feat: Add support for prefix and suffix to formats

include/modules/meta/base.hpp

@@ -59,6 +59,8 @@ namespace modules {
   struct module_format {
     string value;
     vector<string> tags;
+    label_t prefix;
+    label_t suffix;
     string fg;
     string bg;
     string ul;

include/modules/meta/base.inl

@@ -159,7 +159,7 @@ namespace modules {
     int i = 0;
     bool tag_built = true;
 
-    for (auto tag : string_util::split(format->value, ' ')) {
+    for (auto&& tag : string_util::split(format->value, ' ')) {
       bool is_blankspace = tag.empty();
 
       if (tag[0] == '<' && tag[tag.length() - 1] == '>') {

src/modules/meta/base.cpp

@@ -2,6 +2,7 @@
 
 #include "components/builder.hpp"
 #include "modules/meta/base.hpp"
+#include "drawtypes/label.hpp"
 
 POLYBAR_NS
 
@@ -31,7 +32,11 @@ namespace modules {
       builder->space(padding);
     }
 
-    builder->append(move(output));
+    if (!output.empty()) {
+      builder->node(prefix);
+      builder->append(move(output));
+      builder->node(suffix);
+    }
 
     if (padding > 0) {
       builder->space(padding);
@@ -72,6 +77,18 @@ namespace modules {
     format->offset = m_conf.get<int>(m_modname, name + "-offset", 0);
     format->tags.swap(tags);
 
+    try {
+      format->prefix = load_label(m_conf, m_modname, name + "-prefix");
+    } catch (const key_error& err) {
+      // prefix not defined
+    }
+
+    try {
+      format->suffix = load_label(m_conf, m_modname, name + "-suffix");
+    } catch (const key_error& err) {
+      // suffix not defined
+    }
+
     for (auto&& tag : string_util::split(format->value, ' ')) {
       if (tag[0] != '<' || tag[tag.length() - 1] != '>') {
         continue;