added format_file_conditionally()

src/format/format.cpp

@@ -3,12 +3,43 @@
 #include <iostream>
 #include <string>
 
-static bool replace_once(std::string &str, const std::string &from,
-                         const std::string &to) {
-  size_t start_pos = str.find(from);
-  if (start_pos == std::string::npos)
+// Replace TEMPLATE with REPLACMENT in-place
+static bool replace_once_global(std::string &STR, const std::string &TEMPLATE,
+                                const std::string &REPLACMENT) {
+  size_t start_pos = STR.find(TEMPLATE);
+  if (start_pos == std::string::npos) {
     return false;
-  str.replace(start_pos, from.length(), to);
+  }
+  STR.replace(start_pos, TEMPLATE.length(), REPLACMENT);
+  return true;
+}
+
+// Replace TEMPLATE with REPLACMENT between starting from `start`
+static bool replace_once_between(std::string &STR, const std::string &TEMPLATE,
+                                 const std::string &REPLACMENT,
+                                 const size_t &START) {
+  size_t start_pos = STR.find(TEMPLATE, START);
+  if (start_pos == std::string::npos) {
+    return false;
+  }
+  STR.replace(start_pos, TEMPLATE.length(), REPLACMENT);
+  return true;
+}
+
+// Remove everything from START to STOP
+static bool remove_from_to(std::string &STR, const std::string &START,
+                           const std::string &STOP) {
+  size_t start_pos = STR.find(START);
+  if (start_pos == std::string::npos) {
+    return false;
+  }
+
+  size_t stop_pos = STR.find(STOP, start_pos);
+  if (stop_pos == std::string::npos) {
+    return false;
+  }
+
+  STR.replace(start_pos, stop_pos - start_pos + STOP.length(), "");
   return true;
 }
 
@@ -24,7 +55,36 @@ std::string format_file(const std::string &TEMPLATE_FILE,
   }
 
   while (is_template) {
-    is_template = replace_once(result, TEMPLATE, INPUT);
+    is_template = replace_once_global(result, TEMPLATE, INPUT);
+  }
+  return result;
+}
+
+std::string format_file_condtionally(const std::string &TEMPLATE_FILE,
+                                     const std::string &TEMPLATE,
+                                     const std::string &INPUT) {
+
+  size_t template_pos = TEMPLATE_FILE.find(TEMPLATE);
+  bool is_template = template_pos != std::string::npos;
+
+  std::string result = TEMPLATE_FILE;
+
+  if (!is_template) {
+    std::clog << "There is no template in given file. Is this correct?"
+              << std::endl;
+    return result;
+  }
+
+  // if template is empty then we remove everything in between
+  if (TEMPLATE == "") {
+    while (is_template) {
+      is_template = remove_from_to(result, TEMPLATE, "{{endif}");
+    }
+  }
+
+  while (is_template) {
+    is_template =
+        replace_once_between(result, TEMPLATE, INPUT, result.find(TEMPLATE));
   }
   return result;
 }

src/format/format.hpp

@@ -7,3 +7,13 @@
 // @return Formatted file in std::string
 std::string format_file(const std::string &TEMPLATE_FILE,
                         const std::string &TEMPLATE, const std::string &INPUT);
+
+// @brief Format file conditionally. Replace everything between `{{if
+// _something_}}` to `{{endif}}` If INPUT is empty then everything between
+// this will be removed.
+// @param TEMPLATE_FILE File that you want to format in string.
+// @param TEMPLATE Full name of the if statement. For example `{{if title}}`
+// @return Formatted file in std::string
+std::string format_file_condtionally(const std::string &TEMPLATE_FILE,
+                                     const std::string &TEMPLATE,
+                                     const std::string &INPUT);