ParmParse: Line Continuation

Src/Base/AMReX_ParmParse.H

@@ -32,18 +32,24 @@ class IntVect;
 //
 // Comments in an input file include all text from a '#' character to the
 // end of the line. Here is an example input file:
-//
-// niter = 100 # niter is an integer
-// title = "Double Wammy" # example of a string with spaces
-// cell_size = 0.5 0.75 # cell spacing in each dimension
-// plot.var = Density 1 10 # a list of values
-// plot.var = Energy 5 12 # another list of values
-// bigarray = 1 2 3 4 5 6 7 8 # first part of array
-// 9 10 11 12 # continuation of bigarray
-// test = apple "boy blue" 10 20 30 40
-// FILE = prob_file # insert contents of this "prob_file" here
-//
-// The "FILE = <filename>" definition is special. Rather than just
+/*
+ niter = 100 # niter is an integer
+ title = "Double Wammy" # example of a string with spaces
+ cell_size = 0.5 0.75 # cell spacing in each dimension
+ plot.var = Density 1 10 # a list of values
+ plot.var = Energy 5 12 # another list of values
+ bigarray = 1 2 3 4 5 6 7 8 \
+ 9 10 11 12 # continuation of bigarray
+ multi_line_string = "This is a
+ multi-line string."
+ test = apple "boy blue" 10 20 30 40
+ FILE = prob_file # insert contents of this "prob_file" here
+*/
+// For values spanning multiple lines, one must use '\' at the end of a line
+// for continuation, otherwise it's a runtime error. Note that there must be
+// at least one space before the continuation character `\`. Multiple lines
+// inside a pair of double quotes are considered a single string containing
+// '\n's. The "FILE = <filename>" definition is special. Rather than just
 // adding this entry to the database, it reads the contents of <filename>
 // into the database.
 //
@@ -229,10 +235,12 @@ class IntVect;
 *
 * plot.var = Energy 5 12
 *
-* bigarray = 1 2 3 4 5 6 7 8
-*
+* bigarray = 1 2 3 4 5 6 7 8 \
 * 9 10 11 12
 *
+* multi_line_string = "This is a
+* multi-line string."
+*
 * aBox = ((0,0) (5,5))
 *
 * test = apple "boy blue" 10 20 30 40
@@ -1052,37 +1060,6 @@ public:
  //! Returns [prefix.]* parameters.
  [[nodiscard]] static std::set<std::string> getEntries (const std::string& prefix = std::string());
 
- /**
- * \brief Control multi-line support
- *
- * By default, ParmParse supports multi-line values. For example,
- \verbatim
- plot_vars = dens vx vy vx
- energy entropy
- \endverbatim
- * This can be disabled by calling this function setMultiLineSupport(false)
- * before amrex::Initialize(). This can avoid errors in inputs like,
- \verbatim
- algo.current_deposition = direct
-
- # Enable galilean
- psatd.use_default_v_galilean # Unfortunately we forgot = 1
- \endverbatim
- * With multi-line support, this is equivalent to
- \verbatim
- algo.current_deposition = direct psatd.use_default_v_galilean
- \endverbatim
- * With multi-line support disabled, it will abort. Note that after
- * multi-line support is disabled, one is still allowed to have
- \verbatim
- f = "x + y
- + sin(z)"
- \endverbatim
- * because here what's inside the pair of double quotes is considered a
- * single string.
- */
- static void setMultiLineSupport (bool b);
-
  struct PP_entry;
  using Table = std::list<PP_entry>;
  static void appendTable(ParmParse::Table& tab);

Src/Base/AMReX_ParmParse.cpp

@@ -34,17 +34,8 @@ static bool finalize_verbose = false;
 static bool finalize_verbose = true;
 #endif
 
-namespace {
- bool g_multi_line_support = true;
-}
-
 std::string const ParmParse::FileKeyword = "FILE";
 
-void ParmParse::setMultiLineSupport (bool b)
-{
- g_multi_line_support = b;
-}
-
 //
 // Used by constructor to build table.
 //
@@ -287,6 +278,21 @@ eat_garbage (const char*& str)
  if (*str == '\n') { ++num_linefeeds; }
  str++;
  }
+ else if ( *str == '\\' ) // '\' followed by a line break is continuation to next line
+ {
+ // Unfortunately, a line break has three variants, \r, \n, and \r\n.
+ if (*(str+1) == '\n') {
+ str += 2;
+ } else if (*(str+1) == '\r') {
+ if (*(str+2) == '\n') {
+ str += 3;
+ } else {
+ str += 2;
+ }
+ } else {
+ break;
+ }
+ }
  else
  {
  break;
@@ -703,14 +709,14 @@ bldTable (const char*& str,
  }
  AMREX_FALLTHROUGH;
  case pEOF:
- if (! g_multi_line_support &&
- std::accumulate(cur_linefeeds.begin(), cur_linefeeds.end(), int(0)) > 0)
+ if (std::accumulate(cur_linefeeds.begin(), cur_linefeeds.end(), int(0)) > 0)
  {
  std::string error_message("ParmParse: Multiple lines in ");
  error_message.append(cur_name).append(" =");
  for (auto const& x : cur_list) {
  error_message.append(" ").append(x);
  }
+ error_message.append(". Must use \\ for line continuation.");
  amrex::Abort(error_message);
  }
  addDefn(cur_name,cur_list,tab);
@@ -725,14 +731,14 @@ bldTable (const char*& str,
  tmp_str = cur_list.back();
  cur_list.pop_back();
  cur_linefeeds.pop_back();
- if (! g_multi_line_support &&
- std::accumulate(cur_linefeeds.begin(), cur_linefeeds.end(), int(0)) > 0)
+ if (std::accumulate(cur_linefeeds.begin(), cur_linefeeds.end(), int(0)) > 0)
  {
  std::string error_message("ParmParse: Multiple lines in ");
  error_message.append(cur_name).append(" =");
  for (auto const& x : cur_list) {
  error_message.append(" ").append(x);
  }
+ error_message.append(". Must use \\ for line continuation.");
  amrex::Abort(error_message);
  }
  addDefn(cur_name, cur_list, tab);
@@ -754,14 +760,14 @@ bldTable (const char*& str,
  tmp_str = cur_list.back();
  cur_list.pop_back();
  cur_linefeeds.pop_back();
- if (! g_multi_line_support &&
- std::accumulate(cur_linefeeds.begin(), cur_linefeeds.end(), int(0)) > 0)
+ if (std::accumulate(cur_linefeeds.begin(), cur_linefeeds.end(), int(0)) > 0)
  {
  std::string error_message("ParmParse: Multiple lines in ");
  error_message.append(cur_name).append(" =");
  for (auto const& x : cur_list) {
  error_message.append(" ").append(x);
  }
+ error_message.append(". Must use \\ for line continuation.");
  amrex::Abort(error_message);
  }
  addDefn(cur_name,cur_list,tab);