Add function help_entry() to format command line help entries

Author: danpoe

src/util/parse_options.cpp

@@ -9,6 +9,7 @@ Author: Daniel Kroening, [email protected]
 #include "parse_options.h"
 
 #include <algorithm>
+#include <cctype>
 #include <climits>
 #include <iostream>
 
@@ -23,6 +24,7 @@ Author: Daniel Kroening, [email protected]
 #include "exception_utils.h"
 #include "exit_codes.h"
 #include "signal_catcher.h"
+#include "string_utils.h"
 
 parse_options_baset::parse_options_baset(
   const std::string &_optstring,
@@ -151,3 +153,54 @@ banner_string(const std::string &front_end, const std::string &version)
 
   return align_center_with_border(version_str);
 }
+
+std::string help_entry(
+  const std::string &option,
+  const std::string &description,
+  const std::size_t left_margin,
+  const std::size_t width)
+{
+  PRECONDITION(!option.empty());
+  PRECONDITION(!std::isspace(option.front()));
+  PRECONDITION(!std::isspace(option.back()));
+  PRECONDITION(option.length() <= width);
+
+  PRECONDITION(!description.empty());
+  PRECONDITION(!std::isspace(description.front()));
+  PRECONDITION(!std::isspace(description.back()));
+
+  PRECONDITION(left_margin < width);
+
+  std::string result;
+
+  if(option.length() >= left_margin - 1)
+  {
+    result = " " + option + "\n";
+    result += wrap_line(description, left_margin, width) + "\n";
+
+    return result;
+  }
+
+  std::string padding(left_margin - option.length() - 1, ' ');
+  result = " " + option + padding;
+
+  if(description.length() <= (width - left_margin))
+  {
+    return result + description + "\n";
+  }
+
+  auto it = description.cbegin() + (width - left_margin);
+  auto rit = std::reverse_iterator<decltype(it)>(it) - 1;
+
+  auto rit_space = std::find(rit, description.crend(), ' ');
+  auto it_space = rit_space.base() - 1;
+  CHECK_RETURN(*it_space == ' ');
+
+  result.append(description.cbegin(), it_space);
+  result.append("\n");
+
+  result +=
+    wrap_line(it_space + 1, description.cend(), left_margin, width) + "\n";
+
+  return result;
+}

src/util/parse_options.h

@@ -58,4 +58,10 @@ banner_string(const std::string &front_end, const std::string &version);
 /// ```
 std::string align_center_with_border(const std::string &text);
 
+std::string help_entry(
+  const std::string &option,
+  const std::string &description,
+  const std::size_t left_margin = 30,
+  const std::size_t width = 80);
+
 #endif // CPROVER_UTIL_PARSE_OPTIONS_H

unit/util/parse_options.cpp

@@ -15,3 +15,12 @@ TEST_CASE("align_center_with_border", "[core][util]")
     align_center_with_border("test-text") ==
     "* *                        test-text                        * *");
 }
+
+TEST_CASE("help_entry", "[core][util]")
+{
+  REQUIRE(help_entry("--abc", "xyz", 8, 12) == " --abc  xyz\n");
+  REQUIRE(help_entry("--abc", "xxxx x", 8, 12) == " --abc  xxxx\n        x\n");
+  REQUIRE(help_entry("--abc", "xx xx", 8, 12) == " --abc  xx\n        xx\n");
+  REQUIRE(help_entry("--abcdef", "xyz", 8, 12) == " --abcdef\n        xyz\n");
+  REQUIRE(help_entry("--abcdefg", "xyz", 8, 12) == " --abcdefg\n        xyz\n");
+}