.cc
+++ b/source/base/parameter_handler.cc
@@ -1339,6 +1339,33 @@ ParameterHandler::print_parameters(std::ostream &    out,
   return out;
 }
 
+
+
+void
+ParameterHandler::print_parameters(
+  const std::string &                 filename,
+  const ParameterHandler::OutputStyle style) const
+{
+  std::string extension = filename.substr(filename.find_last_of('.') + 1);
+  boost::algorithm::to_lower(extension);
+
+  ParameterHandler::OutputStyle output_style = style;
+  if (extension == "prm")
+    output_style = style | PRM;
+  else if (extension == "xml")
+    output_style = style | XML;
+  else if (extension == "json")
+    output_style = style | JSON;
+  else if (extension == "tex")
+    output_style = style | LaTeX;
+
+  std::ofstream out(filename);
+  AssertThrow(out, ExcIO());
+  print_parameters(out, output_style);
+}
+
+
+
 void
 ParameterHandler::recursively_print_parameters(
   const boost::property_tree::ptree &tree,
-- 
2.39.5